Author Topic: P-38 compressability chart (Read 1496 times)

Viking · « **Reply #15 on:** November 27, 2007, 06:02:18 PM »

Yes, my mistake; one FG still operated the 38 in the ETO. Still ... we're talking September 1944 when the flaps were factory fitted. Another error on my part: There actually was a second shipment of kits to the ETO. However the ship carrying them was sunk by a U-Boat. Talk about bad luck; one could almost think the 38 was jinxed in Europe.

Captain Virgil Hilts · « **Reply #16 on:** November 27, 2007, 07:42:38 PM »

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Originally posted by Viking
Yes, my mistake; one FG still operated the 38 in the ETO. Still ... we're talking September 1944 when the flaps were factory fitted. Another error on my part: There actually was a second shipment of kits to the ETO. However the ship carrying them was sunk by a U-Boat. Talk about bad luck; one could almost think the 38 was jinxed in Europe.

No, we're not talking September of 44. The P-38L arrived in Europe in the summer of 44. And like I said before, there were factory dive flap fitted P-38J models, and not just the P-38J-25-Lo, but likely some of the P-38J-20-Lo block. Some of the P-38 units that transitioned to P-51's got a couple of P-38L's before they transitioned in June and July. There were certainly more than a few P-38J-25-Lo planes delivered before those units moved to the P-51. Several pilots spoke or wrote of the new P-38J-25-Lo and flying it BEFORE they transitioned to the P-51.

The power assisted ailerons became a factor at higher speeds, where the pilot required some assistance getting the broad chord ailerons to respond when they were under great pressure from air speed. Note that at speeds above 300MPH, the P-38 gained in rate of roll as it got faster, and at higher speeds would actually roll faster than a FW 190 or a P-47.

And yes, the 8th AF command DID jinx the P-38. The 8th AF was rather poorly managed, to put it politely. They were assigning P-38 trained pilots to P-51 and P-47 units, and assigning single engine trained pilots with ZERO P-38 hours to P-38 units. In large numbers and on a regular basis. Spare parts supply was screwed up, fuel supply was screwed up, crew training was screwed up, you name it, it was either FUBAR or SNAFU, take your pick.

Viking · « **Reply #17 on:** November 28, 2007, 03:31:53 AM »

Yes you are right of course: The flaps were integrated into the factory production line in June 1944. September was when there was only one P-38 FG left in Europe. I got the dates mixed up.

Captain Virgil Hilts · « **Reply #18 on:** November 28, 2007, 08:19:18 PM »

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Originally posted by Viking
Yes you are right of course: The flaps were integrated into the factory production line in June 1944. September was when there was only one P-38 FG left in Europe. I got the dates mixed up.

Well, in order for the P-38L-1-Lo to be delivered to the 8th AF before the 20th and 55th transitioned to the P-51, in June and July of 44, they'd have to have been built a month before they arrived in Britain. And as stated earlier, the P-38J-25-Lo preceded the P-38L-1-Lo, had factory dive flaps, on the production line, and was in Europe before it the P-38L-1-Lo. I'd have to do more research, but I'd say dive flaps were on the production line around March or April, at the latest. The reason I say March or April is that P-38's were built in California, test flown, then flown across the country, put on ships, shipped across the Atlantic, unloaded, re-assembled, test flown, and then delivered to the units. New replacement pilots coming to the 8th AF P-38 groups were often stunned to find that the front line groups were flying P-38's without dive flaps when the replacements had trained in P-38's WITH dive flaps.

Viking · « **Reply #19 on:** November 29, 2007, 02:10:08 AM »

Of course Wikipedia is not the best of sources, but they state:

"The flaps were finally incorporated into the production line in June 1944 on the last 210 P-38Js. The delay in bringing the dive flap and its freedom of tactical maneuver to the fighting pilot was far too lengthy. Of all Lightnings built, only the last series would have the dive flaps installed as an assembly line sequence."

P-38's with dive flaps in service before June '44 must have been retro-fitted using field kits.

Captain Virgil Hilts · « **Reply #20 on:** November 29, 2007, 02:20:27 AM »

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Originally posted by Viking
Of course Wikipedia is not the best of sources, but they state:

"The flaps were finally incorporated into the production line in June 1944 on the last 210 P-38Js. The delay in bringing the dive flap and its freedom of tactical maneuver to the fighting pilot was far too lengthy. Of all Lightnings built, only the last series would have the dive flaps installed as an assembly line sequence."

