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P-38 Lightning Speculation Thread

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4 hours ago, PatrickAWlson said:

 Survivability due to two engines.

 

I never read anything on the topic of one-engine handling of the p38. Was it manageable? Some or most planes are a nightmare to keep under control with only one engine running.

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31 minutes ago, danielprates said:

 

I never read anything on the topic of one-engine handling of the p38. Was it manageable? Some or most planes are a nightmare to keep under control with only one engine running.

 

Didn't it tend to flip over when it lost an engine? Maybe that was just during take-off and landing but I remember reading about it.

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28 minutes ago, pfrances said:

 

Didn't it tend to flip over when it lost an engine? Maybe that was just during take-off and landing but I remember reading about it.


Single engine out was a problem on take off and some landing conditions. 

The P-38 was completely flight tested with a single engine, and while not ideal, with appropriate rudder trim, it would at least get you home so you could either attempt a landing or bail out over friendly territory 

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Posted (edited)
6 hours ago, pfrances said:

 

Didn't it tend to flip over when it lost an engine? Maybe that was just during take-off and landing but I remember reading about it.

 

No, if one engine lost power on take off it tended to yaw into the reduced power engine due to uneven thrust. The full power engine oppose to the non feathered, drag inducing, unpowered engine pulled the aircraft to one side. The side with drag and no thrust lost lift, snapping the aircraft into an uneven stall frequently resulting in a crash.

 

a little research tells me that if you reduced power on the good engine and kept even lift under the wings by feathering the prop on the bad one quickly, you could continue the takeoff and proceed on one engine.  No one was bold enough to continue a mission like that, but once they learned how to do it, it was not really life threatening.

 

landing on one engine just meant a slightly increased landing speed to avoid the unpowered side stalling in fist and allow the possibility of going around if the approach was off. The danger there was overrunning the end of runway.

 

i will try to find Tony Levier’s description, I know I have it somewhere.

 

EDIT...

 

Tony Levier on his first day in Europe to demo the P-38 capabilities 1944...

from The Fork Tailed Devil by Martin Caiden 

 

“At twenty-nine thousand feet the right engine blew up and fell apart. As I had already had ten Allison engines blow up on me in the last two years, this was nothing new; usually I could feel it coming, but this time it just went wham and that was it. I switched from my drop tanks to regular wing tanks. My drop tanks were not yet empty so I kept them with me, although I was pretty heavy and on one engine it was sort of cutting it close. However, we had done this quite often in California and I didn’t figure I would be in any sweat. “I had been flying due north toward Scotland, figuring this would keep me over land. Being on top of a heavy overcast, I did not know my position, so when I turned south toward my base I asked for a radio fix. They immediately came back with my exact position and distance from home so fast I thought this was going to be wonderful; you couldn’t get lost over here with this kind of service. I flew the heading they gave me and figured out I should be there in about fifteen minutes. “About ten minutes passed when they came back on the air with landing instructions; if I was west of the perimeter I should turn hard left and land on runway 29, into the wind which was blowing about thirty miles an hour. At once I looked down and there was the field right below me. I thought to myself this was peculiar, as I hadn’t figured on being there yet, but everything was just like I left it and the tower had a green light on me. I swung around left but as I looked at runway 29 the wind was across it, so I called the tower and asked them again what runway to use. “Getting no answer this time, I picked an alternate runway with a headwind, which was the logical thing to do under the circumstances. I turned left into my good engine and with my landing gear down I entered the base leg for runway 24. I was still extremely busy with drop tanks on, and as I turned the airplane started to buffet. I had partial flaps down at the time, but even so I realized I was making too tight a base leg. I opened the throttle and pulled the gear and flaps up and made a wide circle to the right, and this time I came in and landed with room to spare. “Again I called the tower on the radio, requesting taxi instructions, and again there was only a deep silence. Then I looked around to see if anyone was waving at me, and for the first time I realized this was not the field I had taken off from. I could see now it was a B-26 bomber base, laid out identically to the fighter base I had just left. There was nothing to do now but roll to a stop off the side of the runway and get out of the airplane. A jeep came out on the field to get me and I was driven to base operations, where I identified myself. The boys said they sure were sweating me out. They saw me with a dead engine, and the idea was general in the Air Corps over there at that time that a pilot with one engine out on a P-38 was a sad sack.

 

apparently even with drop tanks and most of a fuel load it was practical to go around and land successfully on one engine. I will see what I can find about single engine take off...

 

 

Edited by Jaegermeister

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Posted (edited)
16 hours ago, 71st_AH_Yankee_ said:

 

... the P-47 does? Are you sure? Or do you mean due to its magical flaps? If anything, what I've experienced is the P-47 suffers from poor elevator authority at high speed, which seems inconsistent with reports. And in a turn the P-47 does very poorly until you drop its flaps, but at that point you are so slow that any halfway decent pilots will stop turning and just use the opportunity to gain an overwhelming energy advantage.

 

 

Ya thats nonsense

I still suck hard. We.re talking 1 ot 2 kills a day for WoL and TAW.

