F4U-4 and Ki-84-I performance Q's

[juzz]

Swipe!
 

[niklas]

btw, there exists a specific engine chart for the R-2800-8 engine which says:

takeoff: 54´  >> 2000 hp
wep: 57.5´    >> 2250 hp

now, when 2.5´ difference in manifold pressure gives you 250hp more power, then it´s not difficult to estimate where you are with another 2.5´ (60´) or even another 7.5´  (65´) manifold pressure.

[F4UDOA]

Niklas,

Actually it depends. I have that chart in the F4U-1 pilots manual. Notice the power varies with alt. and manifold pressure.
Notice when the F4U hits 60" of manifold pressure it is at 20,000ft. So that is also the alt where the modified F4U hit 65". But the changes in horsepower at that alt are much less because the lower air density reduces power output.

Take off       54"   2000HP  Sea level
War emergency  57.5" 2250HP  SL
"     "        59.0" 2135HP  15,000FT
"     "        59.5" 1975HP  20,000FT

These numbers are from the pilots manual. It is possible that the numbers are more conservative that was actual use of the A/C. But it still shows the higher the alt. the manifold pressure is checked the less effect it has on actual power output.

Also at the bottom of the page in which this data is printed, these numbers are not from flight test. The P-51B vrs F4U chart is from an actual flight test.

Later
F4UDOA