Stearman XA-21

Stillman XA-21 History

The US Army's road to the classic twin-engine attack aircraft of WWII (1939-1945) was long and saw many promising (and forgotten) types withdraw from the competition. These included the neglected "XA-21" Stillman, of which only one was built and failed to impress. The type first flew in 1938, but never moved beyond prototype status, even after major changes, including a redesigned nose.

However, the product enabled US Army authorities to use twin-engine types (and their inherent advantages and disadvantages), culminating in the introduction of platforms such as the Douglas A-20 Havoc and North American B-25 Mitchell "forms.

The XA-21 was originally a Stearman "Model X-100" designed to meet the USAAC's standing ground attack requirements. The X-100 model was proposed with a unique nose section with a long "greenhouse-like" canopy over the crew area.

A twin-engine configuration was used to power the type (USAAC asked for their new attacker). Three crew members operate their various onboard systems and use a conventional single tail. Main-wing aircraft are mounted high, each with an engine nacelle.

The engine of choice became 2 x Pratt & Whitney R-2180-7 Twin Hornet radials rated at 1,400 hp.

Proposed armament consists of a Browning .30 caliber machine gun located in the nose and four additional machine guns (two each) mounted on the wings. Four more Brownings (.30 caliber) were then mounted aft and dealt with any approaching interceptors.

Will carry up to 2,700 pounds of conventional throwing weapons to meet bombing requirements.

After the Army acquired the X-100, it was renamed the XA-21 during the testing phase. It was soon discovered to have an inherent design flaw - namely its long greenhouse roof, which restricted the pilot's forward vision - resulting in poor ground handling, takeoff and landing characteristics. As a result, engineers were forced to completely redesign the nose section and then reborn as a "stepped" cockpit approach somewhat reminiscent of the Joint B-24 Liberator heavy bomber (detailed elsewhere on this site).

Testing of the XA-21 continued, but no surprising findings were made to recommend it for mass production.

This leaves the only completed prototype form.

Specification

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Production

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Performance

Armor

Changes