Lockheed L-133 A & B

Sienar


I've never seen this model for the L-133, though admittedly it looks simpler than the other versions. It still looks very advanced and honestly reminds me of the Cutlass (twin tails)
 
sienar said:
From code one
Interesting bit of text with the first pic;
"The L-133 was Lockheed's initial design study for a jet propelled fighter. (...) In evolving the design, Lockheed built a similar, 3/4-scale, propeller-driven configuration (shown lower right). The design effort began in January 1942."
Does anyone know more about the demonstrator? Do any photos exist?

I was just as amazed by this piece of information as you are. Frankly, I'd never even heard of this before...
One can imagine that the work was done in high secrecy and that perhaps all information pertaining to that program has been lost.
Otherwise I cannot see why Lockheed wouldn't willingly share a pic or two of that demonstrator 70 years down the line...
 

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A clue to the missing link here is provided in AAHS Journal Vol 44 no. 1, in "The Lockheeds that Never Were" by Bill Slayton. Two Lockheed drawings, labeled L-133-02 and L-133-5, are reproduced. Slayton writes re L-133: "To test the general configuration, a similar but smaller propeller-driven aircraft was built and successfully flown in late 1942." As you see, the "L-133-5" bears a certain resemblance to the Curtiss CW-24B. I'm thinking Lockheed bought data from Curtiss rather than build their own testbed.


--Ian
 

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The L-133-5 design is reminiscent to the Curtiss CW-29B flying mockup of the CW-29 or XP-55 Ascender. -SP
 
Steve Pace said:
The L-133-5 design is reminiscent to the Curtiss CW-29B flying mockup of the CW-29 or XP-55 Ascender. -SP

You mean the CW-24B mockup of the CW-24 Ascender.

CW-29 was the XP-87.
 
I have attempted to compare the L-133-5 and the CW-24B and to determine whether there were more commonalities than differences. Please note that I didn't try to put both plans in the same scale but to make the shapes coincide as best as possible by retaining the fuselage length from one end of the thrust line to the other.

First image compares the L-133-5 with the CW-24B in its first configuration (definitely the closest) while the second image compares it with the modified one.

The general configuration of the two designs are remarkably similar. Here is a small recap of what's different and what's the same:

DIFFERENT
  • Completely different canard shape
  • Greater wing sweep on the L-133-5
  • Narrower wings on L-133-5
  • A little more dihedral on L-133-5
  • Slightly longer wings on the L-133-5
  • Rounded off wing tips on the L-133-5
  • Fuselage considerably narrower on the L-133-5 and presenting a circular section
  • Wing roots blend into fuselage on CW-24B, not on L-133-5
  • Wing roots of L-133-5 more cranked on trailing edge
  • Wheels of main undercarriage closer to fuselage on L-133-5
  • Higher undercarriage on CW-24B
SAME
  • General configuration
  • Fuselage rear fin shape and arrangement, extending above and below fuselage in a trapezoidal shape
  • Eye-like shape of wingtip fins
Despite the many small differences, the commonalities are so obvious that it is more than likely that the two projects are two close stages in the same development phase. The Lockheed plan seems earlier and less thought out than the Curtiss one, which corrects issues such as insufficient height of undercarriage and size of cockpit.

Either Lockheed got wind of Curtiss's efforts and copied their design or (more likely) this is simply Lockheed allocating dash numbers, within a general "L-133" project, to noteworthy competing programs, as Orionblamblam showed us was current practice at Lockheed a couple of days ago in another thread.
Besides, the Lockheed document posted by CodeOne shows a different bird. Therefore I believe there were both a Curtiss prototype and a Lockheed prototype (both company-built and unrelated). There is NO indication that L-133-5 was the configuration of the built prototype, is there, Apteryx?
Because if there was, and the L-133-5 was the final configuration chosen by Lockheed for their prototype, we should therefore consider that the CW-24B was initially a Lockheed product that was passed over to Curtiss!!! I don't personally see this as very likely, if only because the design evolution of the CW-24B through the P-244 and P-249 design proposals is well-documented. Thoughts, anyone?

As a footnote, I'm attaching Lockheed's other canard effort of the same era, the Model 30 twin-pusher canard bomber project.
 

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Stargazer2006 said:
Either Lockheed got wind of Curtiss's efforts and copied their design or (more likely) this is simply Lockheed allocating dash numbers, within a general "L-133" project, to noteworthy competing programs, as Orionblamblam showed us was current practice at Lockheed a couple of days ago in another thread.
Besides, the Lockheed document posted by CodeOne shows a different bird. Therefore I believe there were both a Curtiss prototype and a Lockheed prototype (both company-built and unrelated). There is NO indication that L-133-5 was the configuration of the built prototype, is there, Apteryx?
Because if there was, and the L-133-5 was the final configuration chosen by Lockheed for their prototype, we should therefore consider that the CW-24B was initially a Lockheed product that was passed over to Curtiss!!! I don't personally see this as very likely, if only because the design evolution of the CW-24B through the P-244 and P-249 design proposals is well-documented. Thoughts, anyone?


Stargazer, the Slayton article doesn't link the L-133-5 drawing to the article in any more definite way, no. It should be noted that the CW-24B first flew on December 2, 1941, after a fair amount of development and wind-tunnel work had already been done on the concept by Curtiss. So I don't think the plane originated with Lockheed. I have done my own comparison between drawings, see below--this shows the L-133-5 overlaid on a CW-24B drawing from the AAHS article on the XP-55 by Gerald Balzer (Vol. 41 no. 2). It is described as being a Curtiss-Wright factory drawing; I removed a great many notes and dimension lines for clarity. Note: the CW-24B version shown is actually the FIRST configuration, not the second. I tried to match scales on the two. IMO, the drawings, though not agreeing perfectly, depict the same airplane.
 

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I feel compelled to point out Evan already posted CodeOne's L133 drawing in 2009 here:


http://www.secretprojects.co.uk/forum/index.php/topic,7508.msg75308.html#msg75308


Also CodeOne's post is almost certainly based on info from Bill Slayton's unpublished manuscript (excerpts of which were published in AAHS Journal) so its Bill Slayton's assertion only that a demonstrator was built and flown in 1942.


