Subject: Bomber Series--Keystone LB-6

From: [email-masked] (joseph.f.baugher)
Date: 4 Jun 94 19:47:54 GMT

The Keystone XLB-6 was obtained by fitting the 10th LB-5 (serial number 
27-344) with new straight-chord wings of 75-foot span.  These wings 
were untapered and were slightly swept back.  The twin Liberty engines 
of the LB-5 were replaced by a pair of 525 hp Wright Cyclone radials.  
The engines were suspended between the wings rather than resting on 
top of the lower wing.  

17 production LB-6 aircraft were delivered by Keystone to the USAAC 
between August and September of 1929.  Serials were 29-011/027.  They 
were identical to the XLB-6 except for minor refinements and a revised 
angular shape for the twin rudders.  

The LB-6 served with the 2nd Bomb Group based in the US, plus the 5th 
Composite Bomb Group based in Hawaii.  The LB-6 had a better 
performance than the Liberty-powered LB-5.  It was ten miles per hour 
faster and had twice as fast a climb rate.  The LB-6 was known as 
*Panther* by the Keystone company, although this was not an official 
USAAC name.  

Specification of the Keystone LB-6: 

Two 525 hp Wright R-1750-1 Cyclone alr-cooled radial engines.  Maximum 
speed 114 mph at sea level, 106 mph at 5000 feet.  Cruising speed 95 
mph.  Landing speed 58 mph.  Service ceiling 11,650 feet, Absolute 
ceiling 14,000 feet.  Initial climb rate 600 feet per minute An 
altitude of 5000 feet could be attained in 10.3 minutes.  Range 632 
miles with 2003 pounds of bombs.  Weights: 7024 pounds empty, 12,155 
pounds gross.  Wingspan 75 feet, length 43 feet 5 inches, height 18 
feet 1 inches, wing area 1148 square feet.  Two Lewis machine guns in 
an open gunner's position in the nose, two Lewis machine guns in an 
open dorsal gunner's position, one Lewis gun firing downward through 
an opening in the lower fuselage.  

Sources:

  United States Military Aircraft Since 1909, Gordon Swanborough and
  Peter M. Bowers, Smithsonian, 1989.

  American Combat Planes, Ray Wagner, Third Edition, Doubleday, 1982.

  American Warplanes, Bill Gunston

  Jane's Encyclopedia of Aviation

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