Berloga yesterday? Ace in a flight in a dora. 4 p47s and 1 spit.   I got a triple kill in a g14 next.  2 kills in a dora next. 2 kills in a a8.   Went to the esrly war side.  Less noticeable there. More like 1:1.

So all this shows me is 

1 berlogas artificial setup is fun andnits nice to pwn finally but it makes it rlly easy for less skillful players

2 no.. The p47s are terrible. You have to be a fool to die at the hands of one. I was literally fighting 3 or 4 at a time... Easily

The p47 kills were gratifying. Anything human is.  The spit ix kills x10 more so. I actually was concerned engaging them

Just like my kills i got flying spit ix, and the yak7b were more gratifying... (And generally most my kills anyways in the early war)

So to me... Theres good and bad.  I have no hope for future US planes. I sincerely hope someone quotes this and calls me an idiot when Im wrong. I still love and want the p38 hard. P51s the more realostic sims hace gotten the more Ive realized isnt the joy hotrod to fly I thought - more like a 190 D or A3 or a 109 for me - but still.  If theyre good itll balance out the BP side. If not... Theres still the Tempest.  Spits and Tempests at least (im almost certain the tempest will do well from history and 777s treatment of brit kit) will help a lot for the current situation.

PS everyone raves ant the k4s lethality thats nothing to me compared to doras.  And I usually dont fly her right! The dora lets me fly more turn ans burn which I shouldnt do anyways.

You practice and get the lead down for deflectiom shooting at a few angles and you become insanely lethal.

Same with the Spit - bind a key for those .50s! I had a dora a little too far to throw 20mm at.  I was annoyed at his calm reptition of maneuvers that seemed to have made stalemate. I literallt kept turning with him and openeed key bindingd and bound wpns group one. Then i start poppinh a few rnds of .50 at him every couple of seconds.   Took a lot of .50s but suddenly his wing just fell off. Oops :)

Edited by CommissarSublime

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On 7/27/2019 at 8:48 AM, Bremspropeller said:

 

That holds true for any piston twin.

It's not so much the torque, it's the loss of roughly 80% of all of your available performance, if an engine fails on take-off.

Depending on conditions and the loadout, a twin on one engine might not even be able to sustain (!) altitude.

This is mostly incorrect. Torque is a killer on just about every twin prop driven aircraft. Just about all of them will torque roll on a single engine at full power before they will stall. The higher power twins do so very dramatically.

 

The 120 mph speed threshold for engine failure has everything to do with control  authority (mostly rudder) at low speed. The slower you go, the less effective the rudder is. In a twin engine airplane the speed at which the rudder can no longer fully compensate for the full power, torque and other effects of the operating engine in an engine failure scenario has a name.

 

Minimum control speed or Vmc.

 

Below 120 mph with one engine at full power, the P-38 pilot does not have enough control authority to go in a straight line. This control authority degrades as the speed lowers. The end result is called a Vmc roll.

 

 

The cure for Vmc roll is more speed or less power. 

 

Online games generally vastly undermodel torque so I expect the P-38 to be a pussycat when it comes to its single engine characteristics.

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24 minutes ago, =475FG=DAWGER said:

Online games generally vastly undermodel torque so I expect the P-38 to be a pussycat when it comes to its single engine characteristics.

Is this simulator (IL2 series) an „online game“?

 

Difficult to see what you are trying to show with the video you posted besides what happens when you make a tight turn at insufficient speed down low. It looks the same in the Ju-52.

 

Besides, the 120 mph mentioned in the P-38 manual is not where it „Vmc rolls“, it is where you basically will stop being able to turn outside of your dead engine. Also it is a suggestion to much rather abort takeoff than anything else. This manual was written with a fully loaded aircraft in mind. You don‘t take it into battle lightly loaded. In flight, all you have to do is push the nose down to pick up speed if you are slow and lose an engine. The P-38 flies well on one engine.

 

The P-38 being a larger aircraft should torque roll on one engine less than a Spit or a Mustang.

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1 hour ago, =475FG=DAWGER said:

This is mostly incorrect. Torque is a killer on just about every twin prop driven aircraft. Just about all of them will torque roll on a single engine at full power before they will stall. The higher power twins do so very dramatically.

 

The 120 mph speed threshold for engine failure has everything to do with control  authority (mostly rudder) at low speed. The slower you go, the less effective the rudder is. In a twin engine airplane the speed at which the rudder can no longer fully compensate for the full power, torque and other effects of the operating engine in an engine failure scenario has a name.

 

Minimum control speed or Vmc.

 

Below 120 mph with one engine at full power, the P-38 pilot does not have enough control authority to go in a straight line. This control authority degrades as the speed lowers. The end result is called a Vmc roll.

 

 

The cure for Vmc roll is more speed or less power. 

 

Online games generally vastly undermodel torque so I expect the P-38 to be a pussycat when it comes to its single engine characteristics.

 

It's not incorrect at all. The only reason people slow down to Vmc is because they're running on insufficient power to make the climb-gradient required to clear terrain. That's due to OEI on a twin leading to roughly an 80% loss of gross performance.

