WELCOME TO FLYSTUNT.COM http://www.flystunt.com Dedicated to Control Line Precision Aerobatics Tue, 28 Jan 2014 21:05:44 +0000 en-US hourly 1 https://wordpress.org/?v=4.4.10 BOB BARON’S ACTUAL HUMBUG 60 http://www.flystunt.com/2014/01/28/bob-barons-actual-humbug-60/ Tue, 28 Jan 2014 20:50:30 +0000 http://www.flystunt.com/?p=622 BARON'25





ULTIMATE 40 BIPLANE http://www.flystunt.com/2014/01/28/ultimate-40-biplane/ Tue, 28 Jan 2014 20:47:56 +0000 http://www.flystunt.com/?p=619 by Bradley Walker and Doug Moon

A while back Brad and I had some discussion about Bi-Planes for stunt. He got pretty revved up about it and bought an ARF RC bi-plane with symmetrical airfoil.

It is an Ultimate bipe. Very thin wings, low drag.

I am converting it.

I have created a tunnel for the header muffler.



That thing on top of the wing is the rest of the tunnel to keep heat out of the plane. Should the header come loose it will keep oil out of the plane as well. Looks crude but when you mount the wing it is all internal, you can see it and it gets the job done.

The controls will be external so we can mess with it. I am mounting the crank on two tongues.

Making some progress on the Bi-Plane or “2-Winger” as I like to call it.

Here I have the lower wing on tail section completed.


Notice in the following pics the laser cut incidence alignment tools provided with the plane. You mount the cabane struts and the aluminum wing supports to the upper wing. Then slide on the alignment tabs and screw it to the fuse and you are done! Mistake free installation on the first try! Very cool!


Shear Panic http://www.flystunt.com/2014/01/28/shear-panic/ Tue, 28 Jan 2014 20:41:26 +0000 http://www.flystunt.com/?p=617 gz3 gz1 gz2 shearpanic 4strok4

Dr. Jekyll http://www.flystunt.com/2014/01/28/dr-jekyll/ Tue, 28 Jan 2014 20:37:24 +0000 http://www.flystunt.com/?p=613  





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Mr. Hyde http://www.flystunt.com/2014/01/28/mr-hyde/ Tue, 28 Jan 2014 20:35:25 +0000 http://www.flystunt.com/?p=611 26_25 24_23








The Low Tech World Beater http://www.flystunt.com/2014/01/28/the-low-tech-world-beater/ Tue, 28 Jan 2014 20:27:25 +0000 http://www.flystunt.com/?p=609 The Low Tech World Beater

There Are Only Two Ways-Get Used To It
To be ultimately competitive, you have to be able to go through the pattern at constant speed, without speed up, no matter how bad the conditions.  In my opinion, there are only two ways to run a 2 cycle engine if you want to be competitive at the highest levels of stunt.

One way to successfully run the 2 stroke stunt engine is by using the “cool mode” run.  This is what I call the “stompin 4 cycle”.  Bob Gieseke calls this run “gorilla balls” (he will say this holding his partially clenched hand out in front of him while making a cupping motion) and this type of run has been the standard of his competitive career.  This type of run is achieved when the engine power is set to allow the needle to be set in a very rich and deep 4 cycle.  In this mode the engine will barely change through the pattern, using a growling low 4 cycle to do all of the maneuvers.  If needed, the engine will “8 cycle” if pushed in the wind.  If the engine “8 cycles”, it means it is going to the “cool mode” misfire and further away from the “hot mode” 2 cycle.  The engine is so far into the “cool cycle” that it makes no attempt whatsoever to go leaner.  When the airplane gets pushed by the wind engine just “lays down” and basically sputters rich trying to back off.  Many of the best flyers use this type of engine run.  Some notable flyers include David Fitzgerald, Bob Gieseke, Doug Moon, Brett Buck, Mike Scott, and Frank Williams.

Some typical basic components of this method are high nitro, high compression, a big venturi, and a small diameter or thin propeller with a light load.  All of these things are done to keep the engine in the “cool mode” (this means running in a rich “4 cycle” mode).   While many will argue that their “stompin” engine is making “huge power” chugging along in a 4 cycle, it really *isn’t* compared to the same engine in a full 2 cycle.  This is why it is very common to see “stompers” using small planes or big engines.  This need to run a smaller or lighter plane is due to the fact that an engine running in a deep “4 cycle” is using very little power potential of the engine.  Most of the competitors who use this setup use lighter or smaller airplanes.  It is very common to see a 61/65/75 in traditional .46 sized airplanes right around 650 sq inches or smaller, or lightweight high aspect ratio planes that are low drag.  David Fitzgerald is currently using a PA 75 on a pipe and has just recently reduced his airplane size from 650-660 sq in to 630 sq in an effort to open the performance window and gain penetration in the wind.  Brett Buck’s PA 61 powered “Infinity” uses the wing from Ted Fancher’s “Imitation” that was originally designed for the ST 46.

Another aspect of this setup is that you really need a large fuel tank.  All of the “stompers” mentioned use right around 8 oz of fuel to do a pattern using their Randy Smith PA 61/65/75 engines (all on tuned pipes) while burning 10% to 20% nitro fuel depending on the conditions.  One other downside to this method besides the huge fuel consumption requirement:  if you choose to use this type setup, make sure that you don’t get any trash in your fuel or suck a bug into the venturi.  If you do, the engine will go full lean…if this happens…HANG ON!!!

The other way to successfully run the 2 stroke stunt engine is by using the “hot mode” run.  This is what I call the “east coast run”.  This mode uses the full power of the engine somewhere in the pattern.  For the engine to work in bad conditions the power of the engine has to be limited.  Some typical basic components of this method are low nitro, low compression, a small venturi, or a larger propeller that forces the engine to be nearly fully loaded.  All of these things are done to keep the 2 cycle “hot mode” of the engine controlled.

In this mode the engine will switch rapidly from “4 cycle” to “2 cycle” mode throughout the pattern, even switching rapidly in level flight from upwind to down wind.  This type of run has lots of 2 cycle switching across the tops of maneuvers, even using as much as 10 o’clock to 2 o’clock of 2 cycle across the top of a round loop (or even solid 2 cycle throughout the loops).  Typically, this type of run will have a vertical eight maneuver where the top loop of the eight is completed with the engine in a “full tilt” 2 cycle mode.  If flying in really bad weather, the engine will need to be loaded even more or the power reduced allowing the engine to use even more 2 cycle mode.  At some point the engine simply cannot go any faster no matter how much it is pushed by the wind.  In this sense the engine will need to go *further* into the “hot  mode” to be successful in bad conditions, even up to the point that the engine can be run in 2-2 mode (using a soft 2 cycle into a hard 2 cycle with no 4 cycle mode at all).  My friend Bill Wilson runs many of his engines in a high 4-2 and even a 2-2 mode (soft 2 cycle to hard 2 cycle switching) and he flies his planes in the most horrible conditions.  In fact, many of the best flyers use this type of engine run.  Some notable flyers include Randy Smith, Bill Rich, Curt Contrada, and Derek Berry.  One can also include just about anyone who was a follower of Big Jim Greenaway.

What are some up sides to this method?  Well, for one, it burns substantially less fuel than the “stompin” method.  One other advantage is that the top end is “clipped”.  If the engine sucks up a bug, or runs away during the pattern, the top end is “clipped” so the flyer should be able to complete the pattern albeit at a slightly faster lap time.

What are some down sides of this method?  Well, first of all, the sound…  I know it sucks to say it, but many people simply do not like stunt planes flying around sounding more like combat planes.  Secondly, since there are two distinct “modes” to this run, the user is constantly tweaking both simultaneously.  There is the top end to “2 cycle” mode and there is a bottom end component to the “4 cycle” mode, and both need to be right to work to perform in bad conditions.  With the “stompin” method, the user can always go *deeper* into the 4 cycle mode when things get scary as long as there is adequate power to pull the engine through the pattern.

Finally, I hate to say it, but most everyone else is somewhere in between, which is the last place you want to be.  Unless you have an absolutely *superb* stunt engine that just “knows” when to compensate in the wind, or an inboard mounted tank, you *will* wind up without using one of these methods.

Take the “stompin” mode and get it too lean or get the engine too loaded…ballistic missile.  Take the “east coast” method and make too much top end power…zoomy-zoom-zoom.  It is just that simple.  Both methods fail when the engine simply cannot make enough juice to pull the airplane through bad conditions.

Flipping the Paradigm
The “small plane that looks and performs like a big plane” idea is not a new idea.  Bob Hunt talked about this “small plane” idea in his original Saturn article many years ago.  Randy Smith has been designing these “stealth” smaller planes for years.  Randy’s Staris, Shrike, etc are all based on this larger fuselage/small wing idea, and I think these planes are some of his best examples out there.  Heck, even Dave Fitz is on the band wagon with his latest smaller plane.

The difference here is that I intend to flip the paradigm….and with the new rules change concerning line sizes which start in 2009, I think it is completely appropriate.  Let me explain.

When the tuned pipe came out, Bob Hunt was telling everyone that if they ditched their baffle type ST 60’s and went to the powerful schnuerle 40 coupled to the tuned pipe, they could build a 60 sized plane (supposedly much preferred by judges) and pull it around with a powerful 40.  With the new setup, the pipe would control the windup in the wind.  This tuned pipe was needed due to the fact these original engines had no propensity to “back off” in the wind by design like the older stunt engines.  One of the main advantages that Bob talked about at that time was the rule that allowed those who use engines under .40 cu in. displacement to use .015” cabled lines as opposed to the .018” cabled lines that were required for engines larger than .40 cu in displacement.  Bob touted this as a huge advantage, and I have to somewhat agree.

Small planes lose a tremendous amount of “feel” at the handle with big lines, and they certainly do not penetrate nearly as well in the wind.  For me, the bigger the lines, the more airplane weight and engine power is required to offset the line bow in the lines when the wind starts to blow.  With smaller the lines, less airplane weight and engine power is required at the plane to get the “solid feel” and penetration back (read that “line tension”).  Small lines coupled to a light plane create a much more “big plane” feel.  Many people, including myself, who use .018” cabled lines, tend to use shorter lines even with big planes to control the line drag and bow.  Others use .015” solids to get more solid line tension with their large planes.  While I agree that they are superior, I hate solids.  I am barely able to keep a good set of cables, and I but them in quantity from Tom Morris!

Now, in 2009, that .40 cu in displacement cutoff for line size is out the window!  The new line size rules that will be used in 2009 are based exclusively on weight.
2009 Pull Test and Line Size Requirements

As you can see, .015” cables are allowed for airplanes from 40+ oz to 64 oz (a huge range of 24 oz!).

As you can also see, .018” cables are allowed for airplanes ranging from 64+ oz to 75 oz (a range of 11 oz?  Hmmmm… that’s weird… FYI:  Paul Walker flew his 100+ oz bomber for several years at the highest levels of competition using .018” cables without incident).

With the new rule, pretty much anything from a heavy Ringmaster to an average SV-11 with a PA 75 can be flown on relatively small .015” cabled lines.  Wow!  While I would not want to be a flyer that prefers the Patternmaster and all of its many derivatives, the Strega, or Cardinal due to the restrictive cutoff for line size (even though people have been flying these planes safely for three decades at weights over 75 oz) it is great time to build you’re the low tech “Low Tech World Beater” that will be explained herein.  It is important that this design stay well under 64 oz “ready to fly” for the LIFE of the plane.  Everyone must understand that airplanes will gain weight over time with heavy use, so if a design is close to the cutoff weight, which is bad.

My First Exposure to the Low Tech World Beater
My friend Doug Moon built a plane called the Bear 46.  Basically, it is Bob Geiseke’s oversized high tech Nobler, the “Bear 65” built with the two center ribs removed.  After the modification, the airplane comes out to be about 620 sq inches (I see it as about the size of the bigger Skylark).  It was originally designed for the LA 46, but since it has the full sized Bear fuselage (an important component of the total package) it still looks like a Bear 65.  As built, it came out terribly tail heavy with the lightweight LA 46 because Doug had built the nose like a full sized Bear 65, complete with the short 9” nose and the original tail moment.  On a lark, I gave Doug one of my Big Jim style ST 60’s and restrictive tube muffler to put in the plane.  I had been testing this combination on bigger planes and loved the run but it had only adequate power for a 70 oz plane.  I thought it would be perfect for the smaller plane.

Big Jim Greenaway followers would use the low compression ST engines using unrestricted (and loud) mufflers to get the “big power” needed to pull the very large Patternmasters, Stregas, Cardinals, Spitfires, etc.  Conversely, many of the tube mufflers on the market were developed for the HIGH compression ST 60 engines produced by Randy Smith and Big Art.  Many of these mufflers were also being used for schnuerle engines like the PA, or OS 45 SFR and 46 SF which really like to be restricted on the exhaust side.  These more restrictive tube mufflers have an exit hole closer to .25”, where Big Jim approved tube muffler would have an exit hole from 3/8” to ½”.  This was necessary to make the low compression engine flow the fuel and make the big power.  This Big Jim style low compression head and muffler with the large exit hole has been used in the Northwest for nearly three decades and was also used by Bob Baron to win the 1996 Nats.

