Editing Keystone B-3

{{Short description|Bomber aircraft family by Keystone}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{{Infobox aircraft
 |name=B-3A
 |image=Keystone B-3A (SN 30-281).jpg
 |caption= Keystone B-3A (S/N 30-281), the first B-3A built.
 |type=[[Bomber]]
 |manufacturer=[[Keystone Aircraft]]
 |designer=
 |first_flight=
 |introduction=
 |retired=
 |status=Retired
 |primary_user=[[United States Army Air Corps]]
 |produced=
 |number_built=63 B-3A/B-5
 |variants= [[Keystone B-4]], [[Keystone B-5|B-5]] & [[Keystone B-6|B-6]]
}}

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

==Design and development==
The B-3 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 flight safety.

==Operational history==
The B-3A was a member of the last family of [[biplanes]] 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 [[Keystone LB-6|LB-6]]s 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, in both wingspan and length. 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
:Ordered as LB-10A, 36 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==
;{{flag|United States|1912}}
*[[United States Army Air Corps]]
**[[2d Bombardment Group]], [[Langley Air Force Base|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
*** [[2d Air Refueling Squadron|2nd Observation Squadron]]- operated B-3A 1938–1940<ref name="B-3A fact">[https://web.archive.org/web/20131029211809/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2394 "Fact Sheet – Keystone B-3A."] National Museum of the United States Air Force. Retrieved: 14 July 2017.</ref> 
**[[5th Bomb Wing|5th Composite Group]], [[NALF Ford Island|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 Space Range Squadron|25th Bomb Squadron]] – operated B-3A 1932–1936
**[[7th Bombardment Group]], [[March Air Force Base|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 Air Refueling Squadron|32d Bomb Squadron]] – operated B-3A 1932–1935
**[[10th School Group#Advanced Flying School|Air Corps Advanced Flying School]], [[Kelly Field]], [[Texas]] 
***[[42d Attack Squadron|42d Bomb Squadron]] – operated B-3A and B-5A 1935–1936
;{{flag|Philippines|1936}}
*[[Philippine Army Air Corps]]
**10th Bombardment Squadron

==Specifications (B-3A)==
{{Aircraft specs
    |ref                        = <!-- reference --> 
    |prime units?               = imp
    <!-- imp or kts first for US aircraft, and UK aircraft pre-metrification, 
    met(ric) first for all others. You MUST choose a format, or no specifications will show -->
    <!--General characteristics-->
    |crew                   = 5
    |capacity               = 
    |length m               = 14.9
    |length ft              = 48
    |length in              = 10
    |span m                 = 22.8
    |span ft                = 74
    |span in                = 8
    |height m               = 4.8
    |height ft              = 15
    |height in              = 9
    |wing area sqm          = 106.4
    |wing area sqft         = 1145
    |aspect ratio           = 
    |airfoil                = 
    |empty weight kg        = 3495
    |empty weight lb        = 7705
    |gross weight kg        = 5875
    |gross weight lb        = 12952
    |max takeoff weight kg  = 
    |max takeoff weight lb  = 
    |more general           = 
    <!--Powerplant-->
    |eng1 number            = 2
    |eng1 name              = [[Pratt & Whitney R-1690]]-3
    |eng1 type              = [[radial engine]]s
    |eng1 kw                = <!-- prop engines --> 392
    |eng1 hp                = <!-- prop engines --> 525
    |eng1 shp               = <!-- prop engines --> 
    |eng1 kn                = <!-- jet/rocket engines --> 
    |eng1 lbf               = <!-- jet/rocket engines --> 
    |power original         = 
    |thrust original        = 
    |eng1 kn-ab             = 
    |eng1 lbf-ab            = 
    |more power             = 
    |prop name              = 
    |prop dia m             = <!-- propeller aircraft --> 
    |prop dia ft            = <!-- propeller aircraft --> 
    |prop dia in            = <!-- propeller aircraft --> 
    |rot dia m              = <!-- helicopters --> 
    |rot dia ft             = <!-- helicopters --> 
    |rot dia in             = <!-- helicopters --> 
    |rot area sqm           = <!-- helicopters --> 
    |rot area sqft          = <!-- helicopters --> 
    |rot number             = 
    <!--Performance-->
    |max speed kmh          = 183
    |max speed mph          = 114
    |max speed kts          = 98
    |max speed note         = 
    |max speed mach         = 
    |cruise speed kmh       = 158
    |cruise speed mph       = 98
    |cruise speed kts       = 85
    |cruise speed note      = 
    |stall speed kmh        = 
    |stall speed mph        = 
    |stall speed kts        = 
    |stall speed note       = 
    |never exceed speed kmh = 
    |never exceed speed mph = 
    |never exceed speed kts = 
    |range km               = 1400
    |range miles            = 860
    |range nmi              = 760
    |range note             = 
    |combat range km        = 
    |combat range miles     = 
    |combat range nmi       = 
    |combat range note      = 
    |ferry range km         = 
    |ferry range miles      = 
    |ferry range nmi        = 
    |ferry range note       = 
    |endurance              = <!-- if range unknown --> 
    |ceiling m              = 3870
    |ceiling ft             = 12700
    |ceiling note           = 
    |climb rate ms          = 2.7
    |climb rate ftmin       = 530
    |climb rate note        = 
    |sink rate ms           = <!-- sailplanes --> 
    |sink rate ftmin        = <!-- sailplanes --> 
    |sink rate note         = 
    |wing loading kg/m2     = 55.42
    |wing loading lb/sqft   = 11.31
    |disk loading kg/m2     = 
    |disk loading lb/sqft   = 
    |power/mass             = 0.0811 hp/lb (133 W/kg)
    |thrust/weight          = 
    |more performance       = 
    <!--Armament-->
    