It's nicely shown in your video, which happens to show an airplane at or close to max gross at high ambent temperatures and high humidity.

 

- Vmc has nothing to do with torque, it's asymmetric thrust and p-factor

- Vmc scales with AoA

- the P-38 doesn't have a critical engine, but that's just a fun factor

 

BOX does a reasonably well job in making your life difficult with one engine shut down.

Especially when you can't feather the prop...

 

 

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18 hours ago, Bremspropeller said:

 

Especially when you can't feather the prop...

 

 

Surely we will be able to feather the props on the P-38?

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I thought we already could feather mutlti engines?? 

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15 minutes ago, Sublime said:

already could feather

Depends if you've got them fancy feathering gears built in or not I think...

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Oh.  I just seemed to recall there being a key binding for feathering engines that Id used before on a 110 and also A20 ISTR the same. 

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Posted (edited)
On 8/2/2019 at 9:31 PM, danielprates said:

 

I never read anything on the topic of one-engine handling of the p38. Was it manageable? Some or most planes are a nightmare to keep under control with only one engine running.

 

I think the P38 was still combat effective with only one engine according to some documentaries I have seen, as was the mossie that did barrel rolls with one engine during a demonstration

 

 

This vid may well have been linked in this thread before, I would be surprised if it hadn't but there are some great stories here from the guys that used to fly it.

 

Edit: Mossie one engine barrel roll:-
 

 

Edited by ACG_Herne

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5 hours ago, ACG_Herne said:

 

I think the P38 was still combat effective with only one engine according to some documentaries I have seen, as was the mossie that did barrel rolls with one engine during a demonstration

 

 

This vid may well have been linked in this thread before, I would be surprised if it hadn't but there are some great stories here from the guys that used to fly it.

 

Edit: Mossie one engine barrel roll:-
 

 

 

Shows how AWESOME those two planes were. Even for today's standards.

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On 8/6/2019 at 12:19 PM, Bremspropeller said:

 

It's not incorrect at all. The only reason people slow down to Vmc is because they're running on insufficient power to make the climb-gradient required to clear terrain. That's due to OEI on a twin leading to roughly an 80% loss of gross performance.

It's nicely shown in your video, which happens to show an airplane at or close to max gross at high ambent temperatures and high humidity.

 

- Vmc has nothing to do with torque, it's asymmetric thrust and p-factor

- Vmc scales with AoA

- the P-38 doesn't have a critical engine, but that's just a fun factor

 

BOX does a reasonably well job in making your life difficult with one engine shut down.

Especially when you can't feather the prop...

 

 

Asymmetric Thrust and P-factor are the exact same thing. It's a yawing moment mostly due to higher angles of attack (the descending blade creates more life/thrust than the ascending blade). Maybe you meant accelerated slipstream and P-factor?

 

Torque most definitely affects Vmc. When you go from idle power to 100% obviously you increase torque, the prop is spinning faster - the reaction is now magnified. For every action there's and equal and opposite reaction, right? This would mean that with a conventional engine, where the prop is spinning clockwise from the pilot's perspective, that a rolling moment would occur counter clockwise (to the left). If you were below the published Vmc speed, you lose an engine, and apply full power to the good engine, then you will experience the dreaded Vmc roll (as seen in the video).....you will not be able to maintain directional control.  So if you're slow (below Vmc)and lose an engine, its actually better to first maintain directional control and idle both engines (because a lower amount of torque lowers your Vmc), and slowly start applying power to the good engine only until you start to lose directional control, then pull the power back slightly.  Will it be enough to keep you airborne? Who knows, but I'd rather be upright and looking for an emergency landing spot, than roll myself and turn into a crater.

 

The P-38 doesn't have a critical engine, but with those outward turning engines I would imagine that if you lose an engine (who cares which one) you need to react quickly and reduce power on the good engine....especially if you're slow.

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Posted (edited)
On 8/12/2019 at 6:27 PM, 334th_Five-O said:

The P-38 doesn't have a critical engine, but with those outward turning engines I would imagine that if you lose an engine (who cares which one) you need to react quickly and reduce power on the good engine....especially if you're slow.

 

I'm with you, that's what I learned getting my ATP in the Seminole, reduce power on the good engine. I think the Vmcg for the Airbus 320 is only 115 knots or so. ;)

 

I've been reading through articles (available here) by WWII P-38 pilots about losing an engine on takeoff. One guy mentioned 125 mph as the minimum safe airspeed. Said they'd liftoff around 100-110 mph then accelerate in ground effect to above 125 mph. IIRC this pilot flew mostly sweeps/escorts in the Pacific. Another pilot that flew in Europe referenced 155 mph which sounded like the local procedure because the manual references 120 mph. The manual also mentions with 45" MP and 3000 rpm you should be able to climb at 165 mph.

