From Joe Baugher: 

Douglas XA-26A Invader

In the original Invader prototype contract, it had been specified that one of the two examples ordered was to be completed as a night fighter. This aircraft was given the designation XA-26A-DE, and was assigned the serial number 41-19505. The XA-26A had a crew of two–pilot and radar-operator/gunner. The nose was equipped with a centimetric MIT AI-4 radar. The armament was completely different from the bomber or attack versions. There were four forward-firing 20-mm cannon housed inside a ventral tray underneath the forward bomb bay, with their ammunition boxes carried inside the bay. There was one remotely-controlled dorsal turret with four 0.50-in machine guns. For intruder missions, up to 2000 pounds of ordnance could be carried in the rear bomb bay.

Although the flight trials were successful, the XA-26A was never put into production, since the Northrop P-61 Black Widow night fighter which had already been put into production had a similar performance and was deemed to be adequate to meet the USAAF’s needs.

Specification of XA-26A:

Engines: Two Pratt & Whitney R-2800-27 air-cooled radials, each rated at 2000 hp. Performance: Maximum speed 365 mph at 17,000 feet. Cruising speed 264 mph. An altitude of 20,000 feet could be attained in 10.5 minutes. Service ceiling 25,900 feet. Normal range 700 miles, Maximum range 1420 miles. Dimensions: Wingspan 70 feet 0 inches, length 52 feet 5 inches, height 18 feet 6 inches, wing area 540 square feet. Weights: 20,794 pounds empty, 25,300 pounds loaded, 28,893 pounds maximum. Armament: Four 20-mm cannon in ventral tray. Four 0.50-inch machine guns in remotely-controlled dorsal turret. Up to 2000 pounds of ordnance could be carried in the rear bomb bay.

Serial of XA-26A

Serial Number: 41-19505		
Model: Douglas XA-26A Invader 
Construction Number: 1005

Sources:

  1. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian Institution Press, 1989.
  2. McDonnell Douglas Aircraft Since 1920: Volume I, Rene J. Francillon, Naval Institute Press, 1988.
  3. American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday, 1982.