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Hello to everyone and thanks in advance for your supoort! I am planning to build a new balsa trainer based on the Great Planes Perfect Trainer 40. The idea is to create a versatile Trainer. I he heard that Clark-Y (Default airfoil with the trainer) is easy to build but missing some features of more advanced airfoild like NACA2412. I do not have any probles for building with another profile but I would like to know your comments or suggestion to changing the airfoil. Am I losing or wining something with either of them? AoA will be the recommended one in the original design +2-+3 dregrees.
The idea is to provide more felxibility to that trainer.
All your comments and suggestions will be welcomed.
Thanks!
Dino

speedracerntrixie

My Feedback: (29)

Depends on what your end goal is. With the semi symmetrical airfoil you will gain some speed. With the incidence you mention you will still maintain a fair amount of positive stability meaning the airplane will pitch trim at a narrow speed range. If that is what you want then great. If not, set the wing to zero as it will still generate enough lift to support the models weight but be more “ trim constant “ which would get even better with a CG at 30% to 33% and a couple degrees of down thrust.

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Thank you so much for your comments and suggestions! Very much appreciated!

Propworn

My Feedback: (3)

Many, many years ago I learned on a Telamaster. It used a Clark Y for the wing and a lifting tail with a flat bottom. When I designed my own, I used the same plan form but reduced the dihedral to 1.5 inches each wing tip. With the high wing and a little dihedral it was perfect self righting and pitch recovery. I reduced the incidence to half and the tail plane was zero and the speed range opened up quite a bit. If I flew it 3/4 throttle straight and trimmed it level, I found it perfect for my flying. It would easily do most beginner to intermediate aerobatics in a very scale like shape. I really liked the sheeted wing from the leading edge to the spar top and bottom as it added lots of strength. I scaled it up to 100 inch span and increased the rudder to twice the size, and it made a great glider tug. I promptly increased the rudder in the smaller one and I could carry up to 2 meter sailplanes on a cradle on the top wing. I even have an old Telecaster 66 that I converted to electric, and it has unlimited vertical because I used a motor I had lying around and didn't think it would be that overpowered.

Later I switched to a Lazy Ace, which if you really look at it, you might just see what could be a Telemaster as a biplane. It, too, has both Clark Y's for the main wings and a lifting tail. It's even more fun than the Telemaster and there are quite a few members in my club who's introductory flight was on that Lazy Ace.