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Blutarski2004
03-10-2005, 09:24 AM
The other P38 post led me to look a bit deeper into this P38 dive compressibility issue. There is really a lot of conflicting data here.

This comes from the Yahoo Military Archive -

QUOTE-
This rose to well above 400 mph between 25,000 to 30,000. As the plane approached 30,000 ft, speeds over Mach 0.60 could be sustained in level flight. Thus, manuevering could quickly give the plane compressibility problems. At ach 0.65 (290 mph IAS, 440 mph TAS at 30,000 ft.; 360 mph IAS, 460 mph TAS at 20,000 ft.)
drag began to soar as the plane began to encounter compressibility. At Mach 0.67 shock waves began forming and buffeting began at Mach 0.675. At Mach 0.74 tuck under began. Buffeting developed at a lower Mach number in
any maneuver exceeding 1 g. What this meant to a pilot in combat in say, a P-38H such as that used by the 55FG or 20FG circa Jan. '44, was that if, at high altitude such as Me-109s preferred approaching bomber formations, he locked on to the e/a and it split-S'ed and dove away (typical Luftwaffe evasive maneuver), if
he attempted to follow, his P-38 would start to vibrate, then start bucking like a rodeo bronco, the control column would begin flail back and forth so forcefully it would probably be ripped out of his hands and begin pounding him to ****. Once the plane dropped down to lower altitude where the speed of sound was higher, the buffeting declined and the trim tab
could be used to haul the airplane out of what seemed to be a death dive. Recovery with trim tab resulted in 5 g pull-out. Many a low-time service pilot would be so shaken by this experience that he would never dive the P-38 again, and might be so afraid of the airplane that his usefullness as a fighter pilot was over.

The late J and L models solved this problem with the installation of a dive flap. Extend the flaps at the beginning of a dive and all problems were eliminated. Again, these models weren't available in the critical period between fall 1943 and spring 1944 when the most desperate battles against the Luftwaffe took place, and when the P-38s rep in Europe was
established.
- UNQUOTE

I'm not sure who wrote this and what how authoritative it shouldbe considered, but it SOUNDS like the author was personally familiar with the P38.

Some interetsing points -

(1) Recovering the P38 from a dive by use of the trim wheel. It seems that this technique was not unique to the 109.

(2) The description of being able to ride through the compressibility buffeting until denser air was reached at lower altitudes seems to contradict other comments that P38 dive compressibility was a killer. Maybe there's something we are missing here - perhaps P38-trained pilots were doing something subtly different than the P38 pilots who had not been extensively trained on the a/c prior to flying in combat.

Then the same writer followed up with this -

QUOTE-
It's been pretty well documented that many P-38 drivers were often afraid to
follow German planes into a dive, especially the 109, which routinely broke
contact by Split-S-ing. This has always puzzled me, because the 109 had a
practical dive limit of about 400 mph--well within the P-38's dive
range--because its controls became too heavy. Much has been made of the cold
weather of the northern European winter being a factor, along with the higher
altitudes the ETO boys flew at. But P-38ers in the MTO also seem to frequently
have been afraid to dive after 109s, and they flew in warm weather and at
moderate altitudes, doing a lot of medium bomber escorting.
In the SWPA, the Ki-61 had similar--if not somewhat better--dive
characteristics to the Me 109, yet no P-38 driver ever hesitated to plunge
after a Tony. The trick in the dive was: throttles to idle before dropping
the nose below the horizon, bank left and right to slow when buffeting began.
Pretty straightforward. In any case, compressibility was not a problem for any
model P-38 if the dive were entered from below 25,000 ft.
One thought is that most P-38 drivers in the SWPA transitioned from the P-40, a
diving sono***un if there ever was one, or P-39 (also a good diver), and they
were used to making terminal velocity dives to save their hides. Both these
planes would yaw quite badly as speed built up in the dive and could otherwise
be disconcerting.
Aside from buffeting, which could easily be controlled, the P-38 was a
sweetheart in a dive compared to a P-40, so PTO pilots who had cut their
combat teeth on the Curtiss or Bell never had reason to fear it. If the ETO
boys were entering combat in the P-38, all the shock and confusion of
first-time combat would have been throw onto the P-38, and its quirks
magnified. Just a guess.

> Do you know what version P-38 this was ?

J-10.
- UNQUOTE


Interesting. It's all so very confusing.

ZG77_Nagual
03-10-2005, 09:34 AM
Maybe somewhere in here

P38 Thread at yarchive (http://www.yarchive.net/mil/p38.html)

Also very nice article here

P38 History etc. (http://home.att.net/~ww2aviation/P-38.html)

RedNeckerson
03-10-2005, 10:11 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Blutarski2004:

The late J and L models solved this problem with the installation of a dive flap. Extend the flaps at the beginning of a dive and all problems were eliminated. Again, these models weren't available in the critical period between fall 1943 and spring 1944 when the most desperate battles against the Luftwaffe took place, and when the P-38s rep in Europe was
established.
- UNQUOTE

I'm not sure who wrote this and what how authoritative it shouldbe considered, but it SOUNDS like the author was personally familiar with the P38.

<HR></BLOCKQUOTE>


The dive recovery flap thing for the P-38 seems to be a bit over rated.

8th AF historian Roger Freeman writes:

"The 479th group recieved two aircraft with such flaps in August 1944 - at which time it was the last P-38 group in VIII FC."

Didn't seem to work so well:

"After some hours flying with them they complained that the flaps continually broke down; one aircraft needed repair nine times."

It goes on to say that the group actually exchanged the fighters for two without flaps - and the 479th flew it's last P-38 mission on 27 September, terminating the Lightning service as s fighter with the 8th AF.


See -

Roger Freeman
The Mighty Eighth War Manual

P. 186

hop2002
03-10-2005, 10:26 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>(1) Recovering the P38 from a dive by use of the trim wheel. It seems that this technique was not unique to the 109. <HR></BLOCKQUOTE>

You could do the same on any aircraft, but it carries risks. If you wind on too much trim whilst in compression, when the mach number falss and the controls regain effectiveness the pullout can be too sharp, especially if you are pulling the stick as well.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>The description of being able to ride through the compressibility buffeting until denser air was reached at lower altitudes seems to contradict other comments that P38 dive compressibility was a killer. Maybe there's something we are missing here - perhaps P38-trained pilots were doing something subtly different than the P38 pilots who had not been extensively trained on the a/c prior to flying in combat. <HR></BLOCKQUOTE>

Once a plane is out of control due to compression, recovery is not certain. If you are lucky, you will descend low enough that mach speed drops enough for you to regain control. If you are not lucky, the tuck under will steepen the dive, increase the speed, and the aircraft will break up.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>The late J and L models solved this problem with the installation of a dive flap. Extend the flaps at the beginning of a dive and all problems were eliminated. <HR></BLOCKQUOTE>

They "solved" the problem with the dive flaps that generated a strong pitch up (ie tried to pull you out of the dive) and increased drag enormously, slowing the plane down.

A P-38 with dive flaps wasn't going to crash because of compressibility, but it wasn't going to be chasing any aircraft down in a dive either.

At mach 0.65 the drag factor went from 0.042 without the flaps deployed to 0.1 with the flaps deployed (as an example, at the same speeds the Spit, P-51 and P-47 were all at less than 0.025)

ZG77_Nagual
03-10-2005, 10:45 AM
P38 dive redline chart (http://home.att.net/~ww2aviation/RedLine.html)

GR142_Astro
03-10-2005, 10:53 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Blutarski2004:
In any case, compressibility was not a problem for any
model P-38 if the dive were entered from below 25,000 ft.
<HR></BLOCKQUOTE>

Pretty clear-cut.

Since most engagements in Forgotten Battles happen well below 25,000ft (7,620 meters), this "compressibility" that the P38 is burdened with is gimmicky and fake. Put in place simply to have an excuse to use the nifty Dive/Air Brake on the L.

Lose this feature please Oleg/1C.

http://forums.ubi.com/images/smilies/25.gif

Blutarski2004
03-10-2005, 10:56 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by RedNeckerson:

See -

Roger Freeman
_The Mighty Eighth War Manual_

P. 186 <HR></BLOCKQUOTE>


..... Yes, a very interesting book.

IIRC, Freeman also states that even the J's and L's retained a 22,000 ft operational altitude limit because the engine/turbo-charger problems were never really solved satisfactorily.

