Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Ack-Ack on November 20, 2007, 08:20:38 PM
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For those that have trouble from keeping the P-38 from entering a compressability state.
(http://upload.wikimedia.org/wikipedia/en/f/fe/Compressibility010.png)
ack-ack
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I prefer to level bomb in it. It should get the norden sight tho.
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If my memory serves me correctly,I believe there was a pathfinder version with the norden installed in the nose, and the bombadier laid prone, of course my memory is wholey like swiss cheese....
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Originally posted by stephen
If my memory serves me correctly,I believe there was a pathfinder version with the norden installed in the nose, and the bombadier laid prone, of course my memory is wholey like swiss cheese....
Nope not like cheese.;)
With the increased use of the Lightning as a light bomber, the type was modified to carry in place of the forward-firing armament either a bombardier with a Norden bombsight in a glazed nose enclosure, or a "Mickey" BTO (Bombing Through Overcast) bombing radar in the nose with an operator station between the radar and the pilot's cockpit. These modifications were developed at the Lockheed Modification Center in Dallas, Texas. These so-called "droop-snoot" Lightnings were used to lead formations of P-38s each carrying two 2000-lb bombs which were released on instructions from the lead bombardier.
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Eh, here's how I do it...
Once everything starts creaking, pull up some, cut throttle, slow down...
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I've hit 536 mph Tas in the P-38 in sustained dives from 22k - 20k or so in testing i did to see how accurate AH was with it's modelling in comparison to real life performance It's spot on. However at that speed it seemed to hit a terminal velocity at that time and would not go any faster. I don't know if that happened in real life however. As i've heard actual stories of them going faster.
Widewing ??
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Led,
If you look at the chart,536 is about .68 mach @ SL.
Hmmmm.....:noid
:O
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Originally posted by morfiend
Led,
If you look at the chart,536 is about .68 mach @ SL.
Hmmmm.....:noid
:O
From a dive from aproximately 25k the P-38 was attaining that speed constantly. Seemed to max out at about 8k of altitude. From there i'd pull out afterwards.
That speed definately did not occur at sea level.
Try it out it happens.
Amendment P-38 reached 540 Tas From a dive from 30k. It attained this speed at about 5k during the dive. A pullout was achieved afterwards.
This was done with 100% fuel load in a P-38J.
The test was repeated several times with the same results. The plane remained compressed untill about 4 to 3k at which time a pullout was achieved with trim and a reduction of power. Also use of rudder to slow down.
Ledpig.
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You guys have dive brakes, use them. Leave the lawn darting to the shiney stubby winged pilots
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Originally posted by Mister ED
You guys have dive brakes, use them. Leave the lawn darting to the shiney stubby winged pilots
We don't have dive brakes. Only the P-38L has a specialy designed flap to help get the P-38 out of a compressed condition. When deployed it actualy changes the airflow coming off the wings and expands the shockwaves in such a way as they do not flow over the horizontal stabilizer and make it useless. It is not a dive brake as it does not particularly make the 38 slow down to the point it can dive like an SDD and not gain too much speed.
Only the L model has it. The J model i did those tests in did not have it.
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Originally posted by LEADPIG
Only the L model has it. The J model i did those tests in did not have it.
That's because we don't have the P-38J-25-L0.
ack-ack
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Originally posted by Ack-Ack
That's because we don't have the P-38J-25-L0.
ack-ack
Wasn't that the one that was fitted to J models out in the field. Or is it the J model that was fitted with them in late production of that model.
Either way it turned the P-38 into the fighting machine it was having trouble being in the early models. No more luftwaffe 109's and 190's diving from altitude and not following them.
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We have either the J-5-Lo or the J-10-Lo. Dive flaps started being installed at the factory with the J-15-Lo.
Honestly, it wasn't the lack of dive flaps that was hurting the P-38. The P-38's were being poorly flown and poorly maintained. The P-38 groups for the most part were sorely lacking in experience. While the inability to follow the Luftwaffe down at high speeds was an issue, it wasn't the biggest issue, not by a long shot. Engines and turbochargers being adjusted incorrectly were causing serious problems with performance and endurance. Poor fuel quality was also an issue. Planes being flown at the wrong power settings also caused poor performance, as well as causing the planes to just plain run out of fuel. A large part of the problems were actually solved when the fuel issues were solved, and Levier came over and set the pilots and crews straight on maintenance and flying issues.
The J model brought with it more fuel capacity, power assisted ailerons, and more power, along with better visibility. Later in the J model run the dive flaps appeared. But the dive flaps weren't the most important.
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Originally posted by LEADPIG
Either way it turned the P-38 into the fighting machine it was having trouble being in the early models. No more luftwaffe 109's and 190's diving from altitude and not following them.
The dive recovery flaps were not fitted to P-38's in Europe, only in the Pacific. The plane carrying the flaps bound for European P-38's was mistaken for a Fw 200 and shot down by the British. The lost flaps were not replaced due to manufacturing constraints. By this time the P-38 was being phased out of service in Europe for a number of reasons ... that someone else surely is more qualified to elaborate on.
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Originally posted by LEADPIG
Wasn't that the one that was fitted to J models out in the field. Or is it the J model that was fitted with them in late production of that model.
The P-38J-25-L0 was the first production block with boosted ailerons and dive flaps.
Originally posted by Captain Virgil Hilts
We have either the J-5-Lo or the J-10-Lo.
It's not the J-5-LO as that block did not have the flat armored wind screen. Of the 3 blocks it could be, the -10-LO, the -15-LO, and the -20-LO, the 15 was the largest production block.Originally posted by Viking
The dive recovery flaps were not fitted to P-38's in Europe, only in the Pacific. The plane carrying the flaps bound for European P-38's was mistaken for a Fw 200 and shot down by the British. The lost flaps were not replaced due to manufacturing constraints.
200 retrofit kits were lost in that friendly fire incident. LeVier was assigned a retrofitted P-38J-10-LO supplied out of Lockheed's mod facility in Ireland for his '44 demonstration tour in the UK. The 474th FG were supplied with P-38Ls, so it wouldn't be entirely correct to say that "no" dive flap equipped operated in ETO, but the loss of those kits, and the change over of the 8th AF to a single fighter type, did limit deployment of J-25 or later equipped 38s in ETO.
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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.
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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.
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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.
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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.
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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.
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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.
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And those P-38's could not have been fitted with dive flaps after they left the factory?
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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.
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Could you perhaps provide a more reliable source for your claim then?
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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 (http://home.att.net/~C.C.Jordan/index.html)
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.
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If you have these books can you tell me what they say about when the dive flaps were incorporated into the factory line?
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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.
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Thanks.
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Originally posted by Viking
Thanks.
You're welcome.
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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).
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Originally posted by Brooke
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).
You're right, usually the only warning you get is the severe buffet when you're already in a compressability state. Awhile back, I found a site that calculated the mach threshold at various altitudes so I was able to get rough speed figures as to when a P-38 will approach compressability at a certain altitude. I use those speed figures to help me gauge how fast I can go in a dive at the altitude I'm at.
ack-ack