What are "combat flaps"

[niklas]

Hi

I read sometimes the P51 and F4U had combat flaps.
I know from some reports the plain, slotted, split, zap and fowler flap. But i never read something about "combat flaps".

What are they, how did they work and how much lift/drag  did they add to the wing?

niklas

[funked]

Flaps on most WW2 fighters are intended only for landing (and sometimes takeoff).  These activities take place at low speed, so the flaps and their actuation system are designed for low speed flight where dynamic pressures and resulting stresses are low.  "Combat Flaps" just means that the flaps and their actuation system are stressed for deployment at combat speeds.

[niklas]

thx

so combat flaps are usual flaps that can be lowered at higher speed?

I only ask because sometimes I have the impression that people think their combat flaps should make them able to turn into everything (especially in a stall fight), or give them a lot of lift without more drag.

[funked]

It depends on the design of the flaps.  The only planes I know of that had the flaps specially designed to give more lift without too much drag were the P-38, N1K2, and Ki-84.

[RAM]

 

Originally posted by funked:
It depends on the design of the flaps.  The only planes I know of that had the flaps specially designed to give more lift without too much drag were the P-38, N1K2, and Ki-84.

And Oscar, Funked. It had the same kind of flaps as the N1K2, and the Ki84 (they called them butterfly flaps isnt it?)

[Vermillion]

Yep RAM, they were called "ButterFly" flaps.

And on the N1K2 at least, were automated to deploy at certain speeds by a mechanical system.

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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"

[niklas]

I made a little test. I hit autospeed 160 and let the planes glide (engine out). When sink rate was constant i lowered the flaps one notch.

The result:
P51, F4U, P38, LA5 : sinkrate stays constant
NIK: ~ -100 ft/min more sinkrate
190, 109 : ~ -250 ft/min more
Typhoon : ~ -400 ft/min more

So, when the american and russian fighters have with "flaps one notch down" same sinkrate compared to "no flaps", doesn´t that mean that they all have flaps that can give them in this position a increase in max. lift without more drag?

[MiG Eater]

Straight from their respective flight manual/handbooks and warbird pilot Steve Hinton:

The P-51, F4U and F6F had combat flap settings of somewhere between 10-20 degrees. The -51 and the F4U were manually set by the pilot. The Hellcat's flaps moved automatically with the actual backwards extension and downward deflection being dependant on the airspeed.  

MiG

[Dune]

Normally when a P-51D pilot drops flaps in combat, you're talking about 10deg of flaps.  Or so says Bud Anderson and Bob Goebel.  

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Lt Col Dune
X.O. 352nd Fighter Group
"The Blue Nosed Bastards of Bodney"

"Credo quia absurdum est." (I believe it because it is unreasonable)
- The motto of the Republic of Baja Arizona

[Manx]

Hey funky, why are you not listing Tojo's butterflies? Or is your contention that it causes too much drag?

[funked]

Ruh Roh I forgot about my little buddy the Ki-44.  P.S. Pyro said the Frank will have auto-flaps.