The writer talking about dives appears to describe means of limiting the onset of compression - engines to idle, aileron banking, etc. So maybe what he is talking about is taking steps to prevent excessive speed build-up.

Like I said ..... very confusing, and a lot of apparently contradictory information floating around.

LeadSpitter_
03-10-2005, 02:04 PM
the fast accelaration and slower roll, also p38s were the long range main escorts of the bomber formations and could not leave. Also the p38 which was the main long range escort fighter did not have have the freedom escort pilots did later in the war "free hunting" which was much better tactics but had to remain very close to the bombers formations basically being at the same disadvantage as the bombers.

the p38 in europe suffered from british fuels which were not tested with the supercharger slightly lower octane and very dirty early in the war and did not react well with the superchargers.

The germans and japanese suffered from the same problem late in the war from low quality dirty fuels which effected performance.

That was the problem and was solved with cleaner higher grade fuels. The so called climate conditions cool moist wet conditions had nothing to do with it and is a myth.

I've heard p38 pilots who flew in both theaters say the p38 in europe was better because of cooler temps compaired to the pacific lower alt where the p38 f suffered intercooler problems in the hot moist conditions of the pacific, Dont forget many 38s and lend lease p38fs in europe did not have superchargers lend lease ac.

the compressibility 25000-37000 only happened becuase of then thin air but did not happen lower alts. Dive flaps and elevator counter balances helped great also called "football on a stick"

Another thing i read was alot of p38L pilots would wire the dive flaps closed just like they did on the p51ai and a-36 so they would not jam open high speed.

http://img.photobucket.com/albums/v43/leadspitter/p388.jpg

k5054
03-10-2005, 04:47 PM
Not the bloody fuel again! The P-38 got the same fuel as all the other a/c operating from the UK, P-51, P-47, Spitfire, Typhoon, Mosquito, B-17,24 and 26. In no case will you find a complaint about the fuel except with the P-38. Even though the Fort, Lib and Jug all had turbos too. 'Bad british fuel' is just another excuse made up by P-38 apologists to cover a poor record by the 38 in 8th AF. Beware any source which traces back to Lockheed factory reps, test pilots or historians. They may not be totally objective.

Blackdog5555
03-10-2005, 04:51 PM
Yes, I think the developer has the compresablity of the 38 exagerated but the drag on the dive recovery flaps doesnt seemed too pronounced. According to the table a 500 mph is possible at/ near ;SL without any compressability. I use dive recovery instead of combat flaps on the L in a turn fight because u get better sustained turning radius. interesting though.

horseback
03-10-2005, 04:56 PM
The British ordered, pre-Lend-Lease version of the P-38, the P-322, was the only version lacking a turbocharger (some confusion about why; some versions have the British not trusting or wanting them & some have that it was not exported because it was top-secret technology), and except for a few that Britain evaluated and returned, did not operate outside the Continental US, being used instead for coastal defense or training.

P-38Es and Fs had turbochargers in a somewhat different looking installation than later models.

cheers

horseback

horseback
03-10-2005, 05:14 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by k5054:
Not the bloody fuel again! The P-38 got the same fuel as all the other a/c operating from the UK, P-51, P-47, Spitfire, Typhoon, Mosquito, B-17,24 and 26. In no case will you find a complaint about the fuel except with the P-38. Even though the Fort, Lib and Jug all had turbos too. 'Bad british fuel' is just another excuse made up by P-38 apologists to cover a poor record by the 38 in 8th AF. Beware any source which traces back to Lockheed factory reps, test pilots or historians. They may not be totally objective. <HR></BLOCKQUOTE>

All the other aircraft with turbos used radials, a much more robust and forgiving engine type. The Allison V-1710 was a bit touchy in a number of ways if it wasn't treated right. Flying at low speeds to keep pace with the bombers and conserve fuel, the engine was not running 'hot' enough to burn the fuel efficiently. Hence, plug fouling, pre-ignition problems, and the rest, complicated further by inadvertant abuse by pilots poorly prepared for operations in a complicated twin-engine fighter.

You also forget to note that Mustangs were notorious for plug fouling problems, their Merlins seeing much longer continuous use at high altitude and lower cruising revs than in the Spitfire engines in the same class. The problem for both cases was in the hand-mixed additives, according to some sources I've read, which didn't react the same way if the local humidity or temps differed too much, or if the fuel sat too long before use.

Part of the fault may lie with the British climate and poorly understood mixing instructions, but NOT British fuel.

cheers

horseback

Daiichidoku
03-10-2005, 06:15 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by GR142_Astro:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Blutarski2004:
In any case, compressibility was not a problem for any
model P-38 if the dive were entered from below 25,000 ft.
<HR></BLOCKQUOTE>

Pretty clear-cut.

Since most engagements in Forgotten Battles happen well below 25,000ft (7,620 meters), this "compressibility" that the P38 is burdened with is gimmicky and fake. Put in place simply to have an excuse to use the nifty Dive/Air Brake on the L.

Lose this feature please Oleg/1C.

http://forums.ubi.com/images/smilies/25.gif <HR></BLOCKQUOTE>



NO other ac type in FB/PF suffers from compressability as the P 38 does...alomst as if the 38's notoriety for being one of the first types to experience this effect, which is almost always noted in any bio on it, just HAS to be included in this game

yes, it was one of the first, but certaily not the only....yet it seems to be the only one to suffer

why were "compressability recovery flaps" installed on P 47s from the D-30 block onwards?
becuz it would compress....fly any Jug in FB....you will NEVER compress at any speed or altitude

spitfires will gleefully follow a Jug in a dive through 800kph+ np, also suffering no compress



As Asto says, I second it;

Lose this feature, please, Oleg/1C
(or subject ALL other types to this effect at appro speed/alt)

GR142_Astro
03-10-2005, 11:27 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Daiichidoku:

Lose this feature, please, Oleg/1C
(or subject ALL other types to this effect at appro speed/alt) <HR></BLOCKQUOTE>

Good points about the Jug, etc. Think I must have been going the simplistic route considering the sim is in its twilight hours.

Would seem to be a ton of work to begin adding compress on all planes.

Bull_dog_
03-11-2005, 11:39 AM
I don't have statistics on compressibility deaths, but I understand based on things I've read that compressibility was encountered first by test pilots...once it was known, pilots were trained not to dive from altitudes over 25K...

The actual number of fatalities due to compressibility among combat pilots is low relative to the amount of press the phenomenom gets....this is also true when you realize that in the Med and Pacific combat missions and fights occurred at altitudes low enough to make compressibility a non issue....only the heavy bomber escorts had to deal with it on a regular basis....

For those who think this game/sim is based only on quantitative facts it is not...there are many qualitative interpretations around DM's and quirks in aircraft that Oleg tries to model...If I were to model a Lightning, I'd either model compressibility right or not at all...it is a far worse thing to model it incorrectly especially with all the facts around that demonstrate that the current modelling is erroneous.

Blackdog5555
03-11-2005, 12:32 PM
Bull_dog, I agree, that with compressability, it should be modeded right/correctly and it should be modeled in all planes correctly, or not at all. Sim models are "relative". cheers BD

stathem
03-11-2005, 03:24 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by horseback:
The British ordered, pre-Lend-Lease version of the P-38, the P-322, was the only version lacking a turbocharger (some confusion about why; some versions have the British not trusting or wanting them & some have that it was not exported because it was top-secret technology), and except for a few that Britain evaluated and returned, did not operate outside the Continental US, being used instead for coastal defense or training.

horseback <HR></BLOCKQUOTE>

The British version didn't have counter-turning props either.

bolillo_loco
03-14-2005, 05:38 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by k5054:
Not the bloody fuel again! The P-38 got the same fuel as all the other a/c operating from the UK, P-51, P-47, Spitfire, Typhoon, Mosquito, B-17,24 and 26. In no case will you find a complaint about the fuel except with the P-38. Even though the Fort, Lib and Jug all had turbos too. 'Bad british fuel' is just another excuse made up by P-38 apologists to cover a poor record by the 38 in 8th AF. Beware any source which traces back to Lockheed factory reps, test pilots or historians. They may not be totally objective. <HR></BLOCKQUOTE>

yes but your forgetting one thing, the 38 could pull a lot more manifold pressure at those altituded than could the other a/c. it is well documented that the english did not blend the gas very well. the problem was addressed and fixed. also consider that contrary to popular believe the 38 flew at high altitude in every other theater of war and did not experience the mechanical engine failures as did the men of the 20th and 55th fighter groups. the boys using 38s in north africa and italy fought at the same altitudes against the same germans as did the 20th and 55th. the 38 did as well as the 51 and 47 did in every other theater, so doesnt that make you sit back and suspect that the 20th and 55th fg tactics, pilots, and mechanics had more to do with the failure of the 38 in the eto that did the 38?

all you have to do is take a long hard look at the 20th and 55th fg. after they made the transistion to the 51 they did no better than they did with the 38. during the month of november 1944 is the only time that they actually did well and this time period coencides with a massive allied assualt which the germans put up the most a/c to counter the allies during the entire war. so considering the fact that they went on to use 51s and they used them during a time when there were a lot of novice/green/unseasoned german pilots and they also had the advantage in numerical superiority.. why did the 20th and 55th do so poorly when other mustang groups were shooting down germans in droves?

all that leads me to believe that the 20th and 55th fg suffered moral, command, poor tactics, etc.......it once again boils down to the pilot........not the plane.

