P-38 vs P-51

[P-39 Expert]

Somebody might want to tell that to some test pilots. With the big prop and water injection a P-47 could outclimb a FW 190 at low altitude (lets not even mention high)
the dividing line for turning seemed to be 250mph, below that the FW 190 could out turn the P-47, above that it couldn't .

Of course neither the P-39 or P-40 could do what the P-38 and P-47 could do even if they weren't quite as good as the P-51.

The P-39N outclimbed any standard production P-38F/G or P-47B/C/D up to

Somebody might want to tell that to some test pilots. With the big prop and water injection a P-47 could outclimb a FW 190 at low altitude (lets not even mention high)
the dividing line for turning seemed to be 250mph, below that the FW 190 could out turn the P-47, above that it couldn't .

Of course neither the P-39 or P-40 could do what the P-38 and P-47 could do even if they weren't quite as good as the P-51.

P-39N substantially outclimbed any production P-38F/G or P-47B/C/D up to 26000', above which combat was unlikely. Wouldn't outclimb the P-51B/C.

 

[Shortround6]

P-39N substantially outclimbed any production P-38F/G or P-47B/C/D up to 26000', above which combat was unlikely. Wouldn't outclimb the P-51B/C.

After which your fast climbing P-39 has about 55 gallons of fuel left. And this is from take-off. Operational radius is ?????
Fastest climbing plane in the world isn't any good if it can't reach enemy airspace and return.

 

[FLYBOYJ]

Somewhat over simplified to say the least.

They are the same valves, configured slightly different. They are also a standard part and was probably dictated within the AAF design spec.

My only memory of working in the cockpit of a P-38 (F-5B) was a rh windscreen change in 1972 and it is not a happy memory. I found the cockpit very cramped (I weighed around 150lb at the time) and the large control spectacle and its mast got in the way all the !@#$% time.

I never worked on a P-38 but been in the cockpit and never found it cramped - and I'm 180 Lbs. Then again I didn't have to crawl under the instrument panel.

I could not remember where the fuel selectors were in the cockpit so had to check the -1 manual.

The location on the floor below the window winder, radio controls, cockpit lights and in the narrow slot beside and below the seat it does not look at all user friendly to me.

Compare that to other aircraft of the day, this was a norm and again possibly dictated and/ or accepted by the AAF during the design phase

I do remember the selectors were connected to the valves by cables and pulleys and that arrangement usually makes the valve a lot stiffer to operate. So my guess is that the P-38 fuel controls were not that user friendly given the tight cockpit, especially if you had to contort your body to reach them.

Again, that's your opinion. I've discussed this with several P-38 vets and they never had issues, but then again they had plenty of multi engine time before they were assigned to P-38s

Seeing that the later P-38 aircraft starting at J-15 had a totally different (much taller) handle that was easier to grab and provided more leverage I would say that my guess is right on the mark.

And I'll agree with that.
View attachment 522572

Having a multiple of fuel configurations to remember if not flying the same aircraft all the time was conducive to errors as well.

I think you'll find that assigned pilots, especially fighter pilots WERE NOT flying different aircraft in combat on a regular basis. Combat training was emphasized on the assigned aircraft. Sometimes P-38 drivers would fly B-25s for proficiency.

Having to reduce power when changing off drop tanks while you are being shot at is also not what I would call "user friendly".

I could agree there but if you read the Rau report one of the way to mitigate this was to attempt to configure before reaching the combat zone - not the ideal situation.

The P-51 fuel selector on the other hand is in an easy to access position and the valve is directly connected to the handle by a shaft so there is nothing in the system to increase the torque the pilot must apply to turn the valve from detent to detent.

And the P-51 was designed and built 3 years later.

 

[FLYBOYJ]

And the application of what is now called ergonimics to make fuel selectors easy to operate etc and by putting all the controls used during take-off and landing in close proximity - unlike the Brits and the P-38 (where that !#$ obtrusive handle that was such a pain when changing the RH windscreen was the flap lever).

Ergonomics (in referring to aircraft cockpits) wasn't even in dictionary in 1937, Again, I think many miss the point that the P-38 (like many aircraft of the day) was designed for function with little consideration to the pilot or "ergonomics." Additionally it was very likely that the cockpit configuration was dictated and/ or accepted by the customer at design acceptance. These decisions were many times made by people not qualified to do so....

