What motor?
What wing, tailplane, fus, undercarriage, construction materials, methods and finish, target weight and line length etc.
Everybody else has already done this project - and everyone came up with a different answer. I can only answer for myself - not mentioning anyone's pet project is not intended as an insult.
I would start by studying the best of the current airplanes, what is both right and wrong with them, and presume that we are at the end stage of engine-powered development.
Engines are a no-brainer, PA75 as David has them set up, or RO-Jett 61 BSE "Brett Version", set up as described a million times. The PA obviously has more power, I think I like the way the Jett responds in the wind (when it is running right - unlike the last two NATs) and is less prone to the "unexpected break" issue. A third choice would be a 40VF, but I think the really thick wing models want more.
Airplanes - for either of these it's worth looking at the Infinity, Trivial Pursuit/Star Gazer, the Impact, the Thundergazer, and both versions of the Diva. While I obviously have had a lot of good success with the Infinity, and have watched a lot of winning flights from the Trivial Pursuit, I think both of them (since they were designed along the same ideas we gleaned at a Thanksgiving dinner in about 1990 between Ted, Keith Trostle, and me) have wings that are excessively thick.
I think what is *right* about them is the relatively low aspect ratio wing and very low aspect ratio tail, which is the key to the way the turn and track. I think the Impact is on the edge of too large for most people's building skills - my successor IC airplane would have been an Infinity, same planform, with an Impact airfoil. That would get me less drag and more dependence and control over the response using the engine setup, with (hopefully) not the super-sensitive trim adjustments like the real Impact. That was also the goal of the Infinity, but I think both Ted and I way overdid it with the wing thickness, using 4-2 break era idea of parasitic drag to hold back the power, not fully appreciating the ability to control the engine, and how repeatable they would be.
The only other approach I would look at is the Diva, and the Skinny Diva. These take the idea of "controlled by the engine/motor" to the ultimate by reducing the parasitic drag to a minimum. In that case, it brings the 40VF back into the mix, as by far the easiest to deal with and would be killer in such a thin-wing airplane, having pinpoint control over the power delivery and dead-nuts predictable. The Trivial Pursuit, Infinity, and Impact were all designed around this engine to start with, and it is *very hard to argue* with a Impact/40VF just based on the record. I have flown all of them with a 40VF, but the Trivial Pursuit and Infinity definitely benefit from the extra power.
A completely untried approach, that a lot of us have talked about (only talked, obviously) is a much smaller design for a 25LA or FP, maybe, 400 square inches version of the Infinity - Infinity Jr. All the above airplanes are big-boy planes that sometimes require big-boy muscles to handle in any sort of a wind. We have numerous examples of cases were we were "out-muscled" in bad conditions, like me at the 2021 NATs (where I had some trim and engine setup problems) and David at the 2021 Golden state when he missed his bias point by maybe 15 feet. I look at the trivial ease at which I could pick up the Skyray 35 and go out and drill 5 feet like a pool table on the very first flight in years, maybe you could do that and solve the few real weaknesses (like poor cornering in certain parts of the pattern). I am not at all concerned about "presentation" or other pseudo-competition ideas, if it works better I figure I would get a better score.
None of this is suggesting that you couldn't get "good enough" using some other design approaches, or other engines, but this is what *I* would do. The only thing I think you should avoid are 60's style gigantic 4-2 break engine designs and approaches. That is a complete dead end as far as I am concerned, something we moved on from long ago.
Brett
Topic: The 'Epitome' Stunt project. (Read 1988 times)