Gerald Balzer wrote a book on the pusher designs (http://www.specialtypress.com/vstore/showdetl.cfm?DID=8&Product_ID=1847&CATID=1) and would presumably know if there was a connection. I think that L-133 was probably designed to the same 1940 requirement as the XP-54, XP-55, XP-56 and L-133-5 is just Lockheed's analysis of a competing design.
 
After doing some searchwork about in the past weeks ,I don't think that
the Curtiss CW-24B was related to the Lockheed L-133.

The CW-24B was in fact not a true canard but more a flying wing
with a moveable foreplane.
If one compares the planview of both designs ,but for the forward placed airofoils
there is no further resemblence.

In the excellent article about the L-133 by Will Hawkins-AirClassics Feb.2013- based on
the journal of his father Willis Hawkins,at the time ,head of Lockheed's Preliminary Design Dept. and
the newly formed Advaced Concepts Group , there is not a single mention regarding the CW-24B.

The two other Lockheed canard designs related to the L-133 (the piston- and the jetpowered concepts) were seen
as alternatives for the L-133. Less advanced they responded to an RFP for
a dedicated ground attack/tankbuster aircraft.
The Advanced Concepts team labeled this two designs ' The Finagler' .
Not much evidence is left of their existence other than the
original Hawkins illustration dated 11March 1942.

P.S. Curiss had it's on jetpowerd canard designs in the P-304-4 and P-304-5 concepts of March 1945.
 
I agree with lark's data.

I think that L-133 was probably designed to the same 1940 requirement as the XP-54, XP-55, XP-56

Lockheed L-133 was not related with Request for data R-40C submissions.
 
Flateric

Original Lockheed's cutaway of L-133 ca.1941
Lockheed Horizons, Issue 8
I'm wondering if the suck-in-door structures located on the aft fuselage above and below the engines were designed not just to improve afterburner performance, but some attempt to skim off turbulent flow (due to shockwave formation) off the wing).

I've been doing some searches under patents under Nathan C. Price's name and I found this one: http://www.google.com/patents/US2514513

The idea predominantly focuses around removing turbulent air for high speed flight (then high subsonic or low supersonic speed), and the engine matches the 1942-1943 era L-1000 design (axial flow compressor feeding a 3-stage centrifugal flow compressor with intercooling)


Stargazer2006

Am I correct in my understanding that the L-133-5 has nothing to do with the L-133 Jet Fighter?
 
I'd really love to see more detailing of the main landing gear arrangement.

It's apparent that the main wheels pivoted together on a sort of trapeze affair that then folded itself into the fuselage. It was anything but conventional and more reminiscent of the method the F/B-111 uses.

Yet, details of it are pretty scarce.
 
"After doing some searchwork about in the past weeks ,I don't think that
the Curtiss CW-24B was related to the Lockheed L-133.

The CW-24B was in fact not a true canard but more a flying wing
with a moveable foreplane.
If one compares the planview of both designs ,but for the forward placed airofoils
there is no further resemblence. ... "

Remember that both CW-24 and the Japanese Shinden pseudo-canards were both plagued by severe stability and control problems. Half of their problems were caused by centers-of-gravity too far aft. Curtiss-Wright cancelled their full-sized prototypes after too many crashes. CW-24 suffered flat spins when the rear/outer wing panels stalled before the center sections. A large part of the problem was turbulent, stalled airflow migrating along the swept leading edge to fully stall outer wing panels before wing roots fully stalled. This loss of lift caused them to pitch nose-up, keeping them in deep stalls and unrecoverable flat spins.

It was not until SAAB and Rutan started heavily-loading canard (lifting surfaces) that they solved the stability and control problems. Heavily-loaded, lifting canards stall first, pitching the airplanes nose down. They also install vortilons, fences, to prevent wing tips from stalling before center-sections.
While many modern canard-deltas (Dassault Rafale, Eurofighter Typhoon, SAAB Grippen, etc.) use rear centers-of-gravity to un-load canards, they also depend upon electronic stability augmentation to maintain stability.
 
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On 27 November, 1939 the USAAC announced the competition ‘Request for data R-40C’ for a very high performance fighter that should be equal to the new European models, to be built in 1941.

The Air Corps Interceptor Pursuit Specification XC-622, required:

Single-engine, single-seater with a top speed of at least 425 mph at 20,000 ft, sufficient to attack or leave combat area at will.

Seven minutes to climb to 20,000 ft.

Good pilot visibility

Four guns armament

Enough maneuverability

One and half hours endurance

The 2,000 hp, 24 cylinder ‘H’, liquid-cooled Pratt & Whitney X-1800-A3G engine was initially proposed.

Curtiss proposed the P-248-01design, an Allison powered CW-21 Demon and the CW-24, an unorthodox tailless-canard fighter, with 45 degrees swept-back wings and pusher propeller.

Around fifty projects were presented by nine different companies. By the end of 1940 six of them had been selected: Vultee (XP-54), Curtiss Wright CW-24 (XP-55), Northrop (XP-56), MacDonnell (Mod 1), Republic (AP-12) and Bell (Mod 13).

The first three qualified ones were never mass manufactured because they were of a too radical pusher design, making a failure of the whole $ 6,000,000 programme.

Throughout aviation history there have been designs of the canard or ‘tail-first’ types as an alternative to the conventional ‘engine-first’ configuration. However, in spite of the creativity of designers, manufacturers have systematically left aside the mass production of such solutions. When the second generation of fighters designed during the Second World War started to experiment serious aerodynamic problems, due to the transonic flux, they made several tries to solve them using the canard configuration eliminating airscrew slipstream effects on aircraft drag.

With this new configuration the designers tried to elude the problem of compressibility buffeting by installing the wing behind the center of gravity.

The British firm Miles built and fly tested the M.35 and M.39B prototypes as technological demonstrators of the M.39 bomber.

The German Henschel designed the heavy fighter named P.75 that should be propelled by a DB 613 A/B coupled engine and which mass production was abandoned in favor of the Dornier Do 335.

Several prototypes of canard fighters were built in Italy and USA.

The canard formula had many advantages for the design of fighters; the armament could be grouped around the nose without any hindrance by either the engine or the propeller and it was very easily accessible for maintenance, ground visibility was considerably improved and it was easier to install a tricycle type undercarriage.

The nose foreplanes had been found to serve the purpose of improving take-off performance and low speed control.

The engine, located behind the pilot, acted as protection against the rear impacts and, in the event of a fire, flames did not go to the cockpit as used to happen with the classical designs. Besides, being joined to the main spar meant less weight and stronger structural sturdiness.

