Any P-38 experts around?


--Went to the Mathers AFB air show this past weekend and got to see
4 of the 7 remaining P-38 Lightnings flying. I know they had Allison engines
and I remember the P-51s originally had these as well. Well the P-51 got the
Merlin and a huge boost in performance; why didn't this happen to the P-38s
as well? Talking to a pal at the show we decided it was due to a production
bottleneck; i.e. they couldn't be made in sufficient quantities to equip the
twin engine aircraft. Anyone know the truth of the matter?
Reply to
steamer
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> =A0 =A0 =A0 =A0 --Went to the Mathers AFB air show this past weekend and = got to see > 4 of the 7 remaining P-38 Lightnings flying. I know they had Allison engi= nes > and I remember the P-51s originally had these as well. Well the P-51 got = the > Merlin and a huge boost in performance; why didn't this happen to the P-3= 8s > as well? Talking to a pal at the show we decided it was due to a producti= on > bottleneck; i.e. they couldn't be made in sufficient quantities to equip = the > twin engine aircraft. Anyone know the truth of the matter? > > -- > =A0 =A0 =A0 =A0 "Steamboat Ed" Haas =A0 =A0 =A0 =A0 : =A0Beauty times bra= ins =A0 > =A0 =A0 =A0 =A0 Hacking the Trailing Edge! =A0: =A0is a constant.. > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0www.nmpproducts.com > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0---Decks a-wash in a sea of words-=
Reply to
co_farmer
The P-38 didn't need a moderate increase in power.. By virtue of having two engines it had twice the power of the P-51. The very early ones had engines that turned the same direction.
The torque and P-factor made for a hand full under even fairly normal takeoff conditions. They were quickly replaced with engines that turned opposite directions which tamed the beast. Which is probably the real answer to your question.
Its an awesome airplane!
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Flight Characteristics of the P-38 (video 35 minutes)
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(video) Scroll down to Angel in Coveralls
Reply to
CaveLamb
...
"A batch ordered by Britain did not have counter-rotating propellers." So says
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The counter-rotating props also turned the wrong way.
Reply to
Beryl
They had counter-rotating props since day 1. The prototype had them arranged for best engine-out performance, but that set up some weird turbulence on the center section and tail, so they were reversed.
Reply to
Tim Wescott
From the one book I had on the P-38 it was politics: the RR was a better engine at high altitude, but GM didn't want to see any more work going to Rolls.
But it was probably a bunch of reasons -- things are never simple.
Reply to
Tim Wescott
Ah yes! I remember that (sorta)
Reply to
CaveLamb
> =A0 =A0 =A0 =A0 --Went to the Mathers AFB air show this past weekend and = got to see > 4 of the 7 remaining P-38 Lightnings flying. I know they had Allison engi= nes > and I remember the P-51s originally had these as well. Well the P-51 got = the > Merlin and a huge boost in performance; why didn't this happen to the P-3= 8s > as well? Talking to a pal at the show we decided it was due to a producti= on > bottleneck; i.e. they couldn't be made in sufficient quantities to equip = the > twin engine aircraft. Anyone know the truth of the matter? > > -- > =A0 =A0 =A0 =A0 "Steamboat Ed" Haas =A0 =A0 =A0 =A0 : =A0Beauty times bra= ins =A0 > =A0 =A0 =A0 =A0 Hacking the Trailing Edge! =A0: =A0is a constant.. > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0www.nmpproducts.com > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0---Decks a-wash in a sea of words-=
Reply to
kfvorwerk
Actually, the Merlin used in the P-51 was reversed from the Rolls, and built by Packard under license.
The P-38 didn't need a performance boost primarily because it was turbocharged. The P-39 was hamstrung by its Allison because the Army, in its infinite wisdom had the two speed supercharger replaced with a single speed supercharger, which really limited performance at altitude. The P-38 didn't have that problem.
The P-38 is one of the few army fighters Dad didn't fly during the war (he flew the P-39, 40, 47, and 51). That was the one he really wanted to get in, and would've if he hadn't transferred from the Pacific at the end of '43. But after a year and a half out there, who wouldn't have jumped on a chance to go home for a while. He got in the 47's and 51's in Europe after that.
Pete Keillor
Reply to
Pete Keillor
I think the issue was the turbosuperchargers. The American design needed a lot of room for the intercoolers etc so it was used in larger aircraft like bombers and the P-47. In a small fighter the space right behind the engine was close to the center of gravity and too valuable for fuel to waste on turbo air pipes. It was reputedly too troublesome when installed in a rear-engined small aircraft like the P-39. The P-38 initially used the leading edge of the wing for the intercooler but that proved to be unreliable.
The British two stage supercharger was more compact. The Allison did have an integral one-stage supercharger attached to the crankcase.
Sir StanleyHooker
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Sanford Moss
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I don't have this yet:
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I haven't found much technically-oriented detail on this matter on the Net, or on WW2 aircraft construction in general. I do have graphs that show the relative performances of several of the schemes tested, and mention of the severe weight and reliability problems of variable- speed drives like clutches or the Hydramatic transmission.
