P-51D Max Speed at Different Hg Settings

[Laurelix]

P-51D Mustang used the V-1650-7 engine

* 61Hg (Military Power)
1490hp at Sea Level
1580hp at 2600m
1400hp at 6400m
Supercharger change Height - 4100m

* 67Hg (War Emergency Power)
1630hp at Sea Level
1700hp at 1750m
1555hp at 5400m
Supercharger change Height - 3200m

* 72Hg (War Emergency Power)
1820hp at Sea Level

* 75Hg (War Emergency Power)
1860hp at Sea Level

* 81Hg (War Emergency Power)
1940hp at Sea Level
1810hp at 3650m
Supercharger change Height - 1500m

• P-51D Mustang Max Speed

- 61Hg (Military Power)
586km/h at Sea Level
707km/h at 8500m

- 67Hg (War Emergency Power, +18 psi)
604km/h at Sea Level
711km/h at 7900m

- 72Hg (War Emergency Power)
626km/h at Sea Level
726km/h at 6900m

- 75Hg (War Emergency Power)
631km/h at Sea Level
726km/h at 6400m

- 81Hg (War Emergency Power, +25 psi)
640km/h at Sea Level
698km/h at 2000m


No Matter what Hg a Mustang is set at, they all run at 61Hg at Military Power. War Emergency Power is 5 Minute Rated Power but could work for 10-15 mins but risking to damage the engine. The Military Power is 15 minute rated power but you can run it for 30 mins. The Max Continues Power is unlimited use but I didn't bother with it since it's used to fly to battle and not to be used during battle. But I can include it if enough people ask for it XP


2 Main Sources Used:
http://www.wwiiaircraftperformance.org/mustang/P-51D_15342_Level.jpg
61Hg / 67Hg Level Flight Top Speed

V-1650-7 Power Curve
http://www.wwiiaircraftperformance.org/150grade/Packard_V-1650_Engine_Performance_data.pdf

Edit:
This is with wing racks, feel free to add additional 13km/h to its top speed, if it didnt have them

 

[davparlr]

P-51D Mustang used the V-1650-7 engine


* 67Hg (War Emergency Power)
1630hp at Sea Level
1700hp at 1750m
1555hp at 5400m
Supercharger change Height - 3200m

* 72Hg (War Emergency Power)
1820hp at Sea Level

delete

 

[Laurelix]

delete

67Hg was the most common setting. For example in the pacific no P-51D ran over 67Hg.

 

[davparlr]

67Hg was the most common setting. For example in the pacific no P-51D ran over 67Hg.

I thought you had said that the asterisk meant not approved for use, but on review it seems to be deleted, or I'm crazy (not impossible).

 

[Laurelix]

I thought you had said that the asterisk meant not approved for use, but on review it seems to be deleted, or I'm crazy (not impossible).

it was for 81Hg but i realised the source said that about V-1650-3 not the V-1650-7 that P-51D has

 

[thunderbird]

Max speed at sea level for 81Hg, is about 640 kph, 390 mph.
Increase in speed allowed by running over boost can be relatively easily estimated by the cube root rule. Since power is basically Force x velocity, and drag (Force) is basically cd x rho/2 x ref area x V^2, essentially, the increase in speed due to an increase in power is the cube root of the power ratio.

586kph x (1940/1490)^.333333 = 640 kph, for instance.

most of the WEP ratings have very low altitude limits as the supercharger couldn't maintain those pressures with altitude, so the top speeds at altitude, with some exceptions, weren't improved.

 

[gumbyk]

Being pedantic here, but the units are inches of mercury ("Hg), commonly reduced to inches, not Hg. The other common unit of measurement for manifold pressure is mmHg.

 

[wuzak]

Being pedantic here, but the units are inches of mercury ("Hg), commonly reduced to inches, not Hg. The other common unit of measurement for manifold pressure is mmHg.

Ideally not reduced at all, since inches could also refer to inches of water, another common pressure measurement.

MAP can be measured in any pressure units, and is commonly measured in bar in this day and age.

 

[gumbyk]

Ideally not reduced at all, since inches could also refer to inches of water, another common pressure measurement.

MAP can be measured in any pressure units, and is commonly measured in bar in this day and age.

Haven't seen those used within the aviation industry though.

 

[wuzak]

Haven't seen those used within the aviation industry though.

I have seen it used in cars, though.