With the combination of the low compression head coupled to a restrictive muffler we had a VERY *mild* package that would run very quiet at low RPM (7800 RPM), with a near PERFECT 4-2 break with no real propensity to wind up.  Interestingly, it would complete the entire pattern on 4 ½ oz of fuel.  Imagine the *BEST* ST 46 you ever saw (in your life) that used less fuel than a ST 46.  Once this engine and muffler was placed in the plane we had a plane that “appeared” to be a full sized plane from the side (which is all the judges see) with the airplane/wing drag of a 40-46 sized plane.

Well, in a nutshell, this is one of the BEST “low tech” combinations I have ever, ever, seen…ever.  The judges see a full sized fuselage, the wing is small (so it builds light) and the engine is basically LOAFING to pull the whole package….and oh, the sound was… well… magical.

All total, I think the whole plane is 48-50 oz trimmed with a ST 60 and tube muffler?  That is crazy.

The Time Machine
My friend Steve Fitton flies the Time Machine 60 powered by a Double Star 60 engine.  The Time Machine 60 is basically a 95% Big Jim Greenaway Patternmaster designed by Tom Dixon for Bob Baron.  These airplanes are right around 650 sq inches and typically build between 60 oz and 70 oz (as opposed to the full size Patternmaster that typically builds between 70 oz and 80 oz).  The Double Star 60 engine is a European version of the ST 60 with an ABC piston and sleeve, it has a low compression hemi head based on the Big Jim ST 60, and relatively restrictive muffler (sound familiar?).  This engine was at one time imported by Tom Dixon and was manufactured by the same factory that makes the Brodak 40. Steve has been using this airplane/engine combination for many years, and his setup is based on the setup recommended by Tom Dixon.  This is truly a “low tech” setup and Steve has it mastered.  He can actually hand flip his engine with his finger (like the good old days) without any fear it will rip off his finger.  He even has little marks on the exit hole of the needle valve that looks like a little clock.  After years of constant use, he sets the needle based on this little clock, and he can tell where the needle should be set for any given run or condition.  He can even tell how worn the plug is based on where the needle is set on the clock.  Now that is consistency.

Over the years, Steve has used both of the two modes described previously.  For many years he ran the “stompin 4 cycle” run and recently switched the “east coast run”.  His comments about both were that the “stompin” run was superior for consistency and was  superior in the wind, but lacked the “drive” at the top of the pattern of the hard breaking run.  As explained before, this is due to the fact that the “stompin” run uses only about 2/3 of the total output of the engine in an attempt to keep the engine running very rich.  Keeping the engine running very rich makes it behave in the wind.  Some of this power loss can be made up by using more nitro or reducing the size of the propeller, but only so much can be done before the “sweet” run characteristic of the engine is lost.

Later, Steve switched to a lower compression 4-2 run more indicative of the “east coast run” in an attempt to get more drive.  Ultimately the “hot mode” of any engine is going to produce more peak power than the “cool mode” even when the engine is limited with a drop in compression, smaller venturi, etc.  Steve expressed the wish to look at the Stalker 76 or Double Star 75 (if it ever comes out) for the Time Machine, as these are the closest to the original “classic” baffled stunt engines.  I suggested a completely different route, one similar to the original Time Machine/DS 60 concept developed by Tom Dixon, only more extreme.

Just Crazy Enough to Work
Here is the idea:  Take the smaller plane power to weight ratio to the extreme.  Now that weight is the only factor used for determining line size, we are primed to use large, extremely mild, low tech and (dare I say it) *lower power* engines in even smaller planes than previously thought practical.  It is the next inevitable step in the Tom Dixon Time Machine idea, and is the *flip* of the Bob Hunt sales pitch for the “high tech” tuned pipe of nearly 20 years ago.

Step #1:  Since the goal is to have an engine that can easily function deep in the “cool cycle” if we want it, we will acknowledge that we will need a little extra engine.   We will use a mild .60 sized engine with a muffler.  Consider the PA 61/65, ST 60, Double Star 60, Double Star 60 RE, or the Stalker 61/66 etc.

Step #2:  The engine will not be tuned for big power.  I know… you just did a double take.  Let me explain.  Stunt engines typically run with some kind of limiting factor within the engine.  Something has to “clip” the power of the engine to make it suitable the for relatively low speed use of stunt flying.  Typical limiting factors are the venturi, exhaust back pressure, head compression, internal port timing, port sizes, crank shaft internal diameter, etc.  Most of the best stunt engines use one or more of these factors to “clip” the power.  Use too many of these power limiters at one time and the power is “clipped” too much and the engine is considered a “wimp”.  Consider the Bear 46 example.  We actually took the ST 60 that had been heavily decompressed (originally designed to be used with a wide open muffler) and coupled it to a restrictive muffler.  Now, in its “wimpy” state it would be completely inappropriate for most large .60 sized planes.  However, it is completely appropriate for a .40/.46 sized plane and it runs “prettier” with a great deal more drive than the .40/.46, and would probably last indefinitely.  Note:  One other thing…”wimps” are consistent and typically indifferent to atmospheric conditions compared to their “gorilla balls” brethren.

Step #3:  Fuel consumption will be low relative to the size of the engine.  A low output .60 actually burns less fuel than a smaller engine running at max power, even when running in a “stompin” mode.  The hemi head ST 60 with the restrictive muffler used on the Bear 46 burns 4.5 oz of fuel to complete the pattern using the “east coast run”.  My PA 65 (sans pipe) burns 4 to 4.5 oz of fuel, even on a “stompin” 20% nitro run and appears to run even more indifferent to conditions the more exhaust is restricted at the outlet.  The Double Star 60 as delivered by Tom Dixon burns right at 5 oz of fuel, as does the Stalker 61/66.  Most people do not realize that many of the “classic modern” stunt planes that came out of the 1980’s and 1990’s were designed around the size of the fuel tank.  Most top stunt flyers were using metal stunt tanks of the standard dimensions that held 1 oz per inch.  Many of the top ST 46 ships were designed to carry 7” long metal tanks.  That meant that the nose would need to be 10.5” to 11” long to accommodate the tank and the engine.  Conversely, the tail moment would have to be long enough to turn it.  With the fuel tank limited to 5 oz (or 6 oz for the case of the RC clunk tank) the nose can be limited to 9.5”.

Step #4:  If you have a mild .60 stunt engine and you are only going to use 2/3’s of the power of the engine, then the math goes something like this:  .60 cu in x 2/3 = .40 cu in.  So, the experiment requires a plane that was designed to be used with a typical .40 stunt engine.  There are really few truly modern .40 sized designs out there.  Most true .40 sized designs are classic designs.  In my opinion, the standard for the modern .40 sized design is the Vector 40 by Randy Smith.  The Vector 40 was originally designed to be used with the relatively mild OS Max 40 FP.

Step #5:  Small planes are easier to build light.  If you read my “T-Rex” article in Control Line World a few issues back, you understand that the smaller plane is easier to build “light”.  In other words, the larger the plane, the *harder* it becomes to build the plane the correct weight.  This is due to the fact that surface area is not a linear function. I have a Brodak Vector .40 ARF myself.  My Vector 40 ARF with the obligatory LA 46 with the 5 oz tank weighs in at 44 oz complete ready to fly and these ARF airplanes have not a stick of ultra light contest wood in them.  Again, in my opinion, the *best* flying Vector 40’s are actually a little heavier at 48 oz to 52 oz, and that is in Texas air.  So if we could build a Vector 40 at 52 oz we would be OK.

Step #6:  Low tech is light.  If you add up all of the components used for the typical high tech, three-bladed pipe .65/.75 setup, basically you are looking at a 22 oz drive train (spinner, prop, engine, pipe, coupler, header, zip ties, 8 oz fuel tank).  Now take that and add the 8 oz of fuel consumed to complete the pattern, you have at least 30 oz of weight that you need to haul around before you ever glue two sticks together.  Even if you are light builder, that is lot of stuff to include in your next airplane.  Now compare that to the low tech 60 setup with a 2 blade propeller (spinner, prop, engine, muffler, 6 oz fuel tank) the total is closer to 22 oz fully fueled.  That is a weight loss of 8 oz.  A bushed .60 would be even lighter.

Step #7:  If we retrofit a ST .60/PA 61/65 in the place of the LA .46, we are only going to add a few more ounces than normal to the small airframe.  So, let’s compare the weight gain for substituting the mild ST 60 for an LA 46 in a Vector 40.  I will round up the weights…

•   The ST 60 is a weight gain of 2 oz over the LA 46.
•   The larger tube muffler is a weight gain of 1 oz.
•   The tank is a wash.
•   The nose of a Vector would not be appropriate for a .60 engine.  The nose moment would need to be extended ½” to accommodate the longer ST 60 type engine and the fuselage width would need to be changed to accommodate the wider engine.  I suggest using ½” x ½” maple beams with the large engine instead of the 3/8” x ½” beams normally used for smaller planes.  This is a weight gain of 1.5 oz.
•   The tail moment of the Vector 40 would be too short.  To balance the bigger, heavier engine, the tail moment would need extended to 17” or 17.5”.  This is an extension of about 3” and would result in a weight gain of ½ oz.
•   The stab/elevator *might* be too small.  For the sake of discussion, we will assume it is and add ½ oz to extend the span of the stab elevator 1” on both sides.
•   To make sure the plane “looks” like a big plane, we will add 1 oz for taller fuselage sides.  ½” of height added to the top and bottom of the fuselage sides will make a huge difference in the appearance of the size of the fuselage.  The tail moment will add quite a bit to the larger look.
•   Just to be fair we will assume we will use a larger propeller and spinner.  So, we will add one more ounce just to be sure.
•   So, the total is 7.5 oz…I think that is about it.

So, using my Vector 40 ARF as an example, we will total the weight gain.  My ARF Vector weighs in a 44 oz all up “ready to fly”.  Adding all of the things listed, we have a finished weight of a little less than 52 oz.  Is this too heavy?  Hmmmm?

It is in fact, *not* too heavy.  This equates to wing loading of 13 oz per sq foot.  If you compare wing loadings of larger “world beaters”, most of the 650 sq in airplane crowd build that have wing loading somewhere in the neighborhood of 13-14 oz per sq foot.   This equates to the typical SV-11, Legacy, Trivial Pirsuit, Time Machine, Saturn, etc in the range of 58 oz to 64 oz.  This is a completely normal wing loading for the most successful stunt planes.  In fact, most weigh more, and I think this is going to be apparent when everyone starts weighing their planes before every contest next year.

Let’s say you are stickler for “old school” wing loadings, or worse yet, you want to *paint* your Vector .40/.60.  Oh, no… now it is too heavy.  Well, then do this…change the rib spacing on the Vector approximately .25” to add 2” to each wing bay.  This will result in a increase in wing area of about 40 sq in and will allow 4 more oz to be added for paint, all without any real additional construction weight.

Did I mention we are talking about an ARF, and not a contest wood plane?  I contest wood plane could be built even lighter…think about it.

A Nats Story-2002 http://www.flystunt.com/2014/01/28/a-nats-story-2002/ Tue, 28 Jan 2014 20:24:50 +0000 http://www.flystunt.com/?p=606 I recently updated my PAMPA membership and Shareen sent me all of the 2002 issues at once.  I was very interested to check out the Nats 2002 issue and was a little disappointed to see that there was no Nats coverage for this year (or my picture).  Well, that was just not going to do!  So here’s my little Nats story.  Keep in mind, with my memory I am making no attempt to cover all of the events of the Nationals.  I am only attempting to entertain, and clue you in to the Nationals experience through the eyes of “yours truly”.

Let me first say, that my Nats adventure really began three weeks before, when my 2002 season airplane decided it was going to split in two on the second inside loop.  This was the result of Dallas “dare flying” (a result of comments like “it’s not windy” and “your up, you goin’?” never mind that there are 6 other guys who are not going up at all) invented by Bob Gieseke.

I remember it like it was yesterday.  The big Saito was doing a perfect uphill to downhill transition in the inside loops, absolutely perfect in the high winds, there was no sign of windup at all.  Then there was a loud BOOM and my shiny “Zone” was folded up like a closing a briefcase.  The whole thing went (obviously) crashing to Earth.

Of course, my best EVER Saito 72 leading the way.  The wreckage made it abundantly clear that saving weight by omitting the fillet in the INSIDE of the wing joint is “really not a good idea”.  The wing had been sheared off at the inboard fuselage side, as if by a huge machete.   My best propeller was a pile of splinters, but I managed to find one blade that had all of the pitch data written on the back.  Even my lines were ruined (I hate solids, but I use them anyway).