In combat, an enemy pilot not familiar with the new configuration could easily mistake the direction to which the canard fighter moved during the deflection aiming. Same tactic is used by some tropical fishes that have a spot in the shape of a false eye near the tail to confuse their predators.

Only two inconveniencies marred all the advantages: the difficulty to refrigerate the engine and the baling out, due to the position of the pusher airscrews. At a time when ejector seats did not yet exist, the solution was to install an explosive device to detach the propeller in case of emergency.

Early in 1939 the Italians built the Ambrosini S.S.4 a canard prototype fighter powered by one 960 hp Isotta Fraschini Asso XI RC.40 engine. The airplane was destroyed in 1941 due to a problem of vibration of the engine mount and the project was cancelled.

On 22 June 1940 the USAAC signed a contract for preliminary development of the Curtiss CW-24 and construction of a wind tunnel model, under the designation XP-55.

Such a radical configuration required the construction of the CW-24B, a flying testbed to prove the design viability.

On 21 December 1941 the CW-24B made its first flight, at Muroc Dry Lake test center, powered by a 275 hp Menasco C-6S-5 engine.

Despite the strong security measures, intelligence services of the IJN obtained enough information about the project to believe that it was the successor of the Curtiss P-40 fighter. Early in 1943 Lieutenant Commander Masaoki Tsuruno, of the First Naval Air Technical Arsenal, proposed the construction of the canard fighter 18-shi-Otsu J7W Shinden based on the information obtained on the XP-55.

In fact, the definitive Curtiss XP-55 version was not selected by USAAC for production and only three prototypes were built, two of which were destroyed in accidents.

On 10 July 1942 the USAAF ordered three prototypes, the 42-78845 flew on 13 July 1943 powered by one 1,425 Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

The aircraft was fitted with laminar-flow swept wings angled back 45 degrees and tricycle undercarriage.

USAAF was unimpressed with the 377 mph top speed reached with the Allison engine versus the 507 mph promised with the X-1800 cancelled in October 1940.

The first prototype showed excessive take off run, dangerous stall behaviour, poor longitudinal stability, low-speed handling problems and engine overheating.

On 15 November 1943 the plane was lost, in an inverted spin, when the engine failed.

The second prototype 42-78846 flew on 9 January 1944 suffering from ‘no-warning before stalling’ phenomena. To improve the stall characteristics the nose elevator and the aileron tabs were modified.

The third prototype 42-78847 was flown on 25 April 1944, fitted with wing extensions and modified nose elevator and armed with four 0.50 cal nose mounted machine guns.

On 27 May 1945 the aircraft crashed when the pilot attempted a barrel roll.

Americans were not lucky with the Curtiss XP-55, after four years of flight testing they have not achieved an airplane sufficiently stable to take part in combat operations.

Although it was less sensible to the compressibility buffeting than conventional airplanes, thanks to a NACA 0015 type wing profile, it was also too heavy and slower than the P-47 and P-51 in service.



Curtiss XP-55 technical data

Power plant: one 1,425 hp Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

Wingspan: 44.5 ft (13.56 m), length: 29.6 ft (9.02 m), height: 10 ft (3.05 m), wing area: 235 sq. ft (21.83 sq. m), max speed: 390 mph (630 kph), max weight: 7,330 lbs (3,324 kg), service ceiling: 34,600 ft (10,550 m), armament: six 0.50 cal M2 heavy machine guns.

Before cancelling the project, the Curtiss firm proposed the production of a jet version based on the original P 249-C project, known in the specialized literature as P 286-17 or CW 24-C. It would have been propelled by a centrifugal De Havilland H-1B Goblin turbojet with a fuel tank of 1,059 lt., located behind the pilot, and armed with four 0.50 cal M2 machine guns. Its mass production was abandoned in favor of the Lockheed P-80.

On 31 March 1945 Curtiss proposed two versions of the P-304 a single-jet, medium-range fighter specifically designed to overcome the effects of compressibility, using the accumulated knowledge from the XP-55 programme.



Curtiss CW 24-C technical data

Power plant: de Havilland H-1B Goblin turbojet with 2,460 lbs (1,114 kgf) static thrust.

Wingspan: 39.36 ft (12 m), length: 28.10 ft (8.57 m), height: 9 ft (2.74 m), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-4 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.8 ft (10.3 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq. m), max weight: 14,470 lbs (6,564 kg), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-5 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.4 ft (10.21 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq .m), estimated max speed: 622 mph (1,001 kph) at 10,000 ft, estimated climb rate: 5,530 ft/min, max weight: 14,170 lbs (6,428 kg), combat radius: 500 miles (805 km), armament: four 0.50 cal M2 heavy machine guns.
 

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In 1939 Lockheed Aircraft Co. started the design of the first U.S. jet fighter.

The new airplane was powered by two Lockheed L-1000 turbojets with axial-flow compressor, intercooler, multi-stage turbine, 5,100 lbs (2,310 kg) static thrust and 6,700 lbs (3,035 kg) with afterburner.

The design team proposed three possible configurations: Model A, with the engines buried into the wing roots, Model B, with the engines housed in mid-fuselage and Model C, with the engines mounted in the rear fuselage.

The L-133-02-01, a variant of the Model C, was proposed to the USAAF on March 1942.

The L-133 had stainless steel airframe and 6 per cent thickness/chord wings, with hydraulically-assisted control surfaces and slotted flaps.

The engines would be fed by two long ducts emanating from the nose air-intake and four suck-in inlets were located above and below of the turbojets for laminar-flow control.

In 1942 the L-1000 turbojet was technologically superior to the centrifugal engines of its time, but harder to manufacture.

Lockheed facilities are not adequate for engineering and manufacture of turbojets, in 1943 the USAAF transferred the development of the L-1000, as XJ-37, to Menasco Manufacturing Company and Wright Aeronautical Corporation.

The low-priority of the project delayed the development of the XJ-37 that never materialized as a production turbojet.

L-133 technical data

Power plant: two Lockheed L-1000 axial-flow turbojets with 5,100 lbs (2,310 kg) static thrust, wingspan: 46.7 ft. (14.22 m), length: 48.3 ft. (14.22 m), height: 14.7 ft. (4.47 m), wing surface: 325 sq. ft. (30.19 m), maximum weight: 18,000 lbs (8,154 kg), estimated maximum speed: 612 mph (985 km/h), estimated ceiling: 40,000 ft. (12,200 m), range: 310 mls (500 km) with 500 gallons of fuel housed in three fuselage tanks, armament: four nose mounted 0.50 cal machine guns with 400 rpg. or four 20 mm cannon with 60 rpg.

