Best Pacific Fighter?

[Lightning Guy]

Shiden's did not score countless kills over Corsairs and much of their success was due to the phenomenal skill of their pilots.

 

[wmaxt]

The F would out-turn the P-51 which would turn with the F4U. The L was even better. The P-38 could handle the F4U in a turning fight. It could also out dive it. The higher diving-speed of the F4U proves nothing. The P-38 accelerated faster in the dive, meaning that it will pull away from the Corsair once the dive is initiated.

The P-51 could not turn with the Corsair, where do you get that from?

See P51-B Vs F4U-1 pg. 5. Also see the conclusions on page 7. Keep in mind the -1 corsair was inferior to the -1d which was inferior to the -4, where the P-51B was superior (as a dogfighter) to the D model. As you will see, the Corsair was the better turning plane.

The P-51 could out turn the P-38 at medium speeds and above. Only if the speed got below about 200 IAS would the P-38 start to have a meaningful advantage. Above 300 IAS, the P-51 wins hands down. The F4U-4 could out turn the P-51, and at reasonable combat speeds of over 200 IAS it could out turn the P-38.

Yes the P-38 had better initial dive acceleration than the F4U-4. But even that is subject to limits, the P-38 would start suffering buffeting from compression well over 50 mph before the Corsair would. The P-38 dives better, but not a lot better, probably not enough better to escape.

I will have to check some moe. At this time I've got the data from the following sources:

With the dive slats the P-38 dove quite well and was controllable above 500mph.

Planes and Pilots of WWII where the 38 is a least right there with the F4U-4 or better and at least 3 except for the 38 statements.

C C Jordan and his interviews where he states that P-38/P-51 pilots (some prefering the P-51 overall) and of course Art Heiden who say the P-38 was better/didn't give anything up to the P-51 in ACM at least.

The F4U-4 was/is a great plane but where does 5,500 ft/min come from?

While I think the P-38 was better at least in most areas and with an efective pilot could take on anything in the air in WWII and have a 1 to 1 or better chance of winning.

Please put up some info here.

 

[Anonymous]

The F would out-turn the P-51 which would turn with the F4U. The L was even better. The P-38 could handle the F4U in a turning fight. It could also out dive it. The higher diving-speed of the F4U proves nothing. The P-38 accelerated faster in the dive, meaning that it will pull away from the Corsair once the dive is initiated.

The P-51 could not turn with the Corsair, where do you get that from?

See P51-B Vs F4U-1 pg. 5 <--- click here. Also see the conclusions on page 7. Keep in mind the -1 corsair was inferior to the -1d which was inferior to the -4, where the P-51B was superior (as a dogfighter) to the D model. As you will see, the Corsair was the better turning plane.

The P-51 could out turn the P-38 at medium speeds and above. Only if the speed got below about 200 IAS would the P-38 start to have a meaningful advantage. Above 300 IAS, the P-51 wins hands down. The F4U-4 could out turn the P-51, and at reasonable combat speeds of over 200 IAS it could out turn the P-38.

Yes the P-38 had better initial dive acceleration than the F4U-4. But even that is subject to limits, the P-38 would start suffering buffeting from compression well over 50 mph before the Corsair would. The P-38 dives better, but not a lot better, probably not enough better to escape.

I will have to check some moe. At this time I've got the data from the following sources:

With the dive slats the P-38 dove quite well and was controllable above 500mph.

Planes and Pilots of WWII where the 38 is a least right there with the F4U-4 or better and at least 3 except for the 38 statements.

C C Jordan and his interviews where he states that P-38/P-51 pilots (some prefering the P-51 overall) and of course Art Heiden who say the P-38 was better/didn't give anything up to the P-51 in ACM at least.

The F4U-4 was/is a great plane but where does 5,500 ft/min come from?

While I think the P-38 was better at least in most areas and with an efective pilot could take on anything in the air in WWII and have a 1 to 1 or better chance of winning.

Please put up some info here.

Everything I've read indicates that the dive recovery flaps allowed the P-38L to recover from an otherwise terminal dive, but they still had to cut back on the power. These flaps do not prevent the compression effects, they just allow the plane to recover despite them. If its above about 460 mph, it's flying the wings through compression (they were poorly designed for this, being of a conventional high aspect design), and that means buffeting.

5500 fpm? Where is that? The figures I quoted were 4.9 mins to 20,000 feet with capped pylons (which implies ~4.6 mins to 20k w/o them) for the F4U-4, which comes right out of the declassified F4U-4 pilot handbook from the USN, along with the 464 mph top speed figure. This converts to a sustained climb rate of a little better than 4000 fpm, and you can see from the climb graph in the handbook the overall climb performance (with capped pylons).

As for sources, I've already posted a bunch of P-38 urls (I can post them again if you like?). You can follow the link in the quoted part above (I've located it in red for you) to see the USN comparison data of the P-51B and F4U-1a (upgraded 1944 version with water injection but no paddle prop). Once on the page referenced, you can investigate the other pages of that report.

=S=

Lunatic

 

[wmaxt]

The P-51 developed a strong buffet in a dive if the speeds were getting much above 500mph to. John Lowell in "Top Guns" reported "diving at 600mph" in the Spitfire dogfight story (granted this is probably overstated but shows high speed dives are both possible and controlable in a P-38.

The Plans and Pilots of WWII graph shows 4.9-5 mins to 20,000ft for the P-38L. C C Jordon cites 4,125-4,225ft/mn max climb and 4.91min to 20,000 for the P-38L Identical to the F4U-4. The graph also shows a climb to 20,000ft at 7min in cruise power (1,100hp). My understandind is the planes in the graph are set up for average combat conditions (not capped pylons).

The 5,500 is what the F4U-4 would have to climb to meet the figure of 33% better climb than the P-38.

