Can some of the explanation for the P-38's greater success in the Pacific be attributed to poorer Japanese pilots?

[Wild_Bill_Kelso]

(crap sorry I didn't see 33k in the air's post until after i finished mine)

 

[Wild_Bill_Kelso]

It does seem like P-38 had some extra features a pilot could 'unlock' if he knew about them and how to take advantage of them.

 

[BiffF15]

It does seem like P-38 had some extra features a pilot could 'unlock' if he knew about them and how to take advantage of them.

WBK,

Two things.

First, the difference between a coordinated stall and one that's uncoordinated (reference high powered prop fighters). The P38 could stall (along with most twins that had counter rotating props) in a bank, straight ahead, upside down, whatever, and if it's coordinated (needle and ball centered) it won't bite you as long as you have symmetrical load (balanced external stores and or balanced fuel between the wing tanks). So, left turn or right, the plane flew the same and apparently via "bucking" advertised in a easily read manner that the stall was close. The fact that he kept turning even though he was bucking means he wan't in a stall. In a stall he would stop turning and start losing altitude.

SE prop fighters have a disc on the front of the plane that provides thrust, unequally so (AKA yaw). The prop coming down provides more thrust (skipping the why) than the prop / blades going up. Lopsided power, but is why go arounds in Mustangs have been killing guys for years, as well as causing all sorts of mischief to someone fighting slow in one with the power up. Due to the downward "side" of the prop providing more thrust, the nose wants to turn away (to the left in a plane where the prop spins CW from the pilots perspective) so to keep the plane coordinated (minimum drag) he must step on / trim right rudder. So all trimmed up and now you want to turn, well that means a rudder and stick input. Turn left, some left stick to induce the roll, then recenter to stop the roll, and now a bit of left rudder to keep the plane in trim. Induce max power, same turn to the left, and the plane really needs right rudder to control yaw and you can find yourself flying "uncoordinated". Uncoordinated stalls in this situation lead to spins. Add low altitude and Houston we've got a problem. This is why when you look at turn radius charts there is annotations about a turn to the one direction is smaller than a turn to the other.

The P38 did not have this problem. I thought I read somewhere that McGuire liked to get slow with Zero's due to its turn ability. If someone has turn radius charts please post them, especially if they are slow speed related.

Second, just what does boosted ailerons do for the P38. They help it roll faster, yes, but there is a caveat. It's the start of the roll, and or the stopping of the roll that is the problem area on the Lightning. Those two engines are about 5' away from the aircraft centerline and as such require more force to induce a roll, as well as stop a roll. While the boosted version has a great steady roll rate, dogfighting usually doesn't entail constant rolling. It does have lots of roll, then pull or roll into a bank and stay pretty much there until something changes (usually the other guy doing something you have to compensate for). Bob Johnson talks about mixing it up with a Spit and he could stay inside his turn do to being able to roll faster. Yes, the Spit could out turn steady state a Jug, but if you have a strength the other guy doesn't you can use it to your advantage. The P38 versus Zero is the opposite, or appears so. Maybe the P38 could turn inside the Zero steady state however, I doubt it could out roll one for the first 90 degrees.

I missed an opportunity to speak about this in another thread (Mike Williams had posted a chart with various roll rates of all the leading fighters). My bad.

Cheers,
Biff

 

[FLYBOYJ]

Well, a couple of things. My exact quote was "I would be doubtful that an early P-38 could out turn a P-40 or a Spitfire or a Hurricane" - referring to North Africa basically or the early Pacific war.

Don't matter - this would be dependent on airspeed, angle of bank and pilot skill

 

[Wild_Bill_Kelso]

IIRC the P-47 had a particularly good roll rate. What thread was the roll rates comparison posted in?

I would think the boosted ailerons would matter if the aircraft you were fighting suddenly reversed a turn or got into something similar to a scissors, which seemed to be a fairly common tactic at least by German and some American pilots. I was wondering if it might help ride the edge of a stall though I guess that would mostly be elevators and rudder. In the account it kind of sounds like they just went around in one big circle until he got the guy but it didn't always work out that way.

And again, I don't know precisely the HP advantage of a P-38J vs say a G, but I think any additional horsepower would be very helpful in riding the edge of a stall down low.

