Northrop P-61 Black Widow

https://en.wikipedia.org/wiki/Northrop_P-61_Black_Widow

The Northrop P-61 Black Widow, named for the American spider, was the first
operational U.S. warplane designed as a night fighter, and the first aircraft
designed to use radar. The P-61 had a crew of three: pilot, gunner, and radar
operator. It was armed with four 20 mm (.79 in) Hispano M2 forward-firing cannon
mounted in the lower fuselage, and four .50 in (12.7 mm) M2 Browning machine
guns mounted in a remote-controlled dorsal gun turret.

It was an all-metal, twin-engine, twin-boom design developed during World War
II. The first test flight was made on May 26, 1942, with the first production
aircraft rolling off the assembly line in October 1943. The last aircraft was
retired from government service in 1954.

Although not produced in the large numbers of its contemporaries, the Black
Widow was effectively operated as a night-fighter by United States Army Air
Forces squadrons in the European Theater, Pacific Theater, China Burma India
Theater, and Mediterranean Theater during World War II. It replaced earlier
British-designed night-fighter aircraft that had been updated to incorporate
radar when it became available. After the war, the P-61—redesignated the
F-61—served in the United States Air Force as a long-range, all-weather,
day/night interceptor for Air Defense Command until 1948, and Fifth Air Force
until 1950.

On the night of 14 August 1945, a P-61B of the 548th Night Fight Squadron named
Lady in the Dark was unofficially credited with the last Allied air victory
before VJ Day. The P-61 was also modified to create the F-15 Reporter
photo-reconnaissance aircraft for the United States Army Air Forces and
subsequently used by the United States Air Force.

The P-61 featured a crew of three: pilot, gunner, and radar operator. It was
armed with four 20 mm (.79 in) Hispano M2 forward-firing cannon mounted in the
lower fuselage, and four .50 in (12.7 mm) M2 Browning machine guns lined up
horizontally with the two middle guns slightly offset upwards in a remotely
aimed dorsally mounted turret, a similar arrangement to that used with the B-29
Superfortress using four-gun upper forward remote turrets. The turret was driven
by the General Electric GE2CFR12A3 gyroscopic fire control computer, and could
be directed by either the gunner or radar operator, who both had aiming control
and gyroscopic collimator sight assembly posts attached to their swiveling
seats.

The two Pratt & Whitney R-2800-25S Double Wasp engines were each mounted
approximately one-sixth out on the wing's span. Two-stage, two-speed mechanical
superchargers were fitted. In an effort to save space and weight, no
turbo-superchargers were fitted, despite the expected 50 mph (80 km/h) top speed
and 10,000 ft (3,048 m) operational ceiling increases.

Main landing gear bays were located at the bottom of each nacelle, directly
behind the engine. The two main gear legs were each offset significantly
outboard in their nacelles, and retracted towards the tail; oleo scissors faced
forwards. Each main wheel was inboard of its gear leg and oleo. Main gear doors
were two pieces, split evenly, longitudinally, hinged at inner door's inboard
edge and the outer door's outboard edge.

Each engine cowling and nacelle drew back into tail booms that terminated
upwards in large vertical stabilizers and their component rudders, each of a
shape similar to a rounded right triangle. The leading edge of each vertical
stabilizer was faired smoothly from the surface of the tail boom upwards, swept
back to 37°. The horizontal stabilizer extended between the inner surfaces of
the two vertical stabilizers, and was approximately ¾ the chord of the wing
root, including the elevator. The elevator spanned approximately ? of the
horizontal stabilizer's width, and in overhead plan view, angled inwards in the
horizontal from both corners of leading edge towards the trailing edge
approximately 15°, forming the elevator into a wide, short trapezoid. The
horizontal stabilizer and elevator assembly possessed a slight airfoil
cross-section.

SCR-720 radar

The production model of the SCR-720A mounted a scanning radio transmitter in the
aircraft nose; in Airborne Intercept mode, it had a range of nearly five miles
(8 km). The unit could also function as an airborne beacon / homing device,
navigational aid, or in concert with interrogator-responder IFF units. The
XP-61's radar operator located targets on his scope and steered the unit to
track them, vectoring and steering the pilot to the radar target via oral
instruction and correction. Once within range, the pilot used a smaller scope
integrated into the main instrument panel to track and close on the target.