I checked out the P-51, F4u site, interesting. I can easily accept the F4U over the P-51. I did notice a bias for the F4U with comments like "Not suited to carrier operations" when the F4U was not carrier qualified for the same things at the time of the test, early '44.

I can't buy the superority of the P-51 over the The P-38 for the following reasons.

1. The pilots who flew both felt the P-38 was better/as good, Art H said "There was nothing the P-51 could do that the P-38L couldn't do better". I rate this high for these reasons:
a. They flew both of them in combat. Thier lives depended on it.
b. We both know they flew them against each other, officialy or not, and these pilots knew how to get everything out of a P-38 where other test pilots might not.

2. At 250 and above, the fowler flap was prohibited, affecting turn in F/G/early Js esp. at altitude, however the dive flap of late J and all L models would kick the nose up about 20-25deg for the same effect with the same drag limitations. These slats worked better the faster you flew.

3. The P-38J-25 and L Actually rolled Faster as the airspeed went up the P-51 went down above 300mph.

4. The prefered speed of combat for the P-38, per Tom Lynch, was 300/350mph as this maximizes performance.

5. The controls on a P-51 tightened up considerably above 300/350mph. Exterme turning manauvers High speed/high altitude in a p-51 could also turn into a vicious stall/spin suddenly and without warning.

6. Due to energy loss the speed of a dogfight is down to 300mph range after just a few turns. Flown properly the P-38 is reported to have excellent energy retention and better energy recovery (note acceleration) than a P-51.

7. P-38 acceleration, climb and ceiling are also better that the P-51 at all speeds/altitudes (granted this diminishes to zero as the high end limits are approached).

I think a dogfight between a P-38L and a F4U-4 with experianced pilots would be incredable they are very closley matched! 8)

 

[Anonymous]

The P-51 developed a strong buffet in a dive if the speeds were getting much above 500mph to. John Lowell in "Top Guns" reported "diving at 600mph" in the Spitfire dogfight story (granted this is probably overstated but shows high speed dives are both possible and controlable in a P-38.

The P-51D developed porpousing at about 525 TAS in a dive, due to the bubble canopy. The P-38 (all models) developed shuddering from compression effects before it hit 500 mph TAS. The 600 mph figure is bogus, that puts the airflow over the wings above Mach 1 even at sea level.

Here I found this on the P-38 dive and compression:

A typical dive of the P-38 from high altitudes would always experience compressibility. Starting from 36,000 ft., the P-38 would rapidly approach the Mach .675 (445 mph true airspeed). At this point, the airflow going over the wing exceeds Mach 1. A shockwave is created, thus breaking up the airflow equaling a loss of lift. The shockwave destroys the pressure difference between the upper and lower wing, and disrupts the ability for the aircraft to sustain flight. As the lift decreases, the airflow moving back from the wing also changes in its form and pattern. Normal downwash aft of the wing towards the tail begins to deteriorate. The airflow across the tail shifts from normal to a condition where there is now a greater upload, of lifting force, on the tail itself. With the greater uploading force applied to the tail, the nose of the aircraft wants to nose down even more, which creates a steeper and faster dive. As the aircraft approaches the vertical line, it begins to tuck under and starts a high-speed outside loop. At this point, the airframe is at the greatest point of structural failure. When the angle of attack increases during the dive, it also increases for the tail. The resulting effect is that the pilot cannot move the controls because tremendous force is required to operate the aircraft. The pilot is simply a passenger during this period. Shockwaves become shock fronts, which decrease the lift no matter what the pilot tries to do. Instead of smooth airflow over the wing, it is extremely turbulent, and strikes the tail with great force. The aircraft can only recover when it enters lower, denser atmosphere lower to the ground.

The solution to the problem was in understanding that the speed of sound changes with the altitude. At sea level, it is 764 mph, while at 36,000 ft. it is 660 mph. An aircraft moving at 540 mph at 36,000 ft. is much higher in the compressibility zone. The same speed at sea level results in the aircraft being exposed to lower effects of compressibility, and will respond to pilot controls. The dive recovery flap was a solution to this problem. In the ETO, German pilots would dive out of trouble because they knew the P-38 pilots would not follow. This greatly reduced the effectiveness of the aircraft in normal battle conditions. The NACA tested the flaps in high-speed wind tunnels at the Ames Laboratory. They tried several locations before discovering that when the flaps were positioned just aft of the trailing edge of the wings, it showed definite improvements. The flaps were finally positioned beneath the wings outboard of the booms, and just aft of the main structural beam. The pilots had a button on the yoke, and would simply activate the flap just prior to entering a dive.
http://www.p-38online.com/dive.html

The P-51 didn't hit compression until above 0.81 mach. Regaurdless of the dive recovery flaps, once the P-38 hits compression effects, it would be nearly impossible to aim the guns.

Another thing I'd point out about the P-38L vs. Spitfire story - at low altitude the speed of sound is higher, allowing the high speed dive (though I still think it was more likely about 450-500 mph), AND the P-38's were noted for being "surprisingly manuverable at low altitudes".

The Plans and Pilots of WWII graph shows 4.9-5 mins to 20,000ft for the P-38L. C C Jordon cites 4,125-4,225ft/mn max climb and 4.91min to 20,000 for the P-38L Identical to the F4U-4. The graph also shows a climb to 20,000ft at 7min in cruise power (1,100hp). My understandind is the planes in the graph are set up for average combat conditions (not capped pylons).

The 5,500 is what the F4U-4 would have to climb to meet the figure of 33% better climb than the P-38.

All F4U-4's had capped pylons for WWII. They were so much faster than the Japanese planes they faced that there was no need to remove them. P-38's flew with and without pylons, depending on the mission and the time frame.

