Keystone B-3

B-3A

Keystone B-3A (S/N 30-281), the first B-3A built.
Role	Light bomber
Manufacturer	Keystone Aircraft
Primary user	United States Army Air Corps
Number built	63 B-3A/B-5
Variants	Keystone B-4 Keystone B-5 Keystone B-6

The Keystone B-3A was a bomber aircraft developed for the United States Army Air Corps in the late 1920s.

Design and development

It was originally ordered as the LB-10A (a single-tail modification of the Keystone LB-6), but the Army dropped the LB- 'light bomber' designation in 1930.

Although the performance of the B-3A was hardly better than that of the bombers flown at the end of World War I, it had come a long way. In terms of its safety, it was far superior to its oldest predecessors.

Operational history

The B-3A was the last biplane operated by the US Army; it remained in service until 1940. A few years after it was first produced, the introduction of all-metal monoplanes rendered it almost completely obsolete.

Variants

LB-10: The last of the 17 LB-6s ordered (S/N 29-27) was converted with a re-designed single fin and rudder and two 525 hp Wright R-1750E engines. Delivered to Wright Field on 7 July 1929, it was wrecked on 12 November 1929.
LB-10A: This version used Pratt and Whitney R-1690-3 Hornet engines and was slightly smaller, both wingspan and fuselage. A total of 63 were ordered (S/N 30-281/343). All were re-designated as the B-3A before any deliveries were made, with the final 27 built as B-5A with Wright engines.
B-3A: 36 ordered as LB-10A and delivered as B-3A (S/N 30-281/316). The first aircraft was delivered in October 1930.
B-5A: Ordered as B-3A, re-engined with Wright R-1750-3 Cyclone engines, 27 built (S/N 30-317/343).

Operators

United States

United States Army Air Corps
- 2d Bombardment Group, Langley Field, Virginia
  - 20th Bomb Squadron - operated B-3A and B-5A 1931-1932
  - 49th Bomb Squadron - operated B-3A and B-5A 1931-1932
  - 96th Bomb Squadron - operated B-3A and B-5A 1931-1932
- 4th Composite Group, Nichols Field, Luzon, Philippines
  - 28th Bomb Squadron - operated B-3A 1932-1937
  - 2nd Observation Squadron- operated B-3A 1938-1940^[1]
- 5th Composite Group, Luke Field, Territory of Hawaii
  - 23d Bomb Squadron - operated B-5A 1932-1937
  - 72d Bomb Squadron - operated B-5A 1932-1936
- 6th Composite Group, France Field, Panama Canal Zone
  - 25th Bomb Squadron - operated B-3A 1932-1936
- 7th Bombardment Group, March Field, California
  - 9th Bomb Squadron - operated B-3A 1931-1934
  - 11th Bomb Squadron - operated B-3A 1931-1934
  - 31st Bomb Squadron - operated B-3A 1931-1934
- 19th Bombardment Group, Rockwell Field, California
  - 30th Bomb Squadron - operated B-3A 1932-1936
  - 32d Bomb Squadron - operated B-3A 1932-1935
- Air Corps Advanced Flying School , Kelly Field, Texas
  - 42d Bomb Squadron - operated B-3A and B-5A 1935-1936

Philippines

Philippine Army Air Corps
- 10th Bombardment Squadron

Specifications (B-3A)

General characteristics

Crew: 5
Length: 48 ft 10 in (14.9 m)
Wingspan: 74 ft 8 in (22.8 m)
Height: 15 ft 9 in (4.8 m)
Wing area: 1,145 ft² (106.4 m²)
Empty weight: 7,705 lb (3,495 kg)
Loaded weight: 12,952 lb (5,875 kg)
Max. takeoff weight: lb (kg)
Powerplant: 2 × Pratt & Whitney R-1690-3 radial engines, 525 hp (392 kW) each

Performance

Maximum speed: 114 mph (98 kn, 183 km/h)
Cruise speed: 98 mph (85 kn, 158 km/h)
Range: 860 mi (760 nmi, 1,400 km)
Service ceiling: 12,700 ft (3,870 m)
Rate of climb: 530 ft/min (2.7 m/s)
Wing loading: 11.31 lb/ft² (55.42 kg/m²)
Power/mass: 0.0811 hp/lb (133 W/kg)

Armament

Guns: 3 × .30 in (7.62 mm) machine guns
Bombs: 2,500 lb (1,100 kg); 4,000 lb (1,800 kg) on short runs

References

Notes

↑ "Fact Sheet - Keystone B-3A." National Museum of the United States Air Force. Retrieved: 18 September 2011.

Bibliography

Andrade, John. U.S. Military Aircraft Designations and Serials since 1909. Leicester, UK: Midland Counties Publications, 1979, pp. 43, 135. ISBN 0-904597-22-9.
The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985). London: Orbis Publishing, 1985, p. 2255.
Maurer, Maurer. Combat Squadrons of the Air Force, World War II. Maxwell AFB, Alabama: Air Force Historical Studies Office, 1982. ISBN 0-89201-097-5.

External links

Wikimedia Commons has media related to Keystone B-3.

Aircraft produced by Huff-Daland Aero, Keystone Aircraft, and Keystone-Loening

Manufacturer designations	K-47 K-55 K-78 K-84 K-85 Air Yacht Commuter Pathfinder Pronto

Bombers	LB-1 XLB-3 LB-5 LB-6 LB-7 LB-8 LB-9 LB-10 LB-11 LB-12 LB-13 LB-14 XB-1 B-3 B-4 B-5 B-6

Trainers	TA-6 TW-5 AT-1 AT-2 NK

Patrol aircraft	PK

USAAS/USAAC/USAAF/USAF bomber designations, Army/Air Force and Tri-Service systems

Original sequences
(1924–1930)

Light Bomber	LB-1 LB-2 LB-3 LB-4 LB-5 LB-6 LB-7 LB-8 LB-9 LB-10 LB-11 LB-12 LB-13 LB-14

Medium Bomber	B-1 B-2

Heavy Bomber	HB-1 HB-2 HB-3

Main sequence
(1930–1962)

B-1
B-2
B-3
B-4
B-5
B-6
B-7
B-8
B-9
B-10
B-11
B-12
B-13
B-14
B-15
B-16
B-17
B-18
B-19
B-20
B-21
B-22
B-23
B-24
B-25
B-26
B-27
B-28
B-29
B-30
B-31
B-32
B-33
B-34
B-35
B-36
B-37
B-38
B-39
B-40
B-41
B-42
B-43
B-44
B-45
B-46
B-47
B-48
B-49
B-50
B-51
B-52
B-53
B-54
B-55
B-56
B-57
B-58
B-59
B-60
B-61
B-62
B-63
B-64
B-65
B-66
B-67
B-68
RB-69
B-70
FB-111

Long-range Bomber
(1935–1936)

Non-sequential

Redesignated A-series	B-20 B-26

Tri-Service sequence
(1962–current)

See also: SR-71 (designation in bomber sequence)
2037 Bomber

This article is issued from Wikipedia - version of the 9/9/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.