Non-production P-47 Variants, esp XP-47F and XP-47H Performance figures?

[Conslaw]

I was looking for performance test information on the experimental models of the P-47, specifically the XP-47F with laminar-flow wings, and the XP-47H with the Chrysler IV-2220 engine. I found nothing on either plane in America's Hundred Thousand. I found no performance information online at all on the XP-47F. On the -H, Wikipedia said that it flew over 500 MPH (no citation given)

This is what Joe Baugher said of the XP-47H

"Although the project was begun in August 1943, the two P-47D-15-RE airframes were not actually converted until 1945. Test flights began on July 26, 1945. One of my sources (Green) says that during flight trails, one of the XP-47Hs actually attained a speed of 490 mph in level flight. However, another one (Wagner) says that the Chrysler engine failed to deliver the promised power output, and that the maximum speed attained during tests was only 414 mph at 30,000 feet, poorer performance than the "stock" P-47D. In any case, the Chrysler XIV-2220 engine never achieved production and the advent of jet propulsion killed any further USAAF interest in the development of even faster piston-engined fighters. Consequently, no further work was undertaken on the XP-47H project."

I'm curious where the 490 MPH figure fore the -H comes from. Some insight from h**p://www.enginehistory.org/phpbb/viewtopic.php?t=650&sid=b726628cae767f7dc6f3930a0df410ef

 

[grampi]

I'm still trying to figure out how ANY P-47 model was capable of achieving 500 MPH in level flight...if memory serves me correctly the P-47 was the largest and heaviest single engine fighter of the war...how it managed to go faster than other, smaller and more aerodynamically sleek fighters (such as the P-51, Spitfire, and Me/BF-109) is beyond my comprehension level...

 

[herman1rg]

https://books.google.co.uk/books?id...g=PA93#v=onepage&q=xp-47f performance&f=false

 

[herman1rg]

The XP-47F model was plucked from a P-47B and modified as a test-bed for laminar-flow wings. Testing revealed that the new wings would not improve performance much and the aircraft soldiered on in other related flight tests thereafter. She was officially lost in a fatal accident on October 14th, 1943.

The XP-47H was an interesting P-47 development in that it attempted to mate the P-47 airframe with the Chrysler XI-2220-1 16-cylinder, inverted-vee, liquid-cooled engine of 2,300 to 2,500 horsepower (sources vary). Two P-51D-15 models were used in this conversion test sans their armament. The complicated and untested engine proved highly unfeasible and overly complicated to fit into the existing airframe without major modifications. As such, the project was dropped. First flight was achieved in July of 1945, achieving a paltry 414 miles per hour for the USAAF - far lower than the projected 490 miles per hour originally envisioned (and reportedly reached) by Republic. Range was approximated to 700 miles.

 

[tomo pauk]

I'm still trying to figure out how ANY P-47 model was capable of achieving 500 MPH in level flight...if memory serves me correctly the P-47 was the largest and heaviest single engine fighter of the war...how it managed to go faster than other, smaller and more aerodynamically sleek fighters (such as the P-51, Spitfire, and Me/BF-109) is beyond my comprehension level...

There is a certain value in having 2800 HP available at 30000-35000 ft, where the air is so thin for the aircraft to encounter
I not 500 mph (XP-47J), the 480 mph (P-47M) is also a fine turn of speed.

 

[grampi]

There is a certain value in having 2800 HP available at 30000-35000 ft, where the air is so thin for the aircraft to encounter
I not 500 mph (XP-47J), the 480 mph (P-47M) is also a fine turn of speed.

That's another thing, how did they manage to get 2800 HP at that altitude?

 

[Shortround6]

The Production P-47M could just about do it.

http://www.wwiiaircraftperformance.org/p-47/p-47m-republic-wepchart.jpg

2800hp at 32,000ft for highspeed level flight and 28,000ft while climbing.

RAM does help turbo charged planes.

 

[kool kitty89]

The P-47 also WAS a fairly sleek, streamlined, low drag (for its power/weight) aircraft, especially with the more streamlined cowling and reduced weight of the XP-47J. It may not have used a NACA Laminar Flow airfoil, but it was already using a low-drag profile airfoil developed by Seversky/Republic.

Given the critical mach limits of the P-47, it may not have had much room to DIVE without trouble at high alt (without recovery flaps), but the level speeds claimed would still not be breaking limiting mach, especially with the somewhat warmer climates in the US testing grounds.

 

[tomo pauk]

That's another thing, how did they manage to get 2800 HP at that altitude?

The turbo-charger, powered by exhaust gasses, was there to compress the air, 'push' it through the intercoolers to cool it a good deal, then water-alcohol injection in the carb cooled it further, and such the air, along with fuel, water and alcohol was fed in the 2800 cu in engine doing 2800 rpm.