 

545477647_P-38JEngFailTO.jpg.3dce6af4ac201a0ca57125dd034baed1.jpg

Edited by busdriver
Added Engine Failure on Takeoff jpg

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7 hours ago, 334th_Five-O said:

Asymmetric Thrust and P-factor are the exact same thing. It's a yawing moment mostly due to higher angles of attack (the descending blade creates more life/thrust than the ascending blade). Maybe you meant accelerated slipstream and P-factor?

 

No. They amount to the same thing, but they're not the same thing:

Asymmetric thrust scales with your chosen power-setting.

P-factor creates an asymmetric thrust distribution accross the prop disc (and thus creating a critical and a non-critical engine) and scales with AoA.

 

7 hours ago, 334th_Five-O said:

 

Torque most definitely affects Vmc. When you go from idle power to 100% obviously you increase torque, the prop is spinning faster - the reaction is now magnified. For every action there's and equal and opposite reaction, right? This would mean that with a conventional engine, where the prop is spinning clockwise from the pilot's perspective, that a rolling moment would occur counter clockwise (to the left). If you were below the published Vmc speed, you lose an engine, and apply full power to the good engine, then you will experience the dreaded Vmc roll (as seen in the video).....you will not be able to maintain directional control.

 

The Vmc-roll has nothing to do with torque on the prop. It's a reaction to yaw-induced roll - you're runnng out of rudder.

The problem with picking up a low wing with sizeable amount of aileron is that you'll kill some lift on the good wing (bad) and you're creating quite some drag on the bad wing (worse).

 

7 hours ago, 334th_Five-O said:

 

So if you're slow (below Vmc)and lose an engine, its actually better to first maintain directional control and idle both engines (because a lower amount of torque lowers your Vmc), and slowly start applying power to the good engine only until you start to lose directional control, then pull the power back slightly.  Will it be enough to keep you airborne? Who knows, but I'd rather be upright and looking for an emergency landing spot, than roll myself and turn into a crater.

 

That's nice if you're losing an engie at cruise, but if you lose an engine on take-off, it's chop and drop.

That's why pre-departure briefings are important: Knowing where to put the airplane before an engine quits saves valuabe seconds.

Some airfields might not have that option - there, you're basicly dead if an engine fails, until you have reached some altutude giving you options.

 

7 hours ago, 334th_Five-O said:

 

The P-38 doesn't have a critical engine, but with those outward turning engines I would imagine that if you lose an engine (who cares which one) you need to react quickly and reduce power on the good engine....especially if you're slow.

 

One could say that with both props turning outboard, any engine is the critical engine.

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Posted (edited)
On 8/7/2019 at 7:50 AM, ACG_Herne said:

 

I think the P38 was still combat effective with only one engine according to some documentaries I have seen, as was the mossie that did barrel rolls with one engine during a demonstration

 

 

This vid may well have been linked in this thread before, I would be surprised if it hadn't but there are some great stories here from the guys that used to fly it.

 

Edit: Mossie one engine barrel roll:-
 

 

 

Have you seen this one?  At 14:30 there's a video of one performing a barrel roll where one of the engines cuts out, with bad results.  The way the guy talks about them they don't sound like something easy to fly, but something with thin thresholds and some very bad stall characteristics.  It looks like the torque completely takes over the aircraft once he looses one engine.

 

https://youtu.be/J6uDpyScWg0

 

Edited by CAFulcrum

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On 8/2/2019 at 6:26 PM, PatrickAWlson said:

 

P38

- Low speed turn radius.

 

Not a snowball's chance in hell. The P-38J test that led you to believe this had some clerk transcribe indicated airspeeds in the table of the stall test, not calibrated airspeeds.

 

See here for reference: http://www.wwiiaircraftperformance.org/p-38/P-38G_42-12690_FS-M-19-1492-A.pdf

 

Same airfoil, but without the ludicrously high (as in, way above the theoretical maximum determined by wind tunnel testing) CLmax the J's test alleges comes with it.

 

Anyways, sustained climb and high speed roll will be in the P-38's favor, as will low speed acceleration (probably). High speed handling, maybe, but only at low altitude unless you want to drop dive flaps and start bleeding energy like a stuck pig.

On 8/13/2019 at 1:27 AM, 334th_Five-O said:

The P-38 doesn't have a critical engine, but with those outward turning engines I would imagine that if you lose an engine (who cares which one) you need to react quickly and reduce power on the good engine....especially if you're slow.

 

That's because it has two critical engines. P effect mandates the center of thrust be outboard of the propeller shafts for both engines.

 

In fairness to its designers, they tried building the plane with engines turning inboard, but that ended up screwing with the guns' accuracy.

Conversely, the P-82's engines were initially set to turn outboard, which literally blanked out the middle wing section and caused it to not generate any lift until the engines were switched around to make them turn inboard. A part of me wonders if any test engineers may have elected to find out whether hats can be eaten and subsequently digested. Another part of me prefers relative uncertainty on the topic.

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3 hours ago, PainGod85 said:

A part of me wonders if any test engineers may have elected to find out whether hats can be eaten and subsequently digested. Another part of me prefers relative uncertainty on the topic.