Wiki is wrong. Like I said, guys from the 55th and the 20th both got P-38's with dive flaps before they transitioned to P-51's. That happened in June and July. Birds built in June would not be in Europe in June. MAYBE late July.

And the 8th AF may have transitioned out of the P-38 by July 44, but the 9th AF did not. The 9th AF had the P-38 until the end of the war in Europe.
P-38's with dive flaps in service before June '44 must have been retro-fitted using field kits.

Viking · « **Reply #21 on:** November 29, 2007, 04:32:38 AM »

And those P-38's could not have been fitted with dive flaps after they left the factory?

Captain Virgil Hilts · « **Reply #22 on:** November 29, 2007, 08:54:06 AM »

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Originally posted by Viking
And those P-38's could not have been fitted with dive flaps after they left the factory?

No. They were P-38J-25-Lo and P-38L-1-Lo models, all were fitted with dive flaps at the factory. And powered ailerons. Wiki is way off, as are most common sources. You really should look at something else. What they're saying is not backed up by any reliable source on the P-38.

Viking · « **Reply #23 on:** November 29, 2007, 09:48:21 AM »

Could you perhaps provide a more reliable source for your claim then?

Captain Virgil Hilts · « **Reply #24 on:** November 29, 2007, 10:33:38 AM »

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Originally posted by Viking
Could you perhaps provide a more reliable source for your claim then?

Warren Bodie's "The Lockheed P-38 Lightning", THE definitive source on the P-38, Bodie was a Lockheed engineer, and has access to all of the Lockheed archives. Or "Lockheed P-38 Lightning" by Steve Pace. Widewing has some great information on his website, so you don't have to buy a book you don't really want. ALL of his stuff has been verified and is factual information from the best sources around.

Planes and Pilots of World War II

Widewing's stuff is FAR more reliable than Wiki. Not only does he have stuff from Bodie, but he also has stuff directly from REAL P-38 pilots. And we know they are real, they've been researched and verified by several people. Art Hieden and Stan Richardson are the real deal, and knew most every well known P-38 pilot in Europe. Widewing's articles on the P-38 are in fact probably the very best on the web.

Viking · « **Reply #25 on:** November 29, 2007, 10:40:17 AM »

If you have these books can you tell me what they say about when the dive flaps were incorporated into the factory line?

Captain Virgil Hilts · « **Reply #26 on:** November 29, 2007, 11:38:09 AM »

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Originally posted by Viking
If you have these books can you tell me what they say about when the dive flaps were incorporated into the factory line?

From Bodie: The Lockheed P-38J-25-Lo was delivered from June thru November 1944. The P-38J-25-Lo was FACTORY equipped with dive flaps and powered ailerons. That's DELIVERED. The P-38L-1-Lo was delivered during that same period of time. The P-38L-1-Lo is for all intents and purposes the same as the P-38J-25-Lo, except for a slight increase in power for the P-38L-1-Lo. Again, there was a delay between production and delivery. So a June delivery was produced earlier.

To give you an idea of how long it took to get a P-38 to the units in England, here's what had to happen. The P-38 was completed at the Burbank California factory. It was then test flown and adjusted. Then it was accepted. Then a ferry pilot flew it from Burbank to the east coast of the U.S. Then it was partially disassembled. The props were removed, as were the outer wings. The plane was loaded on a ship, and taken to England. It was then unloaded, and towed to a depot. The props and outer wings were re-installed, the plane was again test flown and adjusted, and then ferried to the unit it was assigned to. The process could take well over a month.

Viking · « **Reply #27 on:** November 29, 2007, 01:34:55 PM »

Thanks.

Captain Virgil Hilts · « **Reply #28 on:** November 29, 2007, 10:21:49 PM »

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Originally posted by Viking
Thanks.

You're welcome.

Brooke · « **Reply #29 on:** December 17, 2007, 05:16:37 PM »

I fly the P-38 a lot, and I still occasionally hit compressibility and smash into the ground.

The issue isn't so much the compressibility itself (as most planes can hit compressibility), but that in a steep dive the P-38 gives a short amount of warning, then it is locked up solid (even after chopping throttle, full up elevator, full aileron, and full rudder at the same time).

Other planes, like the P-47, for example, give lots of warning and remain maneuverable (although very sluggishly) seemingly deep into the compressibility buffet compared to the P-38, and can recover much more easily with chopped throttle and max force on the controls.

I have had similar problems with the Ki-84 shedding parts if flown too fast, and so on.

It just takes attention to a detail that I sometimes seem not to notice (namely, taking action immediately once you notice that buffet if you are in a moderate to steep dive).