Northrop P-61B Black Widow

Last revised January 2, 2021

The P-61B was the next production version of the Black Widow. It was basically similar to the P-61A version, but introduced numerous improvements and refinements that were suggested by operational experience in the field.

The P-61B version of the Black Widow introduced the improved SCR-720C A/I radar. The P-61B also had an eight-inch longer crew nacelle. The A-model's hydraulically-operated main landing-gear doors which had experienced reliability problems in the field were replaced by mechanically-operated doors. The P-61B introduced split main landing gear doors. The split main-gear doors allowed the aft three-quarters of the doors to close back down again after the gear had been extended, preventing mud, rocks and other debris from being thrown up into the wheelwells during takeoffs or landings. A main landing gear down-lock emergency release was introduced, which allowed the pilot to release the locks in an emergency even if the entire hydraulic system malfunctioned. A safety latch was added to the main gear hydraulic valve handle to eliminate the possibility of the pilot inadvertently retracting the gear while the plane was on the ground.

One way of visually telling the difference between a P-61A and a P-61B was by a readily-noticeable access panel which was added behind the radome on the P-61B.

The B-model had a bigger and better heater system for the crew, and it had automatically-operated lower engine cowl flaps, oil-cooler air exit flaps, and intercooler flaps. The oil tanks were mounted inside the engine nacelles instead of inside the outer wings. A taxi lamp was added to the landing gear strut. The aileron trim tabs were deleted, and a built-in fire extinguisher system was added.

Operational crews in combat theatres as well as training squadrons in the USA determined very early on that the Black Widow pilot needed to have night-vision binoculars in order to see his target. These were introduced on the B-model. Night-vision binoculars consisted of a combination of 5.8-power night glasses and an optical gunsight. In place of the circle and the dot of light in his regular gunsight, there was a horizontal row of four illuminated dots in the gunsight of the binoculars. The pilot lined up these dots with the wing of the target aircraft he was sighting on, and if he knew the type of aircraft he was looking at, he could easily determine its range and quickly calculate a firing solution. Night binoculars were later retrofitted to many P-61A already in the field.

Starting with the P-51B-5-NO production block, the SCR-718 radio altimeter was replaced with an APN-1 low-altitude altimeter.

Starting with the P-61B-10-NO block, an APS-13 tail-warning system was added. Some P-61As and many early P-61Bs were retrofitted in the field with the APN-1 and APS-13 systems. The B-10 production block also introduced underwing pylons for four 258-gallon drop tanks or four 1600-pound bombs

The P-61B-15-NO reintroduced the dorsal turret (General Electric Type A-4), the buffeting problem caused by earlier turrets having by now been largely corrected.

The P-61B-20-NO used the General Electric Type A-7 turret with a revised fire-control system.

The Black Widow night fighter used its on-board radar only to plot intercept courses when pursuing enemy aircraft. Once having used closed with his target, the pilot of the Black Widow sighted his prey by eye and used a conventional optical gunsight to fire his guns at the enemy. Operationally-practical radar-directed airborne fire control was still many years in the future. Nevertheless, there were some experiments with the Black Widow in which automatic airborne fire control was tried out. The P-61B-25-NO was a block of seven experimental aircraft which were fitted with a Western Electric APG-1 gun-laying radar which was coupled with a General Electric remote-controlled turret system. The radar fed data into an analogue computer, which in turn directed the turret guns onto the target. One P-61B-15-NO was also modified in this fashion, and the first six P-61B-20-NO aircraft were also modified to this configuration. All of these aircraft were tested by the Air Proving Command at Elgin Field, Florida and at the night fighter training establishment at Hammer Field in California. However, I don't think that this innovation ever made it to the field.

During 1945, 16 P-61Bs were converted to P-61Gs for weather reconnaissance. All armament was deleted.

Serials of the P-61B were as follows:

