Built by EDO for refugee Russian WWI pilot Alexander de Seversky, the SEV 3 set several speed records in 1933. Seversky and fellow Russkies had formed an American corporation in 1931 but since they didn’t have a factory of their own at the time, the first airplane was built by EDO and given the SEV 3 classification, with the “3” standing for its three seat configuration. Seversky set amphibian speed records in the plane, powered by a 420 hp Wright Whirlwind, and then went after military business.
Designed by Michael Gregor and Alexander de Seversky, it was first flown in June 1933 as SEV-3, registered NX/NR2106 c/n 301, first with EDO wheeled floats for 1935 Thompson race, in which Lee Miles managed to place fifth at 196 mph.
The Army tested the Seversky but since it had no need for an amphibian at the time, the builder converted it into a landplane in 1934. Powered by a 350hp Wright R-975E with a faired landing gear it was re-designated SEV-3L
This was the Army’s first monoplane training aircraft and its first all metal trainer built using modern construction techniques.
It became the SEV-3XAR to win the Air Corps’ 1935 BT-8 contract, then back to amphibious SEV-3M in 1935 with a 710hp Wright R-1820, to set a world speed record of 230.4 mph.
The design, with wheels, became an Army BT-8 with 450hp P&W R-985. The basic aircraft evolved into the P 43, later, with a stretch of the fuselage and a 2,000 hp Pratt & Whitney R 2800 engine, it became the P 47 Thunderbolt.
Seversky went on to build other versions of the plane. Six of the 1934 SEV-3M-WW export version (NX15391, NX15689, NX15928 c/ns 37 to 39, plus three unlicensed).
“In Sever the Sky we find [NX15391, NX15689, NX15928]; US Register shows c/ns as 1, 2, and 3, but were actually c/ns 3, 4, and 5 aircraft by factory.’ This seems logical since [X2106] was c/n 1 and [X18Y] c/n 2. Then came [X189M] as c/n 6, 30 BT-8s as c/ns 7/36, and 3 SEV-3M-WWs for Columbia’s second order as c/ns 37/39.”
The 1937 SEV-DS NX1291 c/n 42 was built for the Shell Oil Co and piloted by James Doolittle.
The 1934 BT-8 Basic trainer was the AAC’s first monoplane trainer and was based on the SEV-3XAR, with faired landing gear. Thirty were built.
SEV-3
Engine: 420hp Wright J-6
Undercarriage: floats
SEV-3L
Engine: 350hp Wright R-975E
Wingspan: 36’0″
Length: 24’4″
Max speed: 210 mph
Cruise: 185 mph
Undercarriage: wheels
SEV-3XAR
SEV-3M
Amphibious
Engine: 710hp Wright R-1820
Max speed: 230.4 mph
BT-8
450hp P&W R-985
Wingspan: 36’0″
Length: 24’4″
Useful load: 1033 lb
Speed: 175 mph
Undercarriage: wheels
Seats: 2
SEV-DS
Engine: 850hp Wright R-1820 Cyclone
Seats: 2
Undercarriage: retractable wheels
All Aero 