How good (or bad) was the P-38, really?

[Sisu]

But what a great shape...

 

[Thumpalumpacus]

I though the reference to the lack of torque being an advantage an interesting one. I also recall reading somewhere how differential power application to the engines could also help tighten turns.

While I understand the concept of differential powering, using that in the moment of combat ... phew.

I do get the balanced torque effect, but jockeying two throttles against each other, that's some crazy schtuff there.

 

[GrauGeist]

I though the reference to the lack of torque being an advantage an interesting one. I also recall reading somewhere how differential power application to the engines could also help tighten turns.

I don't recall that being used in combat with the P-38, though I've read many accounts of bombers having to resort to that procedure in order to steer their ship after catastrophic damage.
In order to manipulate the P-38's engines indepently, the throttle quadrant had to be uncoupled and then each throttle maneuvered in order to perform the needed move(s) - that is a rather complex procedure in the heat of battle.

 

[Ascent]

I think everyone is used to it's shape now but looking closely at it and really thinking about it , it really was quite different to anything out there, a product of the experimentation of the late 30's which produced some quite far out designs.

 

[BiffF15]

But what a great shape...

The lead 38 in that shot is Lefty Garners, now seen on YouTube as the Red Bull Lightning.

 

[BiffF15]

I don't recall that being used in combat with the P-38, though I've read many accounts of bombers having to resort to that procedure in order to steer their ship after catastrophic damage.
In order to manipulate the P-38's engines indepently, the throttle quadrant had to be uncoupled and then each throttle maneuvered in order to perform the needed move(s) - that is a rather complex procedure in the heat of battle.

I've read of guys doing it in the P-38 to "tighten the turn". I would have to have one explain what they "think" was happening. As for splitting throttles in combat, it was almost a standard procedure amongst the experienced guys in the Eagle. There was only a few times we would do it, but the yawing you can get is impressive from your adversaries point of view (SE fighters can't do it obviously, so it's not in their fight mindset).

If you have seen a SE plane do a "hammer head" at an airshow, think about a twin doing the same maneuver. The difference being the twin can pull one back and use the split thrust to pirouette for a more controlled pure vertical turn. There are other places to use it, but the caution is you are pulling power off when you do it, and there are few times in my experience that it's smart to accomplish that when offensive in a slow speed fight.

Cheers,
Biff

 

[Shortround6]

Is the plane actually turning (changing direction of flight) or is it skewing/yawing (changing orientation to the direction of flight?) or perhaps a bit of both?

I don't fly so just asking.
It might be useful for a quick snap shot?

 

[BiffF15]

Is the plane actually turning (changing direction of flight) or is it skewing/yawing (changing orientation to the direction of flight?) or perhaps a bit of both?

I don't fly so just asking.
It might be useful for a quick snap shot?

Short answer is both. In the case of a pirouette, the plane goes straight, or almost straight up, gets slow on speed, then you pull the inside motor back inducing a strong enough yaw to rotate the plane from pointing up to pointing down. The key is when to pull, how much, and when to push it back up. Pull too soon, and there isn't enough yaw to induce the rotation, too late and you are starting to tail slide and the airflow is wrong such that again, you can't induce the yawing moment for the desired outcome.

If your opponent is in a more horizontal turn, and you find yourself inside his turn circle (inside his turn) but with your nose well above the horizon, it can be an option. It also allows for rotating ones axis such that you reorient your lift vector (think of lift vector as to where you are pulling your nose) to come down inside his turn into an offensive position.

I'm guessing here but think the tighten the turn comments could actually be the initial turn in to a fight. In a twin, when you lose an engine, especially at a high power setting there is a yaw and a roll towards the dead engine. The 38 was initially a "slower roller" due to all the mass you need to move via ailerons (think engine mass / weight outside the centerline of the plane / prior to boosted flight controls). I'm thinking that the guys who pulled power to tighten the turn were actually using it only to start the roll, then pushing the the power back up as they started the pull portion of the "turn". Pulling power would / could have been accompanied with a bit of rudder into the pulled engine to help induce the rolling motion. Pulling power on one engine while in a turn will not make a smaller turn circle.

