The last production example of the Republic P-35A had been equipped with a 1,200 hp (895 kW) supercharged Pratt & Whitney R-1830-19 engine, instead of the R-1830-45 engine which powered the remainder of the batch acquired by the US Army Air Corps. This re-engined example was designated XP-41, and was one of two projects initiated by the company to produce a developed version of the P-35. The second was a private-venture exercise by the company, identified as the AP-4, involving the same engine and airframe. The difference lay in the powerplant: the engine of the XP-41 had an integral two-stage supercharger, producing its maximum rated power at medium altitude; that of the AP-4 had a separate turbocharger installed in the rear fuselage which enabled the engine to deliver over 90 per cent of its rated take-off power to a much higher altitude. Both of these airframes had one feature which distinguished them easily from the P-35/-35As which had been supplied to the US Army. The narrow-track aft-retracting main landing gear units were replaced by a wide-track inward-retracting layout which housed the retracted main wheels in the undersurface of the fuselage/wing roots, achieving a far superior aerodynamic structure in flight.

Testing of these aircraft resulted in a USAAC contract, awarded on 12 March 1939, for 13 preproduction YP-43s. These had a number of modifications, including installation of the R-1830-35 engine, and re-siting of the turbocharger intake from the port wing root to within a new deep oval-shaped cowling. There were also a number of aerodynamic refinements, and armament was increased to four machine guns. The first of these was delivered by Republic in September 1940 and all were in service by April 1941, and although service trials progressed without problems, it did not take long to discover that the improvement in performance over the P-35s had already been surpassed by new aircraft developed in Europe.

Although Republic had already evolved an improved AP-4J, 80 of which had been ordered under the designation P-44 as early as September 1939, with follow-on contracts bringing the total to 907, these were all cancelled in September 1940 in favour of a much improved design which was to become the P-47 Thunderbolt. This, however, was unlikely to materialise for some months and, as an interim measure, the USAAC ordered 54 P-43s, with the name Lancer and the same powerplant as the YP-43s, plus the 80 P-44s ordered in September 1939 to be completed as P-43As with R-1830-49 engines.

Delivery of the foregoing Lancers began in 1941, and in June of that year a further 125 similar aircraft were procured for supply to China through Lend-Lease. Designated P-43A-1, these differed by having improved armour and self-sealing tanks, four 12.7 mm (0.50 in) machine guns and provision for a 50 US gallon (189 litre) drop tank or six 20 lbs (9 kg) bombs, and the installation of an R-1830-57 engine. Of this production batch, 107 were delivered to China during 1942. They saw a certain amount of action there, but they proved uniformly unequal to the task at hand. They were handicapped by poor manoeuvrability and inefficient self-sealing fuel tanks and achieved little success against the Japanese.

The P-43s and P-43As supplied to the USAAC were considered unsuitable for combat operations and these, together with the balance of the 18 P-43A-ls built for China, were all converted for use as photo-reconnaissance aircraft. They comprised 150 P-43Bs and two, with a different camera installation, as P-43Cs.

In August of 1942, six P-43 Lancers were withdrawn from USAAF stocks and transferred to the Royal Australian Air Force (RAAF). They served with No. 1 Photo Reconnaissance Unit, based at Coomlie, Northern Territory. The aircraft were two P-43Ds and four P-43A-1s. Two more P-43Ds were delivered in November of 1942. One was damaged beyond repair in a landing accident, and the other went missing on 28 April 1943 on a flight from Wagga Wagga in central New South Wales (the wreckage was not found until 1958). The remaining six were returned to the USAAF 5th Air Force at Charters Towers in 1943. I don't think that the RAAF Lancers ever saw any combat. In October 1942, all surviving P-43s were redesignated RP-43, with the 'R' standing for restricted from combat use.

Variants

XP-41: The last example of the Seversky P-35 was completed as an improved version with a turbocharged engine under the designation XP-41 and this, in effect, served as the prototype of the Republic P-43 Lancer.

YP-43: After extensive testing of the XP-41, the company developed a further improved version and, as a result, received a USAAC order for an evaluation batch of 13 aircraft under the designation YP-43. This model differed primarily from the P-35 by having a revised wing centre-section, landing gear that retracted inwards instead of aft and, of course, installation of the turbocharged Pratt & Whitney R-1830-35 engine. Testing showed improvements in both maximum speed and high altitude performance, leading to an order in 1940 for 54 production P-43 fighters with the R-1830-47 engine.

P-44 Rocket: On September 13, 1939, the Army ordered eighty examples of the more advanced AP-4J from Republic under the designation P-44. The P-44/AP-4J was basically similar to the P-43 but was provided with the more-powerful Pratt and Whitney R-2180-1 radial engine of 1400 hp. Drawings of the projected P-44 show an aircraft which looked very much like the P-43 but with a somewhat longer nose and a somewhat heavier armament of six machine guns.

