P-38L stall/spin correction? any news on this? dive flaps too

[Citabria]

 http://home.worldonline.dk/~winthrop/p38op7.html

HT was meaning to look into the P-38 FM was curious if there is any word on it.

I was reading the operating manual for the P-38 particularly the stall/spin section and dive flaps section:

 

STALLS

a. With power off., the airplane stalls at the following air speeds and gross weights noted.

                         15,000 lbs 17,000 lbs 19.000 lbs
Flaps and landing gear up 94 mph 100 mph  105 mph
Flaps and landing gear DOWN 69 mph 74 mph  78 mph

b. As stalling speed is approached, the centre section stalls first with noticeable shaking of the airplane, however the ailerons remain effective.

c. In either power ON or power OFF stalls with flaps and landing gear up the airplane rushes straight forward in a well controlled stall. With flaps and landing gear down there appears to be a slight tendency for one wing to drop. There is however no tendency to spin. Under these conditions, the nose drops slightly and as the speed increases, the wing will come up.

d. On airplanes equipped with rocket installation the stall characteristics are the same.

SPINS

a. Spin Characteristics

The spin is fast, but recovery is prompt and easy if the proper technique is used.

b. Recovery

The airplane can be brought out of the spin any time by kicking full rudder against the spin for a minimum of half a turn then easing forward the control column. The procedure is as follows:

1. Close throttles.

2. If flaps are down pull them up.

3. KICK FULL RUDDER AGAINST THE SPIN AS BRISKLY AS POSSIBLE, WAIT AT LEAST HALF A TURN BEFORE ATTEMPTING TO PUSH THE WHEEL FORWARD. Recovery is slower by one turn with flaps down. If the flaps are down or on their way up the rudder should be held against the spin for at least one full turn before pushing the column forward.

4. After half a turn, with rudder full over the control wheel may be eased forward as the rotation stops. Recovery can be accomplished in one-and-a-half turns under any condition except with flaps down when two turns will be required. The airplane will come out of the spin in a vertical dive and recovery from the dive should be made slowly in order to avoid a highspeed stall which may cause a spin in the opposite direction. Any attempt to push the wheel forward before kicking full opposite rudder will immediately increase the speed rotation and the acceleration to which the pilot is subjected. If this is encountered pull the wheel full back and hold full rudder against the spin for a minimum of half a turn. Then push the control column forward.

DIVE RECOVERY FLAPS

The airplane without these flaps becomes very nose heavy and starts to buffet above diagram dive speeds (Dia.2.). The dive recovery flaps which are installed under the wings between the booms and tile ailerons restore the lift to this portion of the wing and thus cause the uncontrollable nose heaviness to occur at a higher speed. The flaps also add some drag to the airplane which in conjunction with the higher allowable dive speed permits safer dives at a much steeper diving angle. The dive recovery flaps should be extended before starting the dive or immediately after the dive is started before a buffeting speed has been reached. If the airplane is buffeting before the dive recovery flaps are extended the buffeting will momentarily increase and then diminish. With these flaps extended, the nose heaviness is definitely reduced but the diving speed should never be allowed to exceed the placard by more than 15 or 20 mph. With the dive recovery flaps extended before entering the dive, angles of dive up to 45 degrees may be safely accomplished. Without dive recovery flaps extended the maximum angle for extending dives is 15 degrees. Diving characteristics are better with power off than power on.

the 1.03 stall model was more in line with the p38 stall but still wasn't great. now with 1.04 our AH p-38 will always torque roll to the right and directly into a spin. the P-38 should have no tendancy to spin in a level stall if both wings are stalled equally. but in AH there is no way to get a full blown stall without spinning.


also dive flaps should induce a 10 degree nose up attitude at low speeds with the excess lift and drag they create but in our AH p38 their is no nose up tendancy and no noticeable drag from the flaps.


well thats my only 2 gripes on the p38.

1. snap rolls to the right always in a stall
2. dive flaps offer no lift and drag increase

[flakbait]

Yep, the P-38 stalls in a REAL vicious manner. I tried it earlier this morning vs. drones offline. Pulled up on the nose too hard and the damn thing nearly snaped inverted! Went back and eyeballed the film. Sure enough, the left wing dumped HARD. In a spin it nearly swaped ends on me during recovery.

Also:

A minor 109 problems I've experienced. For some reason, the right wing dumps in a stall. It should dump the left wing with power on in landing configuration. Add power at low speeds and the aircraft doesn't really do much. Floor it and it barely protests when it should nearly roll over. Torque increased 3 times huh, feels like it was cut in half.

Flakbait
Delta 6's Flight School

[Fishu]

Stall recovery of P-38 sounds almost like  of Camels in Dawn of Aces  

flakbait,

109 was easy to 3-point land though  
but I wonder where from F4u got that famous "ensign eliminator" callsign, because even in my honest opinions I can't find that much torque, that would promptly kill me.
(oh, C model seems to have less torque effects than D.. C feels like nice kitty. extra device installed with the hispanos?)

Many of AH planes has very low torque effect (you only get torque effect after cutting your wing in half...)

but.. oh.. I can still say that this 109 feels better than others for torque, because in one version it was impossible to keep straight with autopilot below 200mph.

[MiG Eater]

Some additional yet non-quanatative remarks:

Was flying the P-38 offline doing some low speed work and found a dramatic increase in drag once the airplane drops below 100mph.  If the wings are perfectly level, it could climb at 2k per minute with full flaps at 70mph at a very steep angle.  Introducing the slightest bit of bank cause the left wing to drop off like a brick.  It felt like all of the lift on the left wing was replaced by induced drag.  Nearly inverted flight was almost instantaneous with a 30 degree nose down angle preceding the spin. (I felt like I was spin testing a PA-38 Tomahawk. <G> did that during flight training )

I found that induced drag almost completely disapears on this airplane when in ground effect without flaps, however.  It is possible to roll the entire lenth of the runway on the nose wheel with the engines off and the airspeed above 100mph with flaps up. You can glide in nearly level flight in ground effect with no power at 160mph and stay at 160mph.  I ran out of gas at 600 ft on the base leg during approach to landing, one full runway length from the threshold. I raised the gear at 120mph to extend the glide a bit.  Big mistake.  I couldn't get the airplane on the ground until the second runway crossing and promptly rolled off of the end on the nose wheel alone.  I couldn't get the main wheels down on the ground without flying again.  wow.  

I also noticed that with CT and auto takeoff turned off (I never fly with them), there is a noticable right yaw on take-off with the trim centered.  Pull back power and the yawing force stops.  Could there be some rogue torque/p-factor/precession strangeness affecting the airplane?  

The P-38, as modeled, is very good at approximating the experience of soft field take offs in a real airplane.  Full back trim, 60% flaps, hold brake, full power, release brakes, full back on stick and you are flying in ground effect at 70mph.  Lower the nose after liftoff until 100mph and resume normal climb.  

These are some initial observations flying the -38 for the first time since 1.04 was introduced.

MiG

[This message has been edited by MiG Eater (edited 09-18-2000).]

[Ripsnort]

That right yaw you just described, Mig, is within the F4U FM as well.  Shouldn't be there.  F4U, fully loaded with bombs and  fuel, will take off by itself with no stick input and roll slightly right after take off (yes, auto-takeoff is disabled)