249th_Harrier
03-14-2005, 09:21 PM
P-38G,H, and J were excellent long range, multirole fighters below 25k ft altitude. The design was poorly suited to 5 hour 30k+ alt escort missions. P-38 pilots in the MTO primarily escorted medium bombers and attacked air transport before the 15th air force was formed. They built up a lot of experience before they started B-24 escorts. And not all of these missions were at high altitude. Quite a few were Carpetbagger missions at low altitude, dropping supplies to Yugoslav partisans. 55th and 20th pilots were inexperienced pilots, thrown into a fight where every mission was pushing the limits of what could be done with their machines. It is no surprise that they didn't rack up kills, but it is to their credit that they were able to materially reduce bomber losses and force the Luftwaffe to divert resources.

Anyway, this is the wrong forum for this discussion.

BigKahuna_GS
03-16-2005, 11:35 AM
S!

quote:
--------------------------------------------------------------------------------
Originally posted by k5054:
Not the bloody fuel again! The P-38 got the same fuel as all the other a/c operating from the UK, P-51, P-47, Spitfire, Typhoon, Mosquito, B-17,24 and 26. In no case will you find a complaint about the fuel except with the P-38. Even though the Fort, Lib and Jug all had turbos too. 'Bad british fuel' is just another excuse made up by P-38 apologists to cover a poor record by the 38 in 8th AF. Beware any source which traces back to Lockheed factory reps, test pilots or historians. They may not be totally objective.
__________________________________________________ _________________________



Brit fuel was one of many problems the P38 was experiencing in Europe. Unfortunitly ETO P38 pilots were instructed in the wrong way to fly long distance in the US prior to shipping out. They were trained to use high RPM and low MAP when cruising on combat missions. This was very hard on the engines and not consistent with either Lockheed or Allison technical instructions.

It appears the fuel providied in England for the P38's during the winter of 42/43' was not entirely adequate, as the TEL would condense in the manifolds, particularly during cruise and lead to destructive dentonation.

The improved intercoolers were providing considerably lower manifold tempatures, which allowed TEL condensation during cruise as well as increasing the likelihood of plug fowling.

The P38H had a WEP rating of 1,425bhp, the P38J had a WEP rating of 1600bhp. Exacting maitenance at this WEP rating was critical. Exhaust plugs were to be changed after every flight that WEP was pulled. This was not always done, leading to lead fouling and an increased chance of detonation during subsequent operations at WEP.

Gen.Doolittle commander of the 8th Air Force thought the fuel problem enough to sign an order in March 1944 for a special fuel blend just for P38 operations.

Vee for Victory pg143,144


__

hop2002
03-16-2005, 01:25 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Not the bloody fuel again! The P-38 got the same fuel as all the other a/c operating from the UK, P-51, P-47, Spitfire, Typhoon, Mosquito, B-17,24 and 26. In no case will you find a complaint about the fuel except with the P-38. Even though the Fort, Lib and Jug all had turbos too. 'Bad british fuel' is just another excuse made up by P-38 apologists to cover a poor record by the 38 in 8th AF. Beware any source which traces back to Lockheed factory reps, test pilots or historians. They may not be totally objective. <HR></BLOCKQUOTE>

100% agree.

Figures from the recollections of Lockheed engineers are being bandied about as gospel, despite there being no evidence they were ever used apart from in Lockheed test aircraft.

So far no-one has produced any evidence that the USAAF actually ran their Lightnings with more than 1600 hp per engine.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>yes but your forgetting one thing, the 38 could pull a lot more manifold pressure at those altituded than could the other a/c. <HR></BLOCKQUOTE>

Not at all.

Spitfire IXs were pulling 18 lbs boost (67" manifold pressure) up to about 27,000ft, and don't seem to have had fuel problems doing it.

That's higher manifold pressure at those sort of altitudes than the P-38, and far higher than the early models that began reporting the problem.

The P-38 had major engine problems (intercoolers, radiators etc cooled too much at altitude).Trying to blame those on the fuel is a bit silly.

BigKahuna_GS
03-16-2005, 02:19 PM
S!
__________________________________________________ _________________________
hop2002 posted Wed March 16 2005 12:25
quote:
Figures from the recollections of Lockheed engineers are being bandied about as gospel, despite there being no evidence they were ever used apart from in Lockheed test aircraft.
So far no-one has produced any evidence that the USAAF actually ran their Lightnings with more than 1600 hp per engine.
__________________________________________________ _________________________



Incorrect Hop.


P38L :

"The F-30 engine was still rated as the F-17's but incorperated many internal improvements, most notably the 12-counterweight crankshaft. As a consquence it could be operated up to 3200rpm. Using 150 fuel it could deliver 1,725bhp under WER conditions."

Directly from Allison Aircraft engines.

Vee's for Victory pg145

I got a personal email directly from Warren Bodie explaining this. The Allison engine rating stayed the same when factory installed in the P38L's(1725bhp-WER,3200rpm). It is just that at the time the USAAF was not comfertable with recommending engine operation above the 3000rpm level. But in combat you do whatever is necassary to win and it was common place for these engines to be operated at max capacity--3200rpm @ 1725 brake horse power in the ETO & PTO.

That is a difference of 300bhp @ WER.


As for the Brit fuel issue read my post below B-locos.



____

hop2002
03-16-2005, 02:34 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>ncorrect Hop.


P38L :

"The F-30 engine was still rated as the F-17's but incorperated many internal improvements, most notably the 12-counterweight crankshaft. As a consquence it could be operated up to 3200rpm. Using 150 fuel it could deliver 1,725bhp under WER conditions." <HR></BLOCKQUOTE>

P-38s never got 150 octane fuel in service.

The only service users of 150 fuel were RAF ADGB (from Spring 1944), US VIII AF (from summer 44), RAF 2nd TAF (from Dec44/Jan45).

AFAIK, P-38Ls never operated with any of these forces during the time they were using 100/150 fuel.

I've no doubt Lockheed demonstrated such engine ratings, they were after all anxious to keep P-38 production going, but again I've never seen any evidence that it was actually used.

For that, you need to find some USAAF sources showing the use of such ratings, not Lockheed sources.

Blackdog5555
03-16-2005, 05:25 PM
the P-38s were in the 364th in the mighty 8th.
http://www.oldgloryprints.com/Coming%20in%20Over%20the%20Estuary.htm

So they had Purple Passion available. right?

hop2002
03-16-2005, 07:30 PM
Only Js, and a few very early Ls afaik.

The stuff I have seen for 150 octane shows no increased ratings for Allison engines, so the P-38Js probably couldn't take advantage of 150 octane fuel, even if they did use it for a brief period.

The early P-38Ls had the same engines as the J, again afaik (the L at the JFC had -17 engines, I believe).

And, again afaik, Allison didn't clear the F30 for the higher ratings until October 44, by which time I'm pretty sure the P-38 was out of the USAAF.

(There's a lot of afaiks and believes there, so I stand to be corrected on any of that I've got wrong)

249th_Harrier
03-16-2005, 10:05 PM
There are a lot of conspiracy theories regarding the p-38 problems in service with the 8th AF. I don't think it is sacriledge to suggest it was mediocre when forced into a role it was poorly suited. The Lightning had a huge impact on the war in Europe, but more in the MTO than the ETO. Wasn't it important to keep the Suez canal and the middle east oil fields out of Axis hands? Wasn't it important to take Italy out of the war? Wasn't it important to establish a base of operations to bomb the Ploesti oil fields, mine the Danube, and make aid drops to Yugoslav partisans? Most of all, wasn't it important to divert resources from the eastern front at a time when the outcome of the war with the Soviets was still in doubt? The p-38 was a great design that accomplished great things. On escort missions at 30,000 ft for over 5 hours, with green pilots, it was not the best solution. Why blame the gas? Why blame the top brass? Why blame the pilots and the mechanics? For the 8th AF escort mission profile, the p-51 and p-47 with drop tanks were better, period.

