Curtiss adopts short span version of P-60 wing for the P-40

[wuzak]

The P-60 program began when the XP-46 failed to win a production contract, the prototypes were still under construction at that time.

Curtiss' next move was to propose the XP-53, basically a P-40D fuselage with the IV-1430 (which was optimistically rated at 1,600hp at the time) and a NACA laminar flow wing.

The Army ordered 2 prototypes of the XP-53, but that was quickly changed to one XP-53 and one XP-60, which had the same airframe but the IV-1430 was replaced by the V-1650-1 Merlin (actually a Merlin 28 in the prototype).

The XP-60 had its first flight in September 1941, before the XP-46 had flown.

The XP-60 managed a top speed of 387mph at 22,000ft.

The wing of the XP-60 had a span of 45 feet 5.25 inches (13.85m), compared to the P-40's 37 feet 3.5 inches (11.37m).

It also housed 8 heavy machine guns (0.5" M2 Browning).

The other feature that was different to the P-40 (but similar to the XP-46) was inward retracting main landing gear that did not protrude from the wing.

What if Curtiss was to adopt a shorter span version of this wing for the P-40, with a wing span the same, or nearly the same, as the actual P-40s?

Using 4 to 6 hmgs instead of the 8 in the XP-60, how would the performance compare to the standard contemporary P40s?

Is the performance sufficient to warrant the alteration to part of the production line?

 

[Akuma]

The P-60 program began when the XP-46 failed to win a production contract, the prototypes were still under construction at that time.

Curtiss' next move was to propose the XP-53, basically a P-40D fuselage with the IV-1430 (which was optimistically rated at 1,600hp at the time) and a NACA laminar flow wing.

The Army ordered 2 prototypes of the XP-53, but that was quickly changed to one XP-53 and one XP-60, which had the same airframe but the IV-1430 was replaced by the V-1650-1 Merlin (actually a Merlin 28 in the prototype).

The XP-60 had its first flight in September 1941, before the XP-46 had flown.

The XP-60 managed a top speed of 387mph at 22,000ft.

The wing of the XP-60 had a span of 45 feet 5.25 inches (13.85m), compared to the P-40's 37 feet 3.5 inches (11.37m).

It also housed 8 heavy machine guns (0.5" M2 Browning).

The other feature that was different to the P-40 (but similar to the XP-46) was inward retracting main landing gear that did not protrude from the wing.

What if Curtiss was to adopt a shorter span version of this wing for the P-40, with a wing span the same, or nearly the same, as the actual P-40s?

Using 4 to 6 hmgs instead of the 8 in the XP-60, how would the performance compare to the standard contemporary P40s?

Is the performance sufficient to warrant the alteration to part of the production line?

Could you clarify the question? Do you mean a Laminar flow airfoil wing the same length as the P-40 wing or shorter than the P-40 wing?

 

[wuzak]

Could you clarify the question? Do you mean a Laminar flow airfoil wing the same length as the P-40 wing or shorter than the P-40 wing?

I mean a laminar flow wing the same length as a P-40 wing.

 

[Akuma]

I mean a laminar flow wing the same length as a P-40 wing.

An XP-60 with a Laminar Flow wing shortened to the span-length of a P-40 would have had less wing area which in turn means heavier wing loading. That usually means faster diving, take-off and landing speeds and less maneuverability. Without wind tunnel or prototype flight test data, changes in performance can only be guesses.

 

[Jugman]

The XP-60 had a wingspan of 41' 5.25" a wing area of 275.4sq.ft. and a chord of 120"/40" root/tip. Vs the P-40 span 37' 3.5", area 236sq.ft. chord 108"/54". If the wings simply clipped wing are should be in the 255sq.ft ballpark. If the wing is scaled down wing area would be ~223sq.ft.

 

[wuzak]

The XP-60 had a wingspan of 41' 5.25" a wing area of 275.4sq.ft. and a chord of 120"/40" root/tip. Vs the P-40 span 37' 3.5", area 236sq.ft. chord 108"/54". If the wings simply clipped wing are should be in the 255sq.ft ballpark. If the wing is scaled down wing area would be ~223sq.ft.

The XP-60C had that wing span.

 

[Graeme]

The wing of the XP-60 had a span of 45 feet 5.25 inches
The XP-60 managed a top speed of 387mph at 22,000ft.

Hi Wuzak. Greetings from the mainland!

Admittedly I'm looking at a very old edition of Wagner, but you seem to be describing the Packard version?
The whole P-60 story is a wiggling can of worms - but for this version I keep seeing a wing span of 41' 5'' or for Bowers, 41' 5 1/4".

But for your 'what if' scenario, whatever the span - just stick it on a stock standard P-40. Why reduce the span?

Cheers.

 

[wuzak]

I got the span from Joe Baugher

Empty weight was 7008 pounds, gross weight was 9277 pounds, and maximum takeoff weight was 9700 pounds. Dimensions were wingspan 45 feet 5 1/4 inches, length 33 feet 7 1/2 inches, height 12 feet 4 inches, and wing area 275 square feet.

Curtiss P-60

The wing area is quoted as the same as in your reference. Which means I was mistaken about the wingspan of the XP-60.

Baugher also has:

The XP-60A (42-79423) flew for the first time in this form on November 11, 1942. Empty weight was 7806 pounds, gross weight was 9616 pounds, and maximum takeoff weight was 10,160 pounds. Dimensions were wingspan 41 feet 3 3/4 inches, length 33 feet 7 1/2 inches, height 12 feet 4 inches, and wing area 275 square feet.

and

The XP-60C was powered by a Pratt & Whitney R-2800-53 engine delivering 2000 hp. Empty weight was 8698 pounds, gross weight was 10,785 pounds, and maximum takeoff weight was 11,835 pounds. Dimensions were wingspan 41 feet 3 3/4 inches, length 34 feet 1 inches, height 12 feet 4 inches, and wing area 275 square feet.

Why reduce wing span?

I was working on the idea that the XP-46 had the45 foot wingspan, which seemed to big for such an aircraft.

Though the 41 foot wingspan is still bigger than the P-47's the wing area was less.

So reducing the span would not be necessary.

To reframe the question - how would a P-40, with an unmodified fuselage and Allison engine, perform with the wings of the XP-60?

 

[Shortround6]

Well, one can look at the XP-60 and make a few guesses. Same engine as the P-40F, a fuselage not far removed from the P-40
It was a few mph faster than the P-40F at roughly the same altitude. Climb and ceiling were worse. Range was better due to higher internal fuel capacity.
Normal gross weight was 9,350lbs.

Trying to figure out how much of the increased speed is due to the wing, how much to the new landing gear and how much to the new nose contour and radiator (if any) is the hard part.

 

[tomo pauk]

I have nothing against the P-40 with a better wing, but P-40's problem was in front of the firewall as the war progressed.