As for climb rates, initial rate of climb figures are pretty meaningless, you need to use time to altitude figures to get any feel for the real climb performance of a plane. The Jordan sight uses the Lockheed-Martin climb chart:

The problem with this chart is there is no verification of the data anywhere. Lockheed-Martin will not provide any info, in fact they won't even reply to an email requesting the source of this data. All other sources indicate ~7 mins to 20k for the P-38L-5-LO. Furthermore, the late J series is consistantly quoted as having been faster to alitude than the L series (which makes sense as it weighed less) at 5.9 minutes to 20K. I suspect these Lockheed figures are for a hot-rodded P-38L, or, more likely, they are really the figures for the P-38K.

On the other hand, we have every reason to believe the USN report. The figures in the report were never intended for non-military viewing and represent what the Navy was telling its pilots to expect from the plane. The .pdf's at the USN site are the Navy's way of complying with the FIA without having to respond to individual requests. If it'd been up to the USN, we'd never have seen these documents. They don't like to declassify anything!

My Dad did these tests on the FJ (Navy F-86) and the way they did it was for 4 planes to takeoff and the first thing they'd do is time the climb. The two middle performers results were used compile the test results. Ordinary USN pilots (usually an advanced flight instructor and 3 of his students) were used to conduct the tests. If the two planes were way off the best performer, they'd land and have the planes checked out and redo the test. Also note that 115/145 fuel was used in the F4U-4 test, not 135/150.

I checked out the P-51, F4u site, interesting. I can easily accept the F4U over the P-51. I did notice a bias for the F4U with comments like "Not suited to carrier operations" when the F4U was not carrier qualified for the same things at the time of the test, early '44.

I agree, that site is biased against the P-51. The USN pilot handbook excerpt .pdf file is a better source for info on the F4U-4.

I can't buy the superority of the P-51 over the The P-38 for the following reasons.

1. The pilots who flew both felt the P-38 was better/as good, Art H said "There was nothing the P-51 could do that the P-38L couldn't do better".

I rate this high for these reasons:

a. They flew both of them in combat. Thier lives depended on it.

This letter (a reply to a magazine writer's questions) was posted on the usenet forums back in 1998. It comes from an article in a flight magazine. The pilot was only refered to by first name, he did not want to be contacted by readers.

Regarding the various comments about throttling back or up a P-38 engine to increase maneuverability I can only repeat that this was not practiced as far as I know. When I was overseas in 44 and 45, flying the J winter thru summer, the policy was to drop tanks and push up MP to 45 inches when German fighters were spotted in a position where an engagement was likely. When you actually went for them, throttle up to WEP, 60 inches or so, rpm all the way up too, up past 3000 rpm. And there it would stay until the engagement was over and you remembered to throttle back. You could easily be at WEP for 20 minutes or more.

Full power all the time was wanted because maneuvering bled off so much speed and altitude. What you wanted was more power and more power. All the prop fighters were underpowered and the only way to keep them turning was to keep them descending. The more power you had available, the slower the descent and the easier the recovery. The 38 seemed to have plenty of power for a prop job and certainly below 15,000 ft. no German fighter could get away from it.

That may sound pretty low, but if you initiated an engagement at 27,000 ft. going into a shallow dive and making a few parring turns, you could easily lose 10,000 ft. Certainly in a 38 without dive flaps you would not want to drop the nose too sharply above 20,000 ft. As krauts got to know the 38 they would tend to dive sharply away from it, convinced it would not follow. But that was just fine, because the 38's job was to protect the bombers. If a gaggle of 109s approached the bombers, escorting P-38s turned to engage them and the 109s bugged out for the deck, the 38's job was done. Those 109s wouldn't have enough gas to climb back up to altitude, chase the bombers and position for an attack. And if they did, the 38s would turn in to them and the process would repeat.

The krauts figured this out pretty soon and knew they had to hit the 38s. They would climb very high (109s, the 190s weren't seen at very high altitudes)and bounce the 38s, who would be cruising at around 220 or so if they hadn't spotted the krauts. Most losses were the result of surprise bounces, the krauts keeping on moving so there was no chance for retaliation. The 38 formation would be broken up, with guys turning looking for the enemy, leaving a way open for other German fighters to hit the bombers.

The only solution to the surprise bounce was to open up the escort fighter formation, have high cover several thousand feet above the bombers and close escort, and keep your head on a swivel. Of course, simply having MORE escorts also helped. (I would wager that was a big problem for the two early 38 groups. They just didn't have enough people to play both the infield and the outfield.) The trick was to spot the Germans as they maneuvered into position for a bounce. That's where having outstanding eyesight mattered, mattered a LOT more than dive flaps or a few more horsepower. One man in a squadron with exceptional eyesight was a real lifesaver. If a high group of krauts was spotted, some of the escort would be tapped to go after them. They didn't have to shoot them down to succeed. All they needed to do was break up their party and force them to dive away.

The 51 could operate at altitudes higher than we usually encountered krauts so had less trouble with being bounced, although, of course, you had to fly at the altitude dictated by the bombers. It had a trickier stall than the 38 so that it was not at all unusual to snap out a tight turn curving in after a kraut.

The first time I lost a 51 in a high speed stall I lost 13,000 ft. before I was able to recover and thought I was going to have to bail out. Man, at that point I HATED that airplane. But by about the third or fourth time that happened, I could recover losing less than 500 ft. and wasn't afraid to push the plane till it snapped. I'd just get it right back under control and keep going. I got so I could catch it just as it departed and it would only wiggle a bit before getting back down to business. I knew what the airplane was going to do before the airplane did and was ready for it. I didn't even have to consciously think about it. What I had thought was a very big deal was, after a while, no problem at all. The airplane was OK. The pilot just had to learn how to handle it. Stick time does make a difference. To those who have said the 38 was a more complicated airplane than the 51 and so pilots needed more time to master it, I would answer that the 51 could be a contrary beast and a pilot needed time to learn to master IT.

