real planes flat wings

[inedesca]

Should we use the same idea of leading and trailing flaps like the f-104 in our flat depron wings, that is: include these flaps built in to increase lift efficiency.

Real fighters deploy these flaps at low speeds to increase lift so if we put these in our wings as fixed, not deployable woudl this help?

thank you for your ideas :confused:

[bwalt822]

I need more info before I can say for sure. But my guess is that if you are building a flat depron wing then whatever you are building is light enough where flaps or leading edge droops wont matter.

[JetPlaneFlyer]

Should we use the same idea of leading and trailing flaps like the f-104 in our flat depron wings, that is: include these flaps built in to increase lift efficiency.

Real fighters deploy these flaps at low speeds to increase lift so if we put these in our wings as fixed, not deployable woudl this help?

thank you for your ideas :confused:

Flaps etc. dont "increase lift efficiency".. Lift efficiency would usually be defined as l/d (lift divided by drag).. What the flaps and leading edge devices do is increase tha cambar (curve) of the wing and therefore increase Clmax.. i.e. they increase the maximum lift that the wing can produce. They also dramatically increase drag; so the wing is usually less efficient with them deployed not more.

If they would be usefull on a model or not depends on what you want the model to do. If the slowest possible flying speed is your goal, and nothing else (top speed, aerobatics, etc) is important then maybe fixed flaps, or better still bend the depron into a slight curve to give the wing camber, may help.

Steve

[HX3D014]

Should we use the same idea of leading and trailing flaps like the f-104 in our flat depron wings, that is: include these flaps built in to increase lift efficiency.

Real fighters deploy these flaps at low speeds to increase lift so if we put these in our wings as fixed, not deployable woudl this help?

thank you for your ideas :confused:
The heading has me a bit confused.

Are you saying
Flat foils on RC plane with LE TE Control Surfaces such as those on Full scale Aircraft of same/similar Design.?

If so. then I would wonder if the weight penalty for the mechanics of such a set up would outweigh the benefit.

Like JPF said.

"You could make a leading edge permanently cambered" Not Verbatim
Jeff;
This may play havoc with your Trim. may need more Nose up when in No TE flap system. Clean. Would a tad of Up flaps be needed now ?

Really dose come down to "why you want to do this?"
and then "how do you want to fly it?"


(here is a bit of a dream addition to a plane with working LE flaps)

hook the LE TE flaps up to a Percentage mix on top of the Elevator. IE Elevator will actuate them <Your choice of modes> (When are where on your stick range will be your choice) Flapevators.

Being a flat wing and carefully rigging the LE flaps. You could work the Range to +6 to -6 (That's UP and Down)

Lots of playing to be done with creating a Working LE Flap system. so the incentive to do so would be "To be able to Experiment and Test and do some other Tricks ;)

To answer the Question. (Fixed non working)

Yes it would help decrease the stall speed if you had a permanent LE bend, but at what cost? (What would it do to your CP and NP) <I am actualy asking what would it do! Any takers ? -I am thinking it will Move your CP forward. Still not got the gist of Neutral points-

Bryce.

[inedesca]

There is no cost, just cut the flaps and glue them in bended position.

You will have to compensate for the CP and NP shift but I think is only of matter of stab trim.

The benefit would be a more efficient airfoil, if you may call it airfoil.

Is like curved flat airfoils, only easier to build.

I am right?

[BMatthews]

If you're a fan of flat slab airfoils then adding these camber changing devices will help. But comparing the use of these on our models to the application on transonic/supersonic fighters is folly. The full sized stuff uses those super thin and sharp airfoils to produce the optimum shockwave patterns to generate minimal drag and avoid pitching moment changes during high speed flight. Last I checked our models were in no danger of forming a sonic boom.... :D

Keep in mind that using leading and trailing edge flaps on our models is a bandaid for laziness in selecting a more suitable airfoil. These movable surfaces alter the camber of the flat plate to help to avoid a high drag stall condition. A good airfoil with a "real" shape will do the same thing by avoiding the massive separation bubble that forms during pitch changes in the first place.

Now if this is intended for a scale model and you're looking to get more out of the really bad performance of the scale airfoil at our model speeds then using drooping leading edges and coupled flaps and ailerons will help. Not as much as a proper airfoil but it's a darn sight better than the scale flat plate style.