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Cegull
08-04-2007, 05:56 PM
The P38 was originally designed to intercept enemy bombers encroaching on the continental United States. It was not really thought of as a fighter to fighter aircraft. The streamlined design which incorporated twin engines and turbocharging worked very well in tests and the XP38 reached speeds of over 400mph in level flight. In its rush to make a propaganda statement in support of this lockeed creation, the army aircorp sent the only xp38 in existence on a cross continental flight from Los Angeles to New York. The aircraft broke the existing speed record in the making the trip in record time but the tired pilot ran it into a ditch on landing and turned it into a heap of scrap metal so that development was delayed about 18 months. Many have mentioned "compressability" which affected this aircraft. (It effects all higher speed aircraft but wings have different MACH ratings.) As the aircraft gains speed especially at high altitude the air which was flowing over the wing surfaces smoothly begins to compress and "bubble and bounch" over the wing. The plane looses lift and nose goes down and the controls may not respond until the plane gets into denser air. Budding physics student should look up the difference in the speed of sound at 30,000feet and at 1000 feet, this will give you additional clues. Since the P38 was used at higher altitudes in Europe than in the Pacific theatre it had more problems when getting closer to speed of sound. Engineers sought to solve the problem by installing small dive breaks on some of the existing P38's(model G's as I recall). However, the C54 transport carrying thedive brake kits was shot down by an ambitious brit fighter pilot who mistook it for a FW200 condor. So the dive brakes never got into action until later models (L) were produced with them installed at the factory. The ulitimate solution according to Milo Burcham, long time Lockeed test pilot was to extend the leading edge of the wing forward about 30 inches. This wide wing gave more time for the air to flow over it at high speed. Burcham said this modification created the "fastest diving prop plane he ever flew". I know of no sims that can simulate variable air density at different altitudes so I think the P38 as model in IL-2 probably has a little too much compressabilty affect when its at lower altitude, but considering (as others have noted) one can use trim to raise the nose as was done by the real pilots on occassion, this P38 "ain't too bad". The simulated air brakes on the L model also work good in this sim. I recall that it may have been general "Nuts" Moore that said, when told about the P38's dive problem the he'd " rather a plane that went like hell with some wrong with it than one that was slow and had something wrong with it". Good flying and read your history.

Cegull
08-04-2007, 05:56 PM
The P38 was originally designed to intercept enemy bombers encroaching on the continental United States. It was not really thought of as a fighter to fighter aircraft. The streamlined design which incorporated twin engines and turbocharging worked very well in tests and the XP38 reached speeds of over 400mph in level flight. In its rush to make a propaganda statement in support of this lockeed creation, the army aircorp sent the only xp38 in existence on a cross continental flight from Los Angeles to New York. The aircraft broke the existing speed record in the making the trip in record time but the tired pilot ran it into a ditch on landing and turned it into a heap of scrap metal so that development was delayed about 18 months. Many have mentioned "compressability" which affected this aircraft. (It effects all higher speed aircraft but wings have different MACH ratings.) As the aircraft gains speed especially at high altitude the air which was flowing over the wing surfaces smoothly begins to compress and "bubble and bounch" over the wing. The plane looses lift and nose goes down and the controls may not respond until the plane gets into denser air. Budding physics student should look up the difference in the speed of sound at 30,000feet and at 1000 feet, this will give you additional clues. Since the P38 was used at higher altitudes in Europe than in the Pacific theatre it had more problems when getting closer to speed of sound. Engineers sought to solve the problem by installing small dive breaks on some of the existing P38's(model G's as I recall). However, the C54 transport carrying thedive brake kits was shot down by an ambitious brit fighter pilot who mistook it for a FW200 condor. So the dive brakes never got into action until later models (L) were produced with them installed at the factory. The ulitimate solution according to Milo Burcham, long time Lockeed test pilot was to extend the leading edge of the wing forward about 30 inches. This wide wing gave more time for the air to flow over it at high speed. Burcham said this modification created the "fastest diving prop plane he ever flew". I know of no sims that can simulate variable air density at different altitudes so I think the P38 as model in IL-2 probably has a little too much compressabilty affect when its at lower altitude, but considering (as others have noted) one can use trim to raise the nose as was done by the real pilots on occassion, this P38 "ain't too bad". The simulated air brakes on the L model also work good in this sim. I recall that it may have been general "Nuts" Moore that said, when told about the P38's dive problem the he'd " rather a plane that went like hell with some wrong with it than one that was slow and had something wrong with it". Good flying and read your history.