    |guns                   = 3 × .30 in (7.62 mm) [[M1919 Browning machine gun|machine gun]]s
    |bombs                  = 2,500 lb (1,100 kg); 4,000 lb (1,800 kg) on short runs
    |rockets                = 
    |missiles               = 
    |hardpoints             = 
    |hardpoint capacity     = 
    |hardpoint rockets      = 
    |hardpoint missiles     = 
    |hardpoint bombs        = 
    |hardpoint other        = 
    |avionics               = }}

==See also==
{{aircontent
|related=
* [[Keystone LB-6]]
* [[Keystone B-4]]
* [[Keystone B-5]]
* [[Keystone B-6]]
|lists=
* [[List of bomber aircraft]]
* [[List of military aircraft of the United States]]
}}

==References==
;Notes
{{Reflist}}

;Bibliography
{{Refbegin}}
* Andrade, John. ''U.S. Military Aircraft Designations and Serials since 1909.'' Leicester, UK: Midland Counties Publications, 1979, pp.&nbsp;43, 135. {{ISBN|0-904597-22-9}}.
* ''The Illustrated Encyclopedia of Aircraft (Part Work 1982–1985)''. London: Orbis Publishing, 1985, p.&nbsp;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}}.
{{Refend}}

==External links==
{{Commons category|Keystone B-3}}
*[http://www.joebaugher.com/usaf_bombers/b3.html Encyclopedia of American Aircraft]
*[http://1000aircraftphotos.com/APS/4234.htm Photograph of B-3 on the ground]
*[https://airandspace.si.edu/collection-objects/keystone-b-3a-lb-10a-military-usa-army-air-corps-bases-nichols-field-philippines Photograph of B-3 landing]
*[https://web.archive.org/web/20131029210228/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2408 USAF Museum article on LB-10]
*[https://web.archive.org/web/20131029211809/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2394 USAF Museum article on B-3]

{{Keystone aircraft}}
{{USAF bomber aircraft}}
{{Authority control}}

[[Category:Keystone aircraft|B-3]]
[[Category:Light bombers]]
[[Category:1930s United States bomber aircraft|Keystone B-03]]
[[Category:Biplanes]]
[[Category:Twin piston-engined tractor aircraft]]