One of the things John Tilley mentioned in the account was that he chose to 'mix it up' with the Ki-43 partly because his unit had numerical superiority of about 5-1. One problem with a big plane like a P-38 is that while it's fast, it may not have the acceleration of a smaller plane down low. Just going by Wikipedia (I know, sorry, I don't have time to go pull books from the shelf) it says a P-38L (no subtype given) has a power/mass ratio of 0.16, which is pretty good, but a Ki-43-IIb has a power/mass ratio of 0.2, which is better. This might be worse for the P-38 in the thicker air down low where the drag is more of a factor.

I would think being caught low and slow in a P-38 would be particularly dangerous, partly because it will take you a while to pick up speed with no option to dive. A lighter plane with a better power/mass ratio could conceivably do vertical maneuvers (yo yo, immelmaann, split s etc.) a little more readily in a lower speed dogfight, though probably not if already down close to stall speed.

He also makes this interesting comment which perhaps provides some insight into the limitations of doing vertical maneuvers:

"On several other occasions I can remember following an Oscar or Zeke zigzagging full throttle down hill to about 1000' above sea level where they'd pull a split S and slip right between our legs so to speak. I was somewhat unhappy about losing them this way so decided to see for myself just how much altitude it took for a full split S in the P-38. From a fast cruise at a safe altitude I cut both throttles, pulled the nose up, rolled over as fast as possible and pulled back as hard as possible. I never made it in less than 2500'. If I had tried to follow those guys, I'd have earned a submariner's badge posthumously."

Like a lot of good pilots, he was figuring out precisely what the flight envelope of his aircraft was and learning that of the enemy simultaneously. That's how you find the tactical sweet spots in any fight, for example in martial arts.

 

[FLYBOYJ]

And again, I don't know precisely the HP advantage of a P-38J vs say a G, but I think any additional horsepower would be very helpful in riding the edge of a stall down low.

About 200 hp per engine and any increase in power would help

. This might be worse for the P-38 in the thicker air down low where the drag is more of a factor.

"Thicker air" (dense air) makes an aircraft perform better

I would think being caught low and slow in a P-38 would be particularly dangerous, partly because it will take you a while to pick up speed with no option to dive. A lighter plane with a better power/mass ratio could conceivably do vertical maneuvers (yo yo, immelmaann, split s etc.) a little more readily in a lower speed dogfight, though probably not if already down close to stall speed.

The P-38 accelerated very well and in many cases better than many single engine fighters. This would vary with altitude

 

[BiffF15]

IIRC the P-47 had a particularly good roll rate. What thread was the roll rates comparison posted in?

I would think the boosted ailerons would matter if the aircraft you were fighting suddenly reversed a turn or got into something similar to a scissors, which seemed to be a fairly common tactic at least by German and some American pilots. I was wondering if it might help ride the edge of a stall though I guess that would mostly be elevators and rudder. In the account it kind of sounds like they just went around in one big circle until he got the guy but it didn't always work out that way.

Boosted ailerons do help with reversals, or rapid changes to where you put your lift vector (point your vertical tail). Between single engine types, the boosted should help either by "keeping up" or "being outright faster" than the equivalent unboosted type. There is some talk that the Ta-152H had boosted ailerons which if true would make sense. A longer wingspan (slower roller) as compared to the standard wing on the Fw-190 means the boost is most likely for "keeping up" with the unboosted shorter wingspan brethren. In the P38 it was known for sluggish roll, and that is due to getting all the mass moving(engines / turbos / weight not mounted on centerline). Boosted was about keeping or catching up to it's SE counterparts. Once established in a roll, the boosted P38s were known to be quite good rollers. Continuous rolls don't really have a place in combat that i've seen.

And again, I don't know precisely the HP advantage of a P-38J vs say a G, but I think any additional horsepower would be very helpful in riding the edge of a stall down low.

One of the things John Tilley mentioned in the account was that he chose to 'mix it up' with the Ki-43 partly because his unit had numerical superiority of about 5-1. One problem with a big plane like a P-38 is that while it's fast, it may not have the acceleration of a smaller plane down low. Just going by Wikipedia (I know, sorry, I don't have time to go pull books from the shelf) it says a P-38L (no subtype given) has a power/mass ratio of 0.16, which is pretty good, but a Ki-43-IIb has a power/mass ratio of 0.2, which is better. This might be worse for the P-38 in the thicker air down low where the drag is more of a factor.