Also in one of the above posts there was comments by a 38 driver regarding not being worried about the stall quite so much as he had no torque issues. In an Eagle, in that position (stick aft against the seat pan to hold the nose up), you can then use either throttle modulation or rudder input, or both, to get your nose and flight path to track in a given direction. It would have been an option for the Lightning guy as well.

The snapshot answer is yes. Sometimes you are unable to "fly" your nose to where you want it. In some cases, you can get your nose to move via yaw (induced by rudders, throttle modulation, or both) into a position to employ weapons. The difference between a snap and a tracking kill in training is the number of rounds you get on a guy, and where on his plane (assuming you got hits from the snap shot). In combat if you get hits in the right place (cockpit or other vital areas) very few rounds are required. Also if you get hits on your jet in real life, your chances of making a gross error go up exponentially. In training you can can sometimes induce an error on your opponent allowing you and entry / kill you might otherwise not have gotten.

Cheers,
Biff

 

[FLYBOYJ]

I though the reference to the lack of torque being an advantage an interesting one. I also recall reading somewhere how differential power application to the engines could also help tighten turns.

Supposedly the more experienced pilots did this in combat to great effect!

 

[drgondog]

I think your question requires discussions of which P-38? Like many other fine aircraft, the P-38 definitely morphed from 'high performance with major criticisms' along the way to an end product that could be named in the pantheon of great airplanes of the period.

For me, the P-38 from YP-38 through mid-block P-38E, while formidable based on speed and operational ceiling - they were more along the line of prototype/early production airframes with much unknown regarding how to transform from Interceptor (intended role) to General Purpose Fighter.

The Introduction of Pylons and plumbing kits (Late P-38E); to production maneuvering flaps and more reliable engines and turbos (F/G/H) but limited by Intercooler design to ~1000 Hp; to the Transition block P-38J-5/-10 and early J-15s which improved an solved Intercooler re-design and added 55gal LE tanks and introduced improvements in cockpit ergonomics and late block cockpit heating and improved fuel management; to the J-15 through L in which the dive flaps/boosted ailerons and the final Intercooler/turbo improvements that finally yielded full performance potential of the P-38.

ALL had compressibility issues due to airfoil selection, even though the dive flap introduced in the J-15 alleviated the dive control management issues (P-47 also and solved the same way).

The second block (P-38F/G/H acquitted itself well and was probably the most desired Fighter by AAF combat commands due to speed and range and load capability - but they did not operate reliably or well in the extreme cold of high altitude operations in the ETO. For this reason, 8th AF abandoned the P-38 in favor of the P-51B/D. The last block was formidable in the hands of mediocre and skilled pilot familiar with twin engine ops.

One question that you should ask is "why didn't the P-38J/L assume role of Long Range escort in Pacific operations against Japan? One of the answers that occurred to me - unproven - is that the operating 'best cruise' speed for LR escort for the Allisons was lower than both the P-51D and the B-29 Cruise speeds.

All were very complex to maintain, had longer training requirements, were much more expensive to buy and operate than P-51/P-39/P-40. It was easy to spot, it was relatively complex to spool from Cruise to Combat settings, visibility to rear below the horizontal plane of the wing was more obscure that the S/E fighters. Before introduction of dive flap it was easy to evade in a dive. Before boosted ailerons it was easily out-rolled - an attribute more important than turn, but also out-turned by most S/E fighters (despite much touted differential throttles - which was best for yaw management in a high bank, rather than turn?).

Biff could school me in this - but I wonder how the analogy of a twin engine fighter with thrust vectors close to C/L correlate to P-38 thrust vectors. I shudder in my feeble mind cutting low engine in LH turn to try to tighten the turn. Hold my beer!

 

[FLYBOYJ]

ALL had compressibility issues due to airfoil selection, even though the dive flap introduced in the J-15 alleviated the dive control management issues (P-47 also and solved the same way).