In June 1943 it became clear that the development of the L-1000 axial-flow engine required more time and resources than expected and that the prototype would not be available until June 1946. The Lockheed design team began work on a new version of the L-133 fighter powered by one British centrifugal turbojet.

Knowing the poor results obtained by the Curtiss XP-55 during flying tests the USAAF decided not to accept any other canard design and the L-133 configuration was dropped in favour of the L-140 project, with conventional airframe and the laminar-flow wings of the L-133, under the designation XP-80.
 

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On 27 November, 1939 the USAAC announced the competition ‘Request for data R-40C’ for a very high performance fighter that should be equal to the new European models, to be built in 1941.

The Air Corps Interceptor Pursuit Specification XC-622, required:

Single-engine, single-seater with a top speed of at least 425 mph at 20,000 ft, sufficient to attack or leave combat area at will.

Seven minutes to climb to 20,000 ft.

Good pilot visibility

Four guns armament

Enough maneuverability

One and half hours endurance

The 2,000 hp, 24 cylinder ‘H’, liquid-cooled Pratt & Whitney X-1800-A3G engine was initially proposed.

Curtiss proposed the P-248-01design, an Allison powered CW-21 Demon and the CW-24, an unorthodox tailless-canard fighter, with 45 degrees swept-back wings and pusher propeller.

Around fifty projects were presented by nine different companies. By the end of 1940 six of them had been selected: Vultee (XP-54), Curtiss Wright CW-24 (XP-55), Northrop (XP-56), MacDonnell (Mod 1), Republic (AP-12) and Bell (Mod 13).

The first three qualified ones were never mass manufactured because they were of a too radical pusher design, making a failure of the whole $ 6,000,000 programme.

Throughout aviation history there have been designs of the canard or ‘tail-first’ types as an alternative to the conventional ‘engine-first’ configuration. However, in spite of the creativity of designers, manufacturers have systematically left aside the mass production of such solutions. When the second generation of fighters designed during the Second World War started to experiment serious aerodynamic problems, due to the transonic flux, they made several tries to solve them using the canard configuration eliminating airscrew slipstream effects on aircraft drag.

With this new configuration the designers tried to elude the problem of compressibility buffeting by installing the wing behind the center of gravity.

The British firm Miles built and fly tested the M.35 and M.39B prototypes as technological demonstrators of the M.39 bomber.

The German Henschel designed the heavy fighter named P.75 that should be propelled by a DB 613 A/B coupled engine and which mass production was abandoned in favor of the Dornier Do 335.

Several prototypes of canard fighters were built in Italy and USA.

The canard formula had many advantages for the design of fighters; the armament could be grouped around the nose without any hindrance by either the engine or the propeller and it was very easily accessible for maintenance, ground visibility was considerably improved and it was easier to install a tricycle type undercarriage.

The nose foreplanes had been found to serve the purpose of improving take-off performance and low speed control.

The engine, located behind the pilot, acted as protection against the rear impacts and, in the event of a fire, flames did not go to the cockpit as used to happen with the classical designs. Besides, being joined to the main spar meant less weight and stronger structural sturdiness.

In combat, an enemy pilot not familiar with the new configuration could easily mistake the direction to which the canard fighter moved during the deflection aiming. Same tactic is used by some tropical fishes that have a spot in the shape of a false eye near the tail to confuse their predators.

Only two inconveniencies marred all the advantages: the difficulty to refrigerate the engine and the baling out, due to the position of the pusher airscrews. At a time when ejector seats did not yet exist, the solution was to install an explosive device to detach the propeller in case of emergency.

Early in 1939 the Italians built the Ambrosini S.S.4 a canard prototype fighter powered by one 960 hp Isotta Fraschini Asso XI RC.40 engine. The airplane was destroyed in 1941 due to a problem of vibration of the engine mount and the project was cancelled.

On 22 June 1940 the USAAC signed a contract for preliminary development of the Curtiss CW-24 and construction of a wind tunnel model, under the designation XP-55.

Such a radical configuration required the construction of the CW-24B, a flying testbed to prove the design viability.

On 21 December 1941 the CW-24B made its first flight, at Muroc Dry Lake test center, powered by a 275 hp Menasco C-6S-5 engine.

Despite the strong security measures, intelligence services of the IJN obtained enough information about the project to believe that it was the successor of the Curtiss P-40 fighter. Early in 1943 Lieutenant Commander Masaoki Tsuruno, of the First Naval Air Technical Arsenal, proposed the construction of the canard fighter 18-shi-Otsu J7W Shinden based on the information obtained on the XP-55.

In fact, the definitive Curtiss XP-55 version was not selected by USAAC for production and only three prototypes were built, two of which were destroyed in accidents.

On 10 July 1942 the USAAF ordered three prototypes, the 42-78845 flew on 13 July 1943 powered by one 1,425 Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

The aircraft was fitted with laminar-flow swept wings angled back 45 degrees and tricycle undercarriage.

USAAF was unimpressed with the 377 mph top speed reached with the Allison engine versus the 507 mph promised with the X-1800 cancelled in October 1940.

The first prototype showed excessive take off run, dangerous stall behaviour, poor longitudinal stability, low-speed handling problems and engine overheating.

On 15 November 1943 the plane was lost, in an inverted spin, when the engine failed.

The second prototype 42-78846 flew on 9 January 1944 suffering from ‘no-warning before stalling’ phenomena. To improve the stall characteristics the nose elevator and the aileron tabs were modified.

The third prototype 42-78847 was flown on 25 April 1944, fitted with wing extensions and modified nose elevator and armed with four 0.50 cal nose mounted machine guns.

On 27 May 1945 the aircraft crashed when the pilot attempted a barrel roll.

Americans were not lucky with the Curtiss XP-55, after four years of flight testing they have not achieved an airplane sufficiently stable to take part in combat operations.

Although it was less sensible to the compressibility buffeting than conventional airplanes, thanks to a NACA 0015 type wing profile, it was also too heavy and slower than the P-47 and P-51 in service.