BigKahuna_GS
03-16-2005, 11:54 PM
S!

Hi Guys,

Brit gas was just one of many issues for the P38 in the ETO. Also it must be remembered that the P38 was extremely succesful in the PTO and flew at similar high altitudes.

Altitude is altitude and the P38 in the PTO had very few engine and fuel issues. In fact Allison and Lockheed at first thought the ETO pilots to be just a bunch of whiners.

The differences between the ETO vs PTO were most of all pilot training with the ETO pilots actually being trained incorrectly in long range flight and operation of the engines back in the US. This incorrect training caused catastrophic engine failures.

Next was the enviorment, electronics and batteries were subjected to some of Britains coldest winters at night and then flown again in the subzero cold of high altitude. The cold-soaking of electrical equipment/batteries was a major issue during the winter of 43'.

Tatical mistakes, the early P38 squadrons were out numbered by the Luftwaffe and were forced to stay close to the bombers formations giving away any advantages they might of had. There was no free roaming ahead of the bomber stream to intercept enemy formations. That is the same complaint 109 pilots had escorting He111's during the Battle of Britain.

The tactical solutions in the PTO were more fluid and incorperated differential throttle and prop pitch control to wring out all the performance of the P38's roll rate and turning ability. These manuevers were not widely known in the ETO. Diving after enemy A/C in the PTO was common place, in the ETO not practiced do to pilot skill levels and fear of compressing.

Finally if Brit fuel was not a source of engine problems then why did Gen.Doolittle commander of the 8th Air Force sign an order in March 1944 odering a special fuel blend for P38 Fighter Groups ?

If ETO P38 pilots had had the proper training and were allowed more tactical freedom to fight from a superior position, I think they could have been just as succesful as their counterparts in the PTO.

Here is an actual USAAF P38J test. The AEP/PF P38 does not have the same performance specs in WEP and climb.

Here are official performance numbers of an USAAF fighter evaluation of the P38J-10, P47D-10, P39Q-5 and P51B. The P38J-10 serial number AC42-67869 was flown by 3 pilots during a 30hour accelerated flight test on December 2, 1943.

Maximum horsepower at 60.8 inches of Hg manifold pressure, 3000rpm was listed at 1,612 brake horse power (WEP) per F-17 Allison engines. (P38 J10-LO) pg.213 "The Lockheed P38 Lightning" by Warren M. Bodie Lockheed engineer/historian.

USAAF flight test results P38J-10 :
Maximum Sea Level speed -----------------------------345mph
Maximum critical alt speed --------------------421.5mph (WEP) (25,800ft)
Rate of climb (SL) ----------------------------------4000fpm
Rate of climb (critical alt) ------------------------2900fpm (23,400ft)
Time to critical alt --------------------------------6.19 mins. (23,400ft)
Service ceiling -------------------------------------40,000ft



The P38J had the F-17 engines rated at 1600bhp-WEP. Logically, the next version of the P38L with Allison F-30 engines would be more powerful.
The P38L was fitted with high-output Allison F-30 engines capable of 1,725hp (WEP) rating.

I have contacted the USAF historical archives to find flight test information at this WEP rating. Because the USAAF was being conservative and telling their P38L pilots only to operate at 3000rpm, that will be the ratings listed in the information printed in the pilots handbooks.

This is a direct email to me from Warren Bodie Lockheed engineer/historian and currently a featured writer for Flight Journel magazine. Bodie worked closely with Kelly Johnson and Gen.Kelsey (USAAF)P38 flight test pilot when writing his book. Bodie also cites Whitneys excellent book Vee's for Victory as his source for Allison engine specs.

Bodie:


----- Original Message -----
From: Warren Bodie
To: 'Keith'
Sent: Friday, March 11, 2005 10:30 AM
Subject: RE: P38L WEP rating of 1,725hp


Hello Keith,


"What in the world is going on outside of my small enclave of residents here on the shore of beautiful Lake Chatuge?
I am being deluged this week by all sorts of people wanting to know if I can provide the best possible accurate info on several related and unrelated av subjects. What will happen when the new Special Edition of FLIGHT JOURNAL gets into circulation in the next couple of weeks. I have a feature story in there on the subject of Supermarine Spitfires.
They only used half of what I submitted, but they are constrained by top management to about 7 or 8 pages for any one story. Umpteen thousands of Spitfires in more models and modified models than anyone can believe were in the fight during WWII.

First of all, let me advise you that with my 43 years of experience in various engineering jobs in the manufacturing industry, and having been on very friendly basis with people from Kelly Johnson and Gen. Ben Kelsey to Jack Northrop and a host of others (I have been a senior service engineer specialist, technical publications supervisor, structural repair designer, etc.,), there are no two engines or no to airplanes that perform to exactly the same level anywhere in the world. Too many manufacturing, rigging, adjusting, etc. factors involved, not to mention what each flight hour does to different airframes and engines of the same model, for any two engine-airplane combinations to perform in the same, exact way. I suspect that even two identical appearing cement blocks might not give exactly the same results. Airplanes are subjected to too many different actions and material combinations to work anywhere near exactt standards.

The really most definitive book on the subject that you have forwarded to me is the great study and product from my friend, Daniel D. Whitney. Published by Schiffer Publishing Ltd. with ISBN: 0-7643-0561-1; try your local bookstores first, then, if unsuccessful, e-mail to schifferbk@aol.com for info.

But, meantime get this single fact: Allison Engineering qualified the F-30 engine WER at 1,725 bhp at 3200 rpm. However, the USAAF NEVER authorized that rating, with ATSC preferring to stick with a 3000 rpm limitation. These engines were in Lockheed P-38L, F-5G and P-38M airplanes. Aircraft installation, maintenance, rigging, supercharger performance, propeller performance, etc. all affected individulal engine and airplane performance. And, as certain pilots, including the great Col. Cass Hough who shared command with Col. (later B/Gen.) Ben Kelsey, would have been glad to tell you, if you needed more in combat situations, you did whatever was necessary to escape being defeated. If you did it right and if you were lucky enough to have a top-quality PRODUCTION engine set, you won the game. Ben Kelsey would be among the first to agree with me on that assessment. (Just think of how many things can affect friction in an operating engine, with detonation being the most fierce ingredient and fuel being high on the list as well.

No matter who throws other figures at you, with little to fall back on (maybe even Martin Caidin's pitiful Lightning book as a reference), you will not find a better reference source than Dan's book. He pursued facts for years, maybe decades. I never asked. Read the back, inside dust jacket of the book, before you read it. You will learn about Dan's background. When I did my P-38 book, I had already retired from 40 years in the aerospace industry, several years (decades), in fact, of writing for magazines as a side effort. Dan focused on one primary subject out of several millions that could have attracted his attention. His coverage is indisputable. And don't let anyone tell you otherwise.

Cordially, Warren Bodie


____


B/Gen.) Ben Kelsey, would have been glad to tell you, if you needed more in combat situations, you did whatever was necessary to escape being defeated.B/Gen.)

That means operating at 3200rpm @ 1,725bhp WEP rating. According to Allison engine techs this was common place.

__

Daiichidoku
03-17-2005, 05:12 PM
who knows? maybe in BoB we will get a CORRECT lightning....if at all

SkyChimp
03-17-2005, 06:48 PM
I've perused my copy of "Vees For Victory" and can't find any evidence that the USAAF "permitted" such high manifold ratings such as to generate 1,700+ bhp. Can't find anything that says it wasn't used anyway. We already know that 8th AF P-47 groups were running at higher than permitted manifold pressures. So I'm not sure that it wasn't done, even if it wasn't officially sanctioned.

BTW, I can't find any references to "fuel problems," either. I did find that the P-38 suffered from vapor lock due to improper fuel metering. Also found that the recce Spitfires flown by the 8th suffered the same problems.

BigKahuna_GS
03-17-2005, 10:35 PM
S! Skychimp

I am waiting for an email back from Daniel Whitney on this matter. According to Bodie who is close friends with Whitney, Allison engine techs were in the ETO always monitering the P38 engine performance. It was Allison engine techs that told Whitney that operating the F-30 engines at 1725bhp was a routine matter. In other words everybody was flying the P38L this way.