Thicker air helps make power and lift. Even though it's bigger, I would not be surprised if the P38 was of lower drag than the Ki-43. It's also understandable to go after an adversary in a less than normal manner when you have a large amount of backup.

I would think being caught low and slow in a P-38 would be particularly dangerous, partly because it will take you a while to pick up speed with no option to dive. A lighter plane with a better power/mass ratio could conceivably do vertical maneuvers (yo yo, immelmaann, split s etc.) a little more readily in a lower speed dogfight, though probably not if already down close to stall speed.

In his example both aircraft were slow, and doing max performance (albeit low g) turns. For the Ki-43 to be able to do vertical maneuvers it would need probably a bit more speed. To get that speed it would have to ease up on it's turn (make the turn circle bigger) or line out (go in a straight line to allow for acceleration). Both would have made the plane predictable, and if Tilley couldn't get into a position to shoot could easily have called in reinforcements. I have been offensive behind guys but not able to bring my nose to bare and had them ease up on the turn, or even line out. When fighting a guy of similar thrust to weight it makes you salivate as you do the same, and the geometry works in your favor as you align fuselages, and go up as required to nail him.

He also makes this interesting comment which perhaps provides some insight into the limitations of doing vertical maneuvers:

"On several other occasions I can remember following an Oscar or Zeke zigzagging full throttle down hill to about 1000' above sea level where they'd pull a split S and slip right between our legs so to speak. I was somewhat unhappy about losing them this way so decided to see for myself just how much altitude it took for a full split S in the P-38. From a fast cruise at a safe altitude I cut both throttles, pulled the nose up, rolled over as fast as possible and pulled back as hard as possible. I never made it in less than 2500'. If I had tried to follow those guys, I'd have earned a submariner's badge posthumously."

Like a lot of good pilots, he was figuring out precisely what the flight envelope of his aircraft was and learning that of the enemy simultaneously. That's how you find the tactical sweet spots in any fight, for example in martial arts.

Agreed.

 

[wuzak]

See my post above and read the attached story. Tilley out-turned an Oscar at low speed which can easily out turn "a P-40 or a Spitfire or a Hurricane." "Pilot Skill" has a lot to do with this. His story...

Secrets of a P-38 Ace. John Tilley's electrifying story

By age 21, Capt. Tilley was an Ace combat pilot! By age 21 Capt. Tilley had received a DFC, 7 Air Medals, and a Campaign ribbon with 7 battle stars

www.kilroywashere.org

Here is Tilley's account as quoted in The Great Book of World War II Airplanes by Jeffrey Ethell et. al. (p.47):

"Alright, so how come I got my second kill by turning a full 360º circle to the left, at low speeds and on the deck with an Oscar? Primarily I think it happened because the Jap and I both believed he could out turn me. I never would have tried to stay with him if there hadn't been 12 of us and only two of them. I figured I could always holler for help if I got in a jam. And I'm sure the Jap figured the usual tight turn was his best bet when he didn't have enough air under him for a split-S. Miracle of miracles, the big old P-38 actually turned inside the nimble little Oscar. I was on the deck, in a vertical bank, the airspeed under 90 mph, and the yoke bucking and shuddering in my hands. That turn was nothing more nor less than a controlled stall. But without torque (good old counter-rotating engines) I didn't worry about 'snapping' out of control and into a spin, as with a single engine aircraft, so I was able to pull enough lead for my guns to really hit him hard."

I take it that an airspeed under 90mph would require the flaps to be fully deployed?

 

[Wild_Bill_Kelso]

About 200 hp per engine and any increase in power would help

yes, that's more than I thought

"Thicker air" (dense air) makes an aircraft perform better

I was referring to acceleration ...

The P-38 accelerated very well and in many cases better than many single engine fighters. This would vary with altitude

Well from what I understand, acceleration is largely a function of power to weight ratio and drag... I think Ki-43 is better in both areas though I'm willing to learn otherwise. of course acceleration will also vary by speed and power, and will depend on how long each engine can maintain full (or more than full) power

 

[Shortround6]

I'm not an expert on the P-38 by any means but i gather the J had some more available power due to the redesigned intercooler system, it had the dive flaps, and the J-25-LO onward had the hydraulic boosted ailerons. Again, not a P-38 expert and not a pilot, but I would think boosted ailerons might help ride a stall. Seems like the extra power definitely would though I don't know how much extra was available precisely.