Curtiss XP-55 technical data

Power plant: one 1,425 hp Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

Wingspan: 44.5 ft (13.56 m), length: 29.6 ft (9.02 m), height: 10 ft (3.05 m), wing area: 235 sq. ft (21.83 sq. m), max speed: 390 mph (630 kph), max weight: 7,330 lbs (3,324 kg), service ceiling: 34,600 ft (10,550 m), armament: six 0.50 cal M2 heavy machine guns.

Before cancelling the project, the Curtiss firm proposed the production of a jet version based on the original P 249-C project, known in the specialized literature as P 286-17 or CW 24-C. It would have been propelled by a centrifugal De Havilland H-1B Goblin turbojet with a fuel tank of 1,059 lt., located behind the pilot, and armed with four 0.50 cal M2 machine guns. Its mass production was abandoned in favor of the Lockheed P-80.

On 31 March 1945 Curtiss proposed two versions of the P-304 a single-jet, medium-range fighter specifically designed to overcome the effects of compressibility, using the accumulated knowledge from the XP-55 programme.



Curtiss CW 24-C technical data

Power plant: de Havilland H-1B Goblin turbojet with 2,460 lbs (1,114 kgf) static thrust.

Wingspan: 39.36 ft (12 m), length: 28.10 ft (8.57 m), height: 9 ft (2.74 m), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-4 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.8 ft (10.3 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq. m), max weight: 14,470 lbs (6,564 kg), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-5 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.4 ft (10.21 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq .m), estimated max speed: 622 mph (1,001 kph) at 10,000 ft, estimated climb rate: 5,530 ft/min, max weight: 14,170 lbs (6,428 kg), combat radius: 500 miles (805 km), armament: four 0.50 cal M2 heavy machine guns.
Stunning artwork.
 

On 27 November, 1939 the USAAC announced the competition ‘Request for data R-40C’ for a very high performance fighter that should be equal to the new European models, to be built in 1941.

The Air Corps Interceptor Pursuit Specification XC-622, required:

Single-engine, single-seater with a top speed of at least 425 mph at 20,000 ft, sufficient to attack or leave combat area at will.

Seven minutes to climb to 20,000 ft.

Good pilot visibility

Four guns armament

Enough maneuverability

One and half hours endurance

The 2,000 hp, 24 cylinder ‘H’, liquid-cooled Pratt & Whitney X-1800-A3G engine was initially proposed.

Curtiss proposed the P-248-01design, an Allison powered CW-21 Demon and the CW-24, an unorthodox tailless-canard fighter, with 45 degrees swept-back wings and pusher propeller.

Around fifty projects were presented by nine different companies. By the end of 1940 six of them had been selected: Vultee (XP-54), Curtiss Wright CW-24 (XP-55), Northrop (XP-56), MacDonnell (Mod 1), Republic (AP-12) and Bell (Mod 13).

The first three qualified ones were never mass manufactured because they were of a too radical pusher design, making a failure of the whole $ 6,000,000 programme.

Throughout aviation history there have been designs of the canard or ‘tail-first’ types as an alternative to the conventional ‘engine-first’ configuration. However, in spite of the creativity of designers, manufacturers have systematically left aside the mass production of such solutions. When the second generation of fighters designed during the Second World War started to experiment serious aerodynamic problems, due to the transonic flux, they made several tries to solve them using the canard configuration eliminating airscrew slipstream effects on aircraft drag.

With this new configuration the designers tried to elude the problem of compressibility buffeting by installing the wing behind the center of gravity.

The British firm Miles built and fly tested the M.35 and M.39B prototypes as technological demonstrators of the M.39 bomber.

The German Henschel designed the heavy fighter named P.75 that should be propelled by a DB 613 A/B coupled engine and which mass production was abandoned in favor of the Dornier Do 335.

Several prototypes of canard fighters were built in Italy and USA.

The canard formula had many advantages for the design of fighters; the armament could be grouped around the nose without any hindrance by either the engine or the propeller and it was very easily accessible for maintenance, ground visibility was considerably improved and it was easier to install a tricycle type undercarriage.

The nose foreplanes had been found to serve the purpose of improving take-off performance and low speed control.

The engine, located behind the pilot, acted as protection against the rear impacts and, in the event of a fire, flames did not go to the cockpit as used to happen with the classical designs. Besides, being joined to the main spar meant less weight and stronger structural sturdiness.

In combat, an enemy pilot not familiar with the new configuration could easily mistake the direction to which the canard fighter moved during the deflection aiming. Same tactic is used by some tropical fishes that have a spot in the shape of a false eye near the tail to confuse their predators.

Only two inconveniencies marred all the advantages: the difficulty to refrigerate the engine and the baling out, due to the position of the pusher airscrews. At a time when ejector seats did not yet exist, the solution was to install an explosive device to detach the propeller in case of emergency.

Early in 1939 the Italians built the Ambrosini S.S.4 a canard prototype fighter powered by one 960 hp Isotta Fraschini Asso XI RC.40 engine. The airplane was destroyed in 1941 due to a problem of vibration of the engine mount and the project was cancelled.

On 22 June 1940 the USAAC signed a contract for preliminary development of the Curtiss CW-24 and construction of a wind tunnel model, under the designation XP-55.

Such a radical configuration required the construction of the CW-24B, a flying testbed to prove the design viability.

On 21 December 1941 the CW-24B made its first flight, at Muroc Dry Lake test center, powered by a 275 hp Menasco C-6S-5 engine.

Despite the strong security measures, intelligence services of the IJN obtained enough information about the project to believe that it was the successor of the Curtiss P-40 fighter. Early in 1943 Lieutenant Commander Masaoki Tsuruno, of the First Naval Air Technical Arsenal, proposed the construction of the canard fighter 18-shi-Otsu J7W Shinden based on the information obtained on the XP-55.

In fact, the definitive Curtiss XP-55 version was not selected by USAAC for production and only three prototypes were built, two of which were destroyed in accidents.

On 10 July 1942 the USAAF ordered three prototypes, the 42-78845 flew on 13 July 1943 powered by one 1,425 Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

The aircraft was fitted with laminar-flow swept wings angled back 45 degrees and tricycle undercarriage.

USAAF was unimpressed with the 377 mph top speed reached with the Allison engine versus the 507 mph promised with the X-1800 cancelled in October 1940.

