Best Fighter

[the lancaster kicks ass]

what makes you think i have to beat you, you're allowed to have your opinion, as am I, I don't have to change your, you sure as hell aint gonna change mine.............

 

[cheddar cheese]

I didnt say you have to beat us, Im just saying you wouldnt if you tried...

 

[DaveB.inVa]

A lot has been written about the Merlin and the Allison, namely that the Merlin was a much more powerful engine. When in fact it was not! The Allison and the Merlin were both closely matched in displacement and at sea level and up to about 10000' they both had very similar power levels!!

Up higher than 10000' you MUST consider the induction system. Most Allison's like the ones in the P-39, P-40 and early P-51's had just a single stage supercharger. Most Merlin's like used in later P-51's, Spitfires and Lancasters had a two speed two stage supercharger. This makes a world of difference!!!

Once the Merlin got above a certain altitude the supercharger on the Merlin would shift into high blower. This greatly increases power at altitude... not because its a Merlin... but because you have more air!

The P-38 was an exception to the Allison's mentioned above. The reason was because it has a turbocharger feeding the Allison in addition to its own engine mounted single stage supercharger. This is a more flexible system than the two speed two stage setup could be. You can regulate the amount of turbo boost much more easily than you can with a two speed two stage supercharger. Using a turbo also provides a seamless level of power from sealevel all the way up to rated altitude.

This was not so with the two speed two stage supercharger used with the Merlin. As the aircraft got to a certain altitude the low blower speed would begin to lose power. Sometime at a little higher altitiude the supercharger would shift into high blower. This was a fairly violent operation, but because it did increase the speed of the blower you will make more power because your now getting more air.

Later Allisons used a two speed two stage supercharger and these could definatley run with a two speed two stage Merlin at high altitudes!

You also have to compare apples to apples here. There were different versions of each engine. For instance most Allisons had a single stage supercharger that in the case of the P-38 was supplemented by a turbocharger. While the P-51 and most Merlins used a two speed two stage supercharger.

However there were single stage Merlins out there too for instance the P-40F had a single stage two speed Merlin producing 1300hp takeoff while the Allison engined P-40K produced at the exact same time made 1325hp takeoff.

Thats the closest comparison between the two I know of. The induction was similar and for takeoff both were making close to the same numbers.

There were later versions of the Allison equipped with two speed two stage superchargers that made 1700hp at altitude, these were used in later versions of the P-82 Twin Mustang as well as the XP-51J . In contrast the Merlins with a two speed two stage supercharger used in the P-51B/C produced 1450hp and the P-51D made 1695hp at altitude.

The Germans used a different system than the Allies that was slightly superior to the two speed two stage supercharger but not as great as using a turbocharger. On DB 601s and 605s they used a single stage vairable speed supercharger. Speed was varied by a viscous coupling. So at low altitudes they could have a high slip and as altitude increased slip would be reduced to produce higher supercharger speeds for more power. This was a seamless operation for them as well!

So Ill say it again. It was NOT the Merlin in its self that was so great. It WAS the two speed two stage supercharger that made the Merlin so great.

This is a fact, if you can give ANY engine the amount of air it requires to make its rated power and can cool it effectively you can make its rated power at any realistic altitude!

The reason the Allison wasnt able to make its rated power at 30000' was because it couldnt get enough air. The Merlin could get enough air!

If the Allison could get the same amount of air as the Merlin at 30000' then Im sure today that the Merlin would seem much less mystical... it would just be another engine.

 

[wmaxt]

Exelent! The points you made are valid and rarly presented.

The P-38 had a higher ceiling partly because the turbo's fed it more air. The P-51 was down to around 1,400hp at 30,000ft and it went down from there, the P-38L was still pulling 1,750hp/WEP at that same altitude. At that point the air density was a major problem in climb speed.

Does everyone notice when fighters are compared the qualification "Single Engine" is almost always added?

The P-38 is a class of it's own!

 

[Lightning Guy]

I believe the Allisons in the P-38 were turning out 1,725hp on WEP.

I do find it interesting that the P-82 adopted handed engines. I believe that particular feature was unique to the P-38 among twin-engine, piston fighters of WWII. And those were a major bonus when it came to handling.

 

[R Pope]

If I remember correctly, the "handed" engines on the Lightning were handed the wrong way! They were outward turning, rather than the superior inward rotation. This is better because of the phenomenon of thrust migration at high angle of attack. In the event of one engine failing, the thrust on an inward turning prop is closer to the centerline, resulting in better control. Possibly, the choice was influenced by the slipstream's effect on the unique tailplane of the P-38.

 

[R Pope]

Forgot to mention that the deHaviland Hornet had "handed" engines, only they turned the right way! As for the Lightning being in a class of its own, you may be right, the Hornet was first class! The Fastest Propeller-Driven Aircraft In The World in 1945.