Great info Bill! Amazing how the P-38 has always been the "compressibility whipping boy" but how so many forget (or never knew) how other aircraft had the same issue.

 

[BiffF15]

Biff could school me in this - but I wonder how the analogy of a twin engine fighter with thrust vectors close to C/L correlate to P-38 thrust vectors. I shudder in my feeble mind cutting low engine in LH turn to try to tighten the turn. Hold my beer!

Bill,

The P-38 is a non-centerline bird while the Eagle is, or was (I think this changed) considered CL thrust. The reason the Eagle is considered CL is due to the engine out min control speed being well below the actual flown approach speed (engine out). However, while fighting you can get below that speed and easily influence nose movement through adverse yaw / power management. The Eagle has a Yaw Rate Warning Tone, that beeps above a certain rate of yaw IAW the rate of yaw. More yaw, the faster it beeps. A F-15C model guy transitioned to an E model and subsequently had an accident. It came to light that he was using the yaw rate warning tone as an indicator of max performing the jet and the community stopped that. Or thought they did. Before I left the jet 3 beeps were allowed, up from none for awhile.

When offensive, but without enough nose authority to get a guy under the pipper, there is sometimes an option to yaw the plane enough to get the adversary under, or close enough to your nose to employ weapons. When established in a hard or max performance turn, any reduction in power, whether in a SE or a multi, will not help you turn better.

There are other times you can or would do this, but don't want to compromise those who still fly it by letting the bad guys know everything we can do.

My examples are extreme cases. If you watch a SE air show performer, in an Extra / Sukhoi go straight up, then pin wheel turn to go down that is known as a pirouette. Most SE piston fighters don't do this normally (although I've seen it done in a Mustang at low altitude in 356FG markings called Jagersvelt or something along those lines). This is predominantly due to what I think is rudder authority. If you can go straight up in a piston, you will have full or close to it right rudder. When you get to the top you swap rudder and go left (only choice in this instance). In a Eagle, you can go either direction, just like a Lightning. The Hornets FBW flight controls can do this automatically if the pilot asks it to.

While this is a slightly exploded view of split throttle operations, I think the P-38 guys who talked about it did it only with the roll portion (setting his lift vector) of a turn.

Cheers,
Biff

 

[Shortround6]

Thank you for your replies.
I was thinking about this on a long drive yesterday about your comment for initiating the roll/turn.
You could very well be right as I cannot figure out how once the plane is turning at even a 2 G turn rate and the plane is banked at 60 degrees how throttling back one engine helps.

In a 60 degree bank cutting the "inner" (lower) engine doesn't seem like it is going to do much except perhaps lower the nose of the aircraft?
Any turn with a steeper bank angle is just going to make things worse?
Keeping the "inner" (lower) engine at full throttle and cutting the outer/upper engine doesn't seem like it would affect the turn rate either. It might momentarily cause the nose to point higher as the plane skews but the turn rate is now controlled by the elevators isn't it?

Point is, as I see it, (nonpilot) that the rudders and "skewing/yawing" the plane with the throttles aren't going to do much for turn rate once the bank angle gets close to 45 degrees.

Am I missing something?
If throttling back on one engine causes that side of the airplane to dip as the plane starts to roll to that side I can understand getting to the desired bank angle a bit quicker.

 

[special ed]

Is there any mention of P-38 pilots using the dive flaps as combat flaps to pitch up the nose in a turn.

 

[BiffF15]

Thank you for your replies.
I was thinking about this on a long drive yesterday about your comment for initiating the roll/turn.
You could very well be right as I cannot figure out how once the plane is turning at even a 2 G turn rate and the plane is banked at 60 degrees how throttling back one engine helps.

