Which US piston-fighter prototype do you like best?

[wuzak]

Northrup XP-56...

General characteristics

Crew: one, pilot
Length: 27 ft 6 in (8.38 m)
Wingspan: 42 ft 6 in (12.96 m)
Height: 11 ft 0 in (3.35 m)
Wing area: 306 ft² (28.44 m²)
Empty weight: 8,700 lb (3,955 kg)
Loaded weight: 11,350 lb (5,159 kg)
Max. takeoff weight: 12,145 lb (5,520 kg)
Powerplant: 1 × Pratt Whitney R-2800-29 radial, 2,000 hp (1,492 kW)
Performance

Maximum speed: 465 mph at 25,000 ft (749 km/h)
Range: 660 miles (1,063 km)
Service ceiling: 33,000 ft (10,061 m)
Rate of climb: 3,125 ft/min at 15,000 ft (953 m/min)
Wing loading: 37 lb/ft² (181 kg/m²)
Power/mass: 0.18 hp/lb (0.96 kW/kg)
Armament

2 × 20 mm (.79 in) cannons
4 × .50 in (12.7 mm) machine guns

Unfortunately, like my other favorite, The XP-67 Moonbat, it never fullfilled its promise,

The performance shown in that chart would only have been Northrop's predicted performance. Its actual performance was around 100mph less. I believe it was also very unstable. I have a book around here on the XP-54, XP-55 and XP-56 - but I can't find it at the moment.

Talking of unstable - two of the XP-55s crashed. The first stalled and flipped on its back during stalling tests. The engine cut out and with no forward momentum no recovery could be attempted. It fell several thousand feet vertically and landed on its back. The test pilot managed to escape - though it took him some time to get out. The other one to crash did so at an air show demonstration, hitting a car on a highway and killing (IIRC) its occupants - this is post war.

The XP-67 showed similar performance to the XP-49 - a cleaned up P-38 fitted with turbocharged Continental IV-1430s.

Specifications (XP-49)

General characteristics
Crew: One
Length: 40 ft 1 in (12.2 m)
Wingspan: 52 ft (15.8 m)
Height: 9 ft 10 in (3.0 m)
Wing area: 327.5 ft² (30 m²)
Empty weight: 15,410 lb (6990 kg)
Loaded weight: 18,750 lb (8505 kg)
Powerplant: 2 × Continental XI-1430-1 inverted V-12s, 1,600 hp (1,193 kW) each

Performance
Maximum speed: 406 mph (653 km/h) 15,000 ft (4,570 m)
Range: 679 mi (1,093 km)
Rate of climb: 3,300 ft/min (16.8 m/s)

Armament

2 × 20 mm (.79 in) cannons
4 × 0.5 in (12.7 mm) machine guns

It is unlikely that the IV-1430s ever reached their rated power in flight, and probably barely made over 1000hp.

Merlins or Allisons of 1600+hp would have been great in the XP-67. Drop the 6 x 37mm for 4 x 20mm, put in 2 stage Merlins or Allisons - or, more radically, try out some Sabres hooked up to C-series turbos (from scale drawings it looks as though those nacelles are large enough to house a Vulture (which was discontinued before the XP-67 was started, of course) or a Sabre. Imagine 4800hp in that baby instead of the 2000hp or so that they had! And with the turbo this power could be maintained to 30,000ft.

Yes, the XP-67 is it for me.

btw, the book I mentioned before

Amazon.com: American Secret Pusher Fighters of WWII: XP-54, XP-55, and XP-56 (9781580071253): Gerald H. Balzer: Books


shows a drawing of the predecessor of the XP-67 - the McDonnell Type/Model 1, with fuselage maounted single engine (V-3420, H-2600 among the options) driving a pair of wing mounted pusher props via gearboxes, right angle drives and extension shafts.

 

[R Pope]

I figure the Blackhawks knew best! They flew F5F's! Hawkaaaaaaaaa!

 

[grampi]

I'd pick one that wasn't on the list...don't know if it qualifies as a prototype, because it was a variant of a plane that was produced, but it was the P-51G...it was said to have a top speed of 500 MPH, and a climb rate of 5000+ fpm...in fact, I'm not quite sure why the P-51H was chosen over the G model as it sounds like the G was a better performer...

 

[tomo pauk]

I'd pick one that wasn't on the list...don't know if it qualifies as a prototype, because it was a variant of a plane that was produced, but it was the P-51G...it was said to have a top speed of 500 MPH, and a climb rate of 5000+ fpm...in fact, I'm not quite sure why the P-51H was chosen over the G model as it sounds like the G was a better performer...

The P-51H was the 'useful P-51G' - 150% more fuel + drop tank facility, and 50% more .50s. The speed was in the ballpark - 470+ mph for both.
link

 

[davparlr]

Old thread but I have to comment. In my opinion, one of the most impressive XP plane was the XP-72 which first flew in February, 1944. With its supercharged 3500 hp, with a future possibility of 4000 hp, it seems by all accounts, to have "displayed exceptional performance" per wikipedia and others, so much so the Air Force ordered production of 100. If aggressively pursued, it could have reasonably been a 500 mph fighter in the summer and surely fall of 1944. Changing war situation emphasized long range escort over high speed interceptors and the order was cancelled.

 

[wuzak]

Old thread but I have to comment. In my opinion, one of the most impressive XP plane was the XP-72 which first flew in February, 1944. With its supercharged 3500 hp, with a future possibility of 4000 hp, it seems by all accounts, to have "displayed exceptional performance" per wikipedia and others, so much so the Air Force ordered production of 100. If aggressively pursued, it could have reasonably been a 500 mph fighter in the summer and surely fall of 1944. Changing war situation emphasized long range escort over high speed interceptors and the order was cancelled.

Doubtful that more than a handful P-72s could be built before the end of 1944.

Also, at that stage the R-4360 was "only" producing 3,000hp. 3,500hp was a couple of years into the future and 4,000hp was some way off.

And I dare say that the advent of jets would have cut the P-72's career very short.

 

[swampyankee]

X5U was probably the most innovative piston-engined aircraft prototype of its era. That's why it got my vote.