However, combat reports coming out of Europe in the spring of 1940 indicated that even the P-44 Rocket would not be up to the task, and Alexander Kartveli and his design team began to consider an even more advanced project known under the company designation of AP-10. A prototype of the AP-10 had been ordered by the USAAF in November 1939 under the designation XP-47. Since the USAAF regarded the XP-47 as showing greater promise, they cancelled all work on the P-44 project on September 13, 1940, before any P-44 prototype could be completed. 170 P-47Bs and 602 P-47Cs were ordered in their place.

Alexander Kartveli and his team then concentrated all their efforts on the P-47 project, which was to turn out to be a wise decision indeed. However, P-47 development promised to be protracted, the first production aircraft not scheduled to roll off the production lines until late 1942. The Army felt that Republic's Farmingdale production lines needed to be kept busy in the interim. Consequently, the P-43 was ordered into production as a stop-gap measure.

P-43A: 80 examples of which were ordered. Deliveries began in September of 1941. The P-43A was essentially the same as the earlier P-43, but differed in having the turbo supercharged R-1830-49 which afforded its full 1,200 hp (895 kW) at 25,000 ft (7620 m). Armament was increased to a full four 12.7 mm (0.50 in) machine guns, two in the fuselage and two in the wings. Deliveries began in September 1941. Maximum speed was 356 mph at 25,000 feet. An altitude of 15,000 feet could be reached in 6 minutes. Service ceiling was 36,000 feet, and range was 650 miles. Wingspan was 36 feet, length was 28 feet 6 inches, height was 14 feet, and wing area was 223 square feet Weights were 5996 pounds empty and 7435 pounds gross. Maximum takeoff weight was 8480 pounds. In the USAAF, the P-43 went to the 1st Pursuit Group at Selfridge Field, Michigan, to the 55th Pursuit Group at Portland Field, and then to the 14th Pursuit Group at March Field, California. Their service life with these groups was quite brief, and they were quickly replaced by P-38 Lightnings as soon as they became available.

P-43A-1: Final version was the P-43A-1, of which 125 were contracted in 1941 with a further improved engine variant, the Pratt & Whitney R-1830-57. In 1942 the survivors of these 272 aircraft were converted for use in a reconnaissance role.

RP-43/43A/43A-1: All surviving P-43, P-43A and P-43A-1 aircraft were redesignated respectively RP-43, RP-43A and RP-43A-1 for use in a reconnaissance and advanced trainer roles.

P-43B: 150 of the above type aircraft converted to specialized photographic reconnaissance aircraft.

P-43C: Two aircraft similar to the P-43B but with different camera equipment.

P-43D: Six aircraft similar to the P-43C with only minor differences.

P-43E: The designation P-43E was applied to a projected but photo-reconnaissance version of the P-43A with different types of equipment. Never built. 

Specifications (Republic P-43A-1 Lancer)

Type: Single Seat Fighter / Fighter Bomber

Design: Alexander Kartveli

Manufacturer: Republic Aviation Corporation

Powerplant: (YP-43) One Pratt and Whitney R-1830-35 engine, offering 1,200 hp (895 kW) for takeoff and 1,100 hp (820 kW) at 20,000 ft (6096 m). (P-43A) One 1,200 hp (895 kW) Pratt & Whitney R-1830-49 which afforded its full 1,200 hp (895 kW) at 25,000 ft (7620 m). (P-43A-1) One 1,200 hp (895 kW) Pratt & Whitney R-1830-57 Twin Wasp 14-cylinder radial piston engine.

Performance: Maximum speed 356 mph (573 km/h) at 20,000 ft (6095 m); cruising speed 280 mph (451 km/h); service ceiling 36,000 ft (10975 m).

Range: Range 650 miles (1046 km); maximum ferry range was 1450 miles (2335 km).

Weight: Empty 5,996 lbs (2720 kg) with a maximum take-off weight of 8,480 lbs (3846 kg). Normal weight 7,435 lbs (3371 kg).

Dimensions: Span 36 ft 0 in (10.97 m); length 28 ft 6 in (8.69 m); height 14 ft 0 in (4.27 m); wing area 223 sq ft (20.72 sq m).

Armament: Four 12.7 mm (0.50 in) machine guns, plus one 41.6 Imperial gallon drop tank, one 200 lbs (90 kg) bomb or six 20 lbs (9 kg) bombs.

Variants: XP-41 (prototype), YP-43 (service testing), P-43, P-44 (abandoned), P-43A, P-43A-1 (major production), RP-43/43A/43A-1 (reconnaissance), P-43B, P-43C.

Avionics: None.

History: First flight (XP-41) March 1939; (YP-43) contract awarded 12 March 1939; (P-43) first delivery 16 May 1941, last 28 August 1941; project ended in favour of the P-47 on 13 September 1940.