F4U Corsair vs P-51 Mustang

[drgondog]

The Corsair wasn't "close" to the P51 in maneuverability at all, it actually outclassed the P51 in maneuverability at all speed, in all aspects, still, contemporaries Mustang outclassed the Corsair in speed, climb and endurance.

The Corsair was superior in roll, turn and landing speed - all related to 10% lower wing loading. The Mustang was superior in acceleration, climb, speed, zoom climb, dive all related to 2/3 Drag values compared to Corsair.

I suppose the definition of "close" needs some scrutiny. As to "all speed", the relative turn capability of the Mustang matched the Corsair at high altitude and the roll rates matched at high speed. The comparisons basically need to be period vs period such as F4U-4/-5 vs P-51H; F4U-1 vs P-51B/D

 

[drgondog]

The problem with many of the comparisons is that the HP to altitude performance between the two aircraft (and other R-2800 engine fighters vs Mustang) needs to have the Available Horsepower to Horsepower Required for all the altitudes.

 

[Zipper730]

It include both.

Gotcha

Warm up time also varied with the installation (and weather conditions), They main thing was to warm up the engine to operating temperature and the oil! Cold oil flowed like molasses and warming up the oil in the engine while the oil in the oil tank/oil cooler was still cold and thick would lead to flow and lubrication problems, big ones. Many planes had variable oil supplies. Oil tank was only filled to capacity if the plane was using max fuel (aux tanks or drop tanks)
Actual warm up time was dependent on the temperature gauges but for flight planning a worst case scenario would be adopted. A few of these categories had a little bit of fudge factor in them to give a bit of reserve. Cutting warm up to the minimum in planning for a max range mission and then running into a higher than expected head wind on the way home leaves you with a lot of lost aircraft.

I wouldn't have though that would have affected range as I'd have thought the oil would have been steadily heated as the plane flew.

See Marianas turkey shoot where about 80 US aircraft were forced to ditch on the return flight due to low fuel as an example of operating at extreme range/s.

Holy shit: How many planes were sent out?

It did?

According to America's Hundred Thousand the P-51B rolled better at all speeds and had a tighter turning radius than the F4U-1D.

Wait, I thought the P-51B/D had the same rate of turn?

 

[Shortround6]

I wouldn't have though that would have affected range as I'd have thought the oil would have been steadily heated as the plane flew.

Flying the plane kept it warm. But starting a engine with a few quarts of oil in it and having a number of more quarts in the oil cooler and piping is far different than having gallons of oil in a remote oil tank. Warm up was done at idle or a High idle. Taking off at full throttle and climbing to operational attitudes was done at high power settings meant that oil had to be circulated through the oil system and oil cooler/s. Even Liquid cooled engines got rid of approximately 20% of the engine heat through the oil system and around 80% though the radiators so you can't (even if possible, which it wasn't) shutoff the oil tank, that was the reserve of 'cool' but not cold oil. Cold oil isn't going to flow properly (at the right number of gallons per minute) and it isn't going to lubricate properly leading to excessive wear if not engine failure.
Burning 12 -25 gallons on the ground and getting to 5,000ft on climb out affects range compared some "yardstick" ranges which simply divide the total fuel tank capacity by the number of gallons an hour at a certain speed to calculate a "nominal" range.

Holy shit: How many planes were sent out?

240 were launched, 14 aborted, 226 attacked the Japanese fleet, about 20 were shot down by Japanese defenses (fighters and AA).
The 1st strike was launched without exact knowledge of the Japanese position. More information came in later and the 2nd strike was NOT launched although the first strike was not recalled. Difference in location was 60 miles ???. While the attacking aircraft only sank one Japanese carrier they damaged 3 others and also scored hits on a battleship.
In climatic naval battles (1st large fleet carrier battle in almost two years) perhaps risks could be taken.
In a land campaign were air strikes were almost an every day occurrence (weather permitting) loosing aircraft due to poor planning of range/fuel would hardly ever be justified.

The US did manage to recover almost 3/4s of the downed crews although some spent several days in the water.

 

[drgondog]

Gotcha

I wouldn't have though that would have affected range as I'd have thought the oil would have been steadily heated as the plane flew.

Holy shit: How many planes were sent out?

Wait, I thought the P-51B/D had the same rate of turn?

Depends on Gross Weight for the comparison - when the B is full load internal it has 1 gun and 400 rounds of 50cal less load per wing than the P-51D. Net 400 pounds lighter than the P-51D.

 

[CORSNING]

I thought I already answered these questions.

The Corsair was superior in roll, turn and landing speed - all related to 10% lower wing loading. The Mustang was superior in acceleration, climb, speed, zoom climb, dive all related to 2/3 Drag values compared to Corsair.

I suppose the definition of "close" needs some scrutiny. As to "all speed", the relative turn capability of the Mustang matched the Corsair at high altitude and the roll rates matched at high speed. The comparisons basically need to be period vs period such as F4U-4/-5 vs P-51H; F4U-1 vs P-51B/D

 

[CORSNING]

These aircraft were two of the best propeller fighter aircraft ever produced. They excelled
in there prospective rolls. They were not interchangeable. The Corsair was the perfect
Pacific US Marine fighter and the Merlin Mustang was the perfect USAAF fighter
of the time. In late 1943 and early 1944 the F6F-3/4 was exactly what was needed by
the USN.