Remote turret

The XP-61's spine-mounted dorsal remote turret could be aimed and fired by the
gunner or radar operator, who both had aiming control and gyroscopic collimator
sighting posts attached to their swiveling seats, or could be locked forward to
be fired by the pilot in addition to the 20 mm (.79 in) cannon. The radar
operator could rotate the turret to engage targets behind the aircraft. Capable
of a full 360° rotation and 90° elevation, the turret could be used to engage
any target in the hemisphere above and to the sides of the XP-61. A brief
assessment of the turret by the British Aeroplane & Armament Experimental
Establishment in 1944 found problems with the aiming and "jerky movement" of the
guns.


Role
Night fighter

National origin
United States

Manufacturer
Northrop

First flight
26 May 1942

Introduction
1944

Retired
1954

Primary users
United States Army Air Forces
United States Air Force

Number built
706

Unit cost

US$190,000


Variants
Northrop F-15 Reporter

https://en.wikipedia.org/wiki/Northrop_F-15_Reporter

The P-61 had an inauspicious start to its combat in the European theatre. Some
believed the P-61 was too slow to effectively engage German fighters and medium
bombers, a view which the RAF shared, based on the performance of a single P-61
they had received in early May.

The situation deteriorated in May 1944, when the squadrons learned that several
USAAF generals - including General Hoyt Vandenberg - believed the P-61 was too
slow to effectively engage in combat with German fighters and medium bombers.
General Spaatz asked for de Havilland Mosquito night fighters to equip two U.S.
night fighter squadrons based in the UK. The request was denied due to
insufficient supplies of Mosquitoes which were in demand for a number of roles.

At the end of May, the USAAF insisted on a competition between the Mosquito and
the P-61 for operation in the European Theater. RAF crews flew the Mosquito Mk
XVII while crews from the 422nd NFS flew the P-61. In the end the USAAF
determined that the P-61 had a slightly better rate of climb and could turn more
tightly than the Mosquito. Colonel Winston Kratz, director of night fighter
training in the USAAF, had organized a similar competition earlier. He said of
the results:

"I'm absolutely sure to this day that the British were lying like troopers. I
honestly believe the P-61 was not as fast as the Mosquito, which the British
needed because by that time it was the one airplane that could get into Berlin
and back without getting shot down. I doubt very seriously that the others knew
better. But come what may, the '61 was a good night fighter. In the combat game
you've got to be pretty realistic about these things. The P-61 was not a
superior night fighter. It was not a poor night fighter. It was a good night
fighter. It did not have enough speed.

However, on 5 July 1944, General Spaatz ordered a competition be held between
the P-61 – using an example from the 422nd which had its Double Wasp radials
carefully "tuned up" for the competition – against a Mosquito NF.XVII, and
Lieutenant Colonel Kratz made a $500 bet in favor of the Mosquito being a faster
and more maneuverable night fighting platform. The "tweaked" P-61 proved Kratz
wrong, as according to the 422nd's squadron historian it "... proved faster at
all altitudes, outturned the Mossie at every altitude and by a big margin and
far surpassed the Mossie in rate of climb."

In England, the 422d NFS finally received their first P-61s in late June, and
began flying operational missions over England in mid-July. These aircraft
arrived without dorsal turrets, so the squadron's gunners were reassigned to
another NFS that was to continue flying the P-70. The first P-61 engagement in
the European Theater occurred on July 15 when a P-61 piloted by Lieutenant
Herman Ernst was directed to intercept a V-1 "Buzz Bomb." Diving from above and
behind to match the V-1's 350 mph (560 km/h) speed, the P-61's plastic rear cone
imploded under the pressure and the attack was aborted. The tail cones failed on
several early P-61A models before this problem was corrected. On 16 July,
Lieutenant Ernst was again directed to attack a V-1 and, this time, was
successful, giving the 422nd NFS and the European Theater its first P-61 kill.

Pacific Theater

The 6th NFS based on Guadalcanal received their first P-61s in early June 1944.
The aircraft were quickly assembled and underwent flight testing as the pilots
changed from the squadron's aging P-70s. The first operational P-61 mission
occurred on 25 June, and the type scored its first kill on 30 June 1944 when a
Japanese Mitsubishi G4M "Betty" bomber was shot down.

