P-38 kill ratio...out of whack.

[BnZs]

my problem with the flaps is that they are distributed subjectively, and that the liabilities seem underrepresented to such an extent that the envelopes of the set are now very suspect.  

The reason you do not hear much about flap settings beyond a certain limit in r/l is that beyond a certain point they harm, rather than helps, sustained turn rate.

In AHII, beyond a certain point, flap deployment harms rather than helps sustained turn rate.

HMMMMMMMMM....

[Captain Virgil Hilts]

COUGH!

Actually.... no.

Downwash and aeroelastic bending of the tail boom was the P-38s problem. You can read all about it and the design of the P-38 'brakes' in the book 'Mechanics of Flight' by Warren F. Phillips (chapter 6). Dont bother reading this book if you dont understand calculus and physics (and I mean understand).

"Compressibility effects at high subsonic airspeeds can amplify the tendency for an airplane to tuck under in a dive as a result of aeroelastic bending."

The full description of the problem with the P-38 and the phenomenon are included and the relationship of wing (airflow) and tail position are all important but in the case of high subsonic airspeeds the placement is redundant since there is no good place to be.

In the case of the P-38 in particular (because of tail boom flexibility) continued flight at high subsonic airspeed should permanently affect the aircrafts ability to manoeuvre but it is also true of every airplane in the game.

Absolutely untrue. I don't care what Warren Phillips says. I'll take the words of Hall Hibbard, Kelly Johnson, Colonel Ben Kelsey, Colonel Cass Hough, Tony Levier, and Milo Burcham, over Warren Phillips every time. Why you ask? Because every person I mentioned was either a design engineer on the P-38 who solved the compression problem, or a test pilot who flew the compression program. Read my post above, where Tony Levier, who flew the test program on compression and dive flaps for months, dove to Mach 0.72, and pulled 7.5G recoveries from those dives, in the P-38 during that program.

They moved the tail on the P-38, and ended up putting it right back where it was. That comes directly from the Lockheed P-38 program records from 1937 until the program ended in 1945.

[Vinkman]

Vinkman, you are wrong. The relationship between the positions of the wings and the elevator has nothing to do with compression, or how it effects the P-38. Ignore "Great Planes" and the rest of the television crap. They are wrong, very wrong. To get the truth, you have to read.


When the P-38 (or any plane, as the P-47 suffered from compression as well) entered into compression, the elevator didn't matter at all, as no deflection of the elevator could overcome the amount of force that the wing, suffering under compression, was pushing down on the nose with.

Yours is a different description of the 'compression' than I've seen before. True I haven't read any Kelly Johnson papers on the subject. Maybe I should.  

[Captain Virgil Hilts]

guys i believe the stand i took issue with is that "the dive brakes did not slow the plane down".

that statement is false "."

you can introduce all the design intent and situational exceptions you wish ...

but it does not change the fact that the above statement is false, even if AH does not model it that way.


++S++

t

And you are more qualified to state that than the original engineers who designed the plane, and the test pilots who flew the plane, are to say the reverse is actually true?   

So now you are smarter than Lockheed engineers and Lockheed test pilots?   

So, please, as we all wait with anxious anticipation, tell us about all the planes you designed and all the planes you have flown as a test pilot. Please, I just cannot wait to hear what world altering planes you are credited with designing and flying. 

[thorsim]

i was also questioning the reasoning and understanding of some of the other experts in this discussion.

so the misinformation you read in my post was not my own and i was not taking much credit in it my self, it was more of an "ok if this is true ..." approach.

my main point of contention was about their stating that somehow secondary flight control surfaces on the p-38 are not subject to the same laws of physics as they would be on other aircraft.

i was of the opinion they were incorrect just as you were, i am sorry my approach confused you.

good posts so far you seem to take such things as physics and aerodynamics into account instead of attempting to ignore them.  i believe someone was attempting to state that mass was inconsequential to maneuverability somewhere earlier in this thread.

sigh ...

++S++

t

The dive flaps on the P-38 do not change the angle of attack of anything. They do not result in a constant skid.