 

[davparlr]

The P-51, except the A at high altitudes, was always faster, often significantly so (20-30 mph) at all altitudes, than the corresponding F4U model. Speed is life.

 

[Zipper730]

How did the P-51A/B/D compare to the P-40B/E? The reason I ask this is that I remember it being stated that the P-40 could out-turn (barely) the ME-109, but the P-51 could be out-turned by the Me-109...

 

[wuzak]

How did the P-51A/B/D compare to the P-40B/E? The reason I ask this is that I remember it being stated that the P-40 could out-turn (barely) the ME-109, but the P-51 could be out-turned by the Me-109...

No, the Bf 109 could not out turn a Mustang

http://www.wwiiaircraftperformance.org/wade-turning.jpg

 

[CORSNING]

No, the Bf 109 could not out turn a Mustang

http://www.wwiiaircraftperformance.org/wade-turning.jpg

The turning circle of the aircraft on this page appears to be at high altitudes. The Mustang
could outturn the Bf 109 at high altitudes where the Messerschmitt was hanging in the air.
At lower altitudes the tables turned and the Bf 109 turned better at speeds below about
330 mph.

 

[drgondog]

I agree - Turn is largely a function of wing loading and power available versus power required.

Power Required is a function of Parasite Drag, Induced drag and cooling drag for straight line, but Form Drag as a function of AoA comes into play in turns and climbs.

The Power Available for the RR and Daimler are very different as a function of altitude and the drag of the Mustang is far below the Bf 109G

The Bf 109G should out turn the Mustang in low to medium altitudes below 300 mph. The comparisons are about even in higher altitudes through 22,000 feet and then advantage goes to the P-51B/D as the Rolls outperforms the Daimler.

 

[Zipper730]

The turning circle of the aircraft on this page appears to be at high altitudes.

Yeah, I'm surprised the P-47 would be able to out-turn a Tempest except at high-altitudes where the turbocharger would provide the advantage.

Does anybody have a chart that would cover turn circle and/or rate of turn for the following aircraft at different altitudes?

 

[drgondog]

I doubt that any such data exists.

Calculations would required extensive aero data not available today. Turn rate and circle presentations calculated on CL are approximations at best for all the reasons I suggested above.

Turn and climb analytics require wind tunnel data concerning Parasite Drag and Form Drag to extract Power Available calculations.

Not to mention accurate CLmax values for high AoA in asymmetrical flight conditions - which are Not the same as Level Flight Stall conditions.

 

[GrauGeist]

Something I have always been curious about, Bill, is environmental factors during testing.

For example, would performance results differ between a summer day (with high temps/low humidity) at Muroc and a cool late autumn day (low temps/high humidity) at Freeman?

Same aircraft, same test routines.

 

[drgondog]

slightly different temp/pressure factors affect instrumentation as well as density variations - but most Brit and US flight test results were scrupulous about applying corrections for both compressibility and temperature.

that said, there were bigger variations between engine performances vs Static Bench specs.

 

[grampi]

It should be noted that in the Fighter Conference, the P-51 was selected as the second best fighter above 25k, behind the P-47

I've seen this stated before, and besides diving ability, what performance aspects were superior for the P-47 as compared to the P-51? It certainly wasn't going to out climb, or out maneuver it...

 

[grampi]

I gets mine too. It's faster and same weapons and it's prettier

You've got to be kidding...there's never been a plane as pretty as the Mustang...before or after...

 

[Zipper730]

The Bf 109G should out turn the Mustang in low to medium altitudes below 300 mph. The comparisons are about even in higher altitudes through 22,000 feet and then advantage goes to the P-51B/D as the Rolls outperforms the Daimler.

Just to be clear what combat configuration are we talking about for the P-51?

• Short/Medium Range: No drop-tanks, fuel only in the wings. Percentage of available fuel is lower than any other configuration, weight is lowest
  
• Medium/Long-Range Escort: Fuel in center tank is filled up from 65-85 gallons, wing-tanks are full and drop-tanks are carried. At start of combat, the center tank is either empty, or nearly empty, wing-tanks are full or nearly full (for the longest range missions the center tank is filled, on medium missions probably not so a little bit of fuel would be burned up during taxi, warm-up, initial climb), and drop-tanks are gone.

Different weight affects the stall-speed, maximum g-load, and power to weight ratio and all affect the turning arc. You know this of course, but I was just trying to make a point.

Calculations would required extensive aero data not available today.

So you'd have to make guesses based on what you don't have, and use available data collected?

Turn rate and circle presentations calculated on CL are approximations at best for all the reasons I suggested above.

Cl = L/(A*0.5*r*V^2) or Cl = L/(q*A)?

I've seen this stated before, and besides diving ability, what performance aspects were superior for the P-47 as compared to the P-51? It certainly wasn't going to out climb, or out maneuver it...

I thought the P-47 didn't have turning ability that was all that remarkable? From what I remember the Silverplate B-29's could turn inside a P-47 (they had 7200 pounds reduced over a regular B-29, sure...)

 

[pbehn]

I thought the P-47 didn't have turning ability that was all that remarkable? From what I remember the Silverplate B-29's could turn inside a P-47 (they had 7200 pounds reduced over a regular B-29, sure...)

The P 47 could out turn a Bf 109 at 30,000 ft.