Like a lot of other planes P-38s evolved over time.
The P-38F got new model engine.
The P-38F-15 got the maneuver flap setting.
The P-38G was in production in June 1942
G-3 got new turbo chargers
G-5 got revised turbochargers
last 200 Gs were upgraded to two 300 gallon drop tanks
P-38H (march 1943) New engine model, new B-33 turbos, automatic engine controls, automatic oil cooler exit doors
P-38J (Sept 1943) New props, higher capacity radiators
J-10 electrical generator on each engine, improved cockpit heating
J-15 new leading edge fuel tanks
J-25 dive recover flaps fitted, power boosted ailerons
P-38L (June 1944) automatic powerplant controls, uprated engines

Now I will note that some of the middle period P-38s were limited to the altitudes at which they could use WER due to several things. One was the intercoolers wouldn't cool the air at higher altitudes (turbo was compressing/heating the air more) and the 2nd was that radiators weren't built to handle 1425hp engines at altitude. The engine-turbo combination could make more power than the radiators could handle in thin air.

What the they could do at low altitude????

Does the article state which model P-38 was used, it could be either way. New P-38s just delivered or P-38Js still in service.

Please note that the P-38G was rated at 1600hp combat, at sea level the turbo wasn't working that hard and the old intercoolers could do the job (at least for short period of time) and like wise the dense air would keep the engines cool (remember at just over 20,000ft the air is 1/2 as dense as sea level so you only get about 1/2 the cooling power per cubic foot of going through/over the radiators/intercoolers)

 

[Wild_Bill_Kelso]

Boosted ailerons do help with reversals, or rapid changes to where you put your lift vector (point your vertical tail). Between single engine types, the boosted should help either by "keeping up" or "being outright faster" than the equivalent unboosted type. There is some talk that the Ta-152H had boosted ailerons which if true would make sense. A longer wingspan (slower roller) as compared to the standard wing on the Fw-190 means the boost is most likely for "keeping up" with the unboosted shorter wingspan brethren. In the P38 it was known for sluggish roll, and that is due to getting all the mass moving(engines / turbos / weight not mounted on centerline). Boosted was about keeping or catching up to it's SE counterparts. Once established in a roll, the boosted P38s were known to be quite good rollers. Continuous rolls don't really have a place in combat that i've seen.

Right agreed makes sense

One of the favored strategy of German pilots in the MTO in the early days was to reverse turns repeatedly to shake a Hurricane, because (according to the Germans at least) the Hurricanes had a poor initial roll rate. This didn't work so well against Kittyhawks though, or later on against P-47s in particular. I wonder if the P-38 boosted ailerons were instantaneously fast or if it took a minute for them to begin to 'boost' the roll rate...

I also would assume that in a turn like that the P-38 pilot would be using some kind of partial flap setting.

Interestingly the Ki-43 had automatic maneuvering flaps.

Thicker air helps make power and lift. Even though it's bigger, I would not be surprised if the P38 was of lower drag than the Ki-43. It's also understandable to go after an adversary in a less than normal manner when you have a large amount of backup.

I just figured thicker air meant more drag, I would be surprised if the P-38 had lower drag than a Ki-43 just because it had so much bigger wingspan plus things like turbo etc. sticking out into the slipstream, though other than that it was a fairly well streamlined aircraft and the Oscar had a radial engine. We can probably check the numbers easily enough.

In his example both aircraft were slow, and doing max performance (albeit low g) turns. For the Ki-43 to be able to do vertical maneuvers it would need probably a bit more speed. To get that speed it would have to ease up on it's turn (make the turn circle bigger) or line out (go in a straight line to allow for acceleration). Both would have made the plane predictable, and if Tilley couldn't get into a position to shoot could easily have called in reinforcements. I have been offensive behind guys but not able to bring my nose to bare and had them ease up on the turn, or even line out. When fighting a guy of similar thrust to weight it makes you salivate as you do the same, and the geometry works in your favor as you align fuselages, and go up as required to nail him.

