Fighter by Vne speed

[Rubenova]

I'm interested to see which piston fighter had the highest "do not exceed" rating. All countries and prototypes.

 

[Rubenova]

I'd like to use an existing airframe design and a newer engine and prop to get a 400 mph cruise. Say a Supermarine Spiteful and a P-3 Orion turboprop.

 

[GregP]

Have you done any research on it or are you expecting the forum to do it for you?

 

[pbehn]

A Turbo prop doesn't have pistons.

 

[Rubenova]

I had the idea of using a more powerful engine/prop combination and flat-rate it to a higher cruise speed. I've just started researching aircraft V speeds and found I needed a place to start when comparing designs. Picture a XP-51 (491mph max) with a turbo-prop that could generate 2300 horsepower continuously. The Orion has a cruise of 377mph and a max of 473. Should I be asking about Vno or Vb instead?

 

[Rubenova]

I just found '
WW2-fighter and critical Mach speed
and
WWII A/C: Maximum Mach Number & Airspeed in Dives
I've got some studying to do! Thank you both

 

[drgondog]

I'd like to use an existing airframe design and a newer engine and prop to get a 400 mph cruise. Say a Supermarine Spiteful and a P-3 Orion turboprop.

IIRC a P-51D clean will cruise at 46"/2700 rpm (max continuous power) at 9300 # T.O. weight - as follows:
5k 342
10k 362
15k 382
20k 384
25k 404 --------> in 100 to 92 gph range of fuel consumption in V-1650-7
Source June 1945 Flight Tests to re-validate POM tables. P-51D-15-NA

 

[drgondog]

I'm interested to see which piston fighter had the highest "do not exceed" rating. All countries and prototypes.

The Mustang will be high on your list if you are selecting a combination of low drag/high structural integrity. The Placard VNE is 0.75M for Q loading. Obviously Voodoo closely approached 0.75M at 5k with runs of TAS of 550mph.

You should closely check sources for Spiteful and Orion 'dashspeed' altitudes and validate test data before drawing conclusions regarding potential Vne.

You have some gnarly calcs to make regarding prop efficiencies, drag deltas as tip speeds approach M=1 and exhaust gas thrust contributions - unless the manufacturer of the prop and engine have the requisite tables to draw from.

Will be curious to see where you start pulling Parasite drag factors for pure scale model wind tunnel - or whether full scale data for your airframe choice is available. Altitude is a factor in all your drag calcs as well as pressure drag delta due to angle of attack at it increases for increasing altitude/low density air.

Will you have tables to provide CDp as a function of M? What assumptions for loss of THp due to pressure drag on the airframe/wing immersed in the prop vortex?

Asking for a friend?

 

[pbehn]

You have some gnarly calcs to make regarding prop efficiencies, drag deltas as tip speeds approach M=1 and exhaust gas thrust contributions - unless the manufacturer of the prop and engine have the requisite tables to draw from.

This is mentioned in the testing of the Spitfire 21
.....5.2 The propeller tip mach numbers attained during the level speed tests exceeded 0.90 above 18,000 ft., the maximum being 0.97 at 36,000 ft. The outside air temperature on test varied from 12 deg.C above to 15 deg.C below the ICAN standard values. No allowance has been made for the possible effects of high tip speeds on the reduction methods.
Spitfire Mk 21 Performance

 

[Peter Gunn]

The Mustang will be high on your list if you are selecting a combination of low drag/high structural integrity. The Placard VNE is 0.75M for Q loading. Obviously Voodoo closely approached 0.75M at 5k with runs of TAS of 550mph.

You should closely check sources for Spiteful and Orion 'dashspeed' altitudes and validate test data before drawing conclusions regarding potential Vne.

You have some gnarly calcs to make regarding prop efficiencies, drag deltas as tip speeds approach M=1 and exhaust gas thrust contributions - unless the manufacturer of the prop and engine have the requisite tables to draw from.

Will be curious to see where you start pulling Parasite drag factors for pure scale model wind tunnel - or whether full scale data for your airframe choice is available. Altitude is a factor in all your drag calcs as well as pressure drag delta due to angle of attack at it increases for increasing altitude/low density air.

Will you have tables to provide CDp as a function of M? What assumptions for loss of THp due to pressure drag on the airframe/wing immersed in the prop vortex?

Asking for a friend?

There you go with those simplistic vague answers again, the fellow needs an in depth explanation of what formulas and calculations will be needed on this project, I mean, my God man, you left out how much alcohol he's going to need.