I packed up my broken machine, most of the parts (the big ones), and headed home.  I was in shock…most of the Dallas crew looked pretty darn shocked as well.  I had spent most of the last six months preparing for the big event which was now only three weeks away.  “The Zone” was definitely the shiniest airplane I had ever built (which was sure to prove deadly in Appearance Judging) and was a solid flyer, as it showed no real bugs and I was really getting into the groove with that plane.  But now, all was lost…

I think on the drive home, most specifically at somewhere about Highway 75 and Arapaho, I just snapped.  Seriously, I snapped.  I think I was actually twitching at that point.  My mind began to form an elaborate logistical plot to resurrect my shattered Nationals dreams.  It couldn’t be that bad, really!  All I had to do was the following:

1.       Build an airplane and finish it to a Nats level.

2.       Get it trimmed, or hope the airplane required no trim.

3.       Make an exact reproduction of my best prop. 

4.       Rebuild the shattered top end to my best Saito and bench-test it.

5.       Practice a few days.

6.       Drive to Muncie and hope I don’t embarrass myself in front of the whole CL Stunt community. 

Simple!  It was a short list really, and it was really the only prescription for my shattered dreams and broken heart.  What choice did I have? 

I did, however, have a few “Aces in the Hole”: my friends.  Most specifically, Doug Moon.  The Dallas crew is a pretty tight knit group and we tend to try to take care of one another.  We loan each other props, fuel, tools, and pretty much take the responsibility for coaching one another.  I had a PA 65 that Doug liked a lot, and I was in desperate need of some expert building help, so I hoped a deal could be struck.  I think Doug would have helped no matter what, because it seemed no one wanted to leave anyone in Dallas this year.

I had an Ultra Hobby Products Impact wing about 90% complete.  It was sitting in my front dining room still suspended from Rabe wing jig that Al had made for me.  In short work the wing could be completed. I asked Doug to finish the wing and bend up some gears.  Now all I needed was the rest of the airplane.  Lucky for me Thomas Edison invented the light bulb and some other really smart guy invented the LASER.  Because if him, we have LASER CUT MODELS.  I made pretty short work of the Impact tail feathers and fuselage.  To cut a few corners, I installed my own design motor crutch (which is also laser cut) and salvaged a molded top block and rudder from construction of the “Zone”.  I decided on a look and ran with it.

I came home from work every night at about 6:30, changed clothes and worked diligently until about 1:00 am every night.  Doug did likewise (it is normal for him).  My wife and I barely spoke for the next ten days, but she completely supported me and hoped I would be successful.  I had the airplane framed and covered in silkspan and filled (ready for color) in 13 days.  On the 14th day, Doug came over to my house, where we proceeded to mask, paint color and clear the airplane in 4 ½ hours.  I buffed the airplane the next day, and assembled the now repaired Saito 72 (with the same clunk tank from the crash) and new hand carved replica of the destroyed propeller and headed to the field for a test flight.

Long story short, the newly christened “Shear Panic” flew more satisfyingly than any other airplane I had ever built.  It was dead straight and tracked like a truck.  It flew a reasonably good corner and did excellent rounds.  Oh, and it was REAL YELLOW so it looked HUGE!  I was stoked!  I practiced as much as I could the rest of the week.  Everyone was very pleased with the new creation, and the airplane got very good reviews considering the timeframe.  All was right in the world once again so I began packing for Muncie.

Steve Moon had purchased a 90’s something Chevy Suburban that appeared to be still “like new”.  His reasoning being that Jake, Doug, and he would require a lot of space for the drive to Muncie every year.

All in all, it was a good investment.  I loaded up the old reliable Pathfinder with the Shear Panic, 7 books on tape and enough high nitro fuel to blow up a small village.  Even though the Moons insisted that they ride the entire way together, forcing me to ride BY MYSELF the entire way, I persevered. I kept a steady diet of Diet Cokes and Harry Potter books on tape, and kept the cruise set on about 80 MPH.

The first night we made it to Joplin in about 4 hours and we settled into the local Motel 6 for a little shuteye.  I was so hopped up on caffeine that I knew sleeping was going to be, at best, difficult.  To make matters much worse, apparently some high school jackass was having a dispute with his ex-girlfriend who just happened to be staying in the room next door to mine.  This fella’s idea of conflict resolution was to pull his poopbox Chevy out front, wind up his anemic post-pollution control V8 and dump the clutch.  The idea being that he would burn off the tires and raise a lot of noise.  Instead all he could manage was a mere “chirp” and then his engine would die.  This doofus literally tried to smoke off his tires for an hour, as apparently what he lacked in brains and horsepower he was more than adequate in resolve.  Imagine it.  I had 4 hours to hope for sleep before I drove ALL THE NEXT DAY, and I gave one hour of sleep up to

VRRRRRRRRRRRRROOOOOOOOOOMMMMM                <chirp>     (die) (pause) crankcrankcrankcrankcrankcrankcrank (start)

 VRRRRRRRRRRRRROOOOOOOOOOMMMMM               <chirp>       (die) (pause) crankcrankcrankcrankcrankcrankcrank  


You get the idea…

I lay there in a dizzy fog knowing that if I got up out of that bed I was going to be sleeping the Joplin City Jail because someone was getting a severe beating.  It was at this moment that a sighed, covered my head with the pillow, and thanked God that I had left my .45 at home.

I was up at 5:00 am (three hours after I went to bed) and woke up the sleeping Moons (man, that is not a pretty sight).  The second day of driving it was becoming increasingly obvious that keeping an eye on the Big Blue Moonmobile was becoming more difficult.  It was quickly becoming apparent that every human being on the planet had recently purchased a Chevy Suburban, and was now test-driving it through the Ozarks.  No kidding…  We stopped in Missouri on the second day and I commented on the “Suburban factor” to Doug as we stood and pumped gas into our thirsty SUV’s.  We watched the adjacent overpass, and we figured that 7 out of 10 vehicles that we saw pass were the exact same truck as Steve’s.  Just in the short time it took to fill the tanks.  We Americans really are SUV happy, aren’t we?

I was living my Nats dream, but I couldn’t help but realize that I was feeling progressively worse physically.  You see, I had been struggling with what I thought was “asthma” for several months.  That is, I was frequented with a burning sensation in my lungs, that at times was painful to the point of distraction.   Making it impossible for me to workout or do anything strenuous.  None of the medications for asthma seemed to help much and the trip seemed to be exacerbating the situation.  It felt as though someone was hitting me in the back with a baseball bat while simultaneously forcing me to inhale CA fumes.  I did not feel good at all.  This feeling peaked when I arrived at Muncie, so if I talked to you at all that first night and I seemed a little distracted, sorry…  When Steve said, “let’s get in a few practice flights before dark”, I nearly fainted.

Note:  Incidentally, the pain in my lungs was so horrible in Muncie that when I got home I got a second opinion about the condition.  It turns out that my previous six-month unemployment and the new pressure cooker job had actually extracted their toll after all.  What I had was severe acid reflux.  I was actually inhaling acid from my stomach into my lungs, especially when I got nervous, anxious, or drank Diet Coke…  Ouch…it hurts to think about it to this day.

We arrived at about 5:00 pm on Saturday, and Doug and Steve couldn’t wait to start flying.  I gazed bleary eyed at Doug as he crawled yawning and stretching out of the Moonmobile, obviously just waking from a nap on the road.  Needless to say, I was content to watch that first day, as the world was spinning all though I was sitting still.  After short time, I made a beeline for the motel.  Ah,sleep…  So, really, MY NATS started on Sunday at about noon.  I actually got out of bed sometime before noon, lest anyone think I was not committed to practice that morning, I wasn’t. I slept in on Sunday as you can imagine, missing morning practice.

I took some time to drop in on the Intermediate Nats that was being held down on the grass circles, north of the combat folks.  Rich Peabody and Allen Brickhaus were steady at the helm of the event, and should be absolutely COMMENDED at their efforts and success.  This is becoming a HUGE event and could even be more well attended if it were officially sanctioned (I think).  Either way, I helped Doug and Steve appearance judge Intermediate (I nodded in agreement and pointed a lot) as some of the models were certainly well constructed and finished (the front row finisher was nearly flawless, and we looked it over pretty darn good too).  Then we watched Jake Moon (Jake is the coolest little kid) and the other juniors put in their patterns, and lent a helping hand to Ultra Hobby Products’ own John Grigsby put in his officials in Intermediate. I made a point to take a little time to rap a little with Rich, as we have corresponded several times over the Internet (it is not every day that you get to speak to the self-proclaimed “Stunt antichrist”).  I remember making a comment about how the Intermediate event is the only stunt event at the Nationals where you will one see one contestant do an entire pattern with five foot bottoms, and the next contestant will be lucky to survive the entire pattern.  One flyer could do the entire pattern backwards and inverted—-at the same time-with a huge Saito 91 4-stroke powered Fokker Triplane!  Wow!  You don’t see that every day, especially from an Intermediate!  That Triplane was hard to miss, especially from the L-pad.  Bob G. made one of the best comments of the week when he said, “if that guy does a 5 foot bottom inverted, the top wing is coming off”.

Upon my arrival at the L-pad it became apparent from a few flights that the excessive nitro we had been forced to use in Dallas would not be necessary in the cool Muncie air.  It was very interesting for me needless to say, as for the first time IN MY LIFE I heard Bob Geiseke say we had “too much power”.  I guess the 30% nitro fuel I had brought was going to spend the week in the truck.  After a few flights, I had switched back to my “standard setup” of YS 20/20 and my carved 14” wood propeller.  All was right in 4-stroke land and the big Saito .72 was stunting big and fat.  Doug had dropped from nearly 20% nitro at home to a steady diet of 15% Sig, and the “rock tumbler” PA 65 was cranking out crawling slow runs with the airplane turning lightning corners.  Steve’s 40 VF in his Impact sounded, well, like a 40 VF, kind of “full tilt boogie” and Steve was smiling every flight.  (Note:  the West Coast guys actually go UP in nitro when they come to Muncie while we go down, our conditions are that different).  It became apparent that the L-pad facility could spoil us, as the air is crisp and predictable with little to no “funnies”.  We were perplexed as to how to fly with the air coming straight at us with no turbulence.

The only negative about the L-pad was the fact that it was full to capacity and we were only getting a flight every few hours.  It was to be expected though, as the WHOLE GANG WAS HERE.  Richard Oliver was a practice machine, and was getting in his final trim, he was definitely going to be factor this week.  Rich Giacabonne had this beautiful dope finished monster Stuka that flew backwards and absolutely looked a freight train in a 4 cycle (I voted for Rich for the Concours-sorry Paul, he had a machine gun in his canopy).  Matt Nuemann was practicing hard under the watchful eye of his Dad and coach Len.  Len and I discussed what we were seeing and a few last minute tune-ups for Matt.  Randy Smith and Curt Contrada were busily cranking out solid patterns, and I think I saw Randy smile once while he was flying, his nose could have been itching though…  Bob G. and Mike Scott were, of course, practicing and trimming for the optimum setup, Bob’s engine runs were particularly strong even though it seemed as though a bearing in his #1 PA 65 was starting to whine.  It did not seem to effect the power so we told him to ignore it.  Windy had his newly finished carbon wing Miss Ashley (the red wing made it look so good in the air) but sadly, for the FIRST TIME EVER that I can remember Windy was having some technical difficulties and his motor just never decided to come online.  Dale Berry was also there making his first Open class bid.  Obviously there were a lot of others, I could go on for quite a while…  One point of interest is that it appears that Texas had the largest contingency at the Nationals.  That would include Doug Moon, Steve Moon, Jake Moon, John Grigsby, Bob Geiseke, Mike Scott, Dale Gleason, Don Hutchinson, Jim Young, Phillip Nichols, Richard Oliver, Frank Williams, Frank McMillan, and myself.  That makes fourteen in all, with eleven from Dallas alone!  If we could have had Bill Wilson, Bill Rutherford, Dee Rice, and Al Rabe (yes, Al I said YOU!) we would have totally dominated for attendance.

Monday was golf day, and adherence to the “Moon schedule” was mandatory.  Steve, John G. and I played the local municipal course a few miles from the field.  There was some cursing, truuuuuuue… no one is denying that.  But the course was actually quite nice, certainly a bargain and it made for an enjoyable day.  Somehow I managed to shoot 82.  Good karma I guess…

It was after Golf Day that we discovered the grass circles.  It was obvious earlier in the week that we were not seeing anyone from the West Coast practicing on the L-pad.  This included Paul Walker, Ted Fancher, and Brett Buck.  They were doing all of their flying on the grass circles next to the combat site.  We figured if it was good enough for them we would give it a try, and we NEVER fly on grass.  To prove it, I have asphalt permanently imbedded in my skin.  The grass turned out to be a real winner though, and we experienced no problems as the ground was relatively hard and the grass shortly cropped. Our level of practice sure elevated, and it was just like being at home, we were into a standard rotation and had a circle all to ourselves.  We could fly as much or little as we wanted to.  It was also cool because we were right next to Ted Fancher-and-friend’s circle, so we got to watch some good flyers there.  Brett Buck looked super sharp and crisp and Ted was flying very quick and sharp.