Right the one option for a vertical maneuver would be to try to do one of those emergency split S escape manuevers Tiley was referring to but (guy's please forgive me for mentioning this but it's my main point of reference here) in IL-2 if I tried that at low speed I pretty much always got shot. Escape maneuver's aren't automatic it helps a lot to have some space and some speed / E built up.

 

[Wild_Bill_Kelso]

Like a lot of other planes P-38s evolved over time.
The P-38F got new model engine.
The P-38F-15 got the maneuver flap setting.
The P-38G was in production in June 1942
G-3 got new turbo chargers
G-5 got revised turbochargers
last 200 Gs were upgraded to two 300 gallon drop tanks
P-38H (march 1943) New engine model, new B-33 turbos, automatic engine controls, automatic oil cooler exit doors
P-38J (Sept 1943) New props, higher capacity radiators
J-10 electrical generator on each engine, improved cockpit heating
J-15 new leading edge fuel tanks
J-25 dive recover flaps fitted, power boosted ailerons
P-38L (June 1944) automatic powerplant controls, uprated engines

Now I will note that some of the middle period P-38s were limited to the altitudes at which they could use WER due to several things. One was the intercoolers wouldn't cool the air at higher altitudes (turbo was compressing/heating the air more) and the 2nd was that radiators weren't built to handle 1425hp engines at altitude. The engine-turbo combination could make more power than the radiators could handle in thin air.

What the they could do at low altitude????

Does the article state which model P-38 was used, it could be either way. New P-38s just delivered or P-38Js still in service.

The J is the one relevant here - the big difference I read about with the J was (I think as part of the radiator change) the intercooler systems being changed from leading edge and put into the chin radiators, this is what gave them more potential power. Unless I misunderstood.

 

[Shortround6]

Unless I misunderstood.

it is a little trickier.
The engines would make the power, even on the Gs (?), but pilots were supposed to limit the amount of boost at higher altitudes because both cooling systems were over loaded.
We need to look at the manuals, my memory may be faulty, but one of them was rated at around 10,000 ft for full combat power and tapering off above that. A lot of books get it wrong (and the manuals sometimes have errors)

 

[FLYBOYJ]

I was referring to acceleration ...

Yes, and you get better performance in thicker (more dense) air

Well from what I understand, acceleration is largely a function of power to weight ratio and drag... I think Ki-43 is better in both areas though I'm willing to learn otherwise. of course acceleration will also vary by speed and power, and will depend on how long each engine can maintain full (or more than full) power

Well even with the earlier P-38s you're looking at 2800 HP pulling a roughly 20,000 airframe through the air, the later ones 3200 HP. Mr Wiki says the power to mass ratio is 0.16 hp/lb on the K model. For weighing roughly 14,000 pounds less, we're looking at a power to mass ratio of 0.20 hp/lb for the Ki-43. With that said, the P-38 climbed at 4750 a minute, the Ki-43 about 3200 feet per minute. Why? IMO less drag and probably more aerodynamically efficient. You also look at the efficiency of the propellers.

 

[NTGray]

I would be doubtful that an early P-38 could out turn a P-40 or a Spitfire or a Hurricane - in fact several Allied pilots (like DeHaven) noted that it couldn't, though perhaps he didn't know how to do the differential throttle thing.

Keep in mind the distinction between turn rate and roll rate. I would think that early P-38s would turn just as tightly as later -38s would, but they rolled more sluggishly until hydraulic aileron boost was added. So the early models took longer to get into the turn to start with.

 

[Shortround6]

Ok, found some of the manuals.

This may take a bit of time, will edit/add later.

P-38E
take-off..........................1150hp/3000rpm/40.3in...................25,000ft *
Em MAX.........................1150hp/3000rpm/40.3in..................25,000ft
max cont........................1000hp/2600rpm/37in.....................28,000ft

P-38F
take-off..........................1240hp/3000rpm/44.5in...................21,000ft *
Em MAX.........................not possible.....................................................
Military power. ..........1325hp/3000rpm/47in......................15,000ft
max cont........................1000hp/2600rpm/38in.....................27,000ft

P-38G
take-off..........................1240hp/3000rpm/44.5in...................21,000ft *
Em MAX.........................not possible.....................................................
Military power. ..........1425hp/3000rpm/51in......................15,000ft
max cont........................1100hp/2600rpm/41in.....................24,000ft

