Keystone XLB-3

History of the Keystone XLB-3

Despite the promising performance leap from the Martin MB-2 to the Huff-Daland LB-1 series, Army authorities were not convinced of the merits of the single-engine bomber form. Instead, they opted for the twin-engine variant "XLB-3" designed by Huff-Daland.

With the twin-engine layout, the crew nacelles are now freed from complex operating systems, allowing engineers to introduce additional crew storage and work space adding a whole new crew to the original crew of four. The biplane wing arrangement was retained, with each engine driving a two-bladed propeller.

All other features of the aircraft were largely carried over from previous designs.

The original XLB-3 was equipped with 2 x Allison VG-1410 (variant of "Liberty 12") air-cooled inverted V12 engines rated at 400 hp (each), and it was this prototype form that was passed on to Officially tested by the US Army Air Forces in 1927. The crew consisted of two pilots, a bombardier and two full-time machine gunners. The Defensive Shooting Network consists of five trainable ones.

303 Lewis machine guns, while the offensive bomb load reached 2,205 pounds.

However, the original prototype did not perform as well as the previous single-engine LB-1 design, forcing the XLB-3 to be retrofitted to the XLB-3A. The brand modified it by installing a pair of 410 hp Pratt & Whitney R-1340 radial piston engines.

Additionally, the design remains largely unchanged from the original.

Despite the engine change, it still lacked the power it needed, and when USAAC switched to the related LB-5, their interest waned. The LB-5 was even more successful, coming from Keystone in all 36 examples. Keystone Aircraft Corporation was formed when Hayden, Stone & Company acquired Huff-Daland.

From 1929, Keystone was under the Curtiss-Wright brand until it ceased service in 1932.

Only one XLB-3 aircraft was completed.

Specification

Basic

Production

Roles

Dimensions

Weight

Performance

Performance

Armor

Changes