If I was to differentiate between the 38 and the 51, I would say the 38's qualities shone best when it was low and slow. Even a pilot with limited hours in the cockpit could have absolute confidence in it and so push it right into the stall with no fear, even at treetop height. The 51's qualities shone best when it was high and fast. In the upper air at well over 300 per, the German fighters were sitting ducks for a 51. They couldn't outmaneuver it and they couldn't out run it and they couldn't out dive it. That's why you hear these stories about a German pilot simply bailing out as soon as a 51 locked on to him. He knew he had no chance so why hang around for the bullets to hit.

Once the 51 was available in numbers it made sense to shift the 38s to the 9th air force and ground attack. It could easily outfight any Luftwaffe opposition at mid and low altitudes, could carry plenty of bombs and survive ground fire that would have killed the 51 very quickly. The only time I wished I was in a 38 when flying the 51 was attacking ground targets. It wouldn't take much to bring a 51 down, and unlike in an air to air encounter, whether you went down or got home was just a matter of your luck that day. Pilot skill was largely irrelevent, as long as you were good enough to keep the airplane at grass cutting height and didn't fly it into the ground because your reactions were too slow. A 38 on the deck was very stable at speed, and hard to bring down by triple A.

My personal situation was such that I had to lean forward slightly to reach all the controls on the 38 and get a good grip on the control wheel. Because of my body's position, I would tend toward gray out and tunnel vision fairly quicky in hard turns. With the 51, I was able to reach all the controls and have a good grip on the stick while leaning back slightly, so gray out and tunnel vision didn't hit me as quickly. That was one big reason I preferred the 51. Other reasons were that I preferred the high sky for my war, and if I had wanted to follow the 38 thru its war career (assuming I had a choice in the matter) I would have had to have spent it in the 9th shooting up airfields.

No thank you.

George

The point is, you can find pilots who liked the P-38 better than the P-51, and you can find pilots who liked the P-51 better than the P-38.

b. We both know they flew them against each other, officialy or not, and these pilots knew how to get everything out of a P-38 where other test pilots might not.

Perhaps so, but it is questionable if pilots who'd mastered the P-38 ever mock dogfought those who'd masterd the P-51. Usually these would have occured during the transition period, where they had lots of P-38 experiance but little P-51 experiance.

Also, mock dogfights tend to come down to who can stay on who's tail. This is meaningless since in a real dogfight that plane might well have been dead before it ever got to the tail chase.

2. At 250 and above, the fowler flap was prohibited, affecting turn in F/G/early Js esp. at altitude, however the dive flap of late J and all L models would kick the nose up about 20-25deg for the same effect with the same drag limitations. These slats worked better the faster you flew.

The dive recovery flaps are noted as having been used on occasion as a trick to get the nose inside an enemy in a turn fight, never as manuver flaps in combat. The P-51 however, had a 5 degree combat flaps setting that could be dropped at any speed, and a 10 (or 15) degree setting that was useable below about 325 IAS.

While there is no arguing that the P-38 turned better at lower speeds, especially at lower altitude, I think it is clear the P-51 had the turn advantage at high speeds and especially at high speeds at high altitude.

3. The P-38J-25 and L Actually rolled Faster as the airspeed went up the P-51 went down above 300mph.

Yes but the P-51 still rolls better up to 330 mph, and the difference is not that huge thereafter. Also, while it is true the P-38 absolute roll was higher, this was using power boosted ailerons. If you've ever driven a 1950's or early 60's car with power steering you know that power hydrolic units of that time period were very stiff, gave no feedback, and also tended to have a tiny bit of lag on reversal. When it comes to the ability to do a series of rolls and reverse rolls, I'm not sure the P-38 would really have the advantage. In any case, it is questionable if there is enough difference overall to matter much.

4. The prefered speed of combat for the P-38, per Tom Lynch, was 300/350mph as this maximizes performance.

IAS or TAS. As you can see from the quote above, all planes sought to maintain speed. I suspect this is TAS. The P-51 optimal speed was more like 350-500 TAS.

5. The controls on a P-51 tightened up considerably above 300/350mph. Exterme turning manauvers High speed/high altitude in a p-51 could also turn into a vicious stall/spin suddenly and without warning.

In the hands of an inexperianced pilot yes it could, but as you can see from the quote above, in the hands of an experianced pilot this was not a signficant issue. As for the controls tightening up, that didn't happen until higher speeds. The ailerons never tightened up, the rudder was always quite workable. The elevator became stiff, usually well over 400 IAS at lower altitudes.

6. Due to energy loss the speed of a dogfight is down to 300mph range after just a few turns. Flown properly the P-38 is reported to have excellent energy retention and better energy recovery (note acceleration) than a P-51.

The P-51 had better energy retention if flown right (not breaking the laminar flow bucket), though I agree the P-38L had better acceleration (below 300 IAS). Flown properly, the P-51 does not make "turns", it dives into the attack, zoom climbs away, then dives back into the attack. Eventually energy will be lost, but the whole point is that the target should be dead by then.

7. P-38 acceleration, climb and ceiling are also better that the P-51 at all speeds/altitudes (granted this diminishes to zero as the high end limits are approached).

In the ETO, pilots felt the P-51 was superior at altitude to the P-38J (with boosted alerions and dive recovery flaps). In the PTO, "high altitude" was not really high by comparison.

The P-51 is not made to fight by using acceleration or climb. It is intended to start into the fight faster than its opponent and use its superior zoom and E retention to win the fight, and to disengage when these are diminished. At very high speeds it could out turn both the 109 and the 190.