I noticed one of their crew had brought what looked like a Trivial Pursuit and it was obvious that he was flying some sort of 4-stroke, although it was certainly not acting very happy.  I made a point to head over after were done practicing for the day and check out his setup.  There were so far only four 4–stroke setups that I could see, Paul Walker and Jim Aaron (flying in Ted’s group) (Saito .56 with Pat Johnston manifold), Paul Winter (Saito .72 on carburetor), and myself (Saito .72 with Ultra Hobby Products Pat Johnston manifold).  I did not like to see anyone suffer at the hands of our fledging technology, and luckily Ted and Brett were eager to ask me questions on Jim’s behalf rather than me having to interject my unsolicited opinions.  I went through the checklist of the components in Jim’s Saito setup and determined that “it would not work”.  This was undoubtedly a harsh pill to swallow for Jim (understandably) and he seemed rather frustrated (understandably) but Ted finally convinced him to try my suggestions, because, he reasoned, Jim had nothing to lose.  I agreed.  We made a trip to the Muncie Hobby Shop located just offsite where we bent up a Sullivan 6-oz clunk fuel tank on the counter.  The new tank in hand, we headed back to the grass circles.  Jim installed the tank and set the shim per my instructions, filled the tank with some complimentary Powermaster YS 20/20 (thank you Powermaster), and set the needle with my method.  To say the changes were successful, I think, would be accurate.  Jim seemed very happy the rest of the week and I felt pretty good about myself.

Appearance judging was on Tuesday as usual and the models were stunning to say the least.  Paul Walker’s Mustang was the highest quality fit and finish, as were several others.  Several others mind you.  Bob Lampione had a deep shine as well as Kenny Stevens, but as I said my favorite was the great big Stuka.  All the flyers retired to the gym while the judging was taking place to have the traditional Pilot’s Meeting.  Frank McMillan kept everything moving along crisply and made a few announcements.  Sadly one of these announcements being that Jim Hunt had been killed.  Everyone could tell that was a very emotional moment for Frank, but he managed through it.  At the end of the meeting, the floor was opened for discussion.  Frank started us off by bringing up the ruckus over the elimination BOM that Doug, Steve and I had debated with Ted, Brett and others on the Internet.  With Dallas being pro elimination and West Coast anti-elimination.  We bantered about for a while finally agreeing to disagree. There was one pinnacle moment for me however, which was my response to a “painting the airplane constitutes 50% of the building” comment.  I responded by telling the story of the Shear Panic and how Doug and I painted that dude in less than 5 hours.  Gordon Delaney did not believe me, and insisted on looking at the airplane.  I took him to my car where he stood in disbelief and amazement.  We got a good chuckle out of that.

Not to ignore the “Moon Nats Schedule” Tuesday was hand launch glider night.  Since I had my right biceps separated and surgically re-attached only the previous October, I opted to simply coach in the throwing portion of the event.  Doug Moon, although a talented stunt flyer, throws like a little girl <snicker>.  Steve easily pounded his younger brother into the dirt in regards to distance and duration, although their models were of similar design and construction.  Steve simply did not throw like a big sissy girl (like Doug) <snicker>.  I couldn’t believe how eagerly the Moons would charge off into the hack-burr laden high weeds to chase their planes.  Never mind that it was nearly pitch black by that point.  Also, Dan Banjock had his little free flight model puttering in big lazy circles.  I figured one more long tank and that sucker was going to be gone into the night sky, never to return.  Luckily, Dan keeps the engine pretty rich most of the time.

Qualifiers started on Wednesday, and the usual favorites seemed to be scoring very well in Open.  Ted and Paul Walker especially, even though they were flying polar opposite styles.  Ted was flying quick and tight as usual.  Paul was flying very large and soft, especially in the hourglass, but both were scoring equally well.  I think Paul was leading his circle by 30 points at one stage.  Doug Moon was flying the best I have ever seen him fly, and he was eating up all that clean, thick air like a fat chick on Hagen Daas.  Doug gets a lot of coaching and he is very capable trimmer, but mostly he is a tremendous PERFORMER.  In that, he flies BETTER in competition, the more people around the better, it just seems to elevate him even further.  That is a very rare quality.  Richard Oliver was also burning up sky and posting some well deserved high scores.  In fact, I believe he was high score on his circle first day of qualifiers, a stunning victory for a true Rookie.  All that Al Rabe coaching is sure working.  Bill Rich was solid as a rock, as were Randy and Curt.  Brett Buck was one of my favorites for Top 5, I don’t know what happened, it just never panned out for Brett this year, but this is certainly no indication of his flying ability.  His snappy style is very clean and impressive and his airplane was one of the best flying models of the week.

Advanced was a WAR for second place.  In my mind Kenny Stevens was destined to be National Champion from the first pattern.  His flying was clearly a notch above the rest of us and his little Fox .35 powered Tom Morris “Quick Build” Cavalier seemed to suit his nimble style very well.  It also didn’t hurt that he started off the week with 19 appearance points, a result of one of the shiniest Sig dope paint jobs I have ever seen.  Sometimes you just can’t beat that shine!  Kenny is one of my personal favorites, and if I had to get my guts stomped in I certainly don’t mind it being Kenny.  Kent Tysor flew solid all week, as well as Steve Millet, Steve Moon, Jose Modesto, Kevin Stewart, and several others.  If it weren’t for a few overruns and mishaps the finishing order might have been radically different (after Kenny at least).  All in all, I was happy with my flying, considering I refused to trim the airplane any further.  My flying on Friday just simply wasn’t good enough to do better than 6th.  Considering the circumstances I was pretty happy.

On Friday, the impossible was achieved, Doug Moon qualified 5th and was going to be named Rookie of the Year.  To think, I was sorely outvoted when I insisted that Doug was wasting an entire year if he stayed in Advanced.  Oh, yea of little faith… I don’t think I could have felt any better about that moment, even if it had been me.  I do regret that I missed the

Doug water cooler dunking while munching a hot dog in the picnic tent (if I would have been in on it, I would not have missed).  It is too bad I never got to see the Walker Cup fly-off, as I had to return home and had to hear about the placing on the cell phone, but then that is why God invented Windy Videos, right?  Interestingly, I would have won a significant amount of money if I were betting on the outcome of the Walker Cup Flyoff, because I started telling everyone Paul Walker would win in February.

My wife had arrived on Wednesday along with one of my best friends from Columbus, and that made the last part of the week more enjoyable, and certainly the ride home was a LOT shorter.  My friend Dan had brought his son Jeremy along, and much to my surprise Jeremy announced that he would be returning the next year to fly in Junior against Jake.  We even sealed the deal by stopping by John Brodak’s booth and purchasing a Flight Streak trainer for the boy.  That was the same airplane I started on, by the way.  Please, feel free to forward any kits or engines that you are not planning on using, I am sure Jeremy will need lots of fodder for the mill.

Well, that’s one down…  GZ

A Modern Model Finish http://www.flystunt.com/2014/01/28/a-modern-model-finish/ Tue, 28 Jan 2014 20:23:11 +0000 http://www.flystunt.com/?p=602 Used by Permission
Bradley Walker
“This article is dedicated to the late Monte Lawrence
who was one of the pioneers of the Wilson finishing method.  We will miss you.”

This article will attempt to outline a finishing method that can be substituted for the old “dope and tissue” method for finishing balsa models.  This method was outlined to me at the 2001 Dallas Stunt Symposium by the Fort Worth finishing guru Bill Wilson.  I have taken Bill’s method and added a few extremely minor twists, but for the most part it is Bill’s methodology and method, and I am just a humble, humble, student of the Master. I could have never figured out any of this stuff on my own.

One thing to keep in mind is that any new finishing method will follow a learning curve on the part of the user and I in no way guarantee that YOU can do this system to Concourse perfection the first time.  I can assure you that an expectation of perfection on the first attempt will lead only to disappointment.  I know that the doping techniques used by a large part of the control line stunt world have been in development for some time now (about 70 years or so).  I would hope that the modeling community would embrace a method of finishing airplanes that can have a “killer” finish applied in a matter of days (or hours) instead of weeks or months.  However, it is still every modeler’s responsibility to understand that any new method will require patience. 

This is the method starting with a balsa airframe:

1.      The solid sheeted surfaces are finished with Minwax Polycrylic (PC) and 00 silkspan.  PC is available at Home Depot and Lowes and comes in gloss, semi and flat versions.  I have always used the gloss version, and I do not know if there are any advantages to the other versions.  A quart cost about $10 and will last for several airplanes.  Minwax PC has several advantages due to the fact that it is a water based acrylic.  Being water based, it simply has very little solvents and almost no stink.  Being an acrylic makes it a UNIVERSAL undercoat for just about any type of acrylic paint (all of the paints used in modeling are acrylic).  It dries in 24 hours, and once dried it takes on a character that is very similar to hardened thin CA.  Balsa impregnated with PC becomes ROCK HARD (much like thin CA impregnated wood).  It is really not necessary to use any paper with the PC (Bill Wilson sees no advantage to it and he has performed side by side strength tests), but I have found that, for my uses, it is truly wonderful over sheeted surfaces when used with thin silkspan.  Using 00 silkspan in conjunction with the PC helps to level the surface at application.  To attach the silkspan, first wet the surface with the Polycrylic (there is no need to pre-coat the surface like a dope application).  I use the same types of brushes that I use with dope.  WHILE THE PC IS STILL WET apply the slightly water dampened silkspan.  Once all the edges have been pulled and the wrinkles are all pulled out, trim the edges of the silkspan.  Once trimmed, wet the entire surface of the silkspan with a coat of PC.  Make sure to do the entire surface evenly and get all of the edges.  At this point it is possible that there may some “relaxation” in the part, especially for long flat parts like flaps, but no need to worry.  Typically, the relaxed parts will return right back to their former shape upon drying.  For added security, a good method is to lay the “tack free” drying parts on a sheet of Teflon on a flat surface and weight down slightly.  This will basically guarantee that the parts will dry DEAD FLAT and will not warp in the future.  Subsequent coats will have little, if any effect.  Let this first coat dry for a minimum of 24 hours and begin DRY sanding the surface with 180 grit ADHESIVE BACKED 3M OPEN COAT paper.

 Note on sandpaper: Not all sandpapers perform the same, period.  For our uses, except for the case of wet sanding the clear coat, all other sandpapers are severely lacking compared to the auto body open coat papers.  The 3M open coat paper can be found at ANY local body shop supply store.  I have purchased two different kinds, one is made for air files, it is 3” wide, YELLOW and comes on a roll, the other kind is the 6” sticky back YELLOW DA discs, both are the same paper.  Either one will work.  DO NOT SUBSTITUTE!!!  The ONLY acceptable substitute is the generic for 3M (Nikka).  It is EXACTLY the same and costs about $10 less.  A roll of 3m will cost about $30 and will last for many, many airplanes and will be the best all-purpose sandpaper you have ever used.  If in doubt, buy the 3M, it is still cheap in the long run.

At this point watch for a few different conditions.  One, that the entire weave of the silkspan is filled.  If it is, you should basically be able to sand all the silkspan wrinkles, edges, and surfaces exactly the same.  As opposed to dope, which is simply used to attach the silkspan to the surface, the PC makes the silkspan totally solid.  Each individual layer is not longer unique, like when you use dope.  The silkspan simply serves as a very thin sponge to accept the liquid plastic.  Once the weave is filled the silkspan is fully impregnated with plastic.  I use double layers of silkspan over edges that are not quite perfect, fill them with PC and sand it all down flat, so the paper and PC works like a filler.  The PC will sand with some work.  Remember it is HARD STUFF, but hard is good for balsa airplanes, especially for a base coat.  Second, you will notice that the paper will cut all of the surfaces about the same because the PC has served to make all of the surfaces of a uniform hardness.  Glue edges will be the same hardness as punk balsa.  This is a good opportunity to do the final shaping on joints and flatten everything out and get rid of the ridges that can appear on edges of dissimilar hardness (I really love this part of the process and I like to spend a little extra time here).  Lastly, if you do see an edge appear in the silkspan as you are sanding YOU DID NOT FILL THE PAPER (it will appear white if it is not filled).  Re-coat that area and all other dry areas and sand the next day.

2.      For strength, add a second layer of PC and paper to the nose.  Re-coat with a third coat after sanding the second coat.  The nose will be nice and shiny and ROCK HARD!  I have found that the PC prepared nose is harder and more dent resistant than even a nose finished in fiberglass and epoxy, and there is no weave to appear later.  It is also a good idea to re-coat at the fillet areas (we have no fillets at this point).  Make sure that area gets good and shiny also.  This allows you to sand the final fillets without gouging the wood, as the shiny areas will be extra hard.  Please don’t go crazy with the PC at this point.  One coat of PC is equal to about 4 coats of unthinned dope.  Too much all over will add up, so why do it?  A fully sheeted plane with two good coats should appear to have a slight “plastic” look.  The nose should absolutely look like it is fully “plasticized”.