At top speed in level flight, a P-38 cannot reach compression. The only P-38 that could come close was the P-38K, and it did not do it either. So the dive flaps are irrelevant to top speed in level flight. They were not designed to be deployed there, and would not work there for their intended purpose. At speeds below 0.65 Mach, the air flow over the wing was not disrupted by compression, and therefor was not the same as the air flow at speeds over 0.65 Mach. Meaning what the dive flaps did below 0.65 Mach had absolutely no bearing on what the dive flaps did above 0.65 Mach.

The only thing the dive flaps do is change the shape of the wing to reduce the effects of compression, which is caused by the speed of the air over the wing going just sub sonic and super sonic in places.

I have no idea where you are getting the idea that the dive flap, deployed when the plane is in compression, changes the angle of attack. All it does, according to the Lockheed engineers that design it, is change the shape of the wing and redirect airflow over it so that the wing does not lose lift and cause the nose to tuck.

As a side note, compression would not cause the P-38 to break up, and even without the dive flaps, you could pull out of a dive if you stayed with the plane and continued to fly it. Colonel Cass Hough, P-38 test pilot and USAAF officer, dove from over 38,000 feet at an angle of 45 degrees, through 20,000 feet, recovering well before he came close to hitting the ground at over 7,000 feet. All of this in an early P-38 without dive flaps. And Tony Levier, a civilian Lockheed test pilot, who was the test pilot assigned with the comprehensive dive flap test program, reported speeds of 0.72 Mach and safe pull outs of 7.5G.

[Vinkman]

COUGH!

Actually.... no. (not meant at you Hicks)

Downwash and aeroelastic bending of the tail boom was the P-38s problem. You can read all about it and the design of the P-38 'brakes' in the book 'Mechanics of Flight' by Warren F. Phillips (chapter 6). Dont bother reading this book if you dont understand calculus and physics (and I mean understand).

"Compressibility effects at high subsonic airspeeds can amplify the tendency for an airplane to tuck under in a dive as a result of aeroelastic bending."

The full description of the problem with the P-38 and the phenomenon are included and the relationship of wing (airflow) and tail position are all important but in the case of high subsonic airspeeds the placement is redundant since there is no good place to be.

In the case of the P-38 in particular (because of tail boom flexibility) continued flight at high subsonic airspeed should permanently affect the aircrafts ability to manoeuvre but it is also true of every airplane in the game.

Chanllenge thanks for the reference. I will read the book.

[Chalenge]

Absolutely untrue. I don't care what Warren Phillips says. I'll take the words of Hall Hibbard, Kelly Johnson, Colonel Ben Kelsey, Colonel Cass Hough, Tony Levier, and Milo Burcham, over Warren Phillips every time. Why you ask? Because every person I mentioned was either a design engineer on the P-38 who solved the compression problem, or a test pilot who flew the compression program. Read my post above, where Tony Levier, who flew the test program on compression and dive flaps for months, dove to Mach 0.72, and pulled 7.5G recoveries from those dives, in the P-38 during that program.

They moved the tail on the P-38, and ended up putting it right back where it was. That comes directly from the Lockheed P-38 program records from 1937 until the program ended in 1945.

It doesnt matter where the tail is it will have the same problem. You are arguing against yourself here since my post agreed with you. The problem is exactly as I stated it and is not in disagreement with the engineers at all but they had no way to know the tail booms were flexing. By the way the dives that killed pilots like Ralph Virden were not shallow dives of 45 degrees. Phillips is correct.

[thorsim]

no actually the Lockheed Engineer i discussed this subject with this afternoon agreed with me and kelly johnston that the unadjusted p38 was more efficient than one with any of the secondary flight controls deployed.  

that is probably why the p38 had to be adjusted to use these devices in the first place.

the flaps slow the plane down, in the real world.  

"."

++S++

off to play

t

And you are more qualified to state that than the original engineers who designed the plane, and the test pilots who flew the plane, are to say the reverse is actually true?   

So now you are smarter than Lockheed engineers and Lockheed test pilots?   

So, please, as we all wait with anxious anticipation, tell us about all the planes you designed and all the planes you have flown as a test pilot. Please, I just cannot wait to hear what world altering planes you are credited with designing and flying. 