P38L :
"The F-30 engine was still rated as the F-17's but incorperated many internal improvements, most notably the 12-counterweight crankshaft. As a consquence it could be operated up to 3200rpm. Using 150 fuel it could deliver 1,725bhp under WER conditions."
Directly from Allison Aircraft engines.
Vee's for Victory pg145


Skychimp if you have any USAAF speed and climb curves for the P38J and P38L (like the Dec. 2nd 1943 P38J flight test above could you please PM me.
I have requested this from the USAF historical archives but the documents have not arrived yet.

If you read Warren Bodie's email to me it says :

But, meantime get this single fact: Allison Engineering qualified the F-30 engine WER at 1,725 bhp at 3200 rpm. However, the USAAF NEVER authorized that rating, with ATSC preferring to stick with a 3000 rpm limitation. These engines were in Lockheed P-38L, F-5G and P-38M airplanes.


Using 3200rpm and 1,725bhp during combat :

And, as certain pilots, including the great Col. Cass Hough who shared command with Col. (later B/Gen.) Ben Kelsey, would have been glad to tell you, if you needed more in combat situations, you did whatever was necessary to escape being defeated.

The USAAF played it safe and told the pilots not to go over the 3,000rpm setting. If you had another 200rpm & 250bhp avaialble during air combat manuevering would you use it ? Bet your butt you would.


Concerning Brit fuel:
Unfortunitly ETO P38 pilots were instructed in the wrong way to fly long distance in the US prior to shipping out. They were trained to use high RPM and low MAP when cruising on combat missions. This was very hard on the engines and not consistent with either Lockheed or Allison technical instructions.
It appears the fuel providied in England for the P38's during the winter of 42/43' was not entirely adequate, as the TEL would condense in the manifolds, particularly during cruise and lead to destructive dentonation.
The improved intercoolers were providing considerably lower manifold tempatures, which allowed TEL condensation during cruise as well as increasing the likelihood of plug fowling.

The P38H had a WEP rating of 1,425bhp, the P38J had a WEP rating of 1600bhp. Exacting maitenance at this WEP rating was critical. Exhaust plugs were to be changed after every flight that WEP was pulled. This was not always done, leading to lead fouling and an increased chance of detonation during subsequent operations at WEP.

Gen.Doolittle commander of the 8th Air Force thought the fuel problem enough to sign an order in March 1944 for a special fuel blend just for P38 operations.

Vee for Victory pg143,144


_______

Blackdog5555
03-18-2005, 12:22 AM
Another interesting fact about the 150 oct I found in my research is that the P51D using 150 octane, purple passion, at 80 inches of maniford at Sea Level could do an amazing 396mph. thats 396mph at sea level. they used it in P47s to catch V1 rockets too. Im sure it was hell on the engines. but dam!~ BD..

BTW cool e-mail Kahuna

WWMaxGunz
03-18-2005, 08:25 AM
I had a neighbor who used avgas in an old lawnmower to cut down the small field that her
back yard had become. Yes, her. And she was a racing bike mechanic. The mower didn't
break but it did plow right through almost 2 foot growth at about regular lawncut speed.

ZG77_Nagual
03-18-2005, 08:52 AM
Kahuna

I trust you are in touch with Oleg - or are planning to be? Hopefully soon or allready as I sense the patch - which is really going to be more like a HUGE add-on - will soon be in our midst. I expect we won't see too many more upgrades to this amazing simm so it would be good to get our P38 patched while the patchin's still good http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Blutarski2004
03-18-2005, 09:05 AM
Just for yucks, this is what Roger Freeman had to say about ETO P38 engine woes -

QUOTE-

The P-38H with upratedengines and revised turbo-supercharging to give better high altitude performance, also featured automatically-operated air cooling radiator flaps designed to obviate pilot error.

<snip>

High altitude performance proved disappointing with persistent engine difficulties at between 25,000 and 30,000 feet, mostly diagnosed as the old problem of turbo-supercharger inter-cooler inefficiency causing overheated air to be fed to the carburettors.

<snip>

The original inter-cooler system in the P-38 (cooling the compressed air before it was fed to the carburettors), neatly housed in the leading edge of the wings, was not efficient at altitude. The main change between the original J models and the H was the repositioning of the inter-cooler under the engine between the oil radiators, the whole enclosed in an enlarged housing,...<snip>. Unfortunately, the J model did not overcome engine failure or cockpit heating problems.

The engine problems were two-fold. Repositioning the inter-coolers led to too much cooling at high altitude and pre-detonation. Oil temperature also could not be kept high enough above 22,000 feet, and oil consumption rose at an alarming rate, particularly above 25,000 feet. In fact average consumption rate of two to four pints per hour for missions when flying below 25,000 feet rose to from eight to 16 pints per hour at 25,000 to 30,000 feet. Oil throwing due to low temperatures wasso bad that engine life was halved. Moreover, the the sudden increases in power necessary in combat, engines seized or threw connecting rods. Yet another problem was that common to all turbo-supercharged aircraft with hydraulic actuated regulators; low temperatures thickening the oil and allowing the turbine to go out of control and fail. In late February 1944 the two P-38 groups adopted a policy of making the penetration flight at not more than 22,000 feet to avoid the extreme cold. Additionally, every 20 minutes power settings were increased to 3000 rpm and 45" Hg for 30 seconds to raise temperatures and clear the engines. A portion ofthe inter-cooler radiator was blocked off to achieve higher temperatures, while the 20th Group tried piping hot air from the engine exhaust to th esupercharger regulator. these actions eased but did not eliminate the troubles. Oil regulators became the most critical replacement part for the P-38Js by late March. In an effort to control oil consumption wedge-type piston rings were fitted to the Allisons of a 55th Group P-38J, but one engine failed after 44 hours flight time. Another approach was the use of the new 150 octane grade fuel which was tested in two 55th Group P-38Js during the same month in the hope of improving performance.

<snip>

In July 1944 a further cause of engine trouble was identified. It had previously been established that fuel was not being metered properly at high altitude, the problem varying from aircraft to aircraft. Operational Engineering found one cause was vapour lock in the fuel system, minimising it by simplifying the plumbing to eliminate or reduce sharp bends. Nevertheless, poor fuel metering at altitude, with incipient detonation providing the immediate cause of engine failure, still persisted and was recognised as a basic deficiency plaguing the operation of Lightnings during previous months.

- UNQUOTE


Interesting side note - that 150 octane fuel was available in the ETO as early as March 1944.

BigKahuna_GS
03-18-2005, 12:52 PM
S!


__________________________________________________ ________________________
ZG77_Nagual posted Fri March 18 2005 07:52
Kahuna
I trust you are in touch with Oleg - or are planning to be? Hopefully soon or allready as I sense the patch - which is really going to be more like a HUGE add-on - will soon be in our midst. I expect we won't see too many more upgrades to this amazing simm so it would be good to get our P38 patched while the patchin's still good
__________________________________________________ ________________________



Rgr that Nagual.

I have sent all that I have and Oleg is listening. But and this is a big but, Oleg wants the speed and climb curves for these brake horsepower ratings. I have requested then from the USAF historical archives.

They are a long time coming.

If anyone already has them please let me know and send them to Oleg.


____

ZG77_Nagual
03-18-2005, 01:33 PM
Outstanding! On behalf of the uber-civilized and cunningly well-informed P38 enthusiasts lobby I applaud your efforts!

Blutarski2004
03-18-2005, 02:09 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by 609IAP_Kahuna:
Oleg wants the speed and climb curves for these brake horsepower ratings. I have requested then from the USAF historical archives.

They are a long time coming.

If anyone already has them please let me know and send them to Oleg.
<HR></BLOCKQUOTE>


Kahuna,

Not certain what particular curves you are looking for, or what provenance is required, but check these out if you have not already seen them -

http://home.att.net/~ww2aviation/P-38-3.html

Carlo Kopp has posted climb-versus-time and speed-versus-altitude graphs for the P38L-5-LO @ 1725 hp WEP as part of his article. The graphs indicate that the data are courtesy of Lockheed-Martin.

Also provided is a very nice roll rate-versus-speed graph which goes a LONG way toward explaining what a great difference boosted ailerons made in roll performance. Over 350mph TAS the P38L (and the P51) would out-roll the FW190A-4. And, since we know (courtesy of Kurfurst) that the late model 109's were about ten pct inferior in roll rate to the FW190A series, it can be reasonably interpreted that the P51 would out-roll a 109G series above 325 mph TAS or so - although from the look of the P51 graph it seems that below 300 mph both German fighters would have a pretty good roll rate advantage.