 

Considering how well the P38 performed during its time in the real world, I’d say you will never be certain that it was the mess you suggest.

 

Far from perfect, it was the best tool available to get a job done at the time, and fortunately for the free world, it was flown by people a lot more optimistic than some here. It’s only real down sides we’re being a big target, freezing up at extremely high altitude (like most fighters on the cutting edge at the time) and being easy to recognize. The last point was both good and bad at different times. 

 

It it pretty much excelled at everything else it was assigned to. Bomber escort, ground attack, reconnaissance, and air superiority in every theatre from 1943 through 1945. There are only a very few other aircraft that can compare to that record.

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2 minutes ago, Jaegermeister said:

 

Considering how well the P38 performed during its time in the real world, I’d say you will never be certain that it was the mess you suggest.

 

Far from perfect, it was the best tool available to get a job done at the time, and fortunately for the free world, it was flown by people a lot more optimistic than some here. It’s only real down sides we’re being a big target, freezing up at extremely high altitude (like most fighters on the cutting edge at the time) and being easy to recognize. The last point was both good and bad at different times. 

 

It it pretty much excelled at everything else it was assigned to. Bomber escort, ground attack, reconnaissance, and air superiority in every theatre from 1943 through 1945. There are only a very few other aircraft that can compare to that record.

It was a great aircraft in the med and Pacific and when escorting over Europe it was used in temperatures and heights it wasn’t used at before and unfortunately suffered from over cooling of the intake charge witch separated the lead from the fuel and caused pre detonation. Unfortunately 

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23 minutes ago, LP1888 said:

 used in temperatures and heights it wasn’t used at before and unfortunately suffered from over cooling of the intake charge witch separated the lead from the fuel and caused pre detonation. Unfortunately 

 

Wha?:unsure:

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Posted (edited)
1 hour ago, DD_Arthur said:

 

Wha?:unsure:

 

I’m not an airplane mechanic or an aeronautical engineer (although I did study it at Georgia Tech) but my understanding of the high altitude problem is that the turbosupercharger control modules located in the cockpit froze up at -20 degrees or whatever it was at 35,000 feet in Northern Europe during the winter. The pilots’ feet and hands had the same problem. When that happened the engine or engines either got no boost or full boost without moderated control. This caused fouled spark plugs from running too rich or burned valves from being too lean and led to engine failures from improper air fuel mixture.

 

A simple problem that was hard to fix until they installed better cockpit heaters with the J and L models. With the cockpit being in a separate gondola, it was not right next to the heat of the engines like all the other fighters of the time, and it was not well insulated. It was also difficult to pipe in hot air with the limited space involved. What we are getting in game would not have had those problems encountered in ‘43 and early ‘44. They also fixed the dive compressibility problem by then and the cockpit oxygen supply, so what major flaws are we left with again? 

 

Oh wait, I remember, it has twice as many engines to get shot up... or get you home. It was also easy to identify which could get you attacked by the dwindling Luftwaffe... or keep you from getting shot up by the bombers you were escorting or the “friendly” AA over the airfields back across the bomb line.

Edited by Jaegermeister
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Well, I’m going to go ahead and partially correct my previous statement made from memory.

 

This is from Aviation History Online Museum website history of the P-38 Lightning

 

Engine Problems:

 

    The Lightning would become one of the best fighters of World War II, but the early gestation period was one of complete frustration. Early on in the 8th Air Force, engine failures were frequent and flight training for flying on one engine was inadequate. The most serious situation for a new pilot was losing an engine on takeoff with a full load. Many crashes could have been avoided if correct procedures were followed, but the technique for surviving an engine out on takeoff wasn’t developed until years after the P-38 was in service. Many pilots crashed as a result and didn’t survive unless they were lucky. The technique that was finally developed was to pull back power on the good engine, feather the dead engine, trim the aircraft, and gradually advance power on the good engine.

 

    Detonation was a major problem at high altitude. Engines detonated without warning and occurred so quickly that the engine would tear itself apart. Detonation was detrimental to the pistons, rods and crankshafts. High carburetor air temperatures using excessive manifold pressure were one cause of detonation. 45 degrees Celsius was the maximum carburetor air temperature that the engine could withstand. For war considerations, 91 octane was used in training and if more than 44 inches of manifold pressure was used, it would cause engine detonation. 

 

    At 30,000 ft. (9,144 m), the intercoolers separated the lead from the fuel lowering octane and resulted in fouled plugs, thrown rods, and swallowed valves. 150 octane fuels were tried in Europe, but the leaded fuel fouled the plugs, because of the cold operating temperatures and supercharger regulators froze at high altitude.

    

    Due to the high rate of engine failures, Jimmy Doolittle, then commander of the 8th Air Force, decided to pull the P-38 out of Europe. After P-51 Mustangs replaced the Lightning, the kill ratio went from 1.5: 1 to 7:1. However, other war theaters were clamoring for the P-38 and this is where the Lightning would finally shine. Although the Lightning faired much better in warmer climates, when introduced in the Pacific, there were an unusual number of engine failures due to engine bearings wearing prematurely during the first six months of 1944. Pratt & Whitney had a similar problem with bearing surfaces eroding away due to acid buildup in the lubricating oil. The oil formulation was changed and the problem was finally eliminated. Wright Aeronautical also used reformulated oil to correct problems with its R-2600 engine.

