SEV-3

Role	Three-seat amphibian Type of aircraft
National origin	United States
Manufacturer	Seversky Aircraft
Designer	Alexander Kartveli
First flight	1933

The Seversky SEV-3 was an American three-seat amphibian monoplane, the first aircraft designed and built by the Seversky Aircraft Corporation.

Design and development

The SEV-3 was an all-metal cantilever low-wing monoplane powered by a nose-mounted 420 hp (313 kW) Wright J-6 Whirlwind radial engine. It had two cockpits in tandem, a forward cockpit for the pilot and a rear cockpit for two passengers, both with sliding canopies. It could either be fitted with twin amphibious floats which had main wheels fitted in the floats to allow it to operate from land, or with a fixed tailwheel undercarriage with the mainwheels enclosed in large fairings.^[1]

The SEV-3 first flew as a floatplane in June 1933, demonstrating excellent performance as both an amphibian and a landplane.^[2] It was built in small numbers mainly for export.

Operational history

An SEV-3 established a world speed record for piston-engined amphibians in 1933, and on 15 September 1935, a Wright Cyclone-powered SEV-3 set a record of 230 mph (370.8 km/h) which stood for 49 years. A landplane version was also developed with conventional landing gear.^[3]

The design influenced a long line of Seversky and later Republic aircraft, eventually leading to the development of the P-47 Thunderbolt. A landplane version was used by the United States Army Air Corps as a basic trainer with the designation BT-8, 30 of which were ordered in 1935.^[4] This proved grossly underpowered and was quickly replaced by the North American BT-9.^[5]

One BT-8 was delivered to Bolling Field, on 11 June 1936, for use by Chief of the Air Corps Major General Oscar Westover, and assigned to the 14th Bombardment Squadron, GHQ Air Force. It replaced an O-38F, which was reassigned to the 21st Observation Squadron, GHQ Air Force, for general flying.^[6]^[7]

Operators

Spain

Spanish Republican Air Force

Colombia

Colombian Air Force

Variants

SEV-3XAR

Landplane trainer

SEV-3XLR: Landplane
SEV-3M-WW: Amphibian for the Colombian Air Force, six built (only delivered four to Colombia), with Wright Whirlwind engines.
BT-8: Landplane basic-trainer for the United States Army Air Corps, developed from SEV-3XAR. 30 built.
SEV-X-BT: multi-discipline trainer version of the BT-8 with retractable undercarriage. The sole SEV-X-BT lost in competition to the North American BT-9 and was reportedly scrapped for spares to service the Seversky 2PA.^[8]

Specifications (BT-8)

Data from United States Military Aircraft since 1909^[9]

General characteristics

Crew: 2
Length: 24 ft 4 in (7.42 m)
Wingspan: 36 ft 0 in (10.98 m)
Wing area: 220 sq ft (20.4 m²)
Empty weight: 3,017 lb (1,317 kg)
Gross weight: 4,050 lb (1,841 kg)
Powerplant: 1 × Pratt & Whitney R-985-11 Wasp Junior , 450 hp (336 kW)

Performance

Maximum speed: 175 mph (282 km/h, 152 kn) ^[10]

References

Green, William and Gordon Swanborough. "The End of the Beginning...The Seversky P-35". Air Enthusiast, No. 10, July–September 1979, pp. 8–21. ISSN 0143-5450
Howson, Gerald. "A Seversky in the Spanish War". Air Enthusiast, No. 18, April–July 1982, pp. 32–36. ISSN 0143-5450
The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985) London: Orbis Publishing, 1985.
Swanborough, F. G. and Peter M. Bowers. United States Military Aircraft since 1909. London: Putnam, 1963.
Taylor, Michael J.H. Jane's Encyclopedia of Aviation. London: Studio Editions, 1989. ISBN 0-517-69186-8.
"Fast American Amphibians", Flight, 16 November 1933

Republic and Seversky aircraft

Seversky aircraft

Republic aircraft

Fighters	P-43 P-44 P-47 XP-69 XP-72 F-84 F-84F XF-84H XF-91 XF-103 F-105 AP-100
Reconnaissance	RF-84F SD-3 SD-4 XF-12
Missiles	JB-2 KGW KUW
Civil aircraft	RC-1 RC-2 RC-3

Names

Project numbers

AP-1
AP-2
AP-3
AP-4
AP-5
AP-6
AP-7
AP-8
AP-9
AP-10
AP-12
AP-16
AP-18
AP-19
AP-21
AP-22
AP-23
- M/X
AP-24
AP-31
AP-38
AP-41
AP-42
AP-43
AP-44
AP-46
AP-47
NP-48
NP-49
NP-50
NP-52
AP-54
AP-55
AP-57
AP-60
AP-63
AP-71
AP-75
AP-76
85
AP-90
AP-95
AP-96
AP-100
AP-106

United States trainer aircraft designations, Army/Air Force and Tri-Service systems

Advanced Trainer
(1925–1948)

Basic Combat
(1936–1940)

Basic Trainer
(1930–1948)

Primary Trainer
(1924–1948)

Main sequence
(1948–present)

1948 redesignations	T-6 T-7 T-11 T-13² T-13A T-13B/D T-17 T-19
New designations	T-28 T-29 T-30 T-31 T-32 T-33 T-34 T-35 T-36 T-37 T-38 T-39 T-40 T-41² T-41 (I) T-41 (II) T-42² T-42 (I) T-42 (II) T-43 T-44 T-45 T-46 T-47 B T-48² YT-48 T-48TS T-49 T-50 T-51 T-52 T-53 T-54

Alternate sequences

1962 redesignations	T-1 T-2
1990– sequence	T-1 T-2¹ T-3 T-4¹ T-5¹ T-6 T-7

¹ Not assigned • ² Assigned to multiple types

Wright Field project numbers (1930–1934)

XP-900
XB-901
XP-902
XP-903
XP-904
905¹
XB-906
XB-907
XB-908
XC-909
XC-910
XO-911
XPT-912
XPT-913
XPT-914
XPT-915
916¹
XB-917
XC-918
919¹
XC-920
XB-921
922¹
XP-923
XO-924
XP-925
XO-926
XP-927
XC-928
XP-929
XPT-930
XPT-931
XO-932
XPT-933
XP-934
XBT-935
XP-936
XBT-937
XP-938
XO-939
XP-940
XC-941
XC-942
XPT-943
XP-944
XPT-945
946¹
947¹
XP-948
949¹
XB-950

¹ Not assigned