[Captain Virgil Hilts]

Yours is a different description of the 'compression' than I've seen before. True I haven't read any Kelly Johnson papers on the subject. Maybe I should. 

Again, as stated repeatedly here in this thread, the truth, the absolute gospel on the P-38, can be found in the book "The Lockheed P-38 Lighting", authored by Warren Bodie, A Lockheed engineer, who had for sources almost all of the original design staff, and almost all of the original test pilot crew. Bodie had access to the Lockheed archives, Clarence E. "Kelly" Johnson (the man who is considered the father of the P-38, along with the U-2, the F-104, and the SR-71), Colonel Ben Kelsey(the USAAF test pilot and liaison to Lockheed for the P-38 program), Tony Levier (who ended up with more hours as a P-38 test pilot than anyone, and who raced one after the war), and a host of other people too numerous to mention. Bodie goes in to incredible detail in describing what really happened during the 8 years Lockheed was designing and producing the plane, covering in detail the issues with compression and with the dive flaps, as well as engine development,and just about everything else relating to the P-38.

[Chalenge]

Chanllenge thanks for the reference. I will read the book.

I recommend a used copy: http://www.amazon.com/Mechanics-Flight-Warren-F-Phillips/dp/0471334588/ref=sr_1_2?ie=UTF8&s=books&qid=1254191851&sr=8-2

There is a LOT more than just the problems with the P-38 and it is VERY heavy on math and physics.

[Captain Virgil Hilts]

no actually the Lockheed Engineer i discussed this subject with this afternoon agreed with me and kelly johnston that the unadjusted p38 was more efficient than one with any of the secondary flight controls deployed. 

that is probably why the p38 had to be adjusted to use these devices in the first place.

the flaps slow the plane down, in the real world. 

"."

++S++

off to play

t

Yeah, right. Show me where Kelly Johnson ever said that. I've read just about every Kelly Johnson statement on the P-38 that's been recorded for history. The dive flaps do not slow the plane down when it is diving at or above compression speeds of 0.65 Mach. If they did, it would never reach 0.72 Mach.

[CAP1]

no actually the Lockheed Engineer i discussed this subject with this afternoon agreed with me and kelly johnston that the unadjusted p38 was more efficient than one with any of the secondary flight controls deployed.  

that is probably why the p38 had to be adjusted to use these devices in the first place.

the flaps slow the plane down, in the real world.  

"."

++S++

off to play

t

and the flaps slow the plane down in the cartoon ah world too.  

and now another question, since at one point you were on the maneuvering flaps.

 when you drop out say......10 degrees of flaps, what happens?

[Vinkman]

Again, as stated repeatedly here in this thread, the truth, the absolute gospel on the P-38, can be found in the book "The Lockheed P-38 Lighting", authored by Warren Bodie, A Lockheed engineer, who had for sources almost all of the original design staff, and almost all of the original test pilot crew. Bodie had access to the Lockheed archives, Clarence E. "Kelly" Johnson (the man who is considered the father of the P-38, along with the U-2, the F-104, and the SR-71), Colonel Ben Kelsey(the USAAF test pilot and liaison to Lockheed for the P-38 program), Tony Levier (who ended up with more hours as a P-38 test pilot than anyone, and who raced one after the war), and a host of other people too numerous to mention. Bodie goes in to incredible detail in describing what really happened during the 8 years Lockheed was designing and producing the plane, covering in detail the issues with compression and with the dive flaps, as well as engine development,and just about everything else relating to the P-38.

I will check out that book as well. We are way off topic, but this is a facinating subject.

[thorsim]

umm ...

you need to re read this thread ...

no offense ...

++S++

t

Yeah, right. Show me where Kelly Johnson ever said that. I've read just about every Kelly Johnson statement on the P-38 that's been recorded for history. The dive flaps do not slow the plane down when it is diving at or above compression speeds of 0.65 Mach. If they did, it would never reach 0.72 Mach.

[thorsim]

it is what doesn't happen at 30-60 degrees that have problems with, that and when some planes get that 10deg relative to other planes. 

and the flaps slow the plane down in the cartoon ah world too.  

and now another question, since at one point you were on the maneuvering flaps.

 when you drop out say......10 degrees of flaps, what happens?