Best mass produced postwar single engine piston fighter? (1 Viewer)

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Remember that the XP-51G with Merlin 100 equivalent (and 1650-9 equivalent) engine clocked 495+ repeatedly without external racks and had >45000 ceiling.
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So from what I recently learned, XP-51G can run at 120 Hg pressure the high supercharger gear power of 2200 HP will make it considerably more powerful than P-51H had available at 1790 BHP - 3000 rpm at 22700 ft.
Another different is that XP-51G has 5 blades propellers compared to P-51H's 4 blades
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The 1650-9 was experiencing major issues in producing more that 75" MP until late 1946. The SAC tables were assembled from both NAA 1947 and Eglin testing in 1948.
This is the chart from F-51H SAC 1950
P-51 SAC 1950.JPG


On page 3, take off, military and normal powers are listed, but not the war emergency powers

engine rating.JPG


On page 6 they said that the performance on page 3 is guaranteed rating, so that mean WEP below is not guarantee

general data.JPG


That because F-51H in service only use AN 01-60JF-1 fuel, which limit the MP to 80 inches Hg instead of 90 inches Hg using AN-F-33 fuel like in the test
fuel 1.JPG


fuel 2.JPG



So in conclusion, the colour chart below from NA booklet is purely hypothetical, the speed/climb chart inside the F-51H 1950 SAC only apply when F-51H use AN-F-33 fuel. When it use AN 01-60JF-1 then speed is a bit slower due to lower MP.
=> F4U-5 and P-51H are roughly similar in speed and climb rate
hypothetical chart.jpg
 
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So from what I recently learned, XP-51G can run at 120 Hg pressure the high supercharger gear power of 2200 HP will make it considerably more powerful than P-51H had available at 1790 BHP - 3000 rpm at 22700 ft.
Another different is that XP-51G has 5 blades propellers compared to P-51H's 4 blades
View attachment 650838
The 495mph per Gruenhagen, 492 per Wagner (Schmued insisted on 'actual' recorded value when NAA Marketing was pushing for '500mph) was at 20, 700 feet. I don't know why Morgan claimed that XP-51G was first to be 'mathematically designed'. Roy Liming was Chief of Engineering Loft Mathematics and Lofting' but both he and R.K. Weebe introduced the science of Projective Geometry at NAA in 1940 and ALL Mustangs were designed to the rules from Day 1.

Further the R-R Merlin 100 as installed, delivered maximum HP of 2080 Hp at 22,800 ft at 80"MP 3000RPM w/150 octane. 1850 HP with 70" and 130 Octane.

The XP-51G engine was one of two R-R delvered Merlin 100, R.M. 14 S.M. Packard never made this engine but made a version 'Merlin 300 and 301' for the RAF Lincoln.

The XP-51G wing was an NACA 66,2 18155 airfoil ----> with greater thickness to chord ratio of 18 compared to NAA/NCA 45-100 with thickness to chord ratio of 16.

While the XP-51G first flown with Rotol 5 Blade prop, it was replaced with Aeroproducts 4 blade A-542-B1, same as XP-51J and P-51H.

So, wing not thinner, no 120MP, Not first to be mathematically designed, did not achieve 498mph
 
The 495mph per Gruenhagen, 492 per Wagner (Schmued insisted on 'actual' recorded value when NAA Marketing was pushing for '500mph) was at 20, 700 feet. I don't know why Morgan claimed that XP-51G was first to be 'mathematically designed'. Roy Liming was Chief of Engineering Loft Mathematics and Lofting' but both he and R.K. Weebe introduced the science of Projective Geometry at NAA in 1940 and ALL Mustangs were designed to the rules from Day 1.

Further the R-R Merlin 100 as installed, delivered maximum HP of 2080 Hp at 22,800 ft at 80"MP 3000RPM w/150 octane. 1850 HP with 70" and 130 Octane.