I think a dogfight between a P-38L and a F4U-4 with experianced pilots would be incredable they are very closley matched! 8)

Again, i think the F4U-4 would win most of the time, as it really does out-perform the P-38L at any reasonable combat altitude. The only place the P-38L wins is if the fight falls pretty well below 200 IAS.

=S=

Lunatic

 

[evangilder]

Interesting analysis. That is a good point about IAS versus TAS. During dive testing with a P-47, a test pilot reached 725 MPH IAS. That is impossible, because terminal velocity on the P-47 was about 600 MPH. The TAS was estimated to be in the mid-500 MPH range. If the IAS had been accurate, the P-47 would have been the first plane to break the sound barrier. Obviously, that wasn't the case.

 

[wmaxt]

Interesting analysis. That is a good point about IAS versus TAS. During dive testing with a P-47, a test pilot reached 725 MPH IAS. That is impossible, because terminal velocity on the P-47 was about 600 MPH. The TAS was estimated to be in the mid-500 MPH range. If the IAS had been accurate, the P-47 would have been the first plane to break the sound barrier. Obviously, that wasn't the case.

This ia a situation that all WWII fighters went through, I've read several variations on most of the planes we talk about. It took a few years before the effects of trans sonic affects on the air speed indicator.

 

[wmaxt]

RG, A couple of points.

The statement comparing the P-38/P-51 was in one case for certain to be Art Heiden - certainly a P-38 fan but had over 100 missions in the P-38 and 52? in the P-51. In the C C Jordon web site he is quoting "several" pilots including Hub Zemke (who refered to the P-38 as an "icewagon").

If I came off like they, P-51/P-38, pilots All prefered the P-38 "oops" , everybodies got an opinion and they will never all be the same. If those pilots had thought the P-51 was Much worse we would have been hearing it ever since - But it remains fact that some pilots prefered the P-38 in a fight.

Note on the climb speed graph at WEP 20,000 is right at the 4.9/5.0min range and is cited at 4.91 in the C C Jordon web site. Normal power, 1,100hp, is 7 min to 20,000ft. The site also quotes climb at 20,000 is still 3,700ft/min. The P-51 is 8:20+/- in military power(1,590hp_. Art Hieden put it this way "The P-38 was at altitude before we reached the coast, the P-51 still had a long way to go.". The P-51 could not out climb a P-38 anywhere.

The Lockheed graph was a comparison with the p-51 for internal use there would be NO REASON to compare the two if they were not in the same weight and trim. Assuming they used a tricked out P-38 against a standard test loading (full ammo ballast and half fuel est from the test data as it matches the standard data) P-51 is silly esp since it was an internal test. I don't have Bodie's book so I don't have more info on the loadings. Edit: I think one of the reasons this data looks funny is that Lockheed had the Gall to test a P-38 against a P-51 at the same throttle setting WEP.

The Baugher website tells of a P-38 dive that with full control registered 740mph or so (yes we know it was under 600mph) not that this was recomended. I know that IAS redline on the P-38 is 500mph/asl or Mach .68.

The P-51 was not "hands down" the better fighter, like the P-38 it had it's strong points and bad. The F4U with a better airfoil and lighter wing loading (almost the same area as the P-38 and much lighter weight) should be better than either the P-38 or the P-51. In a dogfight there are other complications as well.

In this class of aircraft it comes down to the pilot.

 

[Anonymous]

Interesting analysis. That is a good point about IAS versus TAS. During dive testing with a P-47, a test pilot reached 725 MPH IAS. That is impossible, because terminal velocity on the P-47 was about 600 MPH. The TAS was estimated to be in the mid-500 MPH range. If the IAS had been accurate, the P-47 would have been the first plane to break the sound barrier. Obviously, that wasn't the case.

IAS is always lower than TAS, unless something is wrong. The air-speed indicator is supposed to measure the relative air speed of the plane. As the altitude increases, the air gets thinner, and the amount of air moving past the sensor at a given speed is lower.

However, early air-speed indicators tended to give false readings at very high speeds.

TAS measurements are usually based either on IAS speeds and a conversion function, which relies on the accuracy of the air-speed sensors, which may be incorrect, or they rely on time between two points measured from the ground, which tends to ignore wind speed. Neither method of measurement is truely accurate.

=S=

Lunatic

 

[Anonymous]

wmax,

I'm in no way saying the P-51 was better than the P-38L or late J. All I'm saying it it was not totally outclassed by it. I agree the pilot made the difference. Again I go back to the point that if the conditions of the fight are equally skilled pilots engaging at high alititude, the P-51 enjoys some advantages at the start of the fight which if he can exploit should make him the victor. If the fight drags on and altitude drops much below 20K or speeds drop below 200 IAS, the P-38 gains the advantage.

As you can see below, the P-51 climb was not that much worse than the P-38 climb. However, I suspect the P-38 climb in cruise condition was much better which is what was being refered to by the pilot you referenced.

As for the P-38 being in "full control" at such a high speed, I just don't see how. The dive recovery flaps do not change the laws of physics. Once the airflow over the wings goes into the transonic region the ailerons are nearly useless and the plane is going to suffer buffeting. I really suspect what they mean is that it was fully able to recover from the dive, not that it was in sufficient control for the pilot to aim the guns or do much manuvering.

I've made another post for purposes of displaying I chart I found comparing US plane performance. As you will see the image is so large it would disrupt this chat, so i've put it in it's own thread called US Plane Performance Chart for easy and perminant reference on this forum.

