Subject: Number Sixty-One in the Series--Northrop P-61 Black Widow (7 of 10)

From: [email-masked]
Date: 26 Mar 93 17:43:57 GMT

>From [email-masked]

As you may recall, work on the XP-61C had initially proceeded quite 
slowly at Northrop because of the greater priority of the XB-35 flying 
wing bomber.  Consequently, most of the work on the XP-61C was 
contracted out to Goodyear Aircraft of Akron, Ohio.  Goodyear was a 
natural choice for this work, since the company was already doing some 
subassembly work for Northrop on the Black Widow.  

It was initially planned that Pratt & Whitney R-2800-77 engines with 
General Electric CH-5 turbosuperchargers were to power the XP-61C.  
However, because of the demands of higher-priority projects for this 
engine, the R-2800-14W was substituted.  In reality, there were 
few differences between these engines.  In mid-Feruary 1944, 
arrangements were made to divert a P-61A-5-NO (serial number 42-5559) 
to the XP-61C project.  As a safety measure, Northrop suggested that a 
second Black Widow be converted as well, and since the P-61A 
production line was on Block 10 at that time, a P-61A-10-NO (serial 
number 42-5587) was taken off the production line for conversion to 
XP-61C standards.  

By late April 1944, the engines had been changed yet again, to the 
R-2800-57.  On April 27, Wright Field ordered that the designations of 
these two experimental aircraft be changed to XP-61D so that they 
would not be confused with the production C models.  The XP-61D was to 
be modified to carry four wing pylons (two inboard and two outboard of 
the engine booms) 

Technical difficulties and labor problems at Goodyear delayed the 
XP-61D all throughout mid-1944, and it was not until November 1944 
that the first flight took place.  By this time, the engines were a 
pair of R-2800-77 turbosupercharged radials, rated at a war emergency 
power of 2800 hp.  The flight test program for the two XP-61Ds was 
completed by the fall of 1945.  Maximum speed was 430 mph at 30,000 
feet, and an altitude of 30,000 feet could be attained in 13.5 
minutes.  Service ceiling was 43,000 feet.  Weights were 23,305 pounds 
empty, 29,850 pounds gross, and 39,715 pounds maximum.  

By this time, the basically similar P-61C had already entered 
production, and consequently the XP-61D had a very low priority.  The 
end of the war in the Pacific caused the priority of the XP-61D 
project to drop to zero.  The first XP-61D was scrapped on September 
11, 1945, and the second one in April 1946.  

Sources:

  Northrop P-61 Black Widow--The Complete History and Combat Record, 
  Garry R. Pape, John M. Campbell and Donna Campbell, Motorbooks 
  International, 1991.  

  The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.  

  Warplanes of the Second World War, Fighters, Volume 4, William Green, 
  1964.  

  American Combat Planes, Ray Wagner, Third Enlarged Edition, Doubleday, 
  1982.  

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

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