The first prototype showed excessive take off run, dangerous stall behaviour, poor longitudinal stability, low-speed handling problems and engine overheating.

On 15 November 1943 the plane was lost, in an inverted spin, when the engine failed.

The second prototype 42-78846 flew on 9 January 1944 suffering from ‘no-warning before stalling’ phenomena. To improve the stall characteristics the nose elevator and the aileron tabs were modified.

The third prototype 42-78847 was flown on 25 April 1944, fitted with wing extensions and modified nose elevator and armed with four 0.50 cal nose mounted machine guns.

On 27 May 1945 the aircraft crashed when the pilot attempted a barrel roll.

Americans were not lucky with the Curtiss XP-55, after four years of flight testing they have not achieved an airplane sufficiently stable to take part in combat operations.

Although it was less sensible to the compressibility buffeting than conventional airplanes, thanks to a NACA 0015 type wing profile, it was also too heavy and slower than the P-47 and P-51 in service.



Curtiss XP-55 technical data

Power plant: one 1,425 hp Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

Wingspan: 44.5 ft (13.56 m), length: 29.6 ft (9.02 m), height: 10 ft (3.05 m), wing area: 235 sq. ft (21.83 sq. m), max speed: 390 mph (630 kph), max weight: 7,330 lbs (3,324 kg), service ceiling: 34,600 ft (10,550 m), armament: six 0.50 cal M2 heavy machine guns.

Before cancelling the project, the Curtiss firm proposed the production of a jet version based on the original P 249-C project, known in the specialized literature as P 286-17 or CW 24-C. It would have been propelled by a centrifugal De Havilland H-1B Goblin turbojet with a fuel tank of 1,059 lt., located behind the pilot, and armed with four 0.50 cal M2 machine guns. Its mass production was abandoned in favor of the Lockheed P-80.

On 31 March 1945 Curtiss proposed two versions of the P-304 a single-jet, medium-range fighter specifically designed to overcome the effects of compressibility, using the accumulated knowledge from the XP-55 programme.



Curtiss CW 24-C technical data

Power plant: de Havilland H-1B Goblin turbojet with 2,460 lbs (1,114 kgf) static thrust.

Wingspan: 39.36 ft (12 m), length: 28.10 ft (8.57 m), height: 9 ft (2.74 m), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-4 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.8 ft (10.3 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq. m), max weight: 14,470 lbs (6,564 kg), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-5 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.4 ft (10.21 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq .m), estimated max speed: 622 mph (1,001 kph) at 10,000 ft, estimated climb rate: 5,530 ft/min, max weight: 14,170 lbs (6,428 kg), combat radius: 500 miles (805 km), armament: four 0.50 cal M2 heavy machine guns.
Stunning artwork.
Thank you for a wealth of valuable information. Much appreciated.
 

On 27 November, 1939 the USAAC announced the competition ‘Request for data R-40C’ for a very high performance fighter that should be equal to the new European models, to be built in 1941.

The Air Corps Interceptor Pursuit Specification XC-622, required:

Single-engine, single-seater with a top speed of at least 425 mph at 20,000 ft, sufficient to attack or leave combat area at will.

Seven minutes to climb to 20,000 ft.

Good pilot visibility

Four guns armament

Enough maneuverability

One and half hours endurance

The 2,000 hp, 24 cylinder ‘H’, liquid-cooled Pratt & Whitney X-1800-A3G engine was initially proposed.

Curtiss proposed the P-248-01design, an Allison powered CW-21 Demon and the CW-24, an unorthodox tailless-canard fighter, with 45 degrees swept-back wings and pusher propeller.

Around fifty projects were presented by nine different companies. By the end of 1940 six of them had been selected: Vultee (XP-54), Curtiss Wright CW-24 (XP-55), Northrop (XP-56), MacDonnell (Mod 1), Republic (AP-12) and Bell (Mod 13).

The first three qualified ones were never mass manufactured because they were of a too radical pusher design, making a failure of the whole $ 6,000,000 programme.

Throughout aviation history there have been designs of the canard or ‘tail-first’ types as an alternative to the conventional ‘engine-first’ configuration. However, in spite of the creativity of designers, manufacturers have systematically left aside the mass production of such solutions. When the second generation of fighters designed during the Second World War started to experiment serious aerodynamic problems, due to the transonic flux, they made several tries to solve them using the canard configuration eliminating airscrew slipstream effects on aircraft drag.

With this new configuration the designers tried to elude the problem of compressibility buffeting by installing the wing behind the center of gravity.

The British firm Miles built and fly tested the M.35 and M.39B prototypes as technological demonstrators of the M.39 bomber.

The German Henschel designed the heavy fighter named P.75 that should be propelled by a DB 613 A/B coupled engine and which mass production was abandoned in favor of the Dornier Do 335.

Several prototypes of canard fighters were built in Italy and USA.

The canard formula had many advantages for the design of fighters; the armament could be grouped around the nose without any hindrance by either the engine or the propeller and it was very easily accessible for maintenance, ground visibility was considerably improved and it was easier to install a tricycle type undercarriage.

The nose foreplanes had been found to serve the purpose of improving take-off performance and low speed control.

The engine, located behind the pilot, acted as protection against the rear impacts and, in the event of a fire, flames did not go to the cockpit as used to happen with the classical designs. Besides, being joined to the main spar meant less weight and stronger structural sturdiness.

In combat, an enemy pilot not familiar with the new configuration could easily mistake the direction to which the canard fighter moved during the deflection aiming. Same tactic is used by some tropical fishes that have a spot in the shape of a false eye near the tail to confuse their predators.

Only two inconveniencies marred all the advantages: the difficulty to refrigerate the engine and the baling out, due to the position of the pusher airscrews. At a time when ejector seats did not yet exist, the solution was to install an explosive device to detach the propeller in case of emergency.

Early in 1939 the Italians built the Ambrosini S.S.4 a canard prototype fighter powered by one 960 hp Isotta Fraschini Asso XI RC.40 engine. The airplane was destroyed in 1941 due to a problem of vibration of the engine mount and the project was cancelled.

On 22 June 1940 the USAAC signed a contract for preliminary development of the Curtiss CW-24 and construction of a wind tunnel model, under the designation XP-55.

Such a radical configuration required the construction of the CW-24B, a flying testbed to prove the design viability.

On 21 December 1941 the CW-24B made its first flight, at Muroc Dry Lake test center, powered by a 275 hp Menasco C-6S-5 engine.

