This Date in Aviation History: January 21 - January 24 [New Destinations]
Photo: Author unknown
January 21, 1931 – The first flight of the Vickers Type 161, a unique experimental pusher-engined interceptor designed with a fixed gun firing upward at a 45-degree angle. The biplane configuration featured wings of unequal span, with booms extending back from the inboard brace to the horizontal stabilizer. The pilot was seated to the left of the centerline, with the Coventry Ordnance Works 37mm cannon placed to the right, with the breech within reach of the pilot. The metal monocoque fuselage also housed the Bristol Jupiter 9-cylinder radial, with the tapered fuselage extending to the vertical stabilizer. With the gun fixed at an upward angle, the concept was to have the Type 161 fly underneath enemy aircraft and shoot them from below, similar to the German Schräge Musik concept of WWII. In flight tests at RAF Martlesham Heath, the Type 161 flew well and provided a stable platform for the gun, which did not affect handling while firing. Nevertheless, the RAF chose not to enter production, and only a single example was built.
Air India 707 similar to accident aircraft | Photo: Steve Fitzgerald
January 24 1966 – Air India Flight 101 crashes into Mont Blanc in France. Air India 101 was scheduled Boeing 707 (VT-DMN) service from Bombay to London with planned stops at Delhi, Beirut, and Geneva. The legs from Bombay to Beirut proceeded routinely, and the crew departed for Geneva after noting the failure of their no. 2 VOR navigational system. While flying at 19,000 feet, the crew received instructions to descend after passing Mont Blanc, the highest mountain in the alps at 15,773 feet, which the pilot believed he had cleared despite being warned by air traffic control that the airliner was still five miles away from the mountain. The crew, unaware of their exact location perhaps due to the faulty VOR, descend and struck the mountain 188 feet from the summit, killing all 117 passengers and crew. No black box recorder was found due to the inaccessibility of the wreckage. One of the passengers was Dr. Homi Jehangir Bhabha, head of the Indian Atomic Energy Agency, and some speculation exists that the aircraft was brought down by a bomb placed by the American CIA to derail India’s plans to develop an atomic bomb. So far, this theory is unfounded. Due to the extreme altitude of the crash site, most of the wreckage remains on the mountain, though some objects have been recovered, including a newspaper dated January 23, 1966, a diplomatic pouch, and a box containing approximately USD $265,000 in jewels. When no owner could be located, the jewels were divided between the local government and the climber who discovered them. Melting glaciers have also recently exposed human remains.
Photo: San Diego Air and Space Museum
January 24, 1938 – The first flight of the Armstrong Whitworth Ensign, the largest airliner produced in Britain between the World Wars. In 1934, Imperial Airways began requested a large, four-engine airliner that would be powered by Armstrong Siddeley Tiger 14-cylinder radial engines. After exploring various configurations, Armstrong settled on a shoulder-wing design at the insistence of Imperial Airways, and further requests for changes, as well as the priority of producing the Whitley bomber, delayed development by as much as two years. In its final design, the Ensign featured a tail-dragger configuration with retractable main gear, and the original Tiger engines were replaced with Wright R-1820 Cyclone 9-cylinder engines. On shorter European routes, the Ensign seated 40 passengers, while longer Empire routes and routes to the Middle East, India, and Africa had accommodations for 27 passengers with sleeper berths. The Ensign entered service with Imperial Airways in 1938, and later with British Overseas Airways Corporation following the merger of Imperial and British Airways. Camouflaged Ensigns continued flights during the war, and a handful were flown by the RAF. Of the 14 produced, three were lost to enemy fire and a fourth was captured and operated by the French. However, the aircraft was plagued by reliability and construction issues throughout its service, and the type was retired in 1946, with all remaining aircraft scrapped.
Photo: US Navy
January 21, 1972 – The first flight of the Lockheed S-3 Viking. Submarines, which prowl the ocean depths to loose their torpedoes against unsuspecting ships, have been a constant menace to surface fleets since World War I. The early diesel-electric submarines spent the majority of their cruise on the surface, but the arrival of the nuclear-powered USS Nautilus (SSN 571) in 1954 signaled a quantum leap in capability over its ancestors, primarily due to the sub’s ability to stay submerged for long periods of time and cover vast distances out of sight beneath the world’s oceans. Once nuclear-powered submarines gained the capability to launch nuclear missiles, the task of finding and destroying enemy subs became of paramount importance.
An S-3 Viking flies alongside a Grumman S-2 Tracker, the aircraft it replaced, in 1976 | Photo: US Navy
The year 1954 also marked the arrival of the the Grumman S-2 Tracker, the US Navy’s first purpose-built antisubmarine warfare (ASW) aircraft. But as submarines began diving deeper and moving faster, and more quietly, the Navy issued a proposal in 1967 for a more modern aircraft that would be capable of operating from their carrier fleet. They received proposals from five companies, including a joint proposal from Lockheed and Ling Temco Vought (LTV). The Lockheed offering was chosen as the winner in 1969, and design and production of the S-3 was divided among the partners. LTV, with more experience building carrier aircraft, produced the wings, tail, landing gear, and engine pods, while Lockheed built the fuselage and coordinated the finally assembly and integration of the components. Univac produced the computers and data processing components. Following the success of the Viking prototype’s maiden flight, the Navy allocated additional money to build eight more research and development aircraft, and orders for 179 aircraft quickly followed, such was the perceived need for the Viking.
An S-3 from ASW Squadron VS-32 "Maulers" from the aircraft carrier USS America (CV 66) with its magnetic anomaly detector (MAD) boom extended. | Photo: US Navy
The S-3 was powered by a pair of General Electric TF34 high bypass turbofans that give the Viking excellent range and loiter time while hunting for submarines. It carries a crew of four (three officers plus one enlisted), with the pilot and copilot/tactical coordinator in the front seats and the tactical coordinator and sensor operator in the back. For hunting submarines, the Viking was equipped with an AN/APS-116 sear search radar, forward looking infrared (FLIR), up to 16 sonobuoys that could be dropped to detect submarines underwater, and a magnetic anomaly detector (MAD) boom that could track subs based on changes to the Earth’s magnetic field caused by the passage of the submarine. Unlike the earlier S-2 or Lockheed P-3 Orion, the Viking crew could share data between their screens and combine sensor information, making the 4-man crew as effective as a 12-man Orion crew. Once a sub was detected, the Viking crew could call on nearly 5,000 pounds of bombs, torpedoes, depth charges, or missiles at their disposal. Anti-shipping missiles could also be fitted.
An S-3B Viking assigned to Sea Control Squadron 33 (VS-33) "Screwbirds" prepares to refuel another aircraft during flight operations over the Southern Pacific in 2003 | Photo: US Navy
The Viking became operational in 1974 and immediately began their sub hunting duties to detect enemy ballistic missile submarines and protect the carrier battle group. Following the collapse of the Soviet Union in 1991, and the subsequent breakup of the Warsaw Pact, the threat of Russian submarines was greatly reduced. Most of the Viking’s sub hunting gear was removed and the S-3's role became primarily sea surface search and anti-surface warfare. With the retirement of the Grumman KA-6D Intruder tanker, the S-3B became the primary aerial tanker for the fleet. The S-3 saw service in the 1991 Gulf War and the Iraq War, but by 2009 the Navy announced the retirement of the Viking from carrier service, and its role was taken over by other fixed wing aircraft already in the Navy’s arsenal. A total of 188 Vikings were produced from 1974-1978, and the final Viking was retired from Navy service on January 11, 2016.
A US Marine Corps Douglