Keystone LB-6

Infobox Aircraft
name=Keystone LB-6


caption=
type=Light biplane bomber
manufacturer=Keystone Aircraft
designer=
first flight=1927
introduced=
retired=
status=
primary user=United States Army Air Corps
more users=
produced=
number built=18 (LB-6)
18 (LB-7)
variants with their own articles=The Keystone LB-6 was an 1920s American light bomber built by the Keystone Aircraft company for the United States Army Air Corps. It was called the Panther by the company but adoption of the name was rejected by the U.S. Army.

The LB-6 was the first operational service model of a 13,000-pound twin-tail biplane bomber of a series produced by Keystone that included the follow-on LB-7 bomber. A number of variants were built for test and evaluation purposes but never placed into production or service.

Development

The LB-6 was an upgrade of the earlier triple-tailed Keystone LB-5 with revised extended-span wings and powered by two 525hp (391kW) Pratt & Whitney R-1690-3 Hornet engines strut-mounted between the wings. Other variants were built with differing engines.

The final two variants were ordered before the 1930 change of designators by the United States Army Air Corps from "LB-" (Light bomber) to "B-", but were delivered after the change. Although delivered as bombers, they saw service as cargo and observation aircraft.

Variants

;XLB-6:One LB-5 modified for evaluation.;LB-6:Production version, 17 built.;LB-7:LB-6 with 525hp (391kW) R-1690-3 Hornet engines, 18 built.;LB-8:One LB-7 re-engined with 550hp (410kW) R-1830 Twin Wasp engines for evaluation.;LB-9:One LB-7 re-engined with 575hp (429kW) GR-1750 Cyclone engines for evaluation.;XLB-10:One LB-6 re-engined with 525hp (391kW) R-1690-3 engines.;LB-10:Production version of the XLB-10, 63 built, all redesignated B-3A prior to delivery. 36 built as B-3A with Pratt & Whitney engines; remaining 27 became B-5 with Wright engines.;LB-11:One LB-6 re-engined with 525hp (391kW) R-1750-3s for evaluation.;LB-11A:LB-11 re-engined with 525hp (391kW) GR-1750s for evaluation.;LB-12:Similar to the LB-7, with 575hp (429kW) R-1830-1s for evaluation.;LB-13:Seven aircraft delivered as the Y1B4-1 (5) and Y1B6-1 (2).;LB-14:Production version with 575hp (429kW) GR-1830 engines, three delivered as the Y1B5-1.

Operators

;USA
*United States Army Air Corps

pecifications (B-4A)

aerospecs
ref=The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing, Page 2255
met or eng?= eng

crew=Five
capacity=
length m=14.88
length ft=48
length in=10
span m=22.76
span ft=74
span in=8
swept m=
swept ft=
swept in=
rot number=
rot dia m=
rot dia ft=
rot dia in=
dia m=
dia ft=
dia in=
width m=
width ft=
width in=
height m=4.8
height ft=15
height in=9
wing area sqm=106.37
wing area sqft=1145
swept area sqm=
swept area sqft=
rot area sqm=
rot area sqft=
volume m3=
volume ft3=
aspect ratio=
empty weight kg=3607
empty weight lb=7951
gross weight kg=5992
gross weight lb=13,209
lift kg=
lift lb=

eng1 number=2
eng1 type=Pratt & Whitney R-1860-7 radial engine
eng1 kw= 429
eng1 hp= 575
eng1 kn=
eng1 lbf=
eng1 kn-ab=
eng1 lbf-ab=
eng2 number=
eng2 type=
eng2 kw=
eng2 hp=
eng2 kn=
eng2 lbf=
eng2 kn-ab=
eng2 lbf-ab=

max speed kmh=195
max speed mph=121
max speed mach=
cruise speed kmh=
cruise speed mph=
range km=1376
range miles=855
endurance h=
endurance min=
ceiling m=4265
ceiling ft=14,000
glide ratio=
climb rate ms=
climb rate ftmin=
sink rate ms=
sink rate ftmin=

armament1=3 x 0.3in (7.62mm) Browning machine-guns
armament2=2,500lb (1134kg) Bombs
armament3=
armament4=
armament5=
armament6=

ee also

aircontent
see also=
related=
* Keystone B-3
* Keystone B-4
* Keystone B-5
* Keystone B-6
similar aircraft=
sequence=
lists=
* List of military aircraft of the United States

References

* John Andrade. "U.S.Military Aircraft Designations and Serials since 1909", p.135. Midland Counties Publications, 1979. ISBN 0 904597 22 9.
* "The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985)", p.2255. Orbis Publishing, 1985.