Despite the strong security measures, intelligence services of the IJN obtained enough information about the project to believe that it was the successor of the Curtiss P-40 fighter. Early in 1943 Lieutenant Commander Masaoki Tsuruno, of the First Naval Air Technical Arsenal, proposed the construction of the canard fighter 18-shi-Otsu J7W Shinden based on the information obtained on the XP-55.

In fact, the definitive Curtiss XP-55 version was not selected by USAAC for production and only three prototypes were built, two of which were destroyed in accidents.

On 10 July 1942 the USAAF ordered three prototypes, the 42-78845 flew on 13 July 1943 powered by one 1,425 Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

The aircraft was fitted with laminar-flow swept wings angled back 45 degrees and tricycle undercarriage.

USAAF was unimpressed with the 377 mph top speed reached with the Allison engine versus the 507 mph promised with the X-1800 cancelled in October 1940.

The first prototype showed excessive take off run, dangerous stall behaviour, poor longitudinal stability, low-speed handling problems and engine overheating.

On 15 November 1943 the plane was lost, in an inverted spin, when the engine failed.

The second prototype 42-78846 flew on 9 January 1944 suffering from ‘no-warning before stalling’ phenomena. To improve the stall characteristics the nose elevator and the aileron tabs were modified.

The third prototype 42-78847 was flown on 25 April 1944, fitted with wing extensions and modified nose elevator and armed with four 0.50 cal nose mounted machine guns.

On 27 May 1945 the aircraft crashed when the pilot attempted a barrel roll.

Americans were not lucky with the Curtiss XP-55, after four years of flight testing they have not achieved an airplane sufficiently stable to take part in combat operations.

Although it was less sensible to the compressibility buffeting than conventional airplanes, thanks to a NACA 0015 type wing profile, it was also too heavy and slower than the P-47 and P-51 in service.



Curtiss XP-55 technical data

Power plant: one 1,425 hp Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

Wingspan: 44.5 ft (13.56 m), length: 29.6 ft (9.02 m), height: 10 ft (3.05 m), wing area: 235 sq. ft (21.83 sq. m), max speed: 390 mph (630 kph), max weight: 7,330 lbs (3,324 kg), service ceiling: 34,600 ft (10,550 m), armament: six 0.50 cal M2 heavy machine guns.

Before cancelling the project, the Curtiss firm proposed the production of a jet version based on the original P 249-C project, known in the specialized literature as P 286-17 or CW 24-C. It would have been propelled by a centrifugal De Havilland H-1B Goblin turbojet with a fuel tank of 1,059 lt., located behind the pilot, and armed with four 0.50 cal M2 machine guns. Its mass production was abandoned in favor of the Lockheed P-80.

On 31 March 1945 Curtiss proposed two versions of the P-304 a single-jet, medium-range fighter specifically designed to overcome the effects of compressibility, using the accumulated knowledge from the XP-55 programme.



Curtiss CW 24-C technical data

Power plant: de Havilland H-1B Goblin turbojet with 2,460 lbs (1,114 kgf) static thrust.

Wingspan: 39.36 ft (12 m), length: 28.10 ft (8.57 m), height: 9 ft (2.74 m), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-4 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.8 ft (10.3 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq. m), max weight: 14,470 lbs (6,564 kg), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-5 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.4 ft (10.21 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq .m), estimated max speed: 622 mph (1,001 kph) at 10,000 ft, estimated climb rate: 5,530 ft/min, max weight: 14,170 lbs (6,428 kg), combat radius: 500 miles (805 km), armament: four 0.50 cal M2 heavy machine guns.
Stunning artwork.
Thank you for a wealth of valuable information. Much appreciated.
;);)
 
Regarding the XP-55; once upon a time, some 40 years ago, I used NACA's wind tunnel data on this aircraft for my graduate Stability and Control course and my final conclusion was "Damn, that one was dangerous to fly!" A lot of the data clearly showed that.
 
Many years ago, while on a research trip, I heard a story from someone who will remain nameless but I am still confident would indeed be in a position to know.

It appears that test pilot Tony Levier hated the XP-55 so much that for years afterward when visiting Washington, DC he would make a point of going to see the XP-55 in storage and and kick the aircraft's fuselage because it was such a dangerous and difficult aircraft to fly.

Now, I don't know with absolute certitude that this story is true, but it certainly seems to fit the circumstances, the nature of the aircraft, and it is a delightful story nonetheless.

Submitted for your amusement,

AlanG
 
Rutan said the XP-55 had the neutral point shift forward close to stall.
 
From Le Fana Horse 16.

Eeerh... funny little mistake there (with respect to Hesham - I'm just amused, not a jerk).

Not horse (cheval - huuuuuuuuuh !) but Hors S = hors série that is "out of serial". Long story short: 12 Fana magazine per year, one per month - and H S are additional, trimestrial, thematic additions.
H S also mean "hors service" which essentially means FUBAR except less rude.
 

On 27 November, 1939 the USAAC announced the competition ‘Request for data R-40C’ for a very high performance fighter that should be equal to the new European models, to be built in 1941.

The Air Corps Interceptor Pursuit Specification XC-622, required:

Single-engine, single-seater with a top speed of at least 425 mph at 20,000 ft, sufficient to attack or leave combat area at will.

Seven minutes to climb to 20,000 ft.

Good pilot visibility

Four guns armament

Enough maneuverability

One and half hours endurance

The 2,000 hp, 24 cylinder ‘H’, liquid-cooled Pratt & Whitney X-1800-A3G engine was initially proposed.

Curtiss proposed the P-248-01design, an Allison powered CW-21 Demon and the CW-24, an unorthodox tailless-canard fighter, with 45 degrees swept-back wings and pusher propeller.

Around fifty projects were presented by nine different companies. By the end of 1940 six of them had been selected: Vultee (XP-54), Curtiss Wright CW-24 (XP-55), Northrop (XP-56), MacDonnell (Mod 1), Republic (AP-12) and Bell (Mod 13).

The first three qualified ones were never mass manufactured because they were of a too radical pusher design, making a failure of the whole $ 6,000,000 programme.

Throughout aviation history there have been designs of the canard or ‘tail-first’ types as an alternative to the conventional ‘engine-first’ configuration. However, in spite of the creativity of designers, manufacturers have systematically left aside the mass production of such solutions. When the second generation of fighters designed during the Second World War started to experiment serious aerodynamic problems, due to the transonic flux, they made several tries to solve them using the canard configuration eliminating airscrew slipstream effects on aircraft drag.

