# P-47D with Paddle blade propeler - was she a dogfighter?



## Jank (Apr 13, 2005)

Or was she just a dog?

Been reading some about the performance enhancment that the paddle propeler gave. Could she slug it out ina dogfight with me-109s and fw-190s?


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## Concorde247 (Apr 14, 2005)

The broad chord props were normally used for extra bite at altitude a bit more speed in the rarified air never goes amiss. They werent just put on fighters though, they were used on the B17 B24, Lancaster etc....


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## FLYBOYJ (Apr 14, 2005)

Ask Bob Johnson


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## evangilder (Apr 14, 2005)

The earlier "toothpick blades" had a wide variety of problems as well. I have an interview on tape of a veteran that was a crew chief on the P-47. He remembers a guy coming back from a standard training flight and the toothpick blades, as he called them literally came apart as the guy was flying over the field! He thought he was going to be out of a job for that. It was not his fault, so he was alright.


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## DAVIDICUS (Apr 14, 2005)

Go to:

http://www.lanpartyworld.com/ww2/axisair.htm

Scroll down to P-47 vs. FW-190 for an interesting test comparing the two. One comes away with the impression that the P-47 was a much better performer at lower altitudes and speeds than is generally assumed.


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## Jank (Apr 14, 2005)

Interesting tests. Looks like she could do her part in keeping up with Germanys finest. Always thought she was a dead horse when slow at lower levels. Guess that paddle propeler helped a lot.


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## Anonymous (Apr 15, 2005)

DAVIDICUS said:


> Go to:
> 
> http://www.lanpartyworld.com/ww2/axisair.htm
> 
> Scroll down to P-47 vs. FW-190 for an interesting test comparing the two. One comes away with the impression that the P-47 was a much better performer at lower altitudes and speeds than is generally assumed.



If you check it out, you will see that pages 1 and 2 concern a FW190A vs. P-47D with ADI but apparently no paddle prop. Pages 3 and 4 are an earlier test of an FW190A vs. P-47C.

The difference is night and day.

=S=

Lunatic


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## Anonymous (Apr 15, 2005)

Jank said:


> Interesting tests. Looks like she could do her part in keeping up with Germanys finest. Always thought she was a dead horse when slow at lower levels. Guess that paddle propeler helped a lot.



Supposedly a juiced up P-47D with paddle prop and ADI could climb with a Spit IX. I've never seen any test data to support this (there is practically no test data on updated P-47's) but that is what several pilots claim from improptu mock dogfights with the Brits.

The ADI (water-methanol injection) helped the R-2800 a lot, boosting the HP output from about 2100 BHP to 2550 BHP stock. Another 200+ HP could be tweaked out of it by a good mechanic.

=S=

Lunatic


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## KraziKanuK (Apr 15, 2005)

RG_Lunatic said:


> DAVIDICUS said:
> 
> 
> > Go to:
> ...



What, no tests of the Fw using C3 injection or the 2100ps engine or fitted with paddle bladed props?

A P-47 could climb at 5000f/m which the Spit IX could do? Sure.


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## DAVIDICUS (Apr 15, 2005)

I wonder what the difference was in performance figures for climb, acceleration and speed as to the pre and post paddle blade Jug.


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## Anonymous (Apr 15, 2005)

KraziKanuK said:


> RG_Lunatic said:
> 
> 
> > DAVIDICUS said:
> ...



The comparison was made vs. an early Spit IX with the Merlin 61 engine. And the Spit IX did not have a 5000 fpt climb rate.

German props were rather poor in design, and no such equiped FW's were available. The unit that was available was running at something like 1.5 ata, pretty good for most FW's.


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## Anonymous (Apr 15, 2005)

Look at the P-47M figures, and then account for the difference in weight.

=S=

Lunatic


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## DAVIDICUS (Apr 16, 2005)

I'm not sure that a mere accounting for weight is sufficient to account for the difference in performance RG.

The "M" at normal loaded weight was 13,275lbs.

The "D" at normal loaded weight was 14,600lbs.

The "M" was outfitted with the R-2800-57(C) with a larger CH-5 turbosupercharger. It had a WEP of 2,800hp. It had an initial climb rate of 3,500fpm.

The "D" was outfitted with the R-2800-59. It could achieve a WEP of 2,535hp. It had an initial climb rate of 2,780fpm.

My point is that based on my understanding, as set out above, there appears to be more than a mere reduction of weight that made the "M" such a hot ship. Otherwise, a stripped down "D" model weighing as much or less than an "M" model would be able to achieve the same performance.


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## Anonymous (Apr 16, 2005)

DAVIDICUS said:


> I'm not sure that a mere accounting for weight is sufficient to account for the difference in performance RG.
> 
> The "M" at normal loaded weight was 13,275lbs.
> 
> ...



The M had a C series engine, the D had a B series engine. D's could be tweaked to produce almost 200 extra HP by a good mechanic. Better fuels were also available than the fuels used for the "standard" ratings. The bigger turbo unit on the M was better up high, but down lower the normal Turbo unit could provide as much boost as the engine could handle. The C series engines also had better cooling, so they could sustain higher power levels longer. Supposedly Johnson's and Schilling's P-47D's were both putting out about 2700 HP in the Summer of 1944.