 

[DaveB.inVa]

When the P-82 first was produced it was made with handed engines turning the "wrong way". The reason this was done is because it was thought that the P-82 may exhibit the same problems as the twin boom design of the P-38. However it was found that the wrong way turning props caused a stalling condition and excess drag across the wing center section between the fuselages. The engines were changed to turn the right way and it made a world of difference.

Its also interesting that the English and French ordered P-38s before the fall of France. They were specified to have right handed engines and no turbochargers. The French versions also specified French throttles (pull back for power), French armament and radios as well as French gauges. After France fell the French order was given to the English. After only 3 Lightning I's were delivered and tested it was found that without the turbos the Lightnings at high altitudes were gutless.

The remaining part of the order along with the 3 delivered were then reclaimed by the USAAF and redesignated P-322's. Following Pearl Harbor 20 were pressed into service. They retained the right handed engines and were equipped with 2 .50 calibers and 2 .30 calibers and no 20mm cannon. The remainder of the 140 Lightnings were given the same armament but had handed engines installed with no turbo. They served in the continental US as a type of twin engine trainer/home defence force.

 

[wmaxt]

Forgot to mention that the deHaviland Hornet had "handed" engines, only they turned the right way! As for the Lightning being in a class of its own, you may be right, the Hornet was first class! The Fastest Propeller-Driven Aircraft In The World in 1945.

My refrences give a top speed of 472mph for the hornet The P-51H is 487mph and the P-47N is 467mph the F-4U5 462 and there may be others. Top speed is only one performance catagoryand the Hornet was in fine company.

the P-38K could also do over 472mph but it was deemed the performance increase was not worth the cost of a two weeks of lost production when compared with the performance already available.

The Hornet still could not do the range of missions the P-38 could do.

 

[wmaxt]

If I remember correctly, the "handed" engines on the Lightning were handed the wrong way! They were outward turning, rather than the superior inward rotation. This is better because of the phenomenon of thrust migration at high angle of attack. In the event of one engine failing, the thrust on an inward turning prop is closer to the centerline, resulting in better control. Possibly, the choice was influenced by the slipstream's effect on the unique tailplane of the P-38.

The inward turning props of the first prototype were replaced by the outward rotating props because the did improve the stability.

The P-38 is noted for having the best low speed handling of any high performance fighter and a very mild slow speed stalls with no tourque efect break or snap as is normal in single engineg fighters.

As long as proper techniques were used single engined operation was fine including single engined cruise over 230mph and a top speed in the 300mph range. If the proper procedures were not used it could be nasty.

There are reports of volentary single engine combat in P-38s.

 

[the lancaster kicks ass]

the mossie also had no problem on one engine............

 

[plan_D]

I was playing on Il-2 FB yesterday and lost my engine (flying a P-38) when beating the crap out of Zeros. It still flew, for all of about 2 minutes - looking outside I noticed the engine hadn't shut off. It'd COME OFF! Well, the spinner had.

All round, the P-38L has to be one of the best if not the best. The Spit. XIV is still my favourite and was a better dogfighter.

 

[wmaxt]

I was playing on Il-2 FB yesterday and lost my engine (flying a P-38) when beating the crap out of Zeros. It still flew, for all of about 2 minutes - looking outside I noticed the engine hadn't shut off. It'd COME OFF! Well, the spinner had.

All round, the P-38L has to be one of the best if not the best. The Spit. XIV is still my favourite and was a better dogfighter.

Actuly there a well known mock fight between a Spit XIV and a P-38 where the Spit pilot was to fight the P-38 and then lecture on the prowes of the Spit. The P-38 bounced the Spit and for the entire show remained in firing posion. The Spit tried everything it could including a shollow angle split-s the P-38 followed them all! The Spit went home instead of landing.

Bong was reported to have dogfought the Zoro at speeds where the Zero was supposed to be better.

 

[lesofprimus]

I believe that P-38 Pilot was none other than Ol' Hub Zemke himself......

 

[Lightning Guy]

That may have been possible but the time frame would have been limited. Zemke's group began re-equipping with Mustangs very shortly after he took over (the process may have even been started).

At low-altitudes, the handed props on the P-38 were a major advantage over any single engined fighter. This was especially true against the late model 109s which had far too much torque for its small control surfaces to properly handle. In a tight, low-speed turn the 109 was very likely to snap into a spin as a result of the torque. Also, since the P-38 had two engines it would roll equally well in either direction as it didn't have to fight the engine torque.

 

[Anonymous]

Just a few comments:

1) Turbochargers had a critical altitude as well, though it was typically set higher than for mechanical superchargers. The turbine could only turn so fast, I believe 29-31,000 RPM. Once it topped out, power started to fall with altitude. The P-38 stopped making WEP around 29,000 feet and the P-47 around 32,000 feet (varies some by version).

2) The fluid coupling on the Bf-109 was pretty good, but it also cost some performance. Fluid couplings always involve loss. It was probably superior to the 2-stage-2speed supercharger toward the middle of the ranges between the 4 critical altitudes of those systems, but not a lot. It did avoid the sudden "bump" from the gear changes. The Turbo-supercharger was clearly superior, which is why the German's kept trying to build one till the end of the war.