3.      For very small dings during the pre-primer stages I use plain old spackling (not the light spackling).  In small quantities I have never had any shrinkage problems, especially when saturated with the PC.  For fillets I use Epoxolite or 5 minute epoxy depending on the size of the fillet.  Blend sand the Epoxolite on the PC, you will notice the PC hardness will give you more freedom to be aggressive without cutting into the wood, but still watch carefully. DO NOT overcoat the finished fillets with a coat of PC.  I have found that PC over Epoxolite is a dicey proposition, so don’t do it!  Wait to overcoat the fillets with the primer.

4.      For open bays use medium Sig silkspan or Polyspan (available from Tom Morris) and filled with three coats of nitrate dope with zinc stearate.  This is the slowest step in the entire process.  On my designs I have no open bays, which eliminates the needs for dope altogether. I have tried PC on open bays, and I have yet to make it work. Bill Wilson does, and he is very happy with it. Bill’s preferred method is to apply the Polyspan to the open bays using Balsarite adhesive and a hot iron.  Once the fabric is fastened to the airframe and the open bays shrunk with the iron, the weave of the Polyspan is sealed with two coats of PC.  From that point the rest of the airplane is finished as normal.

5.      The next step is to shoot the entire plane in auto primer.  Typically, I use inexpensive “lacquer primer surfacer” from English Auto Supply (a local Dallas body shop supply chain).  Every auto supply has basically the same lacquer based primer surfacer.  Despite the fact that this primer is lacquer based, I absolutely recommend using only urethane reducer in the primer.  I only use Omni urethane reducer (this is the same reducer I use in the clear-see below).  Omni reducer comes in four heat ranges, which include fast, medium, slow, and super slow.  For primer I would recommend starting with medium and thin the first coat 2 to 1 to 1 ½ to 1 (for over 90 degrees try the slow).  The second coat can be thinned closer to 2 1/2 to 1, depending on how much is left to fill.  The first coat is sanded dry (DRY! ALWAYS DRY!!! NEVER EVER WET SAND!!!!) with 180 open coat paper.  The second coat is sanded with 180 and finished with 320 open coat.

There is really no comparison between the lacquer primer combined with lacquer thinner and the same primer combined with urethane reducer.  The less aggressive urethane reducer allows the primer to “stack”.  A stacked surface appears almost shiny and will appear very flat with a very thin coat, also it will shrink less and absorb less weight of the color and clear coats.  A stacked coat will also sand like it is very thick even when it is not, and it will also allow the clear to shine more.  Faster drying, more aggressive lacquer thinners have a tendency to create a primer surface that is more like a “forest of trees”, if you will.  The trees are all standing up and it takes an incredible amount of material to fill up to the top of the trees.  The primer used with urethane reducer is more like a forest with all the trees laying their sides or “stacked” like bricks in a wall.  A stacked surface will fill faster and retain its “holdout” (the ability of the primer to resist shrinking and swelling at the application of the clear) better through the final coats.  Also, the slower reducers will allow the surface to flow out smoother, even though they also require a little more time to dry also (most lacquer based primers are sandable in about an hour).

On my latest plane I switched to the catalyzed PPG urethane primer K-36. All of the primer coats on this airplane were urethane and I only used lacquer primer for fast spot fills.  The K-36 is really kind of a hassle to use, as it is only sandable after a full 12 to 16 hour drying time.  It also did not tend to “fill” very well as it tended to wick away from imperfections as opposed to wicking into the voids like the lacquer surfacer.  Even though, after all was said and done, there were aspects to the K-36 that I really liked.  The “holdout” was really impressive and it sanded very nicely.  It is also very solvent resistant, which can be handy.  For the next airplane I plan to use the lacquer primer for the base and the K-36 for the final primer coat.


 How to sand filler coats may be the single biggest misconception in finishing.  The goal is to obtain a uniform coat of primer.  The idea is to get it so thin there is no real weight penalty.  If you sand gray auto primer until you can almost read small newspaper print through it, it is PRETTY DANG THIN.  I don’t care if you shot on your primer an 1/8″ thick, if you keep sanding it down until it is uniformly semi-transparent there can’t be a lot of weight there.

Applying primer is really pretty simple.  Make sure you put enough on to fill every imperfection you can see or you will just end up sanding and re-shooting again.  Put on enough coats with the material thick enough to fill. This is a different philosophy than the “dust on a coat and sand, dust on a coat and sand” philosophy that the dope guys use.  As far as the level of fill, your mileage may vary depending on the type of primer used.  The PPG K-36 requires 2-3 full coats to fill every bit of the wood grain in a well-prepped model.  Lacquer primer surfacer can typically do that in one coat with some spot work here and there.  Catalyzed primer does has a shrinkage advantage, which is nice because you hope that all that sanding will be not be in vain once the first coat of clear is applied.

The first part of the sanding process is to “block” the large flat surfaces. I bust the surface with 180 grit and sand until the very first transparent spots start to appear and then I move on. Sand in larger strokes across the known imperfections as much as possible.  At this stage you will start to see the major imperfections (such as wood grain) disappear as you sand.  Once the entire surface is done to this level you should see semi-transparent spots periodically but the surface should still be opaque.

Now it is time to remove the 180 scratches, as much excess primer as possible, and bring the primer coat down to a uniform thickness.  Switch to 320 and sand all of the more opaque spots until the surface is as uniformly NEARLY transparent as possible.  Only sand the opaque areas.  Stay away from the transparent areas!  You should be sanding in very small strokes or circles at this point and being very specific about where you are removing material.  Sanding in long strokes will only serve top break through the more transparent areas.  Then, switch to 400 and take the surface down one more level of transparency (this only takes seconds).  At this point there is a layer of primer so thin that 5 more strokes of 400 grit would bust through the surface.  You seriously can’t get it any thinner.  Busting through the surface is a very bad thing, and accomplishes nothing.  These areas will inevitably swell with the clear and just show the imperfections.  So it does no good to “sand it all off”!  This is a huge misconception about the use of primers (including sanding sealer or dope and talc).  Sanding the primer until only little slivers of gray are left in the wood grain is not a “coat”.  If you sand this far you have effectively removed the entire coat, so why bother? There must be an unbroken LAYER of primer remaining.  I think most would be better served to err on the side of a slightly more opaque stopping point than more transparent.  More opaque means there is less chance for dissimilar surfaces, which leads to swelling.  The difference in weight in two shades more opaque is most likely not even a factor in the final analysis.

6.      For the color coats use 1 to 1 non-catalyzed polyester basecoat.  Common types are Dupont Chromabase or PPG Omni for a good, not too expensive solution.  I use Omni, PPG and Valspar (mostly Valspar).  A lot of people are truly confused about the function of the basecoat part of the basecoat/clearcoat process.  A lot of talk is made of auto clears but there seems to be very little discussion about the basecoat.  Simply put, the stuff is really wonderful to work with.  It has so many advantages over the dope/lacquer-based colors.  One advantage is that it has no gloss binders.  Gloss binders create a sheeting effect across the surface that it is applied.  This sheeting effect creates the gloss.  These gloss binders add needless amounts of weight and are the main culprit for the paint trying to “wick” underneath the masking tape when applying trim.  Basecoat “sticks straight down”, it does not have any gloss binders so it makes no attempt to stick to itself “sideways”.  The sole function of the basecoat is to apply color, so no gloss is needed.  Also, basecoat dries in about 5 to 10 minutes (always use fast reducer) and can be taped on top in that time.   We have a saying that you can tape on top of basecoat “as fast as you can clean the gun”.
Because there are no gloss binders in the color, it is extremely light.  There is simply almost no material to add weight.  Basecoat is also not fuel proof; in fact, it will wipe away with rubbing alcohol.  It is possible to remove an entire color scheme in a matter of just a few minutes with a paper towel and alcohol.  Needless to say I do not recommend sanding the color coats, in fact, I don’t recommend touching them if it can be at all avoided.

Basecoat is to be shot “dry”.  The best applications almost look like overspray.  This is especially true when shooting taped areas.  The drier you can apply the material, the sharper the tapeline will be.  Also, dry shooting the material ensures that there is only enough material for coverage.  Basecoat does not fill like dope colors, so don’t expect it to.  The fill is done at the primer stage, not the color stage.  If you shot the color correctly the surface will have the appearance of 400 grit sandpaper, and it will not be shiny at all.

The best thing about auto color coats is that they come in every color under the rainbow.  I often pick colors by using specific models and makes of cars.  My latest model is VW Bug Cyber Green and BMW Flare Red.

7.      I use 3M blue vinyl masking tape for sharp edges.  I use regular masking tape for all others.  I recommend 3M/Scotch-brand masking tape only. I also use a 3M paper/mask dispenser that I bought at the Sherwin Williams home painting store. Please, do yourself a favor and drop all the newspaper and tinfoil masking and go the system used by every serious car painter in the world.  I recommend that every human being on the planet purchase a tape/paper dispenser.  There simply is no substitute.  The paper rolls (I use the 9” paper rolls myself) can be found at home Depot or Lowes’ and are definitely worth the $1.50 per roll price.  I told everybody about the 4 ½ hour paint job Doug Moon and I did on my 2002 Nats plane the Shear Panic.  I believe the paper/mask dispenser was one of the factors that made that kind of speed possible.

 8.      The clear I am currently using is the Matrix MS-42 2 to 1 premium urethane clear, with the MH006 hardener, or the MH008 hardener in hot weather.  All of the major paint companies offer a “premium” 2 to 1 clear. You could substitute PPG or Dupont, and in particular PPG’s bargain line of paints called Omni has a very nice 2 to 1 clear that is very suitable to our application.  I have also used 4 to 1 clears, including Chromaclear and Valspar and they behave exactly the same as each other.  I like the 2 to 1 clears better. When I first started using the clears myself, Bill Wilson happened to give me the Matrix clear, as it was a sample from a sales rep.  I would have normally been using Valspar brand, because that is what Bill uses, but I took home the Matrix clear and that is what I have been using ever since.  In fact, I have grown to really love the Matrix clear, as it performs wonderfully and is priced very reasonably, at nearly half the cost of Chromaclear.

I thin (or reduce) the clear coat from 33% (2-1-1) to 100% (2-1-3) depending on what I am planning to shoot.  I typically shoot at close to 100% reduction or slightly less.  I use Omni medium, slow, or super-slow urethane reducer depending on the temperature. I use the Omni reducer because I have found that it is IDENTICAL to the PPG urethane reducer that I was using before, and the Omni costs about one-fourth as much (it is also what my local shop carries).  A gallon of Omni reducer costs less than $20 and can be used in the primer also.  Feel free to use whatever brand urethane reducer you want, as I am sure they are extremely similar.

The real function of the reducer in the clear is to give the modeler a chance at a light clear coat.  We are painting model airplanes after all not cars, so a thick heavy coat of clear, (while desirable) is not practical.  Urethane auto clears are “high solids”.  High solids content simply refers to the fact that there is actually more material in the can and less solvents (epoxy, for example would be considered 100% solids-as it loses no weight as it cures).  This has been the trend in auto paints for years, resulting from enormous pressure from the EPA.  Dope clear for example, is typically a 10% solids and 90% evaporating solvents, so it would take 6 times as much dope clear to equal a 60% solids auto clear (it also takes much more time to gas off).  The urethane reducer used in the clear serves to stretch the material into a thinner coat, resulting in a reasonable weight.  The reducer can also serve help the clear flow and flash a little slower if the hardener is a little fast, as most spot repair hardeners often are.  The slower the clear dries the more it will lay out typically, but it will also serve to allow more “trash” to stick to the wet surface, especially if you are painting in your garage.  Everything is really a compromise in the end.

I have been doing pretty well with using “one slower” reducer when thinning the clear if a slow hardener is not available.  So, for example, if the temperature calls for medium reducer (70 deg.-80 deg.)  I use the slow (80 deg. -90 deg.).  Don’t get cute and think that using a super slow reducer when it is 60 degrees will result in a finish that looks like a mirror.  Most likely you only succeed in trapping the solvents in the first coat and “popping” the surface with the second, which will result in a bunch of tiny little air bubbles to appear in the surface.


3 oz of clear, 3 oz of reducer for a total of 6 oz in the gun will do a Nobler sized plane if the overspray is kept to a minimum.  The result will typically be a 1.5 oz clear coat (see note).  The first coat is shot semi-gloss, the second is shot a little wetter.  Allow 10-15 minutes in between to let the reducer gas off out of the previous coat.  Don’t try to fix all the orange peel until you give the material 10 minutes to flow, you might be surprised how much it will. The 2 to 1 clear is just so much easier to shoot and seems to not want to run if “stacked” like the 4 to 1 clears. Not to mention the shine is at least triple.