As you can see in the chart, climb to 20k times and radius of action figures (in parans) are given as follows:

F4U-4: 5.0 mins (615 mi) -- F4U-1: 7.4 mins (500 mi) -- F6F-5: 7.0 mins (500 mi)

P-47D: 7.6 mins (650 mi) -- P-38J: 5.9 mins (450 mi) -- P-51B: 6.6 mins (550 mi)

F2G-1: 5.5 mins (525 mi) -- F7F: 5.2 mins (403 mi) -- F8F: 4.7 mins (208 mi)

Note that the P-51B climb is at MP, all the rest are at WEP. Given that the P-51 is at 67 hg manifold pressure, perhaps they just didn't consider the Merlin had WEP?

=S=

Lunatic

 

[Lightning Guy]

I am immediately skeptical of those numbered. There is no was that the F4U could match the P-38J in radius of action. And the P-47D certainly didn't better any of the fighter in the list (except the F8F).

 

[Anonymous]

I am immediately skeptical of those numbered. There is no was that the F4U could match the P-38J in radius of action. And the P-47D certainly didn't better any of the fighter in the list (except the F8F).

Read the definition of "Range":

Radius of action is based upon Navy requirements for a combat mission. This includes fuel allowances for 20-minute warm-up and idling; 1-minute takeoff; 10-minute rendezvous at 60% normal power at sea level; climb to 15,000 feet , 60% normal power; cruising to objective at 15,000 feet at optimal cruising. 20-minute combat (15,000 ft.) at full power; return to base at 1,500 feet at optimum cruising; and reserve 60 minutes at optimum cruising; An auxillary tank is used for rendevous, climb, and cruising to object and is dropped upon reaching the objective. All other fuel comes from the main protected tank. Radius includes distance covered in climb but not in descent.

Well, this is not terribly clear but by looking at the fuel loading (right under the weights) we can see that on the P-38 the leading edge tanks are empty, the main and reserve tanks (90 gallons and 60 gallons respectively) are filled, giving 300 gallons. For the P-47 however, both the 205 gallon main and 100 gallon aux. tanks are filled, giving it 305 gallons. It is pretty obvious that even though the allisons are more efficient than the R-2800, they are not twice as efficent.

Furthermore the P-38 gains no range advantage from its ability to carry those huge 250 gallon drop tanks because these are dropped upon reaching the objective with the plane needing to meet the remainder of the mission spec, which requires 20 minutes of combat, cruise home, and still have 60 mins cruising time in reserve. So the advantage gained by being able to carry up to 500 gallons in the drop tanks is totally lost.

If the two 55 gallon leading edge tanks were filled, the P-38J would do much better in this chart, as this would apply entirely to the cruise back range and thus allow more time on the drop tanks as well. Given that all of this fuel would be applied to the optimal cruise back, I'm guessing it would increase the overall range by 50% or more - to at least 675 miles. But still a fair amount of the drop tank range would be lost.

So I agree the P-38 is a little short-changed in terms of range in this chart. The P-51B gets short-changed 65 gallons as well, but that does not invalidate the rest of the chart.

Another consideration is that lacking that fuel probably benifited the relative climb rates attributed to the P-51B and the P-38J.

As for the F4U-4, the cruise is done closer to the engines rated altitude than the others, which may contribute some. Also, it could carry two large 150 gallon drop tanks where the F4U-1 and Hellcat could only carry one, so that may also be a factor. Also the R-2800(C) had much better cooling than the R-2800(B) so it may have cruised at a leaner fuel mixture setting which could noticably improve its range.

Finally, I would say that range figures are much more abitrary than climb figures. The Navy probably had to estimate the range capabilities of the USAAF planes in the list based upon USAAF supplied data to some degree, to fit them to their mission profile. But climb to altitude data is very strait-forward and so probably much more accurate.

=S=

Lunatic

 

[wmaxt]

wmax,

I'm in no way saying the P-51 was better than the P-38L or late J. All I'm saying it it was not totally outclassed by it. I agree the pilot made the difference. Again I go back to the point that if the conditions of the fight are equally skilled pilots engaging at high alititude, the P-51 enjoys some advantages at the start of the fight which if he can exploit should make him the victor. If the fight drags on and altitude drops much below 20K or speeds drop below 200 IAS, the P-38 gains the advantage.

As you can see below, the P-51 climb was not that much worse than the P-38 climb. However, I suspect the P-38 climb in cruise condition was much better which is what was being refered to by the pilot you referenced.

As for the P-38 being in "full control" at such a high speed, I just don't see how. The dive recovery flaps do not change the laws of physics. Once the airflow over the wings goes into the transonic region the ailerons are nearly useless and the plane is going to suffer buffeting. I really suspect what they mean is that it was fully able to recover from the dive, not that it was in sufficient control for the pilot to aim the guns or do much manuvering.

I've made another post for purposes of displaying I chart I found comparing US plane performance. As you will see the image is so large it would disrupt this chat, so i've put it in it's own thread called US Plane Performance Chart for easy and perminant reference on this forum.

As you can see in the chart, climb to 20k times and radius of action figures (in parans) are given as follows:

F4U-4: 5.0 mins (615 mi) -- F4U-1: 7.4 mins (500 mi) -- F6F-5: 7.0 mins (500 mi)

P-47D: 7.6 mins (650 mi) -- P-38J: 5.9 mins (450 mi) -- P-51B: 6.6 mins (550 mi)

F2G-1: 5.5 mins (525 mi) -- F7F: 5.2 mins (403 mi) -- F8F: 4.7 mins (208 mi)

Note that the P-51B climb is at MP, all the rest are at WEP. Given that the P-51 is at 67 hg manifold pressure, perhaps they just didn't consider the Merlin had WEP?

=S=

Lunatic

I can go there.

Actually as I understand it the slat both pitched up the angle of attack but also broke up the super/trans sonic airflow that locked the stabilizer/elevator and restored lift. Even in the earlier models of the P-38 the aileron is not affected, in fact the use of aileron/barrel rolls was part of the technique used to control speeds in a dive.