 

[CORSNING]

P-39N substantially outclimbed any production P-38F/G or P-47B/C/D up to 26000', above which combat was unlikely. Wouldn't outclimb the P-51B/C.[/QUOTE]

In 1943 and early 1944 when these Mustangs were being produced with the Packard
V-1650-3 limited to 67"Hg boosting, the P-39N/Qs could outclimb them up to about
12,000 ft. Very limited territory, but perfect for the Russians.

 

[CORSNING]

After which your fast climbing P-39 has about 55 gallons of fuel left. And this is from take-off. Operational radius is ?????
Fastest climbing plane in the world isn't any good if it can't reach enemy airspace and return.

Sounds like an interceptor to me. I believe it would have had a little more than 55 gallons
of fuel left by the time it reached 15,000 ft., but I could easily be wrong.

 

[FLYBOYJ]

P-39N substantially outclimbed any production P-38F/G or P-47B/C/D up to 26000', above which combat was unlikely. Wouldn't outclimb the P-51B/C.

In reviewing Wright-Pat flight tests between 43 and 44 this is true but look at the P-39Ns Vx, climb speed.

 

[CORSNING]

Somebody might want to tell that to some test pilots. With the big prop and water injection a P-47 could outclimb a FW 190 at low altitude (lets not even mention high)
the dividing line for turning seemed to be 250mph, below that the FW 190 could out turn the P-47, above that it couldn't .

Shortround, great stuff. What is your source for this information sir? Does it give altitude(s)?

Of course neither the P-39 or P-40 could do what the P-38 and P-47 could do even if they weren't quite as good as the P-51.

I would not make this statement too closely to Hub Zemke or Dick Bong if I were you.

 

[P-39 Expert]

After which your fast climbing P-39 has about 55 gallons of fuel left. And this is from take-off. Operational radius is ?????
Fastest climbing plane in the world isn't any good if it can't reach enemy airspace and return.

With 120gal internal the radius was about like a Thunderbolt, 250-300mile radius. If each have a 110gal drop tank, the P-47 radius is about 375mi, the P-39 is about 475mi. These are before any reserves for combat or landing, but comparable.

 

[P-39 Expert]

I would not make this statement too closely to Hub Zemke or Dick Bong if I were you.

The pilots who received the first Thunderbolts in England were dismayed at the lack of climb as compared to the SpitIX they had been flying. More than 1000fpm less than the Spit.

Again, I'm no Lightning or Thunderbolt hater, but facts are facts. In hindsight I think most would agree that the AAF would have been miles ahead to develop the P-51 instead of the P-47 or P-38.

 

[CORSNING]

The pilots who received the first Thunderbolts in England were dismayed at the lack of climb as compared to the SpitIX they had been flying. More than 1000fpm less than the Spit.

Well, in climb, you are probably right. Ruggedness, firepower and initial dive acceleration goes to the
early P-47s. Range on internal fuel 434 mi. vs. 640 mi. I don't really have to explain which one is the
P-47, do I?

Again, I'm no Lightning or Thunderbolt hater, but facts are facts. In hindsight I think most would agree that the AAF would have been miles ahead to develop the P-51 instead of the P-47 or P-38.

For long flights over the Pacific, P-38 hands down. I would gladly go through the extra training to
have that extra engine over water.
For ground attack missions in Korea, well, just think about it.

 

[CORSNING]

I just had an after thought. Robert Johnson said that after the P-47D
received the new propeller (that he believed was worth 1,000 hp.), he was
never again outclimbed by a Spitfire. One must think in terms of angle of
ascent. He was referring to a more shallow climb than the Spitfire was
capable of. However, I have read that he claimed his maintenance crew
was able to give him a maximum speed of around 470 out of his P-47D.
Place that in the P-47M category and you get an initial climb of over
3900 fpm.

 

[Shortround6]

With 120gal internal the radius was about like a Thunderbolt, 250-300mile radius. If each have a 110gal drop tank, the P-47 radius is about 375mi, the P-39 is about 475mi. These are before any reserves for combat or landing, but comparable.

