Full Scale Acro guys want help!

[CaptRKO]

Hey guys!

I am a full scale aerobatic competition pilot who started out on R/C several years ago, anyway a friend of mine, Mr Bob Stark flies an Giles 202 and is interested in moving the stab to help in Snaps, he is working with another friend who bought the design rights to the G-202. I said I would try to solict help here on the R/C boards and see if anyone can help.....


Bob is from the South Florida area, and if anyone can help I am sure he would be more than HAPPY to provide a ride of your lifetime in the G-202. If anyone can help please contact him at his e-mail of Imacro@earthlink.net

Many thanks in advance!
Randy Ott
Extra 300S N9K



His idea or "problem" is as follows.......

I have been studying the position of the horizontal stab and elevator on the G202 and that of other aircraft such as the Cap, Extra and Sukoi. The one thing that is clear is that they all have the stab lower than the 202. I looked at a bunch of web sites for 202 models and all of them seem to have the stab lower as well. Do you know of anyone who would have experience with modifying the position of the stab on the 202 or other aerobatic models? Would you know anyone who would be interested in a joint project to investigate the effect of such modifications?

I am thinking that my plane could benefit for the above proposed modification, but considering the magnitude of the modification, I am thinking it might be helpful to do it on a model first. The objective is to improve the snaps.

Bob Stark

[steve wenban]

I have to ask the question Why would lowering the centre line of the stab improve snaps ? I would have thought to maybe shorten the tail moment to improve snap roll capability or perhaps slighty aft CG would have that effect. Would lowering it place more pressure on the control surface by presenting more of that surface to the thrust line?. Anyway I'll pass your request around the modellers of the great southern land and see if we can give you a result . Cheers

[cary c.]

hey randy

on a side note. i am a student pilot in athens GA. do you guys do any kind of unusuall additude training? i would really like to get in some spin training after i get my lincence.

Cary C.

[CaptRKO]

Thanks for the help so far!

As far as the stab location, I am happy with the way Walter Extra designed the 300S, so I am not sure what my 202 friends are trying to do.

As far as spin and upset trng, I HIGHLY recommend it. I have a friend here in Orlando that does this type of trng in a Exrta 300L (two seats) His website is KiethAviation.com

Or do a search for Kieth Lickteig Extra 300L.

Randy Ott
Extra 300S N9K
100% Scale!

[steve wenban]

Hi Ive asked a few Of the aeronautical engineers here at work about this as well and cant seem to see what value it would have but having said that nothing ventured nothing gained .Somesay reducing the vertical fin area but a slight increase in rudder size would have the desired results by reducing directional stability .Take any De Havilland aircraft such as the Chipmunk and you can see that they have always designed with small tail areas compared to wing area .And the chipmunk snaps pretty quick
but they also had to install anti snip strakes to so them locking into the spins. Anyway enough theory I'll keep investigating
Cheers.

[cptcliffhanger]

you say you want to improve snaps... I think I need more information about what you feel is wrong with your snaps.. Do they not start quickly enogh, not stop quickly enough? is the rate to slow/fast.. What control inputs are you using?? have you tried modifying your technique before you modify you plane??

I don't think you would notice much difference in snapping after moving your stab.. You are more likely to notice a difference after adding stall strips to your wingtips, adding more travel to your rudder, and of course moving the CG aft, all of wich are much easier than re-locating your horizontal.

Stephan

[RiBell]

I would gladly build a 30-40% size, and experiment with it to see what happens, if I had the skill and resources (both building and flying).
I would think that the model would need to be at least that big to be able to get a good evaluation.I have seen a couple of large models built with an adjustable stab position. (pic's in magazines) It's a lot eaisier to do it to a model that a full size airplane that's for sure.
I would think that you could put the stab on a couple of screw-jacks so that it would only be a couple of turns back and forth to see changes.

This is what I think might happen:

If the stab is lower the elevator would remain more effective through the manouver. Possibly; the elevator is becoming blanked off as the aircraft is rolling and picks up too much of it's own turbulence from the wing during the snap. When looking at the Extra, as it has been changing wing and tail positions, along with more and more HP the A/C designers must be making these changes for a reason.
Anyway that's my $0.02 worth.
best wishes on the experimenting.
Rick

[CaptRKO]

Please give Mr Bob Stark an E-mail at Imacro@earthlink.net

Bob is on the USA Advanced Team, he DOES NOT have "problems" doing snaps, he is just trying to improve the 202 Aircraft into something better

I am sure he is interested in doing a 1/3 scale prototype I will ask Chris (the new owner of the Giles 202 and G-300 kit line) if he wants to include his e-mail.

Once again THANKS for all the help!

Randy Ott
Extra 300S N9K

[watnsee]

try rounding the wing tips, and stab tips. Ibuilt a profile fun fly and played with this. The one that snaped the best had P 40 style tips on, it would snap,shoulder roll,and met its death in an inverted spin!!! it was awsome.