The P-51D was not supposed to go over 505mph. Above that all bets are off. I've read the P-51 was good for a while after that and Heiden says it's not a problem in the P-38L at least at the speeds needed in a chase of a bf-109/fw-190. Heiden's comment may also have been follow to an altitude/speed suitable for engagement too. Beyond that I just don't know.

Flight manual data: P-51D climb normal power to 25,000ft (the P-38 listing does not show 20,000ft) in a loaded condition 11,200lbs - 24min. P-38L same conditions, 21,000lbs with pylons 14min. The laminar flow wing was good for range and speed but climb and manuvering are hurt. The P-38 was originaly an intercepter - optimized for climb. That being so it's pretty suprising it did as well as it did in other areas.

FYI, The P-38L is given a 1,210 mi range (internal) with a 50 gal reserve and pylons @ 30,000ft/285tas for max range.

 

[Anonymous]

As you can see that is 505 IAS.

This compares with the following for the P-38:

Breaking up the tubulence did help to achieve some proper airflow over the tail, but it also increased the turbulence and thus there had to be buffeting. Remember, air goes from acting like a liquid to acting like a solid when you hit mach speed.

Interestingly, the USAAF P-38L combat range is 450 mph (at 290 mph @ 10,000 feet). I suspect this is where the USN got that figure for the J from.

=S=

Lunatic

 

[Lightning Guy]

I assume you mean 450 miles and not miles per hour. That figure is often posted but is actually the range at maximum power.

It is interesting that the P-38's stats were given for less that optimal conditions, at least in range . . . what else might be wrong on the chart? Maybe nothing, but it does make everything else suspect does it not?

Interestingly, Milo Burcham tested a P-38F (no leading edge tanks) and found that the P-38 had a ferry range without external tanks of 1,300 miles. Granted combat range would be less, but could a P-47 or F4U match that figure? By the end of the war, P-38Ls in the Pacific were flying missions to a RADIUS of 950 miles.

The P-38 never carried 250 gallon tanks so far as I know. They did, however carry 165 gallon tanks (usually referred to as 150 gallon) and 310 gallon tanks (usually referred to as 300 gallon). Correct internal fuel for a P-38L was 430 gallons (2 x 90 gallon mains, 2 x 63 gallon reserves, 2 x 62 gallon leading edge). This is more fuel than two 165 gallon tanks (330 gallons) and this mission load was regularly flown in the ETO. In the PTO, P-38s regularly carried 1 310 and 1 165 gallon tanks (475 gallons) without undue difficulty. No other WWII fighter could match the P-38 for range, ferry or combat.

The P-38 never carried 250gallon tanks. I'm not sure where you got that figure.

 

[wmaxt]

I assume you mean 450 miles and not miles per hour. That figure is often posted but is actually the range at maximum power.

It is interesting that the P-38's stats were given for less that optimal conditions, at least in range . . . what else might be wrong on the chart? Maybe nothing, but it does make everything else suspect does it not?

Interestingly, Milo Burcham tested a P-38F (no leading edge tanks) and found that the P-38 had a ferry range without external tanks of 1,300 miles. Granted combat range would be less, but could a P-47 or F4U match that figure? By the end of the war, P-38Ls in the Pacific were flying missions to a RADIUS of 950 miles.

The P-38 never carried 250 gallon tanks so far as I know. They did, however carry 165 gallon tanks (usually referred to as 150 gallon) and 310 gallon tanks (usually referred to as 300 gallon). Correct internal fuel for a P-38L was 430 gallons (2 x 90 gallon mains, 2 x 63 gallon reserves, 2 x 62 gallon leading edge). This is more fuel than two 165 gallon tanks (330 gallons) and this mission load was regularly flown in the ETO. In the PTO, P-38s regularly carried 1 310 and 1 165 gallon tanks (475 gallons) without undue difficulty. No other WWII fighter could match the P-38 for range, ferry or combat.

The P-38 never carried 250gallon tanks. I'm not sure where you got that figure.

Range is an interesting thing The 1,210miles I noted above was internal fuel only, as listed in the "Flight Operation Instructing Manual" for the P-38L with full internal fuel listed at 410gal-50 gal reserve or 360gal usable. My understanding is that basic range numbers are the radius on internal fuel. So for the P-38L warm-up, takeoff, form-up, mission, combat @WEP, return, landing, and reserve gives 450mi/nominal. The P-51 had more fuel internal so it actually does a little better. All range numbers are theroretical due to all the variables involved, P-38s flew many missions over 2,000 miles R/T with combat. The last combat mission was reported to have been 2,800mi with combat over Borneo on 15, Aug. '45, can you imagine more than 13hrs in a P-38 cocpit?

An interesting point on the P-51 - the last 20 gallons in the Fusalage tank was not recomended for use except in extreme emergancies because of severe CG problems.

 

[wmaxt]

Breaking up the tubulence did help to achieve some proper airflow over the tail, but it also increased the turbulence and thus there had to be buffeting. Remember, air goes from acting like a liquid to acting like a solid when you hit mach speed.

Interestingly, the USAAF P-38L combat range is 450 mph (at 290 mph @ 10,000 feet). I suspect this is where the USN got that figure for the J from.

=S=

Lunatic

I understand your reasoning, however signifcant buffeting is not reported and with correct usage critical speed was not exceeded possibly accounting for that fact.

The range I quoted does not include combat activities possibly accounting for the difference. It also stated 360gal useable fuel to. The USAAF seemed to have a different set of performance rules/specs with the P-38. Then there is the P-51B with Mil power rated at full engine power. The numbers don't always make sense.