For whatever it's worth.

BigKahuna_GS
03-18-2005, 04:32 PM
S!


Thanks Blutarski2004 http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif


I am not sure how Oleg will view these charts. I had seen these charts along time ago--wasnt sure if he would accept them,but sent them just the same. From what Oleg is requesting, I think official docs from Lockheed & USAAF with atmospheric conditions are in order.

Some of these official speed and climb curves are listed in Vee's for Victory. This is a terrific book, highly recommend it. Along with Warren Bodie's book "The Lockheed P38 Lightning" they are the 2 best P38 books out there. I wish I could post scans of the books here to show you what I mean.


___

k5054
03-18-2005, 04:34 PM
Hooray, more Lockheed-produced data. Carlo kopp is not a neutral observer, nor is Corey Jordan, the source of most of the yarchive posts (my own posts from that time seem to have been edited out).

Does anyone think that increasing the speed of the engine to get more power might have some effect on the prop efficiency? turnig the prop 6.6% faster at top speed might just push the tips into mach trouble. You cannot therefore assume that the top speed of the 38L was much better despite the (disputed)1725hp. There was definitely no change of reduction gear ratio, although Lockheed would have liked to do so, as they did on the K prototype.
I still haven't seen the brit fuel deal explained, I reckon its an excuse.
Pilot training? The guys in the PTO just jumped out of their P-40s and into the 38s. No moaning there. Of course the 38 had a speed advantage of 60mph over its fastest opponent in the PTO in 1942-3. Nobody seems to mention the luftwaffe when explaining (excusing) the 38s record in the 8th AF.

BigKahuna_GS
03-18-2005, 05:29 PM
S!

__________________________________________________ ________________________
k5054 posted Fri March 18 2005 15:34
Hooray, more Lockheed-produced data. Carlo kopp is not a neutral observer, nor is Corey Jordan, the source of most of the yarchive posts (my own posts from that time seem to have been edited out).
__________________________________________________ ________________________




The information listed is from "Vee's for Victory" by Daniel Whitney. Whitney's background as a Mechanical and Nuclear engineer is quite impressive. Whitney is not affiliated with either Lockheed or Allison but his study is the result of years of independent research on Allison Aircraft engines during WW2. Whitney's book is considered the definitive book on this subject.

I am waiting for an email back from Daniel Whitney on this matter. According to Whitney, Allison engine techs were in the ETO always monitoring the P38 engine performance. It was Allison engine techs that told Whitney that operating the F-30 engines at 1725bhp was a routine matter. In other words everybody was flying the P38L this way.

P38L :
"The F-30 engine was still rated as the F-17's but incorperated many internal improvements, most notably the 12-counterweight crankshaft. As a consquence it could be operated up to 3200rpm. Using 150 fuel it could deliver 1,725bhp under WER conditions."
Directly from Allison Aircraft engines.
Vee's for Victory pg145

I have posted the Brit fuel problem 3 times as quoted from Vee's for Victory. Guess you didnt read it.


___

WWMaxGunz
03-18-2005, 08:25 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by k5054:
Hooray, more Lockheed-produced data. Carlo kopp is not a neutral observer, nor is Corey Jordan, the source of most of the yarchive posts (my own posts from that time seem to have been edited out).

Does anyone think that increasing the speed of the engine to get more power might have some effect on the prop efficiency? turnig the prop 6.6% faster at top speed might just push the tips into mach trouble. You cannot therefore assume that the top speed of the 38L was much better despite the (disputed)1725hp. There was definitely no change of reduction gear ratio, although Lockheed would have liked to do so, as they did on the K prototype.
I still haven't seen the brit fuel deal explained, I reckon its an excuse.
Pilot training? The guys in the PTO just jumped out of their P-40s and into the 38s. No moaning there. Of course the 38 had a speed advantage of 60mph over its fastest opponent in the PTO in 1942-3. Nobody seems to mention the luftwaffe when explaining (excusing) the 38s record in the 8th AF. <HR></BLOCKQUOTE>

Relax a bit about what the extra revs may mean at the prop tips and reread where Oleg
asks for the actual performance data of the planes.

You do know that prop tip speed is not just rpms but also forward speed to form the
helix of travel? So for acceleration from lower speeds the extra revs should give
a little more efficiency than at full tilt boogie, no? I wonder of sim modelling is
down to such detail as the effective tip speed including forward motion component?
But that's why those performance figures are so important, to remove some of the
purely theoretical "it musta/should be's" like what gets posted here ad nauseum.

Blackdog5555
03-19-2005, 12:10 AM
The fuel thing is easy to research. "The" story is the cold caused the ethyl lead to come out of solution in the Brit's AVgas. for some reason the P38's Allison were seriously affected by this (as reported). Also too efficient intercoolers may have been a factor in causing this (as reported). Too efficient oil cooling caused problems with the supercharger regulator (as reported). This cr*p has been posted to death. The early P38s droped valves as a result (blew alot of engines too). Plug fouling was also a problem. these things were remedied in the J and L's. Do us all a favor, K5054, and do a little research before you post. You argue for arguement's sake. Like a soap opera. Der... do you think more power will make a plane go faster? Duh.

k5054
03-19-2005, 04:42 AM
Oh, I've read the fuel story, I was trying to get somebody to explain why it was the fuel's fault, not a poor engine installation. Among the RAF a/c which operated with the same fuel were Allison Mustangs which operated at 70 in hg, albeit without turbos. Now, the GE turbo installation was supposed in theory (and GE's intent) to deliver air at s/l pressure to the engine, so back pressure was the same and the engine-driven supe would actually provide the boost over 1 ata. So the allison ought to have been seeing the same conditions whether turbo or normal at s/l. The RAF quickly resolved all the problem they had with the mustang I. The same over-cooling of the oil resulting in high temps because of 'coring'. But for some reason nobody could provide quick fixes for the P-38 even though it was operated in british climate for a periods in 1942 (with no real ops) before they went to N Africa. The point perhaps is that Lockheed had years to fix the problems and weren't too quick about it. This is model J we're talking about. (Incidentally, the too-efficent intercooler came in with the J, it was not fixed by the J). The 38 had been in service for years. For any other a/c this would rightly be sen as a fault of the manufacturer and/or the operating service. For the 38, uniquely it seems, efforts were made to blame the men, the commanders, the fuel, the weather, everything but the plane. That these efforts go on to this day despite being blown away years ago, is the reason I can't resist the temptation to post whenever I see P-38 bigotry.

I did my research and posted it long ago. It said that the P-38 in 8th AF service took six times as many sorties to score a kill as the P-51 (in its new merlin from, and suffering all kinds of teething troubles too) and suffered an equal loss rate despite the theoretical advantage of twin engines.

BigKahuna_GS
03-19-2005, 07:39 AM
S!

k5054 the question that needs to be explored is why operationaly did the PTO P38's not suffer the same problems as the ETO P38's ?

What was the difference between the 2 theaters of operation ?

I listed many differences.

I never blamed the new pilots that flew the 38 in the ETO, I blamed their training. Big Difference. When you operate engines at high RPM and low MAP settings over long distances it is very hard on engines and caused catistrophic engine failures.

You will notice that when Charles Lindberg was in the Pacific as a technical rep teaching pilots how to stretch their combat radious he flew with low RPM settings and higher MAP. Exactly the opposite of what the new ETO pilots had been trained to do.

The PTO P38's were very succesful against mid and late war japanese fighters of all types. The P38 did not have a 60mph speed advantage over the Frank, George, Raiden and Shinden. Many USAAF PTO Fighter Groups asked for and recieved the P38 over any other fighter type avaiable including the P51 and the P47N. Why ?


_____

ZG77_Nagual
03-19-2005, 02:44 PM
I think it's pretty clear there were a combination of factors. The P38 was a complex A/C - it was on the scene when the luftwaffe had the advantage in numbers and pilot skill and it had problems - particularly in cold conditions. Pilot training and experience was also a factor - and we've all sseen the memo about additional hours needed to keep it together in the P38. Obviously no one of these factors needs the blame and just as obviously - the p38 was a remarkable plane under the right circumstances. I'd agree the mustang was better - because it was cheaper and easier to fly. It's teething problems were offset by a more advantageous tactical situation (larger numbers vs a degraded enemy, alt, range etc.) and a shorter learning curve. From what I've been able to tell the p38's problems were amplified by the cold - it took a good long time and probably a gifted pilot to fly well and it was often at a disadvantage tactically during much of it's employment in the ETO - both because of the opponent at that time - and because of the rules of engagement. None of that says it was not an excellent fighter.