Note:  If a clear is a 2 to 1 mixture it is typically 60% solids (thank the EPA). Using a gravity fed “HVLP compliant” Harbor Freight gun, which averages about 75% of transfer, 75% of 60% of the weight of the clear (actual clear, not reducer) will end up on the airplane. Using rough numbers, 50% of the clear in the gun will end up on the plane. I found that this does definitely work in practice.  When shooting my profile P-Force I used the 6 oz mixture and 50% of 3 oz ended up on the airplane, so the clear weighed about 1.5 oz.  The mistake I made in the past was not thinning the clear enough to allow the material to flow out nicely (or cover the area). This is not a car, after all, and 50% of what is needed on a car is still quite a lot of clear. When I first started using the auto clears (read that ”did not have a clue”) I typically used a lot of material to try to get the material to “lay out”. I shot 12 oz of unthinned clear on my Oriental. I wish I could go back and do that again. My guess is that clear job weighed about 5-6 oz.  People who are used to shooting dope, which is closer to 10% solids will typically shoot WAY TOO much of a high solids clear. Using logic, one coat of a premium 2 to 1 clear is equal to 6 coats of dope at FULL STRENGTH. Which, by my numbers, equates very nicely to about what the dope guys end up shooting on a plane (10 to 15 coats-Windy uses a quart on a plane). The difference being that two coats of thinned urethane clear will lay flat and will only need rubbing if you are a true aficionado. Most guys would be sufficiently impressed with “OEM” car shine.  

All of the urethane auto clears are extremely fuel proof.  I typically run as high as 30% nitro in my 4 cycle engines.  Even with these high nitro fuels, if spilled directly on the finish, have no effect.  I regularly clean my airplanes with alcohol, and I have even used lacquer thinner for spot cleaning.  Needless to say, an airplane with urethane auto clear will keep its gloss for years and years, long after a dope job has faded and dulled.

9.      Sanding and buffing auto clear is really no different than sanding and buffing dope clear, except for the fact that the auto clear will already be glossy when you start and the buffing compounds may be slightly different.  The beauty of the gloss clear is that it is not necessary to buff every square inch of the airplane, which is typical in a dope clear job, because the material is already shiny.  It is amazing how little sanding and buffing required to have people convinced that you sanded and buffed the entire plane.  I always sand and buff the top and bottom of the wing, but I don’t necessarily buff the flaps.  The top of the fuselage definitely takes priority over the bottom, etc.  I try to get my clear to lay out flat enough that sanding and buffing is simply something to do if I get bored, but very few people notice a huge difference.

The clear is wet sanded in the usual manner, starting with wet 3M 1000 grit Wet or Dry (this is the only time that wet sanding is appropriate in this method), commencing to 1500 and then even 2000 if you wish (not really necessary).  Once the surface is flat, machine or hand-rub using 3M Rubbing Compound.  You will find that the 3M Rubbing Compound will do the bulk of the smoothing and shining work and the surface will be almost back to the original level of shine when completed.  Progress to 3M Micro-Finishing Compound (this material is best used with a machine) and the surface should be back to the original level of shine.  For appearance judging a quick rubbing with 3M Finesse-It will really wow ‘em.


After the Polycrylic stages, this paint method is primarily a spray method, so there are some equipment requirements.  Bill Wilson has spent a great deal of time testing inexpensive equipment solutions for spraying.  Spray guns have been of particular concern. The gun I use for primer, basecoat, and clear is the Harbor Freight HVLP “compliant” gravity feed.


This is the gun that started the gravity feed revolution for the Texas stunt community. Bill Wilson was using one of the several variations at his body shop and after Steve and Doug Moon and I used it, we had to have one. I bought one, the Moons bought theirs, and I got one for Al Rabe, which he gave to Frank McMillan, and so on, and so on…

This gun, as well as all gravity feed type guns, is capable of shooting paint at very low pressures (around 10 to 5 psi depending on the viscosity of the material).  Since it does not rely on the air pressure to feed the paint to the nozzle, overspray is truly minimized. The transfer rate of the gun is approximately 75%.   Not to mention the fact that the cleaning of the gun is truly light years ahead of the cleaning process required for a suction feed gun.

I recently added a “clear only” full sized gun and a Harbor Freight detail gravity feed gun for painting trim colors. The trim gun works very well for the task of shooting masked areas as it naturally shoots very “dry”, which is perfect for basecoat.  It was on sale for $34.95 with the regulator and I just could not turn it down.


This little guy is great for dry coats of small trim, or simply freehanding a camouflage job on your semi-scale. It is capable if a fan varying from 1/8″ to about 3″, and could be used as a main gun, but it would be SLOW GOING. I would recommend buying the big gun first.

I would also recommend a filter unit for your air supply to eliminate the oils and water vapor that can end up in your paint. They can be had real cheap at Harbor Freight, though (under $30).


I would recommend putting the filter unit as close to the gun as possible.  I actually mount mine right after the compressor unit and make sure to keep my hose short enough that there is not a lot of condensation in the feed line.  If you choose to not use a full size regulator/filter unit I would suggest a disposable filter/water trap that can be attached to the base of the gun.  These can be found at your local auto body store.

I have had several people ask me about buying a compressor unit, as it seems to always be the first step to becoming a full time spray painter.  I have a Cambell-Hausfeld 3 hp/110 V single stage with a 20-gallon tank that I bought Wal-Mart more than a several years ago. This compressor is really more than enough for any painting operation I have ever done, and is adequate for most body shop and mechanic’s air tools. It is really not necessary to go quite this big for painting alone. Harbor Freight has a good 2 hp pretty cheap (under $110).



There are a lot of discussions about the potential safety hazards surrounding the catalyzed urethane paints, especially the auto clear coats.  Years ago, when the Imron series of paints from Dupont were popular (a particularly hazardous paint system), there were several horror stories going around the control line stunt community.  In following with these stories there were a lot of half-truths and misconceptions bantered about.  Hopefully, some of that will be clarified here.

The first misconception is that any painting system is “safe”.  There are simply no solvent-based painting systems that do not require proper protections. Without the proper breathing apparatus and protection from skin exposure all of the paints and glues used in modeling are unsafe to a certain degree (excepting the maybe aliphatic glues and their cousins).  Dope systems are certainly not immune to safety concerns, as well as epoxies, enamels, and cyanocrates.

One of the main factors in evaluating whether a system is safe or unsafe is exposure time.  This is one the most overlooked factors when comparing the hazard in each system.  There are certainly addition chemical hazards when dealing with the clear stage of the auto paint systems, but the exposure times are so much drastically smaller in comparison to say, a dope system, that the case could be made that, in the end, the auto system is actually more safe.  For example, for say a .60 sized stunt ship, a dope clear job would typically consist of one to two quarts of reduced material.  This would typically require anywhere from 5 to 10 sprayed coats.  If each coat requires 20 minutes of spraying time, the total exposure would be roughly from 2 to 4 hours.  In comparison, for a .60 sized stunt ship, I typically spend about 10 minutes spraying the tack coat of auto clear and probably 10-15 minutes on the second wet coat (there is a lot more watching and looking on the final coat).  Typically I only fill the spray gun with 6 to 18 oz of reduced material (depending the size of the airplane and the “high zootness” of the paint job).  Due to this fact, it is easy to see that the total amount of atomized paint floating around in the air is drastically less with the auto clear.

As far as the safety of the total system outlined in this article, the exposure to any hazardous chemicals has been minimized.  There is minimal exposure during the Polycrylic stages.  I seldom feel the need to wear a mask and my wife never complains of the stink in the house, so the largest portion of the finishing process is spent with no stink at all.  The primer stages are relatively quick, as only two coats are required, one rough and one final, and both of these could be accomplished in the same day if one is diligent.  The basecoat colors are really quite benign, and have a smell similar to Red Devil Enamel.  Since they gas off so quickly and use such mild solvents, skin exposure risks are also relatively mild.  The clear is the most obvious health hazard, but the exposure is so short I feel the tradeoff is well worth it.

I just so happened to buy a new organic vapor mask, (a 3M silicone half faced model) so I took the opportunity to call the 3M Technical Service Line to get the 411 on the effectiveness of organic vapor “carbon masks” on diisocynates. Diisocyanates are the most hazardous chemicals present in the auto clears.  Much to my surprise, despite what we have been told in the past, carbon based filter cartridges are completely affective against these chemicals, even more so than most solvents.  The use of “fresh air systems” is not even advocated by OSHA under normal conditions.  The only reason fresh air systems were EVER advocated for diisocynates was because there were no “warning signs” for these chemicals (like a smell).  You can read the whole article here.


 This is the “nuts and bolts” of the article.

 Misconception No. 1: Air-purifying respirators should not be used because diisocyanates have poor warning properties.

Although OSHA specifically permits change schedules in lieu of sensory warning properties, some health and safety professionals argue this is not a safe practice. They believe diisocyanates could enter a facepiece through a spent cartridge or defect (e.g., a torn exhalation valve), and the user would be unaware, risking prolonged exposure.

 Misconception No. 2: Air-purifying respirators cannot remove diisocyanates.

In fact, it has been known for many years that diisocyanates are adsorbed by activated carbon and retained extremely well. Cartridge breakthrough equations predict very long service lives for diisocyanates under plausible use conditions. 

Misconception No. 3: Air-purifying respirators are not approved for gases and vapors with poor warning properties.

NIOSH supports OSHA’s requirement for change schedules and recommends against relying on warning properties. In addition, NIOSH recently directed respirator manufacturers to change the cautionary language on cartridge and canister approval labels and user instructions to be consistent with 1910.134.  Specifically, the statement “do not wear for protection against organic vapors with poor warning properties or those which generate high heats of reaction with sorbent” must be changed to “follow established cartridge and canister change schedules or observe ESLI to ensure that cartridges and canisters are replaced before breakthrough occurs.”

Besides the inhaled vapors of any solvent or diisocyanate, there is also the risk of exposure to the skin.  I personally take this very seriously, since the only adverse reaction I have had to the auto paints actually came from DIRECT LONG TERM EXPOSURE TO THE SKIN.  I simply don’t recommend it. My latest method for avoiding skin exposure is wearing treated paper (Tyvek) hooded coveralls over my street clothes when I shoot the clear.  I use the coveralls a few times and throw them in the trash.  Then again I am lucky that I have a convenient supply in that my boss lets me have one every now and then.  They are really inexpensive (there are several sources on the Internet and the price is about $50 a dozen) but still this may not be a good solution for everyone.  Another alternative would be to go to the surplus store and get a set of Air Force mechanic’s light coveralls.  This is what I did when I was in college.  The coveralls lasted for years and cost me about $10.  I still recommend showering after shooting an entire plane in clear; it just never hurts to be safe.

A DISCUSSION ON STUNT CONTEST FORMATS http://www.flystunt.com/2014/01/28/a-discussion-on-stunt-contest-formats/ Tue, 28 Jan 2014 20:19:47 +0000 http://www.flystunt.com/?p=598 Last time I checked, flying model airplanes is generally considered “fun”. I do believe I could find a consensus to this fact, and I think we would all agree that is why we all do it. As a general extension of this fact, flying for fun can sometimes lead to flying in competition. Competition gives us a reason to all get together and have some good fellowship with brother modelers, be exposed to other flyers, learn new approaches to modeling, and measure our abilities against each other (oh… and eat bar-B-Q).

The need for competition leads ultimately to the little thing we call a model airplane “stunt contest”. This is ultimately the subject for discussion here.

There are some people out there that believe that a stunt contest has a great many functions, and that the people running them have a great many responsibilities. One of the functions I hear bantered about is the need to “maintain the traditions of the event”. In my opinion, this perceived function has ultimately led to a nearly total halt to the advancement of the event. Stunt contests as we know them, have remained virtually unchanged for more than 40 years. Other than the addition of the skill classes, nearly all aspects of the stunt contest including scoring, judging methods, contest format, scoring tabulation, and the pattern itself have remained almost completely unchanged.

So, if some people think that remaining unchanged is the ultimate function of our little endeavor, then the event has been very successful. Indeed, in terms of the contest format and practice itself, if remaining true to “the way we did it in 1963” is the ultimate goal of the stunt contest, then control line stunt is (by far) the most successful faction of modeling on planet Earth.

I completely go the other way; I do not feel that stunt contests are for exercising traditions. Admittedly, I have been pretty outspoken about this subject for some time so this may not be any real surprise to many who might read this. It is my view that Classic Stunt and Old time Stunt maintain the “traditions” of the event just fine, and as I understand it, these events were expressly put into place for that function.

It is my belief that the modern CLPA event should be just that; MODERN.

In general, flying for fun is a hobby; flying in competition is a sport. All sports evolve. The reason they evolve is because the competitors get better in succeeding generations. Performance increases as equipment improves, coaching gets better, and as a result margins between the competitors tighten as everyone elevates. As a result, Distinguishing between performers becomes more difficult. As an example, look at golf. Some would argue that golf has remained unchanged for 400 years, and they would be wrong. True, that while the basic rules and premise of the game has remained virtually unchanged, the measure of performance of the players has changed radically. As players and equipment have improved, courses have been made incredibly more difficult. Modern courses have been lengthened, fairways have been narrowed, rough has been grown higher and thicker, and greens have been made faster and more undulating. Even an old course can be made to have a whole new set of “teeth” with a little fertilizer, a mower, and some tricky pin placements. All of this is been done to separate the field and narrow the performance band. As players improve, something is needed to “drive the cream to the top”.