The problem is that a supercharger absorbs several hundred horsepower and unless disconnected it denies the aircraft that power even at low altitudes including takeoff. They size it to give full engine power at the altitude of predicted combat, assuming the enemy follows the plan. Below that altitude it can boost the manifold pressure excessively and damage the engine. Ideally you would drive it with an automatic continuously variable ratio transmission, if one were available then (or now).
The turbosupercharger with waste gate was a partial answer in a fuselage or nacelle large enough for the plumbing. GE simply couldn't make enough of them fast enough.
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jsw
Reply to
Jim Wilkins
The P-38 and P-39 were both designed to the same request for an interceptor. The 38 was more promising so the 39 was repurposed for ground attack, partly to keep Bell from closing. At low altitude the P-39 was good enough to tangle with a Zero with some chance of success. If you look at the power vs altitude chart referenced in my other post you'll see that the low-altitude engine has more power close to the ground, down where all the strafing and bombing targets are.
The P-40 was also intended for low level ground support use since in the late 30's no heavy bomber could threaten the continental US, only smaller carrier aircraft could get close enough. We were far too isolationist to spend scarce funds to prepare for major overseas land operations. Those who knew better counted on several years of preparation time between the start of a war and serious attacks on the US. That's why we had battleships and carriers but too few antisub escorts, which are quicker to build when needed.
Today the F-22 andF-35 suffer the same opposition. It seems we need an occasional Pearl Harbor or 9/11 to silence the delusion that the world will be safe if we all think peaceful thoughts. We'll have peace only when everyone believes they have justice.
jsw
Reply to
Jim Wilkins
Walther makes can openers too? Must be confusing when the local gun shop gets a shipment of them.
Reply to
Bob La Londe
Everyone will believe that they have justice when pigs fly (and the pigs will probably be complaining).
Reply to
Tim Wescott
Google "P-38 can opener".
Reply to
J. Clarke
With sufficient thrust , pigs fly just fine . But not very far .
Reply to
Snag
I've had the joy of seeing P-38's fly at Oskosh EAA. My feeble brain, when seeing the subject line for this thread, was going oh goodie, plane, pistol or can opener. All devices I admire.
Almost bought a P-38 once but I did enough research to realise it was an afterwar alloy frame model. (pistol) Damn. There are three iconic guns I don't have yet, the Lugar, P-38, and the M1911.
Some machines exude sex and hormones. Think Italian sports cars and the P-38 Lightning, like Raquel in her advanced age, is still hot!
Wes
Reply to
Wes
e P-38 Lightning,
My father who was an Air Corps ordnance company CO in the Pacific said the pilots didn't really like the P-38. He didn't know why, but the plane was very advanced for its time and had a lot of teething problems, some very serious like loss of control in a high speed dive. Sometimes the thicker air down low slowed it enough to regain control, sometimes it didn't.....
The closest I'll ever get to flying one is a sim, where it's not nearly the most nimble WW2 fighter and can flip out suddenly if turned too hard too slow. #2 US ace Tommy McGuire crashed that way while chasing a Zero at low level.
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As far as I can tell the MS sims are reasonably accurate. If so, I'll take a land-based Corsair, please.
The sim Lightning does have a lot of 20mm firepower and unlike some others is stable enough to tear up small ground targets from several thousand feet. In Combat Flight Sim 2 it can set fire to and eventually sink a warship. Shooting up the whole Japanese Navy in volcano-rimmed Rabaul harbor on an HDTV monitor is a lot of fun.
jsw
Reply to
Jim Wilkins
Yup, and they'll kill your ass. Jeff Ethell, the photographer, bought it at Tillamook in the classic P-38 crash, engine out followed by spin in. And his dad, a P-38 vet with 10,000 hrs witnessed the crash. The manual says if you're below a fairly high speed, I think 120 with flaps or thereabouts, and you lose an engine, you immediately chop the other engine and go in straight ahead. Below some speed, and Ethell was observed to be going "too slow", you can't keep that thing from spinning on one engine.
Pete Keillor
Reply to
Pete Keillor
Lightning,
Can't help but contrasting that with the Israeli F-15 jockey who brought it home on one wing. A lot of improvement in technology there that is not noticeable until something goes badly wrong.
Reply to
J. Clarke
As a general statement two speed superchargers were designed to give max rated boost in low speed for takeoff, i.e. ~ sea level, while the high speed was used at altitude. At least that is how the radial engines were designed. After the advent of turbos, I don't believe that two speed superchargers were used to any extent. At least the C-97, which as far as I know, was the last strategic reciprocating engine airplane used by the A.F. had a single speed supercharger and turbos.
The procedure for shifting to high blower, by the way, involved throttling back a bit, to prevent over boosting, shift to high speed, and then reset throttles for desired manifold pressure.
Cheers,
John D. Slocomb (jdslocombatgmail)
Reply to
J. D. Slocomb

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