P-38 speed reduction for tight turn?

[FLS]

Dive flap Traveler. Only works in AH when you compress and doesn't add drag.

[JVboob]

itll burn E.
ive done NOE raids and on auto lvl ill pop it out for about 30seconds to slow down and stay with the goon. i hate messing with my throttle settings (lazy) so ill pop it and slow down a few MPH goon shoots ahead, i retract it and repeat in a little bit

[FLS]

itll burn E.
ive done NOE raids and on auto lvl ill pop it out for about 30seconds to slow down and stay with the goon. i hate messing with my throttle settings (lazy) so ill pop it and slow down a few MPH goon shoots ahead, i retract it and repeat in a little bit

You can add drag with your flaps, not with your dive flap. The dive flap is only for moving the center of pressure in compression.

[Randy1]

Got to ask, how is the flap on the P38 "ineffective at low speed"?

remember the purpose of the flap is to allow a pilot to lower the nose of the aircraft without increasing the airspeed.

Traveler, the flap works by disturbing the near mach air flow on the bottom side of the wing enough to counter the  lost lift of the top wing as flow of air gets moving so fast it can't follow the contour of the upper wing creating a lower pressure on the back part of the wing enough to pitch the nose down. 

The flap has too little drag at slower speeds to be effective as a speed reducer lift addition of reducer due its small size and location.. 

At this point no player in AH has been able to detect any added drag at any speed.  Is that right?  I do not know.  Only HTC and Lockheed knows that answer.

An interesting point in history.  The problem with airflow in a P-38 dive was known by prop designers for a couple of years.  The problem is same problem that limits the speed on prop planes due to prop limits.

[Ack-Ack]

Got to ask, how is the flap on the P38 "ineffective at low speed"?

remember the purpose of the flap is to allow a pilot to lower the nose of the aircraft without increasing the airspeed.

He's referring to the dive flap on the P-38L and at speeds below 300knts, it rather useless.

[JVboob]

I didnt say it burned tons. lol re read my jumbled up post. im talking about dropping 5mph while im already running 200mph. NOE i dont like popping flapps its messes with auto level. It will bleed E and like i said not very much or very fast.

[hgtonyvi]

He's referring to the dive flap on the P-38L and at speeds below 300knts, it rather useless.

I agree with ack ack. Thos dive flaps are for compression while diving. It was very useful against German fighters 190 while they tried to dive away.

[Triton28]

I've never felt any differences in the L when the dive flap was deployed vs. when it wasn't.  I've always heard it was best dropped before compression is an issue, so if I'm dropping eggs and screaming at the target straight down, it's always deployed well in advance.  Once the eggs are gone and I'm on the way back up, I click it off and forget it's a feature. 

[Randy1]

There was I think a third party report of a P-38L test pilot being able to do a loop just by activating the dive flap.  I say third party because no quote of the test pilot was used.  Might mislead people.

My guess is one primary design spec of the dive flap was to minimize effects if the dive flap was left on, failed to close, and if only one actuated.

[Traveler]

Dive flap Traveler. Only works in AH when you compress and doesn't add drag.

He didn't say "Dive Flap" he said "Flap".  As to the "dive flap not adding drag, set yourself up in level flight at a constant RPM and MP. Note the seed in the e6B, now lower the dive flap, note the decrease in speed on the e6B, now raise the dive flap, note the increase in speed on the e6B.  that's drag.

[Randy1]

He didn't say "Dive Flap" he said "Flap".  As to the "dive flap not adding drag, set yourself up in level flight at a constant RPM and MP. Note the seed in the e6B, now lower the dive flap, note the decrease in speed on the e6B, now raise the dive flap, note the increase in speed on the e6B.  that's drag.

Traveler I have attempted to measure speed change in the past but no noted change.  I will try again.

[FLS]

He didn't say "Dive Flap" he said "Flap".  As to the "dive flap not adding drag, set yourself up in level flap at a constant RPM and MP. Note the seed in the e6B, now lower the dive flap, not the decrease in speed on the e6B, now raise the dive flap, note the increase in speed on the e6B.  that's drag.

He didn't say "Flap" he said "That flap". If you read the thread it's obvious he is referring to the dive flap.

When I lower the dive flap in the AH P-38L I do not see any reduction in speed. You have film showing drag?

[Drano]

It would probably be best if it wasn't referred to as a flap in the first place. It's not really a flap by any other definition. It doesn't provide lift as other actual flaps do. It does add drag albeit a negligible amount. As such it doesn't slow the plane whatsoever at any speed. It wasn't designed to do that. What it does have in common with a  flap is that it temporarily changes the shape of the wing to redirect airflow. That's what it was designed to do. That's all it does. It's only designed to be effective at higher speeds in order to regain lost directional control. When it's operating it isn't working anything at all like the first notch of ACTUAL flap. It's doing something rise entirely. It does nothing at slow speed.

It doesn't function as a dive brake--EVER. A dive brake is a different animal. Try the same level speed test in a dive bomber and pop the dive brake. You'll see a very noticeable loss of speed. That's because it's designed to do that. THAT is a dive brake. It's designed to add tons of drag on order to stop the plane from building up speed going straight down. With a dive brake deployed you'll never get fast. What's on the P-38L is not that. It's designed to be used WHEN FAST, but NOT designed to slow you down.

Anyone that's trying to use it as such is kidding themselves. Anyone that thinks it's slowing them down is imagining it.  Period. Paragraph. Got actual (not anecdotal) proof otherwise? Post it here. Please.

I fly the L almost exclusively and have for years. I think I have an idea. This conversation keeps coming around every few months. I don't get it. The dive recovery flap is a different animal. Truely unique to the late P-38 Js and Ls. I don't think you'll find a flap like it on any other aircraft.

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[FLS]

I don't think you'll find a flap like it on any other aircraft.

The P-47D-40 and the P-47M both have the same dive flaps as the P-38L.

[Drano]

The P-47D-40 and the P-47M both have the same dive flaps as the P-38L.

OK but even so they are there for the same reason and not being used as a speed brake or lift producer at all on either aircraft.

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