Dawncaster
Airman 1st Class
- 110
- Dec 23, 2013
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From the P-51H Pilot's Manual, 1946:
http://i91.photobucket.com/albums/k304/Major_Sharpe/P-51Hpmcov_zpsa2adbe78.jpg
The 1949 charts do not allow the use of WEP (War Emergency Power), a rating which allowed boost pressures of up to 76" Hg for 1 minute see http://www.wwiiaircraftperformance.org/mustang/p-51h-na117.jpg the other test used up to 90" Hg with water injection.
By 1949 the engines were restricted to using Military Power with a maximum boost of 61 Hg (15 minutes); that accounts for the difference between the P-51H and F-51H.
Also, take a look at the "Compressibility Correction Table" in particular; none of the reports note whether the figures were corrected for compressibility:
http://i91.photobucket.com/albums/k304/Major_Sharpe/P-51HPilotsmanual1_zps240b0b2b.jpg
Engine chart (note WEP):
http://i91.photobucket.com/albums/k304/Major_Sharpe/P-51HPilotsmanual2_zps06ffe887.jpg
Instrument limitations
http://i91.photobucket.com/albums/k304/Major_Sharpe/P-51HPilotsmanual3_zps24a1a965.jpg
The first three charts are NAA charts and most likely represent engineering estimates, which will also have engineering errors, and possibly optimistic. The last two chart state that they are based on flight test data and should be more reliable. There is a question regarding the test weight, however. 9544 pounds at loaded weight seems heavy. "America's Hundred Thousand" states that the loaded weight of the P-51D configured for fighter operations was 9611 lbs. The empty weight of the P-51H is 540 lbs less than the P-51D. I don't know where the extra weight is. No big deal for speed but would impact climb. My estimates of nominal climb at SL is 5600 ft/min at 8800 lbs and max airspeed is 468 mph at 21k ft. clean. Interestingly, top speed at sea level is a very impressive 410 mph, all plus or minus my error.
Confusing conflicting data on these aircraft are not uncommon. Take a look at the F4U-4 sometimes.
P-51D, gross weight 9611lb was 180gal fuel, empty fuslage tank.
P-51H, gross weight 9450lb was 260gal fuel, full tank with clean wing.
P-51H, gross weight 9544lb was 260gal fuel, full tank with x2 bomb racks and x6 rocket racks.
here is P-51D test reports.
P-51D Performance
P-51D, gross weight 9611lb, 180gal fuel.
P 51D Performance Test
P-51D, gross weight 9760lb, 184gal wing tank fuel + 25gal fuslange tank fuel.
and here is P-51 tactical chart.
http://www.wwiiaircraftperformance.org/mustang/p-51-tactical-chart.jpg
P-51D, combat weight 10100lb with 269gal full tank.
92gal x2 wing tanks + 85gal fuslage tank
but P-51D's common combat weight was around 9600~9800lb, without or less fuslange tank fuel.
so, of course P-51H was less weight than P-51D. even with full tank and x8 racks, P-51H was lighter than P-51D with empty fuslage tank, 180gal fuel.
NA-126, Report No. NA-8284-A, gross weight 9450lb, 471mph at 22700ft without racks.
http://www.alternatewars.com/SAC/F-51H_Mustang_SAC_-_22_March_1949.pdf
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North American's Lightweight MustangsPerformance (Air Superiority, with two 165 gallon drop tanks)
Maximum Speed
300~ MPH at Sea Level
413 MPH at Sea Level with Water Injection
391 MPH at 22,700 ft
474 MPH at 22,700 ft with Water Injection
437~ MPH (roughly) at 33,000 ft (roughly) with Water Injection
Hey, Aozora, anywhere to download that manual for the P-51H?
this one is with 2 fuel tank
"All tests at the fighter configuration (bomb and rocket racks only) were flown at a take-off weight of 9544 lbs"
max speed is terrible to compare other tests, only 451mph with 90" hg.
bomb racks and rocket racks were almost decrease 20mph speed.
but SAC's mission profile was.. damn! what happen between P-51H to F-51H?<= confused again.
but, flush position had better performance than open position.
"Opening coolant flap wide open from flush position slowed the airplane from 349 M.P.H. I.A.S. to 325 M.P.H. at 18,000 Ft." from P-51B-1-NA AAF No. 43-12093 report.
and even with flush position, mustang's rear scoop is not completely sealed.
Flight Handbook USAF Series F-51H Aircraft
F-51H handbook, page 11 (pdf page 17)
so, P-51H's coolant shutter is short to seal.
in my opinion, flush position was requirement for maximum performance. if not, why did they did use flush position and result called "Max"?
"coolant shutter flush", meaning there was no ram effect..."
automatic shutter was to ensure optimum airflow through the radiator consistent with keeping the engine at its optimum temperature