The only thing I can conclude is pulling back and engine helps to initiate the roll (in the P-38). Every "twin" I have flown rolls into the dead engine, or less powerful engine as a result of asymmetric thrust. Aircraft (not the F-16/22/35) have a single speed called Corner Velocity (CV). That is the speed you can pull back on the stick hard, hit max G allowable and max degrees per second of turn. If you are above this speed you will over G, or be limited by max G, before hitting max rate, if you are below this speed you will not hit either max G or rate. In the Eagle we would start a max performance turn above this speed, being very cautious to not over G. Once at or below this speed, if desired, one could bring the stick back to the seat pan thereby "max performing" the jet. In both the Eagles case, and with WW2 fighters, pulling the power above CV is done to control the size of your circle (big difference in the Eagle) but once close you accept the larger to only slightly larger circle size in return for a longer pull at highest / higher G.

In a 60 degree bank cutting the "inner" (lower) engine doesn't seem like it is going to do much except perhaps lower the nose of the aircraft?

Correct.

Any turn with a steeper bank angle is just going to make things worse?
Keeping the "inner" (lower) engine at full throttle and cutting the outer/upper engine doesn't seem like it would affect the turn rate either. It might momentarily cause the nose to point higher as the plane skews but the turn rate is now controlled by the elevators isn't it?

Your first question assumes level flight (I think). In a fight the only time it's level is when at the floor. P39 Expert thought the fight would stay up high so his fuel flow numbers would work. That works if the enemy complies, which doesn't often happen. The vast majority of turning fights I have ever done go down. Usually in a spiral, with the nose of each aircraft below the horizon, as if following the threads of a giant bolt down towards the ground.

If you are at or below CV, you don't pull the power to turn better. You may pull it to "tighten the turn" which means decrease the size of your turn circle. Tighten the turn, tighten down, are both examples of bleeding off or cashing in airspeed in order to do something else. The tighten down can be used when offensive to help bring your nose to bear, or when defensive to cause an overshoot (a guy to go outside your turn circle / be unable to bring his nose to bear).

Yes, the turn when established, is controlled primarily by the elevators, but the rudders or ailerons also come into play. As does thrust / power. If you roll to 135 degrees of bank and pull, your nose will go well below the horizon, eventually bottom out, then track back up. Sort of a banana shaped, starting at and coming back to the horizon. To keep the bank in, one must do small continued input of roll.

Point is, as I see it, (nonpilot) that the rudders and "skewing/yawing" the plane with the throttles aren't going to do much for turn rate once the bank angle gets close to 45 degrees.

Am I missing something?
If throttling back on one engine causes that side of the airplane to dip as the plane starts to roll to that side I can understand getting to the desired bank angle a bit quicker.

You are missing nothing. The skewing / yawing does nothing once in the turn to help the turn regardless of bank. The throttling back, in my opine, is done only to help initiate the roll but PRIOR to the pull.

Cheers,
Biff
PS: Sorry for the format, best I could do under the circumstances.

 

[Shortround6]

Is there any mention of P-38 pilots using the dive flaps as combat flaps to pitch up the nose in a turn.

The late P-38s had two flaps or perhaps better stated as one set of flaps and a set of spoilers.

The "dive flap" is what is being pointed to and I doubt it is going to affect the pitch of the plane very much.

From the P-38F on the landing flaps could be lowered 8 degrees as "combat" flaps to increase wing area and lift.

 

[special ed]

Thanks

 

[FLYBOYJ]

The late P-38s had two flaps or perhaps better stated as one set of flaps and a set of spoilers.

View attachment 634751

The "dive flap" is what is being pointed to and I doubt it is going to affect the pitch of the plane very much.

From the P-38F on the landing flaps could be lowered 8 degrees as "combat" flaps to increase wing area and lift.

Milo Burcham with Bong. I met Milo Burcham Jr., briefly worked with him, spitting image of his dad

 

[eagledad]

Greetings Special Ed

In Fighter Tactics of the Aces, John Loisel, an ace of the 475th Fighter Group, mentioned how some pilots were lowering their dive flaps after rolling into a turn, in the mistaken belief that the flaps would pull the nose of the aircraft through their target quicker. So it appears it was tried, but was probably not effective.

Eagledad

 

[special ed]

Many thanks Eagledad. That seems to spark a memory. I probably read it many years ago and like so much else becomes blurred together.