Ah yes, the morphing P-39 that can change to suit the need. Quote the climb with 87 gallons of fuel and then when challanged on range quote range with full internal fuel and at a redicously low air speed or altitude. P-39 will burn 75+ gallons per hour at a cruise speed comparable to a P-47 to a P-47 burning 135 gallons an hour (both planes clean). P-47 holds more than twice the fuel, so no, the radius or range is not the same.

 

[Ivan1GFP]

I just had an after thought. Robert Johnson said that after the P-47D
received the new propeller (that he believed was worth 1,000 hp.), he was
never again outclimbed by a Spitfire. One must think in terms of angle of
assent. He was referring to a more shallow climb than the Spitfire was
capable of. However, I have read that he claimed his maintenance crew
was able to give him a maximum speed of around 470 out of his P-47D.
Place that in the P-47M category and you get an initial climb of over
3900 fpm.

Hello Corsning,
I have always had trouble reconciling Robert Johnson's claims against performance figures.
While I can see that any of the three "Paddle Blade" propellers would have seriously improved the Thunderbolt's climb performance, I don't see how ANY model of the Thunderbolt short of P-47M would be even coming close to the climb rate of a Spitfire Mk.IX much less a Spitfire XIV. His sparring match with a Spitfire IX in which he was able to roll faster is also interesting because it would have had to be a very poor example of the Spitfire without metal ailerons in order for him to win at anything but very high speeds.
The Thunderbolt's roll rate didn't degrade quickly but it wasn't fast to start with.

- Ivan.

 

[P-39 Expert]

Ah yes, the morphing P-39 that can change to suit the need. Quote the climb with 87 gallons of fuel and then when challanged on range quote range with full internal fuel and at a redicously low air speed or altitude. P-39 will burn 75+ gallons per hour at a cruise speed comparable to a P-47 to a P-47 burning 135 gallons an hour (both planes clean). P-47 holds more than twice the fuel, so no, the radius or range is not the same.

Technically the P-39N in the test would have held only 57gals since the tested weight was 376# lighter than the listed weight of 7650#. The weight was an allowance of fuel burned in flight giving an average weight for that flight. The British used a "corrected" figure of 95% of the A/C weight for the same purpose.

Technically the P-39N burns 62gph at normal power/escort height of 25000'. And the P-47 burns 150gph at 25000' and that is from column II, most of not all cruising over Europe in '43 would be at normal power at 190gph. These numbers pretty well match the chart in post #69.

 

[CORSNING]

Hi Ivan,
I do not believe Robert was talking about fpm in altitude. I am pretty
sure he was talking about distance gained in ascending. If his P-47D
was capable of 440 mph. and loses 60 mph. in a 20 degree rise, and
the Spit9 is capable of 410 mph. and loses 50 mph. in a 20 degree rise,
which will gain height and distance the quickest?
All figures quoted for loss of speed are totally fictitious and are null and
void in a court of law. This is just a hypothetical example.

 

[tomo pauk]

...
Technically the P-39N burns 62gph at normal power/escort height of 25000'. And the P-47 burns 150gph at 25000' and that is from column II, most of not all cruising over Europe in '43 would be at normal power at 190gph. These numbers pretty well match the chart in post #69.

These fuel consumption values - what is the source?

 

[MiTasol]

Ergonomics (in referring to aircraft cockpits) wasn't even in dictionary in 1937, Again, I think many miss the point that the P-38 (like many aircraft of the day) was designed for function with little consideration to the pilot or "ergonomics." Additionally it was very likely that the cockpit configuration was dictated and/ or accepted by the customer at design acceptance. These decisions were many times made by people not qualified to do so....

How true in every country

 

[MiTasol]

With 120gal internal the (P-39N)

Which is more than the Spitfire with 85UKG/106USG.

 

[Shortround6]

Standard cruise for US escort fighters was figured at about 205 or 215 IAS not the max cruise that you claim.
Reason the P-39 fuel burn at 25,000ft looks so good is that the engine didn't have much more power to give. It was running at max continuous (2600 rpm and full throttle) to do 330mph true for a Q.
How about we slow the P-47 down to 330mph and figure the Fuel burn?
I believe we have explained before the different allowances used to figure the operational radius of the escort fighters. How about using one method so the playing field is fair?