JG54_Lukas
08-05-2007, 02:08 AM
Large paragraphs FTL.

That, and what does this have to do with ORR?

stanford-ukded
08-06-2007, 05:48 AM
As above, I'm sure what you've written is great, but looking at it just hurts my eyes!

Smaller paragraphs, and move to General Discussion!

BH-21
08-06-2007, 07:43 AM
The P-38 was the only US fighter type in production at the time of Pearl Harbor that was still in production on VJ day. The type also shot down the first german aircraft by the US, near Iceland, an FW-200.

A US fighter pilot, whom was involved in an incident with Russian pilots flying the lastest Yaks said, "The P-38 can beat anybody at low altitude in a dogfight."

If you want to see a real P-38F flying, watch the movie "A Guy Named Joe." Its typical war time farce, but entertaining with actual footage of a P-38. It doens a barrel roll, half rolls and other manuevers for the camera. Don't confuse it with the models doing outlandish things though.

Scen
08-06-2007, 03:50 PM
From my post in the "Compressibility" Thread.


No need to test my friend... The NACA test data supports it along with the Pilots Operating Handbook. The 38 we have in the game suffers from compressibility way to early and the funny thing is it's not really a "compressibility" Problem to begin with. Its a high speed wing stall. I sent a document to Tagart.

Every P-38 was equipped with a dive limit compression chart right in the cockpit for all conditions of speed and altitude. Pretty much in the manual as well.

From Page 30 in the Pilot Operating Handbook for the P-38H Series , P-38J Series, P-38L-1 L-5 and F-5B Airplanes.

I would normally post a cut from the page but I have it in PDF format.

The Dive Chart Limits

Outside of above limits buffing and dive tendency may be expected. If experience reduce acceleration or speed

1 Above 10,000 ft 429 mph Indicated

2. Above 20,000 ft 360 mph Indicated

3. Above 30,000 ft 290 mph Indicated

d. When the above conditions are noticed, the following action should be taken immediately.

1 In accelerated maneuvers (dive pullouts or steep turns) buffeting may be stopped by reducing the acceleration.
2. In steady dives at high speed, the buffeting may be stopped by reducing the airplane speed and pulling out using minimum acceleration. Use the elevator tab if necessary to assist in recovery.

e. A new placard will be installed in late airplanes and may be retroactive to airplanes already in service. This new placard indicates the safe speed range at any altitude for one G flight. As the airplane approaches this critical one G condition, its ability to pull out is gradually reduced and at the critical speed, buffeting and nose heaviness will occur.

f. Dive Recovery Flaps P-38L and Later P-38 J airplanes are provided with dive recovery flaps to improve the dive recovery characteristics of the airplane. As described above, the airplane without these flaps becomes very nose heavy and starts to buffet above the placard dive speeds. This condition is caused by a high speed stall and a consequent decrease in lift in the wing producing the nose heavy condition. The dive recovery flaps which are install under the wings between the booms and the ailerons, restore the lift to this portion of the wing and thus cause the uncontrollable nose heaviness to occur at higher speed. The flaps also add some drag to the airplane, which in conjunction with the higher allowable dive speed, permits safe dives at a much steeper dive angle. The dive recovery flaps should be extended before starting the dive or immediately after the dive 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 then diminish. With these flaps extended, the nose heaviness is definitely reduced but the dive speed should never be allowed to exceed the placard by more than 15 - 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 extended dives is 15 degrees. Diving characteristics are better with power off than with power on.

Warning

Although the dive recovery flaps greatly improve the diving characteristics of the airplane dangerous buffeting and nose heaviness will still be encountered diving at angels above 45 degrees if the diving speed is allowed to exceed the placard limits by more than 15 to 20 mph


The problem is this has been presented to Oleg and Company with several other supporting documents and it was blown off as propaganda over a year ago.

I don't think we will see any changes any time soon if any.

Skoshi Tiger
08-07-2007, 02:34 AM
[QUOTE]Originally posted by BH-21:
The P-38 was the only US fighter type in production at the time of Pearl Harbor that was still in production on VJ day. The type also shot down the first german aircraft by the US, near Iceland, an FW-200.

[/QUOTE
It was a shared victory with 2nd Lt. Joseph D. Shaffer flying a P-40C taking the other half.