 

 

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10 minutes ago, Jaegermeister said:

At 30,000 ft. (9,144 m), the intercoolers separated the lead from the fuel lowering octane and resulted in fouled plugs, thrown rods, and swallowed valves. 150 octane fuels were tried in Europe, but the leaded fuel fouled the plugs, because of the cold operating temperatures and supercharger regulators froze at high altitude.

 

This I don't quite understand, how could the intercoolers separate the lead from the fuel? 

 

Does this mean the cold air from the intercoolers were causing this to happen in the carburettors, a split second before getting sucked into the combustion chamber?

How fast can this phenomenon happen? 

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11 hours ago, Jaegermeister said:

 

Considering how well the P38 performed during its time in the real world, I’d say you will never be certain that it was the mess you suggest.

 

Far from perfect, it was the best tool available to get a job done at the time, and fortunately for the free world, it was flown by people a lot more optimistic than some here. It’s only real down sides we’re being a big target, freezing up at extremely high altitude (like most fighters on the cutting edge at the time) and being easy to recognize. The last point was both good and bad at different times. 

 

It it pretty much excelled at everything else it was assigned to. Bomber escort, ground attack, reconnaissance, and air superiority in every theatre from 1943 through 1945. There are only a very few other aircraft that can compare to that record.

 

It's funny you should quote the one part of my post that poked fun at how the different engine turn directions across two airframes came to be. Everything else I said is nothing but stating facts.

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1 hour ago, Soilworker said:

 

This I don't quite understand, how could the intercoolers separate the lead from the fuel? 

 

Does this mean the cold air from the intercoolers were causing this to happen in the carburettors, a split second before getting sucked into the combustion chamber?

How fast can this phenomenon happen? 

 

Yes, this is what I'm interested in.  

 

9 hours ago, Jaegermeister said:

 froze up at -20 degrees or whatever it was at 35,000 feet in Northern Europe during the winter.

 

Isn't the temperature at 35k  around  -50 degrees even on a North American summers day?

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2 hours ago, DD_Arthur said:

Yes, this is what I'm interested in.  

TEL as additive decomposes naturally to lead oxide which is a conductive solid. Yet it is the lead oxide that actually mediates the anti-knock effect. Problem is now that you have this solid in your engine that you don't want to accumulate in there. For this, you further add a lead scavenger to your fuel, ethylene dibromide. This scavenger reacts with your lead oxide solid deposit to lead bromide, a compound that turns gaseous ~>250°C. You notice upon startup of such high performance engines, that they produce a brownish smoke if you look closely in the blueish white oil cloud. This brown color is the bromide scavenger.

 

You rthus need a higher temperature to make this scavenger work. If you overcool, the scavenger cannot work and lead deposits will form near your sparks (and in the exhaust vanes) and shorten the sparks. You simply cannot reduce carb air temp to your liking, even though you get more air to your engine, because if you run overly cool, lead deposits will accumulate due to you choosing to use leaded fuel. If you had unleaded fuel, this would not be a problem.

 

This is why when using leaded fuels, you have to do startup as well as shutdown at higher revs (~1'200 rpm) instead of idle 600 rpm or so. You silmply couldn't warm up the engine without lead deposits starting to poisoning your sparks. You need to have a certain chamber temp to get the bromide scavenger active. Also, elevated chamber pressure assist in sealing the valves, making lead deposits less likely to exit there and mix with your engine oil. You still do this today with 100LL.

 

In this sense, the overuse of the intercoolers separate nothing, it just prevents things from working as intended.

 

They really had to learn the basics of turbocharging with the Lightning, as they did many things wrong in the beginning, significantly handicaping the Lightnings performance and relaibility.

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11 hours ago, DD_Arthur said:

 

Isn't the temperature at 35k  around  -50 degrees even on a North American summers day?

 

I don't know, which is why I said "or whatever it was". I don't claim to be an expert on high altitude temperatures. I just know its awful darn cold up there and everything froze up until they sorted out the cockpit heating issue. 

 

11 hours ago, PainGod85 said:

 

It's funny you should quote the one part of my post that poked fun at how the different engine turn directions across two airframes came to be. Everything else I said is nothing but stating facts.

 

Funny, maybe. If you consider it poking fun, that's OK. This is a speculation thread on what might or might not be represented and modeled anyway, right? We can all speculate whatever we want.

 

@ZachariasX  thanks for clearing that up. Back when my Uncle was an engineer at NASA he tried to explain to me why you would get better mileage in a car with lower octane fuel than high octane, and it made just as much sense to me as your logical and detailed explanation of lead scavenging. I'm just going to revert back to my original statement that they didn't work right at high altitude until they fixed the cockpit heater and call it a day. I do appreciate the education though. 😉

 

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@Jaegermeister, I wholeheartedly agree that creature comfort should be your concern no.1 if you are to design a high altitude long range fighter. A fighter is only as good as the freezing sod inside can make use of it. 