WWMaxGunz
03-19-2005, 06:24 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by 609IAP_Kahuna:
S!

The PTO P38's were very succesful against mid and late war japanese fighters of all types. The P38 did not have a 60mph speed advantage over the Frank, George, Raiden and Shinden. Many USAAF PTO Fighter Groups asked for and recieved the P38 over any other fighter type avaiable including the P51 and the P47N. Why ?


_____ <HR></BLOCKQUOTE>

It could be just the success rate but it could be another thing included.
Go talk to =any= pilot who flies across big stretches of water and ask about single versus
multi-engine. It's not the same over land.

p1ngu666
03-19-2005, 06:29 PM
for what its worth, merlin engines on lanc, crews where instructed to use the lowest rpm possible to get 200mphish cruising speed. dont know what manifold pressure they used. but was low rpm, high boost

BigKahuna_GS
03-20-2005, 03:54 AM
S!

I argee with you guys.

In the ETO it was several elements contributing to the problems hampering P38 performance. When USAAF looked at the problems they saw an alternative in the P51 that was less exspensive, required less maintenance, easier for pilots to learn to fly and still high performance. It was a simple choice to make. Too bad the P-38J25-LO and P-38L's didnt have the opportunity to reedem themselves fully by this point. But they did shine in the PIO thoigh

I do like the P38 comments after the bugs were fixed and hydraulic airlerons were added :

"Nothing, to these pilots, after the hard winter of 1943-44 could be more beautiful than a P-38L outrolling and tailgating a German fighter straight down, following a spin or split-S or whatever gyration a startled, panicked and doomed German might attempt to initiate. You just couldn't get away from the P-38L. Whatever the German could do, the American in the P-38L could do better." (cited from [8] with permission from Arthur W. Heiden)."

The P-38J25-LO and P-38L's were terrific. Roll Rate? Ha! Nothing would roll faster. The dive recovery flaps ameliorated the "compressibility" (Mach limitation) of earlier Lightnings. An added benefit of the dive recovery flaps was their ability to pitch the nose 10-20 degrees "up" momentarily when trying to out turn the Luftwaffe's best, even when using the flap combat position on the selector. Of course the nose "pitch-up" resulted in increased aerodynamic drag, and must be used cautiously. High speed is generally preferred over low speed in combat situations. Properly flown, the Fowler flaps of the P-38 allowed very tight turning radius."

Max you are right about the pilots wanting the P38 because of the spare engine to fly across vast areas of ocean in the PTO. That was one of several, climb rates superior to P51 & P47, very long range, dive, fowler flaps and a larger bomb/rocket payload than than P51

Pling your right too---Very low RPM and and high map on duratrion flights.


______

BSS_CUDA
03-20-2005, 07:27 AM
since I had to work yesterday. and it was an extremley slow day, I spent most of my time surfing and researching the 38, I can co back and post the URL's if needed, but the one key theme that I kept running across was that, the main reason that in the ETO they used the 51 over the 38 was cost and maintanence, it was not the abilities of the aircraft. in fact in most of the pages that I found it said that the P38 was better than the P51 in almost ALL aspects of flight, the ONLY area that the 51 was better was top speed and that was only for certain altitudes, (20,000 - 25,000 if I remember ) at all other altitudes the 38 was faster, the 38 was a MUCH better climber, with the late J and L it was a better diver,it could turn better and carry twice + the payload. the 51 had its share of teething problems also, but being a single engine aircraft it was easier to maintain. in the PTO they didnt have the problems with the fuel and cold that they did in the ETO. also in the PTO the 38 was the bird of choice, pilots didnt want the 51 for a multitude of reasons the 38 was flat better, there has to be a darn good reason why the USAAF 2 top aces flew 38's and not 51's and against a much wider range of fighter aircraft in the ETO it was the 109 and the 190 not much else, in the PTO there was the Zero and all the KI's all with different flight dynamics, and the 38 fought them all with success. my hope is since we are told that the 38 is limited by the flight model that with the 4.0 patch it will be a fixed aircraft, that they will fix the stall, compression, and head shake, and MAYBE just MAYBE we can get the 1725HP L model http://forums.ubi.com/images/smilies/16x16_smiley-tongue.gif

Blackdog5555
03-20-2005, 02:57 PM
Yes, it was simple economics. by the time the bugs were fixed the P51 and P47 were available. Cheaper to buy and easier to fix and required less training. Its interesting how Kelly Johnson (Skunkworks+SR71) used NACA's wind tunnel to develop the dive slats on the J25 LO. First person to do that. Also, Twin engine with less/similar drag co-dfficient than the P47. Yes, I agree the P-38 never had a chance to redeem herself. Pilots did get frostbite at 30,000 ft and the canopy did ice over at that height. (-60F). I dont know how they solved the heating problem...does anyone know?

Blutarski2004
03-21-2005, 09:04 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Blackdog5555:
Yes, it was simple economics. by the time the bugs were fixed the P51 and P47 were available. Cheaper to buy and easier to fix and required less training. Its interesting how Kelly Johnson (Skunkworks+SR71) used NACA's wind tunnel to develop the dive slats on the J25 LO. First person to do that. Also, Twin engine with less/similar drag co-dfficient than the P47. Yes, I agree the P-38 never had a chance to redeem herself. Pilots did get frostbite at 30,000 ft and the canopy did ice over at that height. (-60F). I dont know how they solved the heating problem...does anyone know? <HR></BLOCKQUOTE>


..... According to Roger Freeman, the fundamental cockpit heating problem was never really solved, but electrically heated flight suits were issued to some degree and proved helpful.

Blackdog5555
03-21-2005, 12:40 PM
Youd think, with two massive engines generating all that heat, you could get some in the cockpit. using heated radiator coolant/ exhaust exchange wasnt really even used in cars in the 30s much.. I had a '37 Cadillac LaSalle that use a gas burner for heat./ Siphoned gas out of the carburator and burned it in a gas burner under the dash. Not real forward thinking. (hobby was restoring antique cars)

Blutarski2004
03-21-2005, 12:56 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Blackdog5555:
Youd think, with two massive engines generating all that heat, you could get some in the cockpit. using heated radiator coolant/ exhaust exchange wasnt really even used in cars in the 30s much.. I had a '37 Cadillac LaSalle that use a gas burner for heat./ Siphoned gas out of the carburator and burned it in a gas burner under the dash. Not real forward thinking. (hobby was restoring antique cars) <HR></BLOCKQUOTE>


..... Just a guess here, but I suspect the designers might have thought it too risky to have cockpit plumbing carrying high-temp pressurized liquid. I wouldn't want to be the guy in the cockpit if it broke.

Blackdog5555
03-21-2005, 08:06 PM
True true. I know about being splashed with superheated coolant. Not fun. Well, if I was Kelly Johnson I would have used an adjustable manifold heat exchange like in the VW air cooled engine. Pilots complained that -60 was so cold tht they couldnt fight..really got frost bite and ice on the cockpit canopy. After all they are sitting on a gas tank surrounded by explossive. Might as well be warm when you blow up. LOL. good post Blutarski...Thanks for the reply.

BigKahuna_GS
03-22-2005, 02:55 PM
S!

This from Warren Bodie on P38 cockpit heaters:


"As for cockpit heat in P-38s, the problem was never solved. Why? I can only guess. One: The War Production Board probably made a decision that production rates must not be reduced to make the changeover, even if they had a good solution. Perhaps, because of the inboard fuel tank locations, ducting heat from the booms was not easy to solve.

They did that on the XP-38K...namely a change to H-S Hydramatic props with broad blades instead of the "toothpick" props offered by Curtiss. (Yet another of the C-W mess during the war.) Knudsen's people said that since the hub diameter was larger, they would have to redesign the cowlings and spinners, about one inch dia larger. Could not stand loss of production. Yet, the WPB in its infinite wisdom kept on producing Vultee A-31s and A-35s, lousy airplanes that nobody wanted. They refused to listen, saying that they could not stand to lose the employees. Bad decision. Finally, in 1945, they did switch to building P-38Ls, after having been at it building subassemblies for a couple of years. I think they only turned out 114 of them (without looking at my book).

