Subject: Number Sixty-One in the Series--Northrop P-61 Black Widow (2 of 10)

From: [email-masked]
Date: 12 Mar 93 17:34:32 GMT

>From [email-masked]

The P-61A was the first production version of the Black Widow.  The 
first P-61A-1-NO rolled off the production line in October 1943.  It 
differed from the experimental and service-test aircraft in having a 
stronger framework structure for the pilot's, radar observer's and 
gunner's canopies.  Tests with the YP-61 had uncovered the fact that 
the greenhouse and tail cone were so weak that they could actually 
implode under the pressure built up during high-speed dives.  This 
strengthening eliminated the smooth flow of the greenhouse and created 
a sharper and more abrupt change in angle in that area.  The welded 
magnesium alloy booms of the prototypes were replaced by more 
conventional aluminum alloy booms, since they were less expensive and 
easier to manufacture.  Unlike the earlier XP-61 and YP-61 aircraft 
which were painted flat black, the P-61A was painted standard Army 
olive drab overall.  

Only the first thirty-seven of the 45 P-61A-1s were actually equipped 
with the dorsal turrets.  In fact, more than half of all P-61As built 
had this turret deleted.  One reason for this omission was that the 
General Electric remotely-controlled turret mechanism was urgently 
needed for the B-29 program.  However, the primary reason was the 
occurrence of severe aerodynamic buffeting when the turret was being 
either elevated or rotated in azimuth during flight.  Many flight-test 
hours were spent in trying to solve this problem, but it was never 
completely eliminated.  In fact, this problem was often so severe that 
many P-61As in the field had the four 0.50-inch machine guns in the 
top turret permanently locked into the forward-firing position, being 
fired only by the pilot, with the gunner having no control at all.  In 
many cases, the top turret was completely removed from the aircraft, 
and the cavity left behind by the deletion of the gun turret was 
filled up by an extra fuel tank and was faired over.  In a few cases, 
the turret mechanism was completely removed from the aircraft and the 
four dorsal machine guns were secured in the upper portion of the 
turret cavity and covered by a nonstandard turret cover.  Some of 
these modifications were made in the field, but others were made at 
forward depots before the aircraft were delivered to their operational 
squadrons.  

Since the gunner of these re-equipped Black Widows now had no guns 
that he could fire, he was sometimes left at home when these planes 
went out on operational missions, and many Black Widow operational 
missions carried only two crew members--the pilot and the radar 
operator.  However, on other occasions, the gunner was nevertheless 
included on operational missions, if only to act as another pair of 
eyes.  

Most of the P-61A-1-NOs went to the USAAF night fighter squadrons in 
the Pacific.  The 6th Night Fighter Squadron was the first to receive 
the new fighter.  

The P-61 was quite docile despite its size.  Full control of the 
aircraft could be maintained with one engine out, even when fully 
loaded.  The plane could be slow-rolled into a dead engine, a maneuver 
which would ordinarily have been suicidal.  

P-61A-1-NO 42-5496 was supplied to the RAF for tests.  It was in 
British hands between March 21, 1944 and February 22, 1945.  The RAF 
was not too enthusiastic about its performance, and never bothered to 
order any Black Widows for its own use, finding that the night fighter 
version of the de Havilland Mosquito was more than adequate for the 
task at hand.  

The P-61A-5-NO introduced a change in engines.  It was powered by a 
pair of 2250 hp R-2800-65 engines, replacing the 2000 hp R-2800-10s.  
Maximum speed was 322 mph at sea level, 355 mph at 10,000 feet, and 
369 mph at 20,000 feet.  Range (clean) was 415 miles at 319 mph at 
20,000 feet and 1010 miles at 224 mph at 10,000 feet.  Range with 
maximum external fuel was 1900 miles at 221 mph at 10,000 feet.  An 
altitude of 5000 feet could be reached in 2.2 minutes, and 15,000 feet 
in 7.6 minutes.  Service ceiling was 33,100 feet.  Weights were 20,965 
pounds empty, 27,600 pounds normal loaded, and 32,400 pounds maximum.  
Dimensions were wingspan 66 feet 0 inches, length 48 feet 11 inches, 
height 14 feet 2 inches, and wing area 664 square feet.  

The P-61A-10-NO had a pair of water-injected R-2800-65 Double Wasps.  
This model was the first to carry the shiny-black paint job which was 
to be the trademark of the Black Widow.  Previous production P-61As 
had conventional olive-drab paint jobs.  120 P-61A-10-NOs were built.  
20 of these were modified prior to delivery by the addition of a pylon 
on the outer wing panels to carry either a pair of 265 gallon fuel 
tanks (later 310 gallon tanks were fitted) or a pair of 1600-pound 
bombs.  These planes were redesignated P-61A-11.  

Serials of the P-61As were as follows: 

42-5485/5529 	Northrop P-61A-1-NO Black Widow 
42-5530/5564 	Northrop P-61A-5-NO Black Widow 
			5559 was modified as XP-61D 
42-5565/5604 	Northrop P-61A-10-NO Black Widow 
			5587 was modified as XP-61D 
42-5605/5606 	Northrop P-61A-11-NO Black Widow 
42-5607 	Northrop P-61A-10-NO Black Widow 
42-5608/5614  	Northrop P-61A-11-NO Black Widow 
42-5615/5634 	Northrop P-61A-10-NO Black Widow 
42-39348/39374	Northrop P-61A-10-NO Black Widow 
42-39375/39384 	Northrop P-61A-11-NO Black Widow 
42-39385/39386 	Northrop P-61A-10-NO Black Widow 
42-39387 	Northrop P-61A-11-NO Black Widow 
42-39388/39397 	Northrop P-61A-10-NO Black Widow 

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