Suitable airfoil for....Aerobatic Lazy Bee

[snakeX2]

I am designing an aerobatic version of the Lazy Bee and i need a suitable airfoil to match the model. Here is the origional page to my thread http://www.rcgroups.com/forums/showthread.php?t=407226#post4205167 . If anyone has any ideas for aerofoils of if my chosen foil (NACA 2409) is ok, i'll be finally relieved!

James,

[Ollie]

Don't worry much about the airfoil. The Lazy Bee wing has a low AR which means the airfoil flow (3D) is not like measured (assumed 2D) flow. The Lazy Bee wing plan form has good tip stall margin with any airfoil.
http://aero.stanford.edu/WingCalc.html


Just keep the airfoil mean camber low. If you keep the wing load low the thickness can be thin. If the wing loading is high then the thickness should be higher.

[snakeX2]

Wow are you sure? I mean i am getting quite mixed response about the airfoils but i never really thought that the LazyBee type airfoil will be suitable. What about when i fly inverted? Still thought my NACA 2409 would be suitable?


James,

[Ollie]

NACA 2409 is OK, NACA 1409 is better and NACA0009 best for very low wing loading.

NACA2412 is OK, NACA1412 is better and NACA0012 best for mid wing loading.

NACA 2415 is OK, NACA 1415 is better and NACA 0015 best for high wing loading.

You must look to wing design melding all aspects for the purpose of the plane: airfoil, aspect ratio, angle of attack, lift distribution at stall and speed and between, taper, sweep, etc.

[snakeX2]

You must look to wing design melding all aspects for the purpose of the plane: airfoil, aspect ratio, angle of attack, lift distribution at stall and speed and between, taper, sweep, etc.



Thanks for stating which airfoils will be sutable. I have little idea in how to choose an airfoil and only know what the main types are suitable for. I
Therefore I can only take your advice. You have truly been helpful and i thank you.
I'll have a play around with Profili and get one sorted :) .


James,

[noodle]

Don't get too technical. Just do something around, say, 12-14% thick and "eyeball" the rest.

But, that said, what is Profili and where can I get it? :rolleyes:

noodle

[Ollie]

http://www.profili2.com/
It is about airfoil shape, chord size, speed, drag, lift and pitching moment.

All the rest of the wing design except airfoil:
http://aero.stanford.edu/WingCalc.html
It is about wing aspect ratio, lift distribution, twist, taper, sweep and angle of attack.

Wing design must meld everything above.

[snakeX2]

Ooo, don't get too technical. I'll go around 12% and eyeball the rest as Noodle said. While wing design is everything in your opinion and maybe that Wingcalc backs up your point, but in my case, just a simple airfoil that 'looks' ok will do, :D . Cheers,

ps, would you concider 10 oz Sq. Ft. wing loading to be 'very low' or 'medium' wing loading?
James,

[noodle]

Ollie, thanks for the link to Profili, although I am having trouble installing it. It keeps on telling me "unable to intialize installation." I'll get it eventually. ;)

Snake, I'd say 10 oz. Sq. Ft. is probably on the light side of "medium."

noodle

[snakeX2]

Hi,

Thanks, i guess i'll go with a 11% thickness on the 1412, making that a 1411 i imagine.

Oh, and its probably worth registering the Profili, the free version is great but i imagine the latest version has alot more. I have registered the Profili but have yet to initialise the latest version. Now where did i put that code...



J,