To evolve, we have to examine where we have been historically. I think that a brief study of the typical stunt contest would be productive. First, we have to ask ourselves, what have we learned after 40 years of stunt contests? It should be a generally accepted fact that we have a huge database of history from which to glean precious contest information, and this history should be useful for determining the strengths and weaknesses of our methods. If we could simply be honest with ourselves, and actually allow some open, honest discussion while throwing politics out the window, we might be able to make improvements.

Some points of our current method:

    • Stunt contests are subjective. Even though the subject of stunt judging has been historically considered a taboo subject for public consumption, it is a set in stone fact that stunt contests are not decided by pilots, planes, or patterns. In fact, they are decided by judges. It is also a fact that judges are human beings and have their own opinions, viewpoints, and pre-conceived notions. At a contest, judges are asked to exercise their opinions, and that is exactly what they do. As pilots we all accept that fact when we pay our entrance fee.


  • As a general fact of history, some judges are more neutral than others. While I am in no way trying to be controversial, it is no secret that historically some judges have brought pre-conceived notions to the circle with them. It is also not a secret that many others are more neutral and are able to disconnect their outside opinions from their judging. Just from my personal observation, I would be willing to assert that very few local level contests are won by total strangers to the area. This might happen on occasion, but it is rare. Although my methods are not scientific, I would be willing to bet that there is data to support the hypothesis that “local flyers generally win local contests, especially when judged by local judges. Put another way, judges score “what they know and who they know” best.


  • Stunt judging in its current form, when done correctly, is very difficult. Not only is stunt judging difficult in terms of being able to recognize mistakes when they are made in tenths of second increments from 100 feet away, it is difficult in the fact that a number must be assigned to the mistake using a completely arbitrary system. Adding to this difficulty is the fact that there is no set deduction scheme for the judge to use to be found in the rulebook. Deduction schemes are found in nearly all judged sports. Some examples are gymnastics, diving, ice skating etc but we do not use them in CLPA. In fact, the stunt portion of the AMA rulebook is really just a series of “suggestions” for judging, not really “rules” for judging.


  • The scoring of the event is subjective, and human beings are prone to error. This is a just a fact. Due to this fact, it would seem that minimizing the subjective elements in judging would be a productive improvement. As discussed before, for some reason, stunt judging has remained virtually unchanged since its very beginning. It is well known fact, for example, that accurately seeing maneuver size from the opposite side of the circle is very, very difficult. It is a pretty well known fact that the addition of a side judge would be a drastic improvement in the ability to see angles defined by the rulebook, but for some reason a side judge has never been used (although it has been proposed several times over the decades).


  • Finding highly qualified judges in large numbers for contests can often be difficult. This is especially true if one is seeking judges that have demonstrated both judging proficiency and neutrality.


  • Stunt contests generally require judges to perform their jobs consistently for long periods of time in difficult conditions. The typical stunt contest format requires a judge to sit out in the sun, wind, heat, rain, etc and judge all of the flyers consistently for hours on end. Some contests have multi day formats, so the abuse can continue for several days.


  • Stunt contests are often decided by a single point or even a fraction of a point no matter how large the scores. Even with expert level scores over 550 in a typical AMA stunt contest, most contests are decided by the slightest margins. For reasons sited above, judges have a tendency to judge very conservatively, so many flyers receive very similar scores. The AMA and FAI scoring systems both, as I see it, basically encourage “middle of the road” scoring because the possibility of ballooning is always a consideration.


  • Stunt contests are often decided by the weather. This is just a fact. I have personally witnessed the weather decide the most prestigious contests. All it takes is a break in a spat of horrific weather for a decent pilot to receive huge scores over pilots who were forced to fly in brutal conditions. In Texas, you want to get a score in the morning before the wind kicks up in the afternoon.


  • The flying order of a contest can often effect the scoring. It is no secret that being first to fly is less than desirable. Typically, the judges are concerned that they will start too high or too low, so they start out scoring very conservatively.


  • Stunt contests require large amounts of scoring tabulation. Someone has to add up all of these scores from all of these flights, and then these scores must be verified and posted. This requires additional manpower and expertise.


  • If the judges need a break, the contest stops.


  • Typically, local stunt contests consist of two official flights and a lot of sitting around waiting to fly. Nearly all local contest formats allow for one flight in the morning and one flight in the afternoon (think of one flight before lunch and one after). This is so common that I have had numerous conversations discussing the fact that pilots must nearly always deal with the fact that one flight of a contest will be in the cool air in the morning and one in the heat of the afternoon. To me, driving for several hours and then sitting out in the sun all day to fly twice does not always seems attractive.


  • Stunt contests are generally not considered much fun to watch. While it could be argued that watching a stunt contest is just completely boring, I think it could also be argued that it is difficult to be engaged as a spectator, and the format of the contest does little to help this situation. Stunt contests are pretty flat… everyone flies and then they announce a winner. That is a about it.


Instead of focusing on what we have been doing historically, let us take a completely different tact. Let us do a little “out of the box thinking”.

Ultimately, the goals of a contest are supposed to be simple. The way I see it, the function of a CL stunt contest is as follows:

    •  Have fun


  • Let every contestant fly as much as practically possible


  • Find the best flier in the bunch


  • Do all of the above using the easiest to manage, most fair, and least subjective manner possible


  • Be fun to watch (this is probably too much to ask, right?)


That is about all that is of a concern to me… everything else is just minutia. If you stop reading right now, I think the point has been made. There is nothing wrong with thinking “outside of the box” when it comes to contest format.

My solution to the issues sited above is the TOC (Tournament of Champions) stunt contest format. This type of contest is based on Phil Cartiers’ “head to head” stunt format. First of all, the format is unlike any other stunt contest flown today, in that it is a “match play” version of what we normally do. In golf terms, the way we organize a stunt contest today would be considered a “stroke play” tournament. The similarities are that everyone flies and the scores are looked at overall to determine the winner. In match play golf, each hole is a separate contest. The only thing that matters in the end is for one contestant to win more holes. The popular Skins Game is a version of match play, and appears to have been invented for television.

Generally, the head to head contest format seeks to pair up flyers that would be required to compete back to back to win individual “matches” to advance to the next round. The TOC format is designed to use a standard double elimination format used in a multitude of sports for tournaments all over the world to determine the order of the matches.

There are many advantages to the “head to head” match style format over the current contest format:

    • Because each match is a totally separate contest of its own, it is not important to have a fixed judging corps judge the entire contest to determine a winner. When it comes to judging a head to head match, the only important thing is to determine at outright winner in each match. The judging corps could literally be different for every single match if needed.


  • Due to the double elimination tournament format, each flyer that enters a head to head tournament would be guaranteed that they get to fly a MINIMUM of two flights. As stated before, the typical stunt contest allows for two flights for everyone in the contest. Using the TOC format, the lowest performing flyer in the contest will get to fly the same number of flights that they would normally be allowed to fly in the current system. The second lowest ranked flyer would fly three matches, and so on and so on, up to the winner.


  • Since matches are flown “back to back” the chances are that both fliers will be flying their match in the same weather. This greatly levels the playing field for the entire tournament,


  • The head to head format makes the flying order of the contest irrelevant.


  • Each match, since it is a contest of its own, would allow for the “pressure players” to thrive. I would propose there would be no re-flies as there are in our current system. I believe that re-fly rules are constantly abused. Do you want a free practice flight at the Nats without penalty? Leave your handle thong hanging. Instant practice flight. The TOC format would change the current AMA rules would be in relation to the definition of an “attempt”. The only “do overs” allowed would be in relation to engine starting. Once the airplane wheels leave the ground, the flight for that match becomes official. Any failures to follow the rules such as losing an airplane part or not wearing your handle thong would no longer be counted as “an attempt” but a loss of the match. If you get a bad engine run, you can either choose to fly anyway or lose the match, it is that simple.


  • Since it is no longer important to be “consistent” over an entire days judging, the current scoring system can be modified. In a head to head contest the only thing that matters is deciding the current match between two flyers. The only important outcome is to determine at outright winner in each match. Due to this fact, the TOC would allow a much more decisive scoring system than the current system. Much of the current scoring system encourages average scoring to eliminate the possibility of ballooning of the scores. Since we do not care about the score ballooning effect any more, we are free to use more extreme measures to be decisive.


In an ideal setting, (4) judges would be used for each match. (3) of the judges would be positioned upwind, and (1) would be positioned to the side.

    • Two of the upwind judges will be judging maneuver shape. The sole job of these two judges is to grade the shape of the maneuver as defined by the rulebook. Is a square a square in shape? Is a triangle triangular, are rounds round, etc. These judges watch the entire maneuver for the correct shape. Position in the hemisphere is irrelevant. Size is irrelevant. Scores are from 1 to 10 for each maneuver. The (2) shape judges’ scores are averaged to make one shape score (in a manpower pinch, (1) shape judge could be used instead of two).


  • The third upwind judge would be responsible for scoring the corner quality, tightness, bobbles, and airplane tracking. The sole responsibility of this judge is to watch the airplane as it flies through the maneuver. Scores are from 1 to 10 for each maneuver.


  • The final judge would be placed 90 degrees to the maneuver. The 90 degree judge would be to stand to the side and grade 45-90 degree aspects of the maneuver, as well as the accuracy of the maneuver bottoms. Scores are from 1 to 10 for each maneuver.


Now we have (3) sets of scores each derived from completely independent variables within the pattern. We have (1) averaged shape score, (1) corner and bobble score, and (1) size, position, and bottom score. To create spread between the flyers it is imperative that the scores be used as multipliers, and not averaged. Using scores that are multiplied is the true secret to creating spread in the finish scores.


  • The beauty of using multipliers is that they can be changed at random. It was the intention to vary the multipliers from round to round of the tournament. For example, we might leave the scores flat for the first round. For example, for the second round we might double the “corner” judges’ multiplier, putting an increased emphasis on corners for that round. For the third round we multiply the “shape” judges’ multiplier by 4, etc. Between rounds numbers could be drawn from a hat to determine multipliers. Each change could be announced before the subsequent round or match. These changes would force fliers to emphasize different aspects of the pattern. This would also reward the flyers truly flying the pattern closest to the rulebook on the whole.


    • One truly important advantage of the TOC judging format is that training judges would be infinitely easier. No longer would a judge be solely responsible to assess every single aspect of a maneuver. Any given judge would only be responsible to watch a specific portion of the maneuver to which he is assigned. For example, I believe that nearly everyone could be taught correct shapes, and could judge whether a round is round, a square is square, etc and assign a 10 point scale to this single attribute. Also, it is certainly easier to assess turns and bobbles if you are free to not watch the shape, etc. Heck, I could train fliers’ wives to judge 5-45-90 with 20 minutes of training. Side judging is very obvious in my opinion (why we do not use it in the current AMA contest format I will never know).


  • Pilots can be recruited for judging. Once a flyer has been eliminated from the contest, he can be recruited to judge for later matches. It is my belief that the best judges of the pattern itself are the pilots. No one spends more time looking at patterns than the pilots.


  • Tabulating could be made easier. Since we are using 10 point scoring, no appearance points (my TOC is a “flying only” event), and no pattern points (no need), scoring becomes much easier. Each judge can add their own scores, and write their scores on a hand held chalkboard and hold it up for everyone to see (no more score sheet runners). In my world, the scores would be entered into an Excel spreadsheet on a laptop PC so that the match formulas could be easily changed. So, the TOC only needs one scorekeeper, one laptop, and no runners.


  • Lastly, dare I say it; I think match flying would be infinitely more interesting to watch. For the first time, the audience would be able to easily understand what is going on in the contest, and the contest excitement would build with each round.


Not to say that the “head to head” format does not have negative issues of its own. One of the issues with this format is that the contest may require more time or more circles to get all of the flights in to complete the contest. The idea is to fly a lot, and there would indeed be a lot of flying with a double elimination format.


Dennis Adamisin ran down the format for a 16 flyer match (Writer’s Note: most people do not know that I secretly want to change my name to Adamisin—this is my blatant butt kissing moment):


“Round 1: 16 flyers, random match, 8 win, 8 lose. Winners fly winners, losers fly losers.


Round 2: 16 flyers, 4 get second win (2-0) 4 get first loss (1-1), 4 get first win (1-1), 4 get second loss (0-2) and are eliminated


Round 3: 12 flyers, 2 get 3rd win (3-0), 2 get first loss (2-1), 4 get second win(2-1), 4 get 2nd loss(1-2) and are eliminated


Round 4: 8 flyers, 1 gets 4th win (4-0), 1 gets first loss (3-1), 3 get 3rd win (3-1), 3 get second loss (2-2) and are eliminated


Round 5: 5 flyers, 1 gets a “bye” (4-0) 2 get 4th win (4-1) 2 get 2nd loss (3-2) and are eliminated


Round 6: 3 flyers, flyer 1 gets another bye (Huh), 1 gets 5th win (5-1) 1 gets 2nd loss (4-2) and eliminated


Round 7: 2 flyers, if 1 wins he wins contest with 5-0 record, loser is 5-2. If he loses his record is 5-1, opponent now 6-1


Round 8: winner takes all; winners record either 6-1 or 7-1.


63 flights for a 16 man contest.”