42-39398/39401 	Northrop P-61B-1-NO Black Widow 
42-39402 	Northrop P-61B-2-NO Black Widow 
42-39403/39405 	Northrop P-61B-1-NO Black Widow 
42-39406 	Northrop P-61B-2-NO Black Widow 
42-39407 	Northrop P-61B-1-NO Black Widow 
42-39408 	Northrop P-61B-2-NO Black Widow 
42-39409/39411 	Northrop P-61B-1-NO Black Widow 
42-39412/39414 	Northrop P-61B-2-NO Black Widow 
42-39415/39417 	Northrop P-61B-1-NO Black Widow 
42-39418 	Northrop P-61B-2-NO Black Widow 
42-39419/39423 	Northrop P-61B-1-NO Black Widow 
42-39424 	Northrop P-61B-2-NO Black Widow 
42-39425 	Northrop P-61B-1-NO Black Widow 
42-39426 	Northrop P-61B-2-NO Black Widow 
42-39427 	Northrop P-61B-1-NO Black Widow 
42-39428 	Northrop P-61B-2-NO Black Widow 
42-39429 	Northrop P-61B-1-NO Black Widow 
42-39430 	Northrop P-61B-2-NO Black Widow 
42-39431 	Northrop P-61B-1-NO Black Widow 
42-39432 	Northrop P-61B-2-NO Black Widow 
42-39433/39451 	Northrop P-61B-1-NO Black Widow 
42-39452/39456 	Northrop P-61B-2-NO Black Widow 
42-39457/39460 	Northrop P-61B-1-NO Black Widow 
42-39461/39462 	Northrop P-61B-2-NO Black Widow 
42-39463/39465 	Northrop P-61B-1-NO Black Widow 
42-39466 	Northrop P-61B-2-NO Black Widow 
42-39467/39470 	Northrop P-61B-1-NO Black Widow 
42-39471/39473 	Northrop P-61B-2-NO Black Widow 
42-39474 	Northrop P-61B-1-NO Black Widow 
42-39475 	Northrop P-61B-2-NO Black Widow 
42-39476/39477 	Northrop P-61B-1-NO Black Widow 
42-39478/39480 	Northrop P-61B-2-NO Black Widow 
42-39481/39482 	Northrop P-61B-1-NO Black Widow 
42-39483/39490 	Northrop P-61B-2-NO Black Widow 
42-39491 	Northrop P-61B-1-NO Black Widow 
42-39492/39493 	Northrop P-61B-2-NO Black Widow 
42-39494 	Northrop P-61B-1-NO Black Widow 
42-39495 	Northrop P-61B-2-NO Black Widow 
42-39496/39497 	Northrop P-61B-1-NO Black Widow 
42-39498/39500 	Northrop P-61B-5-NO Black Widow 
42-39501/39547 	Northrop P-61B-6-NO Black Widow 
42-39548/39572 	Northrop P-61B-10-NO Black Widow 
			39549 and 39557 converted to XP-61E 
42-39573/39611 	Northrop P-61B-15-NO Black Widow 
42-39612 	Northrop P-61B-10-NO Black Widow 
42-39613 	Northrop P-61B-25-NO Black Widow 
42-39614 	Northrop P-61B-15-NO Black Widow 
42-39615 	Northrop P-61B-10-NO Black Widow 
42-39616 	Northrop P-61B-15-NO Black Widow 
42-39617 	Northrop P-61B-10-NO Black Widow 
42-39618 	Northrop P-61B-15-NO Black Widow 
42-39619 	Northrop P-61B-10-NO Black Widow 
42-39620 	Northrop P-61B-16-NO Black Widow 
42-39621 	Northrop P-61B-11-NO Black Widow 
42-39622 	Northrop P-61B-16-NO Black Widow 
42-39623 	Northrop P-61B-11-NO Black Widow 
42-39624 	Northrop P-61B-16-NO Black Widow 
42-39625 	Northrop P-61B-11-NO Black Widow 
42-39626 	Northrop P-61B-16-NO Black Widow 
42-39627 	Northrop P-61B-11-NO Black Widow 
42-39628 	Northrop P-61B-16-NO Black Widow 
42-39629 	Northrop P-61B-11-NO Black Widow 
42-39630 	Northrop P-61B-16-NO Black Widow 
42-39631/39633 	Northrop P-61B-15-NO Black Widow 
42-39634/39636 	Northrop P-61B-10-NO Black Widow 
42-39637/39639 	Northrop P-61B-15-NO Black Widow 
42-39640/39641 	Northrop P-61B-10-NO Black Widow 
42-39642 	Northrop P-61B-15-NO Black Widow 
42-39643 	Northrop P-61B-10-NO Black Widow 
42-39644 	Northrop P-61B-15-NO Black Widow 
42-39645 	Northrop P-61B-10-NO Black Widow 
42-39646 	Northrop P-61B-15-NO Black Widow 
42-39647 	Northrop P-61B-10-NO Black Widow 
42-39648/39649 	Northrop P-61B-15-NO Black Widow 
42-39650 	Northrop P-61B-10-NO Black Widow 
42-39651	Northrop P-61B-15-NO Black Widow 
42-39652 	Northrop P-61B-10-NO Black Widow 
42-39653 	Northrop P-61B-15-NO Black Widow 
42-39654 	Northrop P-61B-10-NO Black Widow 
42-39655 	Northrop P-61B-15-NO Black Widow 
42-39656 	Northrop P-61B-10-NO Black Widow 
42-39657 	Northrop P-61B-15-NO Black Widow 
42-39658 	Northrop P-61B-10-NO Black Widow 
42-39659/39661 	Northrop P-61B-15-NO Black Widow 
42-39662 	Northrop P-61B-10-NO Black Widow 
42-39663/39665 	Northrop P-61B-15-NO Black Widow 
42-39666/39667 	Northrop P-61B-10-NO Black Widow 
42-39668/39757 	Northrop P-61B-15-NO Black Widow 
43-8231/8236 	Northrop P-61B-25-NO Black Widow 
43-8237/8320 	Northrop P-61B-20-NO Black Widow 


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

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

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

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

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

  6. E-mail with correction for production block number for 42-39613