How much extra lift can I expect installing gourney flap?
How much extra lift can I expect installing gourney flap?
(OP)
I have a pre-designed airfoil. It is designed to make 50lbs of lift at 100 mph at 7deg at sea level. It is not a high camber wing. It measures roughly 22 wide with 17" chord 5% camber and 125 chord thickness. I want to install a gourney flap and am wondering how much extra lift I can expect with what size of gourney flap?





RE: How much extra lift can I expect installing gourney flap?
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: How much extra lift can I expect installing gourney flap?
It may help you about Gourney flap performance...
http://ww
Cheers.
RE: How much extra lift can I expect installing gourney flap?
RE: How much extra lift can I expect installing gourney flap?
B.E.
The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor
RE: How much extra lift can I expect installing gourney flap?
Are you running endplates on your wing? If not, what you have is a wing with a very poor Aspect Ratio (AR=Span/Chord). Your AR is about 1.3 which means the lift induced drag will be nearly as great as the lift (you reported 28 lbs. to 50 lbs.) You can do much better than that with the same wing. If you have not already done so, you should add end plates to prevent the wing tip vortices from giving away -lift and inducing drag. These end plates should be as tall as legally (according to your rules) and practically possible.
The relationship between AR and Induced drag is: Cdi=Cl*Cl/(pi*AR*e (e is typically.91) So you can see that doubling your AR has the potential to halve your drag. It will also improve your downforce.
Just a thought.
P6
Change in your endplate design has the potential of being far more important than the Gurney lip.
RE: How much extra lift can I expect installing gourney flap?
RE: How much extra lift can I expect installing gourney flap?
RE: How much extra lift can I expect installing gourney flap?
RE: How much extra lift can I expect installing gourney flap?
RE: How much extra lift can I expect installing gourney flap?
the inner endplate is probably working more as a splitter, keeping the airflow around the nose from affecting the wing.
it's great to get the practical feedback, it'd be nice to see something of what's happening ... tufts probably won't work well.
increasing the camber of the airfoil would increase the lift (and probably the drag too if that's important). are you allowed a fixed L/E slat ? (that'd keep the airlow attached at higher pitch angles).
RE: How much extra lift can I expect installing gourney flap?
RE: How much extra lift can I expect installing gourney flap?
RE: How much extra lift can I expect installing gourney flap?