To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

4,5
Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
Languages
Recent
Show all languages
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.
.
Leo
Newton
Brights
Milds

From Wikipedia, the free encyclopedia

B-4
Keystone Y1B-4 (SN 30-281).jpg
Keystone Y1B-4 (S/N 30-281)
Role Light bomber
Manufacturer Keystone Aircraft
Status Retired
Primary user United States Army Air Corps
Number built 5 Y1B-4
25 B-4A
Developed from Keystone B-3

The Keystone B-4 was a biplane bomber, built by the Keystone Aircraft company for the United States Army Air Corps.

YouTube Encyclopedic

  • 1/2
    Views:
    659
    2 904
  • ✪ Incredible Martin MB-2 Bomber at Air Force Museum
  • ✪ B 24 Liberator Restoration Australia, Werribee Victoria, Engine start and run up.. Attempt 1

Transcription

Contents

Design and development

Originally ordered by the United States Army Air Corps as the LB-13 light bomber. When the LB- designation was dropped in 1930, the first five planes were redesignated Y1B-4. (The Y1B- designation indicates that funds for the design did not come from the normal annual funds.)

The first B-3A (S/N 30-281) was converted to Y1B-4 configuration with the addition of R-1860-7 radial engines and low pressure tires. Because of more powerful engines, the performance of the Y1B-4 was a slight improvement on the B-3, but the only difference between the two planes was their engines. On April 28, 1931, the army ordered 25 improved Y1B-4s as the Keystone B-4A. This production version was part of the last biplane bomber order made by the Army Air Corps (along with 39 B-6As, identical in all respects except their make of engine), and the B-4As, delivered between January and April 1932, were the last biplane bombers delivered to the Air Corps.

Operational history

B-4 was the last of the Keystone biplane bombers ordered by the U.S. Army in late 1931. These aircraft were used primarily as observation and reconnaissance aircraft as early as 1934 when the Martin B-10B went into operational service. Some remained in service into the early 1940s.

Variants

LB-13
Seven aircraft ordered but delivered as the Y1B-4 and Y1B-6 with different engine installations.
Y1B-4
Five pre-production aircraft, as the LB-10 but with two 575 hp (429 kW) Pratt & Whitney R-1860-7 engines.
B-4A
Production version of the Y1B-4, 25 built.

Operators

 United States

Specifications (B-4A)

Keystone B-4A in flight in the Philippines
Keystone B-4A in flight in the Philippines

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 sq ft (106.4 m2)
  • Empty weight: 7,951 lb (3,607 kg)
  • Gross weight: 12,952 lb (5,875 kg)
  • Powerplant: 2 × Pratt & Whitney R-1860-7 radial engines, 575 hp (429 kW) each

Performance

  • Maximum speed: 130 mph (210 km/h, 110 kn)
  • Cruise speed: 103 mph (167 km/h, 90 kn)
  • Range: 850 mi (1,400 km, 760 nmi)
  • Service ceiling: 14,000 ft (4,300 m)
  • Rate of climb: 580 ft/min (30 m/s)
  • Wing loading: 11.31 lb/sq ft (55.22 kg/m2)
  • Power/mass: 0.0888 hp/lb (146 W/kg)

Armament

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

See also

Related development

Related lists

External links

This page was last edited on 1 September 2019, at 10:16
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.