* that is what the manual says, I would also note that this manual does not agree with what "Vees for Victory" says
There may be an error for the P-38G and the engines are good for 1325hp for take-off (or more?)

continuing.
P-38H
take-off..........................1425hp/3000rpm/54in...................22,000ft *
Em MAX.........................1600hp/3000rpm/60in..................10,000ft (with RAM, 7000ft without)
Military power. ..........1425hp/3000rpm/54in...................22,000ft (with RAM)
max cont........................1100hp/2600rpm/44in..................34,000ft (with RAM)

P-38J
take-off..........................1425hp/3000rpm/54in...................26,600ft (no ram)
Em MAX.........................1600hp/3000rpm/60in..................28,700ft (with RAM, 25,800ft without)
Military power. ..........1425hp/3000rpm/54in...................29,000ft (with RAM)
max cont........................1100hp/2600rpm/44in..................33,800ft (with RAM)


P-38L
take-off..........................1425hp/3000rpm/54in...................26,600ft (no ram)
Em MAX.........................1600hp/3000rpm/60in..................28,700ft (with RAM, 25,800ft without)
Military power. ..........1425hp/3000rpm/54in...................29,000ft (with RAM)
max cont........................1100hp/2600rpm/44in..................33,800ft (with RAM)

Yes the P-38 J & L are identical
The first 3 sets of numbers are from one manual and the others are from a different one. The first manual was updated/revised as of 30 Sept 1944 and most/all of those aircraft should have been retired to training use.
Please note the huge jump in altitudes with the P-38J and L even if the peak power doesn't chance much.
Also note that a P-38H at low altitude is a very powerful airplane.

Ok should be done from the manuals

 

[Shortround6]

Well even with the earlier P-38s you're looking at 2800 HP pulling a roughly 20,000 airframe through the air,

Even better for the pilots, if they don't have crap hanging off the wings the planes were under 16,000lbs. for the planes without leading edge tanks.

 

[Gary Cain]

Keep in mind the distinction between turn rate and roll rate. I would think that early P-38s would turn just as tightly as later -38s would, but they rolled more sluggishly until hydraulic aileron boost was added. So the early models took longer to get into the turn to start with.

No, the later P-38's could turn tighter because of the maneuver flap setting. Early on if you had a great pilot they could do things a normal pilot couldn't though, so you are correct in that case.

 

[Shortround6]

No, the later P-38's could turn tighter because of the maneuver flap setting. Early on if you had a great pilot they could do things a normal pilot couldn't though, so you are correct in that case.

The maneuver flap setting came in in the summer of 1942, there weren't that may P-38s without it.
There were 210 "E"s (the "D" s were never sent overseas, all 36).
There were 527 "F"s and the maneuver flap was introduced on on the last batch.

Please note the maneuver/combat flap was not supposed to be used over 250 IAS.

 

[Wild_Bill_Kelso]

Yes, and you get better performance in thicker (more dense) air

Well even with the earlier P-38s you're looking at 2800 HP pulling a roughly 20,000 airframe through the air, the later ones 3200 HP. Mr Wiki says the power to mass ratio is 0.16 hp/lb on the K model. For weighing roughly 14,000 pounds less, we're looking at a power to mass ratio of 0.20 hp/lb for the Ki-43. With that said, the P-38 climbed at 4750 a minute, the Ki-43 about 3200 feet per minute. Why? IMO less drag and probably more aerodynamically efficient. You also look at the efficiency of the propellers.

Wow... you are right the Wiki says P-38L climbed at 4,750' per minute, but I'm really baffled as to where they got that figure. That would be a lot better than most other piston engined Allied or Axis fighters during the war. I had not had the sense that it climbed that well.

This chart for a P-38J gives 3,670 at WEP at one weight (I can't read the other figure... 3,560?) and closer to 3,000 fpm at Military Power. Which is about average for a fighter in that period, and much closer to the Ki-43-II (earlier Ki-43-Is I think didn't climb quite that well).

On the other hand, This 1944 memo gives P-38J 4,050 fpm at WEP (which is damn good) and 3,720 at military power. The P-38K looks even better but was that an actual variant? That's still better than I would have thought for the J.

There isn't very much on the P-38 on WW2aircraftperformance.org, somebody needs to rectify that! Do you have detailed data on the P-38L other than the Wiki?