Author Topic: P-38 compressability chart (Read 1510 times)

Ack-Ack · « **on:** November 20, 2007, 08:20:38 PM »

For those that have trouble from keeping the P-38 from entering a compressability state.

ack-ack

Nilsen · « **Reply #1 on:** November 21, 2007, 07:02:18 AM »

I prefer to level bomb in it. It should get the norden sight tho.

stephen · « **Reply #2 on:** November 21, 2007, 07:18:01 AM »

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....

MiloMorai · « **Reply #3 on:** November 21, 2007, 08:22:27 AM »

Quote

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.

trigger2 · « **Reply #4 on:** November 24, 2007, 03:30:18 AM »

Eh, here's how I do it...
Once everything starts creaking, pull up some, cut throttle, slow down...

LEADPIG · « **Reply #5 on:** November 26, 2007, 01:26:24 AM »

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 ??

morfiend · « **Reply #6 on:** November 26, 2007, 06:12:59 PM »

Led,

If you look at the chart,536 is about .68 mach @ SL.

Hmmmm.....

LEADPIG · « **Reply #7 on:** November 26, 2007, 07:56:41 PM »

Quote

Originally posted by morfiend
Led,

If you look at the chart,536 is about .68 mach @ SL.

Hmmmm.....

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.

Mister ED · « **Reply #8 on:** November 27, 2007, 01:59:02 AM »

You guys have dive brakes, use them. Leave the lawn darting to the shiney stubby winged pilots

LEADPIG · « **Reply #9 on:** November 27, 2007, 02:06:26 AM »

Quote

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.

Ack-Ack · « **Reply #10 on:** November 27, 2007, 04:05:42 AM »

Quote

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

LEADPIG · « **Reply #11 on:** November 27, 2007, 06:05:26 AM »

Quote

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.

Captain Virgil Hilts · « **Reply #12 on:** November 27, 2007, 07:21:49 AM »

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.

Viking · « **Reply #13 on:** November 27, 2007, 10:12:53 AM »

Quote

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.

Murdr · « **Reply #14 on:** November 27, 2007, 03:45:17 PM »

Quote

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.

Quote

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.

Quote

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.