With this new configuration the designers tried to elude the problem of compressibility buffeting by installing the wing behind the center of gravity.

The British firm Miles built and fly tested the M.35 and M.39B prototypes as technological demonstrators of the M.39 bomber.

The German Henschel designed the heavy fighter named P.75 that should be propelled by a DB 613 A/B coupled engine and which mass production was abandoned in favor of the Dornier Do 335.

Several prototypes of canard fighters were built in Italy and USA.

The canard formula had many advantages for the design of fighters; the armament could be grouped around the nose without any hindrance by either the engine or the propeller and it was very easily accessible for maintenance, ground visibility was considerably improved and it was easier to install a tricycle type undercarriage.

The nose foreplanes had been found to serve the purpose of improving take-off performance and low speed control.

The engine, located behind the pilot, acted as protection against the rear impacts and, in the event of a fire, flames did not go to the cockpit as used to happen with the classical designs. Besides, being joined to the main spar meant less weight and stronger structural sturdiness.

In combat, an enemy pilot not familiar with the new configuration could easily mistake the direction to which the canard fighter moved during the deflection aiming. Same tactic is used by some tropical fishes that have a spot in the shape of a false eye near the tail to confuse their predators.

Only two inconveniencies marred all the advantages: the difficulty to refrigerate the engine and the baling out, due to the position of the pusher airscrews. At a time when ejector seats did not yet exist, the solution was to install an explosive device to detach the propeller in case of emergency.

Early in 1939 the Italians built the Ambrosini S.S.4 a canard prototype fighter powered by one 960 hp Isotta Fraschini Asso XI RC.40 engine. The airplane was destroyed in 1941 due to a problem of vibration of the engine mount and the project was cancelled.

On 22 June 1940 the USAAC signed a contract for preliminary development of the Curtiss CW-24 and construction of a wind tunnel model, under the designation XP-55.

Such a radical configuration required the construction of the CW-24B, a flying testbed to prove the design viability.

On 21 December 1941 the CW-24B made its first flight, at Muroc Dry Lake test center, powered by a 275 hp Menasco C-6S-5 engine.

Despite the strong security measures, intelligence services of the IJN obtained enough information about the project to believe that it was the successor of the Curtiss P-40 fighter. Early in 1943 Lieutenant Commander Masaoki Tsuruno, of the First Naval Air Technical Arsenal, proposed the construction of the canard fighter 18-shi-Otsu J7W Shinden based on the information obtained on the XP-55.

In fact, the definitive Curtiss XP-55 version was not selected by USAAC for production and only three prototypes were built, two of which were destroyed in accidents.

On 10 July 1942 the USAAF ordered three prototypes, the 42-78845 flew on 13 July 1943 powered by one 1,425 Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

The aircraft was fitted with laminar-flow swept wings angled back 45 degrees and tricycle undercarriage.

USAAF was unimpressed with the 377 mph top speed reached with the Allison engine versus the 507 mph promised with the X-1800 cancelled in October 1940.

The first prototype showed excessive take off run, dangerous stall behaviour, poor longitudinal stability, low-speed handling problems and engine overheating.

On 15 November 1943 the plane was lost, in an inverted spin, when the engine failed.

The second prototype 42-78846 flew on 9 January 1944 suffering from ‘no-warning before stalling’ phenomena. To improve the stall characteristics the nose elevator and the aileron tabs were modified.

The third prototype 42-78847 was flown on 25 April 1944, fitted with wing extensions and modified nose elevator and armed with four 0.50 cal nose mounted machine guns.

On 27 May 1945 the aircraft crashed when the pilot attempted a barrel roll.

Americans were not lucky with the Curtiss XP-55, after four years of flight testing they have not achieved an airplane sufficiently stable to take part in combat operations.

Although it was less sensible to the compressibility buffeting than conventional airplanes, thanks to a NACA 0015 type wing profile, it was also too heavy and slower than the P-47 and P-51 in service.



Curtiss XP-55 technical data

Power plant: one 1,425 hp Allison V-1710-95, V-12, liquid-cooled engine, with mechanical supercharger, driving a three-bladed (jettisonable) pusher airscrew.

Wingspan: 44.5 ft (13.56 m), length: 29.6 ft (9.02 m), height: 10 ft (3.05 m), wing area: 235 sq. ft (21.83 sq. m), max speed: 390 mph (630 kph), max weight: 7,330 lbs (3,324 kg), service ceiling: 34,600 ft (10,550 m), armament: six 0.50 cal M2 heavy machine guns.

Before cancelling the project, the Curtiss firm proposed the production of a jet version based on the original P 249-C project, known in the specialized literature as P 286-17 or CW 24-C. It would have been propelled by a centrifugal De Havilland H-1B Goblin turbojet with a fuel tank of 1,059 lt., located behind the pilot, and armed with four 0.50 cal M2 machine guns. Its mass production was abandoned in favor of the Lockheed P-80.

On 31 March 1945 Curtiss proposed two versions of the P-304 a single-jet, medium-range fighter specifically designed to overcome the effects of compressibility, using the accumulated knowledge from the XP-55 programme.



Curtiss CW 24-C technical data

Power plant: de Havilland H-1B Goblin turbojet with 2,460 lbs (1,114 kgf) static thrust.

Wingspan: 39.36 ft (12 m), length: 28.10 ft (8.57 m), height: 9 ft (2.74 m), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-4 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.8 ft (10.3 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq. m), max weight: 14,470 lbs (6,564 kg), armament: four 0.50 cal M2 heavy machine guns.



Curtiss P-304-5 technical data

Power plant: one General Electric TG-180 turbojet with 4,000 lbs (1,814 kgf) static thrust.

Wingspan: 40 ft (12.2 m), length: 33.4 ft (10.21 m), height: 9.5 ft (2.9 m), wing area: 240 sq. ft (21.6 sq .m), estimated max speed: 622 mph (1,001 kph) at 10,000 ft, estimated climb rate: 5,530 ft/min, max weight: 14,170 lbs (6,428 kg), combat radius: 500 miles (805 km), armament: four 0.50 cal M2 heavy machine guns.
Stunning artwork.
Thank you, kindly.
 

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