On 30 January 1945, a lone P-61 performed a mission as part of the successful
raid carried out by U.S. Army Rangers to free over 500 Allied POWs held by the
Japanese at the Cabanatuan prison camp (Camp Pangatian) in the Philippines. As
the Rangers crept up on the camp, a P-61 swooped low and performed aerobatics
for several minutes. The distraction of the guards allowed the Rangers to
position themselves, undetected within striking range of the camp.

Poet and novelist James Dickey flew 38 Pacific Theatre missions as a P-61 radar
operator with the 418th Night Fighter Squadron, an experience that influenced
his work, and for which he was awarded five Bronze Stars. The 418th NFS produced
the only US Army Air Force night fighter aces in the Pacific, a pilot-radar
operator team.

Historian Warren Thompson wrote that "it is widely believed" that the last enemy
aircraft destroyed in combat before the Japanese surrender was downed by a
P-61B-2 named "Lady in the Dark" (s/n 42-39408) of the 548th NFS. The aircraft
piloted by Lieutenant Robert W. Clyde and R/O Lieutenant Bruce K. LeFord on
14/15 August 1945 claimed a Nakajima Ki-44 "Tojo." The destruction of the "Tojo"
came without a shot being fired; after the pilot of the "Tojo" sighted the
attacking P-61, he descended to wave-top level and began a series of evasive
maneuvers. These ended with his aircraft striking the water and exploding. Clyde
and LeFord were never officially credited with this possible final kill of the
war.

Summary

Though the P-61 proved itself capable against most German aircraft it
encountered, it was outclassed by the new aircraft arriving in the last months
of World War II. It also lacked external fuel tanks until the last months of the
war, an addition that would have extended its range and saved many doomed crews
looking for a landing site in darkness and bad weather. External bomb loads
would also have made the type more suitable for the ground attack role it soon
took on in Europe. These problems were all addressed eventually, but too late to
have the impact they might have had earlier in the war. The P-61 proved capable
against all Japanese aircraft it encountered, but saw too few of them to make a
significant difference in the Pacific war effort.

Specifications (P-61B-20-NO)

General characteristics
Crew: 2–3 (pilot, radar operator, optional gunner)
Length: 49 ft 7 in (15.11 m)
Wingspan: 66 ft 0 in (20.12 m)
Height: 14 ft 8 in (4.47 m)
Wing area: 662.36 ft2 (61.53 m2)
Empty weight: 23,450 lb (10,637 kg)
Loaded weight: 29,700 lb (13,471 kg)
Max. takeoff weight: 36,200 lb (16,420 kg)
Fuel capacity: Internal: 640 gal (2,423 L) of AN-F-48 100/130-octane rating
gasoline
External: Up to four 165 gal (625 L) or 310 gal (1,173 L) tanks under the wings

Powerplant: 2 × Pratt & Whitney R-2800-65W Double Wasp radial engines, 2,250 hp
(1,680 kW) each
Propellers: four-bladed Curtiss Electric propeller, 1 per engine Propeller
diameter: 146 in (3.72 m)


Performance
Maximum speed: 366 mph (318 kn, 589 km/h) at 20,000 ft (6,095 m)
Combat range: 1350 mi (1173 nmi, 2172 km)
Ferry range: 1,900 mi (1,650 nmi, 3,060 km) with four external fuel tanks
Service ceiling: 33,100 ft (10,600 m)
Rate of climb: 2,540 ft/min (12.9 m/s)
Wing loading: 45 lb/ft2 (219 kg/m2)
Power/mass: 0.15 hp/lb (250 W/kg)
Time to altitude: 12 min to 20,000 ft (6,100 m) (1,667 ft/min)

Armament

Guns: 4 × 20 mm (.79 in) Hispano AN/M2 cannon in ventral fuselage, 200 rounds
per gun
4 × .50 in (12.7 mm) M2 Browning machine guns in remotely operated,
full-traverse upper turret, 560 rpg

Bombs: for ground attack, four bombs of up to 1,600 lb (726 kg) each or six 5 in
(127 mm) HVAR unguided rockets could be carried under the wings. Some aircraft
could also carry one 1,000 lb (454 kg) bomb under the fuselage.

Avionics

SCR-720 (AI Mk.X) search radar
SCR-695 tail warning radar



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