As we can see, that is double the amount of flights for typical local contest (which would have 32 flights for 16 entrants). So, for a large turnout it is possible that more circles would need to be utilized to finish on time, or that the contest might need to be stretched to all day or multiple days. While the expertise of the judges may not need to be high as the current format to be effective, a CD will need to recruit more judges if more circles are utilized.


In closing, no matter what you think of what was written here, the idea behind this kind of discussion is to get the reader thinking. If you read this and thought “this guy is out to lunch” that is fine (it would certainly not be the first time I heard this sentiment). If the head to head stunt format is too much to swallow, then consider the judging format discussion alone. Many of the ideas outlined here are germane to the current event as it stands today. Much of what has been discussed here has been discussed thousands of times in hushed whispers by countless flyers, judges, and contest organizers. Not to mention that discussions of subjects such as judging methods and contest outcomes were occasionally seen in print years ago, but much less now. It is almost like the subject is off limits in the modern era, and anyone who wishes to discuss it is considered controversial. I think this is counter productive in the extreme.


My ultimate message is that we all need to be thinking about the future and not the past. This means that we need open minds and open discussion. It can be very hard to be open minded, and I am in no way claiming to have it all figured out. In general, we need to be constantly asking ourselves questions: What are we doing here? What are our goals? Is change a bad thing? Is it time to address the issues inherent in our event and start to move forward? Asking these basic questions might lead to some wonderful results down the road. No matter what, as long as people are thinking for themselves, I will be happy.


Pull Testing Stunt Planes and the “5 Whys” http://www.flystunt.com/2014/01/28/pull-testing-stunt-planes-and-the-5-whys/ Tue, 28 Jan 2014 20:17:49 +0000 http://www.flystunt.com/?p=594 For those of you that do not know me, I work as a mechanical engineer, and I have spent the bulk of my post graduate 15 year engineering career in manufacturing and assembly. Most of these years were spent in an automotive manufacturing and assembly setting. I am currently working in aerospace assembly and manufacturing. Much of my personal thinking is rooted in manufacturing methodology including Six Sigma and Lean Manufacturing. Basically, this means that I believe that the “real” solution to any difficult problem is to find the real “root cause”.

One of my favorite techniques that can be used to dissect complex problems or find real customer requirements is a technique called the “5 Whys”. Here is a short explanation of the “5 Why’s” from Wikipedia:

The 5 Whys is a question-asking method used to explore the cause/effect relationships underlying a particular problem. Ultimately, the goal of applying the 5 Whys method is to determine a root cause of a defect or problem.

The following example demonstrates the basic process:

* My car will not start. (the problem)

1. Why? – The battery is dead. (first why)

2. Why? – The alternator is not functioning. (second why)

3. Why? – The alternator belt has broken. (third why)

4. Why? – The alternator belt was well beyond its useful service life and has never been replaced. (fourth why)

5. Why? – I have not been maintaining my car according to the recommended service schedule. (fifth why, root cause)

The questioning for this example could be taken further to a sixth, seventh, or even greater level. This would be legitimate, as the “five” in 5 Whys is not gospel; rather, it is postulated that five iterations of asking why is generally sufficient to get to a root cause. The real key is to encourage the troubleshooter to avoid assumptions and logic traps and instead to trace the chain of causality in direct increments from the effect through any layers of abstraction to a root cause that still has some connection to the original problem.

The technique was originally developed by Sakichi Toyoda and was later used within Toyota Motor Corporation during the evolution of their manufacturing methodologies. It is a critical component of problem solving training delivered as part of the induction into the Toyota Production System. The architect of the Toyota Production System, Taiichi Ohno, described the “5 Whys” method as “… the basis of Toyota’s scientific approach … by repeating why five times, the nature of the problem as well as its solution becomes clear.”

After years of being faced with complex problems, processes, and designs, my brain is literally hard wired to use the “5 Whys” to examine just about anything. (Writer’s Note: Keep in mind that saying “why?” “why?” “why?” over and over can get you slapped in my face if you are talking to your wife about “why” you need to do the dishes, but I still do it on occasion). Many times this simple exercise can be quite illuminating. It is very typical that if this exercise is applied to common tasks, much of what we do every single really makes no sense or has no explanation as to “why” we do it all. Much of what we do every day is only done because “we have always done it that way”.

As a logic exercise, I would like to apply this technique to the idea of pull testing. If I were having a discussion about pull testing with a fellow stunt flier you might hear something like this:

We need pull testing for stunt planes.”

1. Why? – The controls need to be tested to be safe

2. Why? – So the plane will not fly away and hit a spectator

3. Why? – So we do not get sued

4. Why? – Because people suing due to fly away stunt planes is a real problem.

5. Why? – Airplane control failure was a common problem before we instituted pull testing, and pull testing fixed the problem.

Nearly always, this discussion seems to go exactly the same way. The gist of the argument is that we need to pull test because we want to be “safe” so we do not “get sued” leading to a “great financial calamity” resulting in the “end our hobby/club/flying site as we know it” (which is an interestingly the inevitable conclusion to many discussions in stunt). Keep in mind the above responses would be perfectly reasonable if #4 and #5 were true in the slightest (which are not). This would be a good analysis of presumed safety requirements if you could compare pull testing, to say, seatbelts in cars. One could easily show that there was ample evidence that people were dying in car accidents in large numbers before seat belts. It was obvious that steps needed to be taken to improve the mortality rate of automobile drivers and passengers. Even if seat belts made no difference the issue was so prevalent that something needed to be tried to improve automobile passenger’s odds of surviving a car crash.

I am in no way saying that safety checks are not needed for model airplane flying. They are needed. REASONABLE AND LOGICAL safety checks and safety measures are always needed. We all need to be safe every single day, in every single way we can, when we are flying our model airplanes. For example, I think there is plenty of evidence to show that mandatory electric engine starters and remote needle valves for gas engines would be effective (although unpopular) safety measures because we DO HAVE a problem with people sticking their fingers in propellers on an ongoing basis. In fact, this happens all the time, and safety articles are constantly written about this safety issue (see the previous issue of CLW). Many times these incidents with propellers have catastrophic results including permanent injury and expense, so it would make perfect sense if someone were to make a rule to reduce the ongoing problem (see seat belts above).

However, I do not think there is any real evidence to show that testing control line model aircraft controls to nearly catastrophic levels on an ongoing basis solves anything.

As a result of this assertion, I am here to ask these questions:

  1. What does a pull test accomplish?

  2. What ongoing safety problem does a pull test remedy?

  3. Have we ever had an in flight control failure/causing injury safety problem?

  4. What was safety record for in flight control failures BEFORE pull testing?

  5. Are other types of model aircraft outside of control line subjecting their control systems to near catastrophic load testing before flight?

  6. Have these pull tests CREATED failures and safety issues where none would have existed before?

#1- What does a pull test accomplish? From what I understand (and I admit total knowledge of this subject is sketchy at best among the control line community) pull tests seek to test the control system of an airplane at loads that approach loads that are equal to “fly away-catch” levels. In other words, the pull test seeks to simulate loads that would be achieved at the handle if the airplane were to fly away in high winds and then be caught in an attempt to recover. This would result in a very high instantaneous force load. While this explanation is reaching, there really is no other explanation to the force loads required by the current AMA and FAI pull tests. They certainly do not reflect anything approaching flight loads.

The pull test requirement of 10G force load adopted by the FAI (to be adopted by the AMA in 2009) certainly does not reflect in-flight loads. For example, it would take a flight speed in the range of 100 MPH to achieve 10G’s of line tension for an average weight .60 sized stunt plane. That would equate to a 4 lbs stunt plane flying on 70’ lines flying right at a 3 second lap time to reach 10G’s. Uh…yah. That happens a lot.

2008 Pull Test and Line Size Requirements

2009 Pull Test and Line Size Requirements

For another logic experiment, I will examine my own pull test requirements and what they mean to the loads on the pilot. I personally fly .60-.76 sized engines for the most part. For the 2008 pull test requirement this equates to a pull test force of 45 lbs. Now I ask you…how many people at your last contest could even LIFT 45 lbs with their flying arm? If I brought a 45 lbs barbell to the next contest, how many people would you suppose could do one single pull up rep, much less pick it up and hold it for any time at all (7 minutes)? What do you think that number would be? 10%? 20%? If I were to throw a 45 lbs barbell up in the air, how many people could you catch it in one hand as in the case of the “fly away-catch”? Do you suppose if you had a “fly away-catch” you would be able to keep hold of the handle?

#2- What ongoing safety problem does a pull test remedy? This is a big one. As in the example of the propeller injuries mentioned before, what ongoing safety problem are we fixing? Are stunt plane “fly aways” an ongoing problem like propeller injuries? I would guess that I have seen a dozen or more serious propeller injuries in the 20 years I have been doing this hobby. There seems to be one a year in my region. Personally, my hands are full of scars. Also, I can honestly say I have NEVER seen a stunt plane “fly away” that has lead to an injury. In fact, I only know of one instance where the airplane even attempted to fly away and that was when Doug Moon let go of the handle when he hit a bird with the lines when flying his Saito 56 Furias in practice. The handle caught on the handle safety thong and went straight into the asphalt.

#3- Have we ever had an in flight control failure leading to personal injury safety problem? While some people might argue that we do not have a safety problem BECAUSE we pull test. In response to that I would simply ask what percentage of all stunt flying is done without pull testing? 95% to 99%? The truth is that for every hour of practice and sport flying we have a micro fraction of that hour of competition flying. Many competitors practice hundreds of flights for every flight they perform in competition. Again, all of this practice is done without any real safety issues to speak of. This in-flight control failure that these pull tests seek to prevent have certainly never been an ongoing safety issue outside of competition. In fact, it is nearly unheard of. In other words, we have no pull tests for practice and sport flying, yet we have no rash of safety issues for sport and practice flying. Hmmmmm…interesting.

#4- What was safety record for in flight control failures BEFORE pull testing? Does the common guy even know the answer to this question? I am not sure there are a lot of people that could tell you when we started pull testing control systems and why we did it. I guess that “fly aways” could be considered a very serious problem for a mono line speed planes (although these events require nets around the circle), and maybe there was a trickle over to stunt, which has no real safety threat.

#5- Are other types of model aircraft outside of control line subjecting their control systems to near catastrophic load testing before flight? Now, this one makes me chuckle (I hope you think it is funny too). If I were to go to the local RC field and walk up to the local RC model aircraft competitor and proceed to tell him that I was going to require that all of his control servos be load tested to 5X or 10X in-flight loads every time they flew a flight they would hit me in the mouth. Seriously!!! No one outside of control line is required to load test the controls of their aircraft. In fact, I think you would find that the entire concept would be considered ridiculous in the rest of the modeling world. Can you imagine walking up to a RC helicopter aerobatics pilot at a contest holding a big torque wrench and cranking a big test load into the rotor system? I can tell you if you do that, you might want to run! Fast!

In fact, RC Pattern Aerobatics competitors are simply required to sign a safety declaration to compete. From the AMA Rulebook for RC Aerobatics: Safety Declaration: At all sanctioned contests, each contestant shall sign an AMA Flight Safety Declaration (perhaps as part of an entry form), attesting to the fact that he/she has previously and is now capable of confidently performing the maneuvers comprising his competitive event. Furthermore, the contestant shall also similarly declare that any and all aircraft he/she uses in said competition have been test flown at least to the extent that they have performed the same competitive maneuvers and are therefore qualified to be flown in the contest and in the presence of fellow contestants, contest officials, and all others who may be in the flight area during the competition period.”

#6- Have these pull tests CREATED failures and safety issues where none would have existed before? I am going to answer this one for myself. The answer is “Yes”. In my relatively short career I remember (at least) three planes that failed in flight shortly after experiencing pull test problems (including issues with the pull test equipment itself). So, in these cases the pull test caused the in-flight failure where none existed before. Many times pull tests can create internal control failures or issues that escape the pilot’s attention until they actually try to fly the plane and the plane crashes. I also have to wonder how many planes that exploded in air failed due to stress encountered during the pull test.

Lastly, I do know that pull tests have served to damage a lot of perfectly safe model aircraft. I am pretty sure I know of at least half a dozen model planes ruined or severely damaged by a pull test in my district recent years. I admit I have never had a failure at a pull test, lest you think I have an axe to grind, so these are not my planes.

Maybe the next time someone tells you that you need to pull test 10G’s on your hand built, hand finished, one of a kind model plane that you have 100 hours of sweat and blood into building, with another 20 hours of trimming (not to mention a hefty pile of pocket change) maybe you should stop and ask this question:

Why”? Maybe even ask it 5 times, even if to yourself… Some other questions you might ask are: What would happen if we cut the pull test requirement in half? To a third? Anything? What if we eliminated these pull tests and changed to a waiver or a visual inspection like our RC brethren? What risk would we be taking? Are the testing requirements that we use today based on anything logical? Are we causing more problems than we are fixing?

As my friend Bill Wilson says, “It seems stupid to test a $5 set of lines with a $10,000 airplane”. So, Bill you owe me one…