My point is that actual combat performance of the P-47D with the paddle prop and ADI was only a little worse than the M. However the M could sustain higher power levels longer and higher than the D.

=S=

Lunatic


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## DAVIDICUS (Apr 16, 2005)

I understand that the performance figures for the "M" model were actually conservative. Supposedly, on one test flight, an "M" achieved 488mph in level flight. And as you pointed out with the "D" models, crew chiefs in the field also supposedly "tweaked" the engines on the "M" models as well. Supposedly, there exist reliable reports from some pilots who claimed an honest 500mph in level flight.


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## DAVIDICUS (Apr 16, 2005)

Certainly, by any measure, the "M" was really an amazing aircraft.

From: http://www.geocities.com/pentagon/quarters/9485/P-47M.html

"_ Right out of the starting gate, the XP-47M was the horse to beat in terms of speed. The XP-47M proved to be nearly as fast as the XP-47J. 488 mph was obtained on at least one flight. The official maximum speed is 470 mph. However, over-boosting the engine could tweek another 15 to 20 mph out of the big fighter. There is adequate evidence to indicate that some of the more resourceful crew chiefs in the 56th Fighter Group, managed to hotrod the P-47M to the point that some reliable pilots were reporting 500 mph at altitude in level flight. Some may find this next tidbit hard to swallow, however, the test documents still exist.

During durability testing of the C series R-2800 by Republic, it was decided to find out at what manifold pressure and carburetor temperature detonation could be induced. They ran the engine at extreme boost pressures that produced 3,600 hp! But wait, it gets even more amazing. They ran it at 3,600 hp for 250 hours, without any failure! This, with common 100/130 avgas. No special fuels were used. Granted, the engines were completely worn out, but survived without a single component failure. Try that with Rolls Royce Merlin or Allison V-1710. _"

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## KraziKanuK (Apr 16, 2005)

RG_Lunatic said:


> The comparison was made vs. an early Spit IX with the Merlin 61 engine. And the Spit IX did not have a 5000 fpt climb rate.
> 
> German props were rather poor in design, and no such equiped FW's were available. The unit that was available was running at something like 1.5 ata, pretty good for most FW's.



The Spit IX @ 25lb boost certainly could do 5000f/m.

An A-8 @ 1.58/1.65 @ SL had RoC of almost 3400f/m. At 20,000ft it was almost 2200f/m. This is without the wide blades or a 2100ps BMW TS/TU engine. There was no time restriction on 1.65.


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## Anonymous (Apr 16, 2005)

KraziKanuK said:


> RG_Lunatic said:
> 
> 
> > The comparison was made vs. an early Spit IX with the Merlin 61 engine. And the Spit IX did not have a 5000 fpt climb rate.
> ...



The Spit IX with the Merlin 61 could not sustain 5000 fpm. As I've said before, initial rates of climb are rather meaningless.

The Spit IXB with Merlin 61 had a best climb rate of 3860 ft.min at 12,600 ft and took 5.6 minutes to reach 20,000 feet. The Spit IXBS with the Merlin 66 managed 4700 ft/min at 7000 ft. and reached 20,000 feet in 4.75 minutes at +18 lbs boost. At +25 lbs boost the figures the figures for the Merlin 66 do go over 5000 fpm, but was down to 3750 fpm by 20,000 feet. On the otherhand, to achieve this high octane fuels had to be used, and these were also available on the P-47's in late 1944 and 1945.

So the claim the P-47D with Paddle Prop and ADI could outclimb the Spit IX by a pilot who tried the matchup pre-paddle prop or ADI probably relates to the Merlin 61 running at +18 lbs boost. And this is not outside the realm of reason. He was after all relating the updated P-47D to his prior experiance vs. the Spit IX in the pre-updated version.



KraziKanuK said:


> An A-8 @ 1.58/1.65 @ SL had RoC of almost 3400f/m. At 20,000ft it was almost 2200f/m. This is without the wide blades or a 2100ps BMW TS/TU engine. There was no time restriction on 1.65.



Yes but it was not an A-8, it was probably an A-5.

The 1.65 ata performance is limited to 0-1250 feet, then it drops of sharply from 1.65 to 1.42 ata by 2500 feet and cannot be increased again until about 5500 feet when it can be increased again, reaching 1.65 ata at about 7500 feet and maintaining that till about 16,000 feet, where it again starts to drop off and is back down to 1.42 ata by 19,000 feet. By 21,000 feet the RoC is below 2000 fpm, and above 24,000 feet performance is unpredictable, the computer could drop into "safe" mode at an time.




click here to see full size chart

Also, the 2700 rpm 1.42 ata rating is listed as "Take-off/Emergency" power, the climb and combat power rating is 2400 rpm at 1.32 ata. This tends to dispute the idea that there was no limit to the 1.65 ata setting, which by the way is +23.5 lbs boost. 

=S=

Lunatic


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