Subject: Number Thirty-Nine in the Series--Bell P-39 Airacobra (4 of 9)

From: [email-masked] (Joseph F Baugher)
Date: 14 Dec 92 17:27:16 GMT

>From Joseph F Baugher <[email-masked]>

Three P-39Ds were modified to flight test the experimental Continental 
V-1430-1 engine under the designation XP-39E.  The company designation 
was Model 23.  The first two machines were ordered on April 10, 1941, 
with a third machine being added later.  Serials were 41-19501, 
41-19502, and 42-7164.  However, the Continental engine was not yet 
ready when the XP-39E airframes were completed, and the 1325 hp 
Allison V-1710-47 engine was installed in its place.  

The XP-39E featured laminar-flow wings with square-cut tips.  Each of 
the three examples tested different vertical tail surfaces--the first 
being conical, the second being cut-off square and rather short, and 
the third being rather similar to that of the P-51.  The carburetor 
air intake was relocated and the wing-root radiator intakes were 
enlarged.  Wing span and gross area were increased to 35 feet 10 
inches and 236 square feet.  Empty and loaded weights were 6936 lbs 
and 8918 lbs respectively.  During tests, a maximum speed of 386 mph 
at 21,680 feet was attained.  An altitude of 20,000 feet could be 
reached in 9.3 minutes.  

The XP-39E was redesignated XP-76 and 4000 were ordered by the USAAF.  
However, the new design was considered to be inferior to the basic 
Airacobra in other respects, and the order for the XP-76 was later 
cancelled in its entirety.  Nevertheless, the XP-39E was to provide 
some valuable basic data for the later P-63 Kingcobra.  

Sources:

  War Planes of the Second World War, Fighters, Volume Four, William Green,
  Doubleday, 1964.

  The American Fighter, Enzo Anguluci and Peter Bowers, Orion Books, 1987.

  United States Military Aircraft since 1909, Gordon Swanborough and Peter 
  M. Bowers, Smithsonian Institution Press, 1989.

  P-39 Airacobra in Action, Ernie McDowell, Squadron/Signal Publications, 
  1980

  The Calamitous 'Cobra, Air Enthusiast, August 1971.

Joe Baugher       AT&T Bell Laboratories    2000 North Naperville Road 
		  Naperville, Illinois 60566-7033.   (708) 713-4548