3) The top speed of the F4U-4 was left out of the plane speed list. It was 463 mph at 20,700 feet (much lower than the other fast planes) in the "clean" configuration (i.e. no capped pylons).

=S=

Lunatic

 

[Lightning Guy]

The GE B-33 turbos used on the P-38 redlined at 26,400 rpms.

 

[wmaxt]

Just a few comments:

1) Turbochargers had a critical altitude as well, though it was typically set higher than for mechanical superchargers. The turbine could only turn so fast, I believe 29-31,000 RPM. Once it topped out, power started to fall with altitude. The P-38 stopped making WEP around 29,000 feet and the P-47 around 32,000 feet (varies some by version).

2) The fluid coupling on the Bf-109 was pretty good, but it also cost some performance. Fluid couplings always involve loss. It was probably superior to the 2-stage-2speed supercharger toward the middle of the ranges between the 4 critical altitudes of those systems, but not a lot. It did avoid the sudden "bump" from the gear changes. The Turbo-supercharger was clearly superior, which is why the German's kept trying to build one till the end of the war.

3) The top speed of the F4U-4 was left out of the plane speed list. It was 463 mph at 20,700 feet (much lower than the other fast planes) in the "clean" configuration (i.e. no capped pylons).

=S=

Lunatic

The F-4U4s top speed was 443mph due to the fabric wings - they would ripple causing drag. The -5 with metal wings could do 462/463 depending on rererence being used.

I did miss read the top speed of the P-38k it should have been 432mph in METO and was expected to max out over 450mph.

 

[Anonymous]

The F-4U4s top speed was 443mph due to the fabric wings - they would ripple causing drag. The -5 with metal wings could do 462/463 depending on rererence being used.

I did miss read the top speed of the P-38k it should have been 432mph in METO and was expected to max out over 450mph.

The P-38K was never produced, it was deemed not worth the loss of 2 weeks of P-38L production to switch over to the paddle props.

The F4U-4 top speed was about 443 mph, but it was due to the drag from the capped pylons, not the fabric covering on the wings (which were good to 550 mph in a dive).

See the pilot handbook excerpts: http://www.history.navy.mil/branches/hist-ac/f4u-4.pdf

Note on the last page of this declassified document it gives the speed w/o capped pylons as 403 knots = 463.76 mph @ 20,600 feet. It should also be noted that these results are "expected performance", not special case test performance. I.e. four planes went up to perform the tests, and the lowest performance (without malfunctions) was used. This data represents what the pilot was to expect from his plane in combat, it was never meant for public consumption (but for the FIA it would probably still be "classified").

The switch to all metal wings was not for performance. There were two problems with the fabric coverings:

1) they required constant maintainence - they needed to be checked (and tightened if needed) after every sortie and they had to be replaced frequently.

2) the fire-retardant they were soaked in was a significant health hazard to the plane crews which handeled them.

Virtually all F4U's now flying have metal wings. The expense of the fabric forces this retrofit for privately owned flying planes. The use of the fabric was never to save on aluminum, it was to increase the survivability and performance of the plane.

=S=

Lunatic

 

[wmaxt]

The F-4U4s top speed was 443mph due to the fabric wings - they would ripple causing drag. The -5 with metal wings could do 462/463 depending on rererence being used.

I did miss read the top speed of the P-38k it should have been 432mph in METO and was expected to max out over 450mph.

The P-38K was never produced, it was deemed not worth the loss of 2 weeks of P-38L production to switch over to the paddle props.

The F4U-4 top speed was about 443 mph, but it was due to the drag from the capped pylons, not the fabric covering on the wings (which were good to 550 mph in a dive).

See the pilot handbook excerpts: http://www.history.navy.mil/branches/hist-ac/f4u-4.pdf

Note on the last page of this declassified document it gives the speed w/o capped pylons as 403 knots = 463.76 mph @ 20,600 feet. It should also be noted that these results are "expected performance", not special case test performance. I.e. four planes went up to perform the tests, and the lowest performance (without malfunctions) was used. This data represents what the pilot was to expect from his plane in combat, it was never meant for public consumption (but for the FIA it would probably still be "classified").

The switch to all metal wings was not for performance. There were two problems with the fabric coverings:

1) they required constant maintainence - they needed to be checked (and tightened if needed) after every sortie and they had to be replaced frequently.

2) the fire-retardant they were soaked in was a significant health hazard to the plane crews which handeled them.

Virtually all F4U's now flying have metal wings. The expense of the fabric forces this retrofit for privately owned flying planes. The use of the fabric was never to save on aluminum, it was to increase the survivability and performance of the plane.

=S=

Lunatic

I know the K was never produced.

Acknowledging the references are wrong at times I do see the 403kts. How did you convert the speed - I get 458mph (nit Picking) either way it's still compettitive with the post war Hornet which was the comparison.