One thing about your report by George, I've read about techniques like differential throttle in many places - it was done and it was effective both in rolling and in turning (check out Jeff Ethels article in the "Flight Journal Magazine"). I've also read that there was more training and ues of such techniques in the pacific. A number of P-38 pilots felt the Aircrews/aircraft was handled very poorly in the ETO, from support to training, where it was always the "Red headed stepchild". George doesn't sound like he ever felt comfortable in a P-38.

 

[Anonymous]

I assume you mean 450 miles and not miles per hour. That figure is often posted but is actually the range at maximum power.

It is interesting that the P-38's stats were given for less that optimal conditions, at least in range . . . what else might be wrong on the chart? Maybe nothing, but it does make everything else suspect does it not?

Interestingly, Milo Burcham tested a P-38F (no leading edge tanks) and found that the P-38 had a ferry range without external tanks of 1,300 miles. Granted combat range would be less, but could a P-47 or F4U match that figure? By the end of the war, P-38Ls in the Pacific were flying missions to a RADIUS of 950 miles.

The P-38 never carried 250 gallon tanks so far as I know. They did, however carry 165 gallon tanks (usually referred to as 150 gallon) and 310 gallon tanks (usually referred to as 300 gallon). Correct internal fuel for a P-38L was 430 gallons (2 x 90 gallon mains, 2 x 63 gallon reserves, 2 x 62 gallon leading edge). This is more fuel than two 165 gallon tanks (330 gallons) and this mission load was regularly flown in the ETO. In the PTO, P-38s regularly carried 1 310 and 1 165 gallon tanks (475 gallons) without undue difficulty. No other WWII fighter could match the P-38 for range, ferry or combat.

The P-38 never carried 250gallon tanks. I'm not sure where you got that figure.

http://www.acepilots.com/planes/p38_lightning.html <--- 250 gal drop tank

Cruise and Range
Typical combat radius for the J/L variants was 275 miles for 410 US gallons of fuel (no external tanks) and 650 miles with 740 US gallons (w/ 165 gal external tanks). These ranges allowed for 20 minutes combat at target and 30 minutes of reserves. With 300 gal tanks, missions were made over ranges in excess of 1000 miles and durations of nine hours or more.
http://www.kazoku.org/xp-38n/articles/p38info.htm

Again, I don't see anything wrong with the chart. It specifies 300 gallons of internal fuel equals a 450 mile combat range. This fits the above info almost exactly, showing a 575 mile range listed above using the full ~410 gallons of internal fuel and only a 30 min reserve. The rest of the data, including the climb rates, are backed up by numerous other sources.

Why did the USN not consider fuel in the wing tanks? Why didn't they consider fuel in the rear tank of the P-51? That's hard to answer, but perhaps they felt that entering combat with fuel in these tanks made the plane too vulernable or hurt manuverability too much. If the tank has had fuel in it at all, it is subject to fire even if the fuel has been expended - in fact, a tank with 25% fuel is much more vulnerable than a full one. If a tank been purged before flight, it's not subject to fire. The weight in the outer wing panels of the P-38 would have detracted from its combat capability which it was assumed would be needed the moment the drop tanks were released, and would make it more vulnerable to fire. Perhaps that is the reasoning?

=S=

Lunatic

 

[Anonymous]

An interesting point on the P-51 - the last 20 gallons in the Fusalage tank was not recomended for use except in extreme emergancies because of severe CG problems.

I accounted only 65 gallons to the P-51B's rear tank for just this reason, it could in fact hold 85 gallons. A skilled pilot could handle a full rear tank, but it was tricky and takeoff with any crosswind whatsoever was very dangerous.

As for the P-38J figures, all I'm saying is the 450 mile return distance is very reasonable given the 300 gallons of fuel stated and the other conditions listed. I agree the P-38J/L could fly a lot further than that, especially if it had full internal fuel and the large (300 gallon?) drop tanks. However, a 1000 mile return flight after combat is doubtful. It might be possible if combat were minimal and altitude was retained (fuel economy is better at rated altitude).

Many PTO sorties were flown such that they landed at a base much closer to the target than they took off from. You cannot look at total distance flown and simply divide by two to get the effective combat radius.

=S=

Lunatic

 

[wmaxt]

An interesting point on the P-51 - the last 20 gallons in the Fusalage tank was not recomended for use except in extreme emergancies because of severe CG problems.

I accounted only 65 gallons to the P-51B's rear tank for just this reason, it could in fact hold 85 gallons. A skilled pilot could handle a full rear tank, but it was tricky and takeoff with any crosswind whatsoever was very dangerous.

As for the P-38J figures, all I'm saying is the 450 mile return distance is very reasonable given the 300 gallons of fuel stated and the other conditions listed. I agree the P-38J/L could fly a lot further than that, especially if it had full internal fuel and the large (300 gallon?) drop tanks. However, a 1000 mile return flight after combat is doubtful. It might be possible if combat were minimal and altitude was retained (fuel economy is better at rated altitude).

Many PTO sorties were flown such that they landed at a base much closer to the target than they took off from. You cannot look at total distance flown and simply divide by two to get the effective combat radius.

=S=

Lunatic

I was primarily clarifing the earlier post, not trying to make a point. As I said earlier the numbers don't allways add up either.

A skilled P-51 pilot could handle it if NO maneuvering took place. Climbout was always on the fusalage tank to get it down to 50gals before combat. The P-51H had the tank reduced to 50/55gal. It should also be remembered the H model was Escort Only and deemed to light to do ground attack in Korea.

I agree, at least to a point, figuring from drop tank release, combat and return through unknown conditions with 400/360gals total fuel and 1,000 miles home was probably not wise. Tom McGuire, made that "keep the Tanks" in combat error himself and we all know the result of that.