Regarding your statement about mileage and octane, this is absolutely true and is one of the reasons the Germans always kept the B4 fuel. In principle, even today a Piper Cub would would fly better with 87 LL (it is rarely available) with its low compression engine instead if the 100LL. It holds not true however with the unleaded high performance fuels for cars.

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6 hours ago, Jaegermeister said:

 

I don't know, which is why I said "or whatever it was". I don't claim to be an expert on high altitude temperatures. I just know its awful darn cold up there and everything froze up until they sorted out the cockpit heating issue. 

 

 

 

Take a look at this handy toy for calculating temperature and pressure etc at altitude.  https://www.digitaldutch.com/atmoscalc/

 

The 'temperature offset" is whatever the ground temperature is compared to the standard 15C , so "-15" if ASL temperature = 0C

 

 

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6 hours ago, ZachariasX said:

... It holds not true however with the unleaded high performance fuels for cars.

 

Yes, that would have been a bad idea in my supercharged Mustang Cobra running 8 lbs of boost pressure. Good way to blow the hood off with various random pieces of scrap metal. Not worth trying to increase the 12 mpg it achieved. 😳

 

4 hours ago, unreasonable said:

 

Take a look at this handy toy for calculating temperature and pressure etc at altitude.  https://www.digitaldutch.com/atmoscalc/

 

 

Yes, that is handy, so -65 degrees F at 35,000 feet on a chilly day in Northern Europe. No wonder they had problems with carburetor intake air temperatures and frozen controls. Pioneering high altitude technology had its challenges.

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2 hours ago, Jaegermeister said:

Yes, that would have been a bad idea in my supercharged Mustang Cobra running 8 lbs of boost pressure.

Boost is not really the issue. High performance gasoline today is almost pure iso octane. It burns most efficient. Best mileage. Thus you also get ~98 octane of pure fuel for "super". You can fudge it a tad more and you get "100" octane. (In practice it can be even more than that.) Basically perfect fuel. That's the juice for your Mustang. Just stay away from ARCO.

 

But back then as well as for normal purposes, fuel is chemically just the cheapest moonshine that you can make in largest volume and still somehow gets your engine going. If you have (as in the 1940's) such turd as base fuel, you have to lace that with some aromatic crap (up to ~50%!)  That stinks like hell and doesn't really burn that well to get your octane rating to ~87, and then you can throw in tons of lead until you get 100 octane. (That is C3 or 100/130 fuel.) What many people are resistant to realize is that the fuel back then that made engine ratings go highest in process doesn't burn as well as unlaced fuel. The impact it has is not in power, but in how much yoe need (if you get less energy by burning a gallon, just use more gallons...), hence the lower mileage on high rated fuels vs. lower rated fuels. That lower compression engines are sometimes more fond of fast burning fuels (usually lower octane) is another side effect. LL AVGAS today has much more lead in it than is required to grease the valve seats. You could go much lower with the lead amount if knocking is not an issue, saving you a lot of handling and maintenance troubles.

 

With the Lightning, they had to find many things the hard way, as that aircraft pushed the limits of what could be done much more then the comparatively conventional P-47. No wonder it took a good while for the aircraft living up to its capabilities. It also did so in environments that were much more permissive toward its design.

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53 minutes ago, ZachariasX said:

Boost is not really the issue. High performance gasoline today is almost pure iso octane. It burns most efficient. Best mileage. Thus you also get ~98 octane of pure fuel for "super". You can fudge it a tad more and you get "100" octane. (In practice it can be even more than that.) Basically perfect fuel. That's the juice for your Mustang. Just stay away from ARCO.

 

But back then as well as for normal purposes, fuel is chemically just the cheapest moonshine that you can make in largest volume and still somehow gets your engine going. If you have (as in the 1940's) such turd as base fuel, you have to lace that with some aromatic crap (up to ~50%!)  That stinks like hell and doesn't really burn that well to get your octane rating to ~87, and then you can throw in tons of lead until you get 100 octane. (That is C3 or 100/130 fuel.) What many people are resistant to realize is that the fuel back then that made engine ratings go highest in process doesn't burn as well as unlaced fuel. The impact it has is not in power, but in how much yoe need (if you get less energy by burning a gallon, just use more gallons...), hence the lower mileage on high rated fuels vs. lower rated fuels. That lower compression engines are sometimes more fond of fast burning fuels (usually lower octane) is another side effect. LL AVGAS today has much more lead in it than is required to grease the valve seats. You could go much lower with the lead amount if knocking is not an issue, saving you a lot of handling and maintenance troubles.

 

With the Lightning, they had to find many things the hard way, as that aircraft pushed the limits of what could be done much more then the comparatively conventional P-47. No wonder it took a good while for the aircraft living up to its capabilities. It also did so in environments that were much more permissive toward its design.

