In 1935 the US Army Air
Corps initiated a series of design competitions aimed at procuring an
advanced monoplane fighter. At an earlier date, however, the Seversky
Aircraft Corporation had begun the design of a two-seat aircraft in
this category as a private venture, completing its construction in
early 1935. This, which had the company designation SEV-2XP, was
submitted for competition, but while being flown to Wright Field on 18
June 1935 to participate, was involved in an accident which caused
sufficient damage to necessitate its return to the factory for repair.
Designed by Alexander Kartyeli who, a little later, was to head design
of the famous P-47 Thunderbolt, the SEV-2XP had fixed landing gear.
During the repair process Kartveli had designed retractable main and
tailwheel units which could be adapted to the original airframe without
major structural change and, at the same time, changed the
accommodation to provide only a single seat. The powerplant comprised
an 850 hp (634 kW) Wright R-1820-65 Cyclone 9, and with the changes
which had been made the company were confident of attaining a maximum
speed in excess of 300 mph (483 km/h).
In this form the
redesignated SEV-1XP was delivered to Wright Field in mid-August 1935,
but failing to achieve the desired performance was taken back to the
Seversky plant where a Pratt & Whitney R-1830-9 Twin Wasp engine was
installed. Theoretically of the same rating as the Cyclone which it had
displaced, it was found during testing that the SEV-7 (as it was then
designated) had suffered a decline in performance. Finally, under the
designation AP-1 and with an R-1830-9 engine which was rated officially
at 950 hp (708 kW), the USAAC ordered 77 of this version as the P-35.
With a low-set elliptical wing that was very similar in planform to
that of the Supermarine Spitfire, these fighters were armed with one
0.50-in (12.7-mm) and one 0.30-in (7.62-mm) synchronised machine-gun
mounted in the close-fitting engine cowling.
P-35s began to enter
service in July 1937, with 76 of them being delivered by August 1938.
The last of the production batch was completed in changed form, with
airframe modifications and the installation of a 1,200- hp (895-kW)
Pratt & Whitney R-1830-19 engine with two-stage supercharger, and this
was designated XP-41.
In 1939 Seversky
adopted the name Republic Aviation Corporation, and in June received an
order from the Swedish government for 15 of the P-35s which, in export
form, were identified as EP-1s. This version differed from the USAAC's
P-35s in having a more powerful Twin Wasp engine and two additional
machine-guns. The initial order, and a following order for 45 more
examples, had been completed by mid- June 1940, but the 60 machines
which comprised the final order were requisitioned by the US government
in October 1940. Allocated the designation P-35A, these had all been
delivered by early February 1941, and during the year 48 were
despatched to the Philippines where, equipping such units as the
USAAC's 3rd, 17th and 20th Pursuit Squadrons, only eight remained
serviceable after the first two days of the Japanese attacks on 7/8
December 1941. The 12 which remained in the US were subsequently
supplied to Ecuador.
As a private venture,
Seversky built the prototype of a two-seat fighter which it designated
Seversky SEV-2XP, but while being evaluated by the US Army Air Corps in
June 1935 this prototype was damaged sufficiently to need factory
repair. The company's designer, Alexander Kartveli, took the
opportunity to introduce retractable main landing gear and revised the
cockpit as a single seater, the aircraft then being redesignated
SEV-1XP. When tested by the USAAC it was found to be underpowered, its
850 hp (634 kW) Wright R-1820-GB Cyclone radial then being replaced by
a Pratt & Whitney R-1830-9 Twin Wasp of similar output, resulting in
the new designation SEV-7. Performance had deteriorated still further,
the R-1830-9 delivering little more than 85 percent of its rated power,
resulting in the installation of an R-1830-9 engine with a guaranteed
output of 950 hp (708 kW) in the aircraft that was then redesignated
AP-1. ln this form the type was ordered by the USAAC under the
designation P-35, the first of 77 aircraft being delivered in July
1937. The last of the batch was completed as an improved aircraft
designated XP-41, which flew shortly before the company changed its
name to Republic Aircraft Corporation, and this was fundamentally the
prototype of the Republic P-43 Lancer.
Under the designation
EP-1 the type was offered for export, the Swedish government ordering
the first 15 of a batch of 120 designated EP-106, which differed
primarily by having a more powerful R-1830-45 engine and heavier
armament. Half of these had been delivered by 18 June 1940, being
designated J9 in Swedish service, but the balance of 60 was
requisitioned for the USAAC and delivered under the designation P-35A.
They were severely mauled by the Japanese when deployed in the
Philippines, only eight of 48 remaining airworthy after the first two
days of enemy attacks, and this represented the first and last
operational use of the type. The remaining 12 P-35As were later
supplied to Ecuador.
2PA-L: The Seversky
corporation developed a two-seat fighter intended for export based on
the design of the P-35. Designated 2PA-L, it was powered by a Wright
R-1820 engine of 1000 hp (746 kW). The sole 2PA-L was sold to the
Soviet Union in March of 1938. An amphibian two-seat fighter similar to
the 2PA-L but powered by a 850 hp (634 kW) Wright R-1820-G2 engine was
acquired by the Soviet Union in the same month, along with a license
for its manufacture. In the event, the Soviet Union never took up the
option for the manufacture of the 2PA-L.
FN-1: In 1937, Seversky
entered a P-35 (designated FN-1) in a US Navy competition for a new
carrier-based fighter to replace the Grumman biplanes then in service.
It competed against the Grumman F4F and the Brewster F2A. It was
powered by a 950 hp Wright R-1820-22 engine, and carried an arrestor
hook and bomb racks. Visibility was improved by the fitting of a larger
bulged windscreen. The top speed was only 267 mph (429 km/h), not much
faster than that of the Grumman F3Fs that was intending to replace. In
any case, the Brewster F2A won the competition.
Span: 36 ft.
Length: 25 ft. 4 in.
Height: 9 ft. 9 1/2 in.
Weight: 5,600 lbs. max.
Armament: One .50-cal. and one .30-cal. fuselage mounted machine
gun plus 320 lbs. of bombs.
Engine: Pratt & Whitney R-1830 of 850 hp.
Maximum speed: 280 mph.
Cruising speed: 260 mph.
Range: 625 miles
Service Ceiling: 30,600 ft.