Designed and flown by Ron Beattie and
Walt Fellers, two North American Engineers who came to work for the Northrop
Division. The aircraft was built by the Acme Aircraft Company (Sierradyne
Inc.) Crawford and Keeney, at the Torrance Airport in late 1948. The first
flight was on 23 November 1953. It was built according
to Goodyear Racing Plane specifications. Although it was never entered
in any races, extensive data was obtained during its many flights.
This experimental aircraft was built to investigate
the advantages of a pusher 
propeller
configuration. It has a "Y" shaped tail incorporating ruddervators
on the upper fins, an unswept wing mounted midway up the fuselage, an engine
mounted directly behind the cockpit, and large air scoops mounted in the
forward end of both wing roots.
Artist's conception of the Northrop A-9A
The aircraft was used by Sierradyne in the
1960's to test and promote Northrop's and Dr Werner Pfenninger's boundary
layer control concepts. Northrop used it as a flying technology demonstrator
for the Air Force’s AX close-support aircraft design competition in
1972. The plane was never officially considered a Northrop aircraft.