 

They started with lead as it served a double purpose lubricating valves, but the real increase in octane number came from ethylene dibromide. Chemically, both are basically radical catchers (Every autoignition event starts with the creation of radicals, which will cause an ignition cascade. Catch enough of those with the right chemicals and you delay the onset of autoignition, hopefully past the point where the sparkplug fires.).

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56 minutes ago, PainGod85 said:

They started with lead as it served a double purpose lubricating valves, but the real increase in octane number came from ethylene dibromide. Chemically, both are basically radical catchers (Every autoignition event starts with the creation of radicals, which will cause an ignition cascade. Catch enough of those with the right chemicals and you delay the onset of autoignition, hopefully past the point where the sparkplug fires.).

Is that how it was introduced? According to my knowledge, they started with TEL. Taken from this book (Prometheans in the Lab: Chemistry and the Making of the Modern World), p.88:

Spoiler

leadedfuel.jpg

They say TEL was the It then goes on directly to the topic of the bromide:

Spoiler

leadedfuel2.jpg

 

But if there's more to that, I'd be interested.

 

So on one side (from what it says above), people knew that iso octane is desirable, the compact version  (2,2,4-Trimethylpentane) it is as standard for the ideal 100 octane "gold" standard), while on the other end of the spectre you have normal heptane, this would be a linear chain of 8 C's plus the 16 Hydrogens. So people knew that. Then they added TEL, then the Bromide along with it and Mr. Boyd got obscenely rich.

 

That n-heptane is the bottom of the barrel regarding knocking was a problem to the Germans, as they made synthetic fuel. They made two fuels made by two different processes. One process would make IIRC isoparaffins, which in turn when added TEL gave you B4. Then they had a different process that was mainly optomised to make anything synthetic, and using that they made the C3 fuel. There they had to play around more either way, so they could come up with different mix of fuel.

 

With the Allies, they had a better fuel base to start with, giving them better mileage. Good for the Lightning.

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Just now, ZachariasX said:

Is that how it was introduced? According to my knowledge, they started with TEL. Taken from this book (Prometheans in the Lab: Chemistry and the Making of the Modern World), p.88:

  Reveal hidden contents

leadedfuel.jpg

They say TEL was the It then goes on directly to the topic of the bromide:

  Reveal hidden contents

leadedfuel2.jpg

 

But if there's more to that, I'd be interested.

 

So on one side (from what it says above), people knew that iso octane is desirable, the compact version  (2,2,4-Trimethylpentane) it is as standard for the ideal 100 octane "gold" standard), while on the other end of the spectre you have normal heptane, this would be a linear chain of 8 C's plus the 16 Hydrogens. So people knew that. Then they added TEL, then the Bromide along with it and Mr. Boyd got obscenely rich.

 

That n-heptane is the bottom of the barrel regarding knocking was a problem to the Germans, as they made synthetic fuel. They made two fuels made by two different processes. One process would make IIRC isoparaffins, which in turn when added TEL gave you B4. Then they had a different process that was mainly optomised to make anything synthetic, and using that they made the C3 fuel. There they had to play around more either way, so they could come up with different mix of fuel.

 

With the Allies, they had a better fuel base to start with, giving them better mileage. Good for the Lightning.

 

The thing is, with the amount of lead needed to achieve the desired octane number, you'd be tearing the engine apart with lead fouling. There's a hard limit enforced by physics how much TEL your engine will still take before it breaks down due to lead fouling, and that's where ethylene dibromide came in. With it you could crank octane number up much higher than with TEL alone, kind of like nowadays there are sweet beverages with both sugar and sweetener as that way, a sweeter taste can be achieved than with either sugar or sweetener alone.

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I gotta say, I'm really looking forward to the P-38.

 

It's the biggest wildcard in the bunch for me... it sounds like it will have some good edges over the opposition, and at the same time might be able to carry an even heavier bomb load than the P47, actually making it a really good attack plane that can then convert to providing fighter cover.

 

The P-47 is a great attack plane, but after you've dropped your bombs you're a mediocre fighter until you manage to climb back up to altitude again, which takes forever in the Jug. But it's looking like the Lightning is a fast one and can climb well even at low altitude, in which case it may very well be a viable fighter even after it's laid its eggs. :)

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5 hours ago, 71st_AH_Yankee_ said:

I gotta say, I'm really looking forward to the P-38....

 

 

Abso-frikkin'-lutely!!!!!!!!!!!!!!!

 

I mean , all this blabbering and yapping is great and all, don't get me wrong... but I'm just gonna leave these here so we can admire 'em all in one place...

 

_P38_1.jpg

 

_P38_2.jpg

 

_P38_3.jpg

 

_P38_4.jpg

 

_P38_5.jpg

 

_P38_6.jpg

 

_P38_7.jpg

 

_P38_8.jpg

 

P38_1.jpg

 

P38_2.jpg

 

P38_3.jpg

 

P38_4.jpg

 

Trio_1.jpg

 

Trio_2.jpg

 

P-38_1.jpg

 

GF_USA.jpg

 

Visibility_1.jpg

 

Visibility_2.jpg


 

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