The XP-51G engine was one of two R-R delvered Merlin 100, R.M. 14 S.M. Packard never made this engine but made a version 'Merlin 300 and 301' for the RAF Lincoln.

The XP-51G wing was an NACA 66,2 18155 airfoil ----> with greater thickness to chord ratio of 18 compared to NAA/NCA 45-100 with thickness to chord ratio of 16.

While the XP-51G first flown with Rotol 5 Blade prop, it was replaced with Aeroproducts 4 blade A-542-B1, same as XP-51J and P-51H.

So, wing not thinner, no 120MP, Not first to be mathematically designed, did not achieve 498mph
This is what i can find. Nevertheless, if R-R Merlin 100 as installed, delivered maximum HP of 2080 Hp at 22,800 ft that will make it significantly superior to V-1650-9 since V-1650-9 can only deliver 1790 Hp at 22,700 ft, which make it 13% weaker. No wonder P-51H is so much slower than XP-51G
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This is what i can find. Nevertheless, if R-R Merlin 100 as installed, delivered maximum HP of 2080 Hp at 22,800 ft that will make it significantly superior to V-1650-9 since V-1650-9 can only deliver 1790 Hp at 22,700 ft, which make it 13% weaker. No wonder P-51H is so much slower than XP-51G

There are a lot of factors when considering comparisons that involve top speed versus different airframes. The XP-51G was 2000 pounds lighter at full GW. The posted speed ranges for P-51H were in full internal combat load at 9600 pounds including full internal fuel and external bomb and rocket stubs. The XP-51G in the speed dash (495mph according to NAA Flight Test docs) was even lighter with only 50% fuel -which separated the GW during flight test by nearly 2500 pounds.

The P-51H vs P-51D (1650-9 vs 1650-7) is faster by nearly the same margin that a P-51G has over the H despite the mismatch in takeoff conditions. You waste a lot of time blurting facts and data without context. Please do me a favor and don't post expecting me to react going forward.
 
There are a lot of factors when considering comparisons that involve top speed versus different airframes. The XP-51G was 2000 pounds lighter at full GW. The posted speed ranges for P-51H were in full internal combat load at 9600 pounds including full internal fuel and external bomb and rocket stubs. The XP-51G in the speed dash (495mph according to NAA Flight Test docs) was even lighter with only 50% fuel -which separated the GW during flight test by nearly 2500 pounds.
Isn't NA-8284A supposed to be a test without rack?
Also, from the chart , it would seem that top speed of 7500 lbs fighter is pretty much same as the 11500 lbs fighter until 22-23k ft, might be parasite drag is the domination factor at top speed?
p-51h-na-8284-pg5.jpg
 
Not a test - a Perfrmance Calculations Report.
well, it seem accurate enough that SAC 1950 still use the data from it.
Still follow their calculation, changing from 7500 lbs to 11,500 lbs seem to affect top speed very slightly except at very high altitude
 
well, it seem accurate enough that SAC 1950 still use the data from it.
Still follow their calculation, changing from 7500 lbs to 11,500 lbs seem to affect top speed very slightly except at very high altitude
Something would only seem accurate enough if you have decided a result in advance.
 
Something would only seem accurate enough if you have decided a result in advance.
Not really.
For P-51H top speed. I couldn't find any chart for the 487 mph test. XP-51G is very fast but also its engine has much better output compared to P-51H. Al otherl test i found for P-51H has lower value than that. Of course, it could be explained that in these test, the condition isn't best for top speed: bomb rack equipped, heavy aircraft ...etc. So , i go for the next best thing that i can find. 1950 F-51H SAC, and they show top speed to be 412 knots (475 mph) in interceptor configuration . since it is the latest one, it should be the most accurate data.
 
Wear and tear on the airframe, certainly not a factory fresh engine.

Just like captured aircraft evaluations were going to show different numbers than tests done when that particular aircraft was fresh from the manufacturer.
I was joking, the average life of a front line type in the RAF was about 6 months as a type, much less for an individual aircraft.
 

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