As I recall, they never were able to install a generator on the opposite engine either. Balony! One smart guy could have solved the problem, I'm sure. Thousands of manhours were wasted on the Kaiser -Hughes flying boat, and on turning out some 5,000+ additional P-40Ns long after they were not useful for anything but training. No P-40s were ever flown against the Germans in the ETO."


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There was some real politcal infighting that stifled P38 production. While most fighters had the luxury of several production facilities, Lockheed did not. When neccasary changes needed to be made the War Production Board interfeared and was short sighted on the ramifications that those changes would mean in true aircraft performance.



Whatever Happened To The Lockheed P-38K?

http://home.att.net/~C.C.Jordan/P-38K.html


http://home.att.net/~C.C.Jordan/Xp-38k.jpg http://home.att.net/~C.C.Jordan/Xp-38k.jpg

The Story Of The Best Performing Variant Of The P-38 Lightning

The Lockheed P-38K-1-LO is now nearly forgotten. No photographs of the aircraft are known to exist today. Only the original test mule was photographed. It has been relegated to that part of history where one off prototypes and special test aircraft usually go. This is rather unfortunate for this aircraft as it was the benchmark against which all other variants of the P-38 Lightning must be compared. Simply said, it was the best performing Lightning ever to take to the sky.

From the very beginning of America‚‚ā¨ôs involvement in World War Two, Lockheed was looking for ways to improve the performance of the P-38. The installation of Rolls Royce XX Merlins was seriously considered. Lockheed went as far as designing the installation package. The advantages of the Merlin engine were numerous. First and foremost was the elimination of the complex turbocharger system. This would also result in a much cleaner engine nacelle. The turbo intercoolers could be removed. That would have allowed for a for more aerodynamic package, closer in shape to that of the original XP-38. Another option was to remove the Prestone radiators and place them under the engine as in the P-40. This location had the additional advantage of reducing the length of the cooling system plumbing. This, in turn, reduced the risk of battle damage to the system. Either option would result in a significant reduction in drag and weight. A further benefit would be gained by the removal of intercooler ducting in the front portion of the outer wings. This volume could be utilized for increased fuel capacity. In fact, that is what was done when the P-38J was designed with revised intercooler cores that eliminated the ducting. This increased internal fuel capacity by 110 gallons.

There were some performance areas that would suffer. While a gain in speed at medium altitudes was expected, the rate of climb would be reduced by as much as 400 feet per minute. Service ceiling would also be reduced as the Packard Merlin XX made considerably less power above 30,000 feet than did the Allison V1710. At the time, no one anticipated the engine and turbocharger problems that developed at high altitude over Europe. Unfortunately, the War Production Board was unwilling to shut down the production line for several months to retool for major design changes required for the engine swap. As a result, the Merlin project was shelved. No P-38 ever flew fitted with Rolls Royce Merlin or Packard engines. The idea of retro-fitting Merlin 61 engines was bantered about 8th Air Force Fighter Command, however there is no evidence that any such conversion ever took place. The prospect of such a modification would have been daunting. This was no simple engine swap, it required large portions of the airframe to be completely redesigned. Stories of Merlin powered Lightnings are, without much doubt, myth.


This, however, did not put an end to seeking greater performance. Lockheed paid close attention to the performance gains achieved with the P-47 when the new "high activity" Hamilton Standard propellers where first fitted on a Republic P-47C in mid 1942 (later, in mid 1943, these propellers were retro-fitted in Britain). The new "paddle" blade prop had significantly increased the rate of climb and acceleration of the "Jug". Lockheed decided that they would install the Hamilton Standard hydraulic propellers on one of the factory test "mules". Thus, was the XP-38K born. The "mule" was an extensively modified P-38E. The original intercoolers were replaced with the newer type introduced on the J model. The initial test results were very encouraging and a P-38G service test airframe (422-81, AFF serial number 42-13558) was selected to be modified.

The new propellers were not the only design changes made in the search for greater performance. This airframe was configured for the Allison V1710F-15 powerplants which were rated at over 1,875 bhp in War Emergency Power (as compared to 1,725 bhp for the V1710F-17 in the P-38L). This was the only P-38 so configured. The potent combination of the engine/propeller promised excellent performance.


http://home.att.net/~C.C.Jordan/P-38props.JPG


There were still other modifications that were necessary. The Hamilton Standard props required a spinner of greater diameter, and the thrust line was slightly higher as well. This in turn, required that new cowlings be manufactured to properly blend the spinners into the engine nacelles. These were hand made and the fit was less than perfect. The new propellers necessitated a change to the reduction gear ratio. The Curtiss Electric props had a normal ratio of 2.00 to 1. The ratio was changed to 2.36 to 1.

Flight tests were conducted from late February through the end of April 1943. Performance was better than hoped for. Maximum speed at critical altitude (29,600 ft) was 432 mph (Military Power). At 40,000 feet, the "K" zipped along at a speed that was 40 mph faster than the current production P-38J could attain at this same height. Maximum speed in War Emergency Power, at critical altitude, was expected to exceed 450 mph. The increase in ceiling was just as remarkable. Flown to 45,000 ft on an extremely hot and humid day, Lockheed engineers predicted a "standard day" service ceiling in excess of 48,000 ft! Improvement of the cowling fit and the elimination of the heavy coat of paint would have gained even more performance. Due to the added efficiency of the new propellers, range was expected to increase by 10 to 15 %. Lockheed appeared to have a world-beater on their hands.

The plane, now designated the P-38K-1-LO was flown to Elgin Field for evaluation by the USAAF. Flown against the P-51B and the P-47D, this Lightning proved to be vastly superior to both in every category of measured performance. What astounded the evaluation team was the incredible rate of climb demonstrated by the P-38K. From a standing start on the runway, the aircraft could take off and climb to 20,000 feet in 5 minutes flat! The "K", fully loaded, had an initial rate of climb of 4,800 fpm in Military Power. In War Emergency Power, over 5,000 fpm was predicted.

In light of this incredible level of performance, you would certainly expect that the Government would be falling all over themselves to quickly get the P-38K into production. Yet, this was not the case. The War Production Board was unwilling to allow a short production suspension in order to get new tooling on line for the required change to the engine cowling. Even when Lockheed promised that the stoppage would only be for 2 or 3 weeks, their request was turned down.

The true consequences of this pig-headed thinking will never be known. What would have been the impact of such a high performance fighter arriving in force to the forward combat areas in mid 1943? How many lost fighter pilots would have survived thanks to the awe inspiring performance of the P-38K? Again, we can never know these things. What we do know, is that due to bureaucratic myopia, neither the P-38K nor a Merlin powered Lightning ever really had a chance to make an impact upon the air war. For all those pilots who died at the controls of lesser aircraft, the War Production Board bears a measure of responsibility for their fate.



RESOURCES:
Warren M. Bodie, The Lockheed P-38 Lightning.
Lockheed Martin Archives.


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SkyChimp
03-22-2005, 08:34 PM
The problem for the P-38 and any desire to increase speed at critical altitude was the fact that the P-38 flew at nearly its critical mach in level flight at high altitudes. Any significant increase in speed would have caused it to get into compressibility in level flight. Extra power and climb may have come in handy at low altitude. But to increase speed at high altitudes, a redesign of the tail would have been necessary.

Blackdog5555
03-22-2005, 08:41 PM
Excellant post Kahuna. I read an account of Merlin - Allison choice. It was because of some Pentagon Genrals who were associated with Allison Corp. would not allow or prevented the change. Im sure they retired with a nice "consulting" job with Allison after the war.

BigKahuna_GS
03-23-2005, 06:15 AM
S!

__________________________________________________ ____________________
SkyChimp posted Tue March 22 2005 19:34
The problem for the P-38 and any desire to increase speed at critical altitude was the fact that the P-38 flew at nearly its critical mach in level flight at high altitudes. Any significant increase in speed would have caused it to get into compressibility in level flight. Extra power and climb may have come in handy at low altitude. But to increase speed at high altitudes, a redesign of the tail would have been necessary.
__________________________________________________ ________________________


Rgr that SC.
Any increase in climb rate and speed is a good thing. The P38K was optimized to operate at high altitudes--just where it needed to be while escorting bomberat 35,000ft.. Too bad the WPB screwed the pouch on that one.

Butlook at speeds posted by Lockheed for the P38L with 1,725hp WEP and 150octane avgas. Looks like there was more room for top end speed at alt :


http://home.att.net/~ww2aviation/P-38speedchart.JPG



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