Good morning boys and girls,
I don't often post or comment about anything on the forums anymore but the thread about Brad Walker's T-Rex certainly caught my attention. I'll say right up front that I know Brad and honestly we aren't best of friends. That does not however detract from my respect for his dedication to doing it better and taking the time to post and write about his efforts. 
Are there any "new" designs? Certainly from an apperance and paint scheme standpoint there have been several over the years. Remember the "Jet age" of design? Are these new? The laws of physics and aerodynamics are set in stone and have been for centuries but our understanding of these principals has greatly increased in the 20th century and is continuing to do so.
Look at the automotive industry. Up to the 1990's even an old duffer like me could spot a Ford, Chevy etc from a block away. Today when driving down the street, I can't tell a Lexus from a Galaxie. Why? because the demands of performance and fuel efficiency are dictating the design and they are all very similar.
I design my own planes and prefer to fly these in contest but I have never had the capacity or the the time to pursue being a NATs calibur pilot. The only reason that anyones even knows I exist is because of my writing for magazines for the past 8-9 years. I am currently flying the Shady Lady in Classic and PA. I designed this plane in my early 20's and it darn sure isn't "original". I took the average measurments from planes that at the time were in the hunt for top honors at the NATs. Palmer's Smoothie, Hurricane. Les McDonalds Shark 35, Ed Southwick's Skylark and of course George's Nobler.
Here is what I stole. The wing is the Shark 35 with the tips turned around. The "numbers" are an average of all the above planes moments and just FYI, if you go measure your's, you will find there is no more than a 1/4" difference in all of the above. That average by the way is 14 5/8ths between hinge lines. The Lady's profile was just drawn on a piece freezer paper but the side area numbers are from the Nobler. Now that begs the question. Did I design the Lady? Is it a NATs "contest proven" winner? No. I did however manage to win Classic and PA Intermediate with the Lady at the Brodak contest and another of my designs had the highest single flight score in Profile 40.
Point of this rambling is that there are some very good designers, inovators and builders out there that no one has ever heard of on the national scene. The top 20 guys at the NATs design, build and are certainly pushing the envelope. I have seen the T-Rex fly and Brad is a proficient pilot. If I flew large planes I would be first in line to purchace a kit.
Have a good one. Later, John
I don't think stunt design has gone as far as it can go. Combining "numbers" of existing airplanes will only get you so far, and will only result in a winner if you fiddle with the airplane extensively to get the details right. This also requires knowing which way to go with the fiddling. My own attempts at it have shown that, for example, a tenth of an inch of flap chord can render a winning airplane borderline untrimmable.
I would look for improvements in:
1. sensitivity to maneuver placement relative to wind direction
2. sensitivity to turbulence in roll
3. sensitivity to turbulence in pitch
4. airplane optimization for electric power.
5. trim sensitivity with weather conditions
6. compatibility with air transportation to contests
1, 2: Combat models have evolved significantly in maneuver placement sensitivity in the last 30 years. The rectangular dog that won combat at the 1970 Nats was OK flying downwind against others of its kind, but it couldn't handle anything upwind in more than a slight breeze. Gary James, Henry Nelson, and--most successfully-- the Eastern Europeans came up with planforms that had a lot less negative (if I got the sign right) rolling moment due to sideslip, and these now prevail. The guy who flew the rectangular airplane in 1970 was able to win matches in the 1984 and 1990 world champs by leading his opponent upwind, where he by then had the advantage. Stunt planes don't suffer so much from wind direction because the flier gets to pick where he does his maneuvers. It would be nice if one’s airplane cooperated when he places his maneuvers in front of the judges after a wind shift. Forward sweep can help with number 1 above, and taper can help with both numbers 1 and 2, but either is hard to change without sweeping the flap hinge line forward, which seems to do bad things. Rather than change the airplane’s aerodynamic yaw response, why not let the airplane yaw to reduce sideslip? Hint for designers: why does the leadout moment arm need to be the same in yaw and roll?
3: For a given airplane turn radius, you want to minimize the response of turn radius to turbulence. I’d look for airfoil improvement, including flaps. The higher the max lift coefficient the better, and the lower the lift curve slope the better. Hints for designers: how do the Beringers’ flaps work? How can you get the Tu-144 canard’s lift curve slope in a symmetrical airplane?
4: Now that we allow electrics to compete, internal combustion engines are obsolete. You can electrify a Nobler or a Max II and have a pretty good stunt plane, but how are airplanes compromised for engines that they need not be for electrics? Beats me, but I’m impressed by Dennis Adamisin’s airplane and by stuff going on in my neighborhood.
5: Trimming is one of the things that stunt winners really know how to do. The ability of the top dogs to know when your leadout position is an eighth of an inch off or your tip weight is a gram off is just amazing to me. If you are designing an airplane to be trimmed by a duffer like me, it would be cool if you could make it insensitive to trim or to conditions that could require trim changes. How does the Yatsenko Shark get away without adjustable leadouts?
6: This isn’t a big deal for most of us, but for guys who make the US team or a guy whose wife has a lot of frequent-flier points, it is. Airlines are much more restrictive now than in the past. Now it is difficult to get away with a take-apart airplane with a one-piece wing. The Eastern Europeans have been putting their stunters into small boxes for years. Now Uncle Jimby wants an airplane he can carry on. There’s a design problem for you. Hush, Larry R.
I am particularly interested in the first four above. I think those are the ones that will help my score. Design away. However, before I commit to hundreds of hours of work, hundreds of dollars worth of paint, and thousands of dollars of contest travel costs, I think I’ll pick a design by somebody who has proven to me that he knows what he’s doing and try to suppress my urge to add originality.
Topic: Designs, "new" planes etc. (Read 14174 times)
