Nice question.  Here are things I consider when choosing a scale subject.

There has to be some personal appeal/interest in the aircraft.  This is really an intangible thing that I cannot really explain.  Either the airplane appeals to me or it does not.  To do a really good job for a really good scale presentation, I really want to do this thing.

Generally, most models on my list are not often seen as a scale subject.  This rules out most kits.  (Besides, I do not generally like to build from kits because of wood selection, construction differences I prefer, control installation, engine/tank mounting arrangements and on and on.)  Another problem with scale kits, is that some (most) have compromised some scale fidelity in the design.  If I deviate from scale on my model, I will do it for my reasons, not for the ideas of somebody else.  Another problem with kits is to find documentation that really matches what that kit represents, particularly if the kit does not have dimensions like span and length that are to the same scale, canopy shape and a whole host of other items where kits make some compromise from scale.  (That may be OK for Sport and Fun scale, but not so good for Precision scale.)

Documentation.  It helps to have some ready source of good 3-view drawings.  This does not necessarily eliminate some obscure but otherwise "interesting" aircraft.  With the internet, it is amazing how much material can be obtained (photographs, 3-views, books, color schemes, other material) in a short time.  I have a list of several dozen airplanes that interest me for various scale projects including some for Profile scale, others for Sport scale, others only for Precision scale, some for the Carrier events, others for the 1/2A scale events that are showing up around the country, and others for semi scale stunt ships.  I will pick up 3-views, books, photos, color reference, plastic kits, and decal sheets (which are great for color references).  Bob's Aircraft Documentation is a great source of 3-views for aircraft that otherwise difficult to find.  Persistence is key to this process of getting documentation and is part of the challenge of putting some obscure airplane together.  (For instance, more than 30 years ago, I started collecting information on a one-of-a-kind aircraft built in England in 1944.  I have found 16 different 3 views and have filled a file drawer of articles, photographs - many unpublished - and correspondence on this one aircraft.)  Part of my interest in scale is to gather information and build models that are not often seen.

Needles to say, I will never finish my bucket list. 

Keith

 

Before I start a model for CL scale competition it must have these items before I even build

1) a good 3-view that matches the plans or kit. Build to that 3-view so your model matches it when it's presented to the scale judges, don't pick your 3-view after you are done building the model.

2) Documentation with color chip information, color and markings, and enough photographs to prove everything. Build to the documention, this way the model matches the documentation and you can get maximum points.

3) Ability to perform 6 options. Single engine, throttle only models can only do the following, getting the 6th option can be stretch sometimes. I don't like doing the over shoot or other flight options. If you remember Taxi use to be worth 2 options, now it's only 1 option. Also retracts and touch and go are worth 2 options. Adding flaps to a model adds the 6th option, or you can use multi-engine for the 6th option. I always plan out the options before the model gets built. Some options are less subjective than others.

5 options a single engine model can easily perform....what will be your 6th option?

   a) throttle control
   b) Taxi
   c) Touch
   d) Go
   e) 45 degree high flight
   f) ??
 
Land softly,
Fred Cronenwett

All of above plus:

Do not build anything that can be confused with an RC ARF.

Or else just buy the RC ARF and put a bellcrank in it.  Everybody will think you did anyway.

Isn't landing considered an option for points?   Yes, I know if you  take off you have to land at some time or another, depending on how well the engine runs and the amount of fuel.

The landing is scored along with the takeoff and level flight elements as part of the overall flight score.  It is not a separate option.

All of the above plus consider ground handling and what might happen in the wind. For me this rules out narrow gear. Will often tip up on the inboard wingtip when taxiing. Many tricycle gear setups, if done to scale, will have the model sitting at too high an angle of attack (F7F, P-38) to get smooth takeoffs and landings. On takeoff the model will jump into the air or "wheelbarrow." Carefully consider the urge to build in more mechanical options than you need; they may be fun and cool, but add weight.
Chuck

When I fly my 41" span profile F7F Tigercat landings are tricky because you have to slow down for landing, put enough up elevator to get nose high landings on the mains without hitting the tail of the model, then once the mains touch then throttle back to idle and apply full down elevator. The whole time you are landing you are making slight changes to the throttles to get just the right rate of desent. Takes Pratice and I guess I have landed that model so many times I don't think about that much any more. The A-20 Havoc I flew for several years also required the same technique.

Narrow gear like WW-I models can be really hard to handle on the ground!

Fred

Dad's and my latest sleds.

One can choose models that are very close to the real thing in outline and select schemes that make the models look realistic. P-51's are the worst in this respect, not one is manufactured without gross shape, cross section and dimensional distortions. Kits and ARF's! The best P-51 model I've seen is Jerry Worth's 1965 Top Flite kit. Burt's must have been really something to look good!
  
Chris...

I'm thinking about a Wayne Handley Raven for that, not an ARF though. I have a pretty well shaped kit with vinyl markings I could use as templates for painting the markings.
Chris...

Brilliant!  Few would try something that size.  I've seen the flight videos.  Very entertaining.  Congratulations on a superb effort!!!

All of what I've built, as Scale models, were for R/C.

Some I still have and some I don't.

Of the ones I still have, all of them can be converted to CL. Easier with some and a bit more effort will be required with others. Some aren't completed and a couple are torn down for a redo.

It's probably obvious by this list, where my interest lies and why I chose these subjects to model.

Here's what I still have left.

Gee Bee E
Wendell Williams racer
Gee Bee Z
Sikorsky S-39
Grumman F3F-1
Ryan P-22 STA
Grumman Widgeon
Waco YMF-3
Stearman PT-17

This Gee Bee Z will be the first R/C model I convert and finish for CL. I hope to start work on it again in the spring!

Charles

According to this web site - http://www.ae.illinois.edu/m-selig/ads/aircraft.html - the Ryan PT-22 used a NACA 2412 airfoil.  It's a semi-symmetrical airfoil.  One of the best.  It's been used on many models, CL and RC - the Berkeley Astro-Hog is one.

Mike

According to this web site - http://www.ae.illinois.edu/m-selig/ads/aircraft.html - the Ryan PT-22 used a NACA 2412 airfoil.  It's a semi-symmetrical airfoil.  One of the best.  It's been used on many models, CL and RC - the Berkeley Astro-Hog is one.

Mike

I think Maxey used it on the P-63 too, Mike.
Chris...

My airfoil preference is the NACA 23xx series. Performance specs are essentially identical to the 24xx series but with the 23xx the high point of the upper camber, and the low point of the lower camber are both at 30% of chord. I find this ideal for building a "D" tube wing with the spars at 30%. On the 24XX series the high and low point locations differ by 5% of chord.
Chuck

I have been fascinated by the Wagner-Hirth Acrostar as a possible scale subject for a while. Short nose may be a problem and the forward location of the U/C might make smooth take off and landings an issue but it has a nice thick (20%) fully symmetrical wing section and interestingly the flaps moved in opposition to the elevators like an F2B ship. My building skills will probably mean it will never happen but I think it would be an interesting choice which might be capable of limited aerobatic options if build light enough.

Info here.
http://translate.google.co.uk/translate?hl=en&sl=ru&u=http://www.airwar.ru/enc/la/hi27.html&prev=/search%3Fq%3Dhttp://www.airwar.ru/enc/la/hi27.html%26hl%3Den%26safe%3Doff%26tbo%3Dd&sa=X&ei=oUbeUNTQAdKa1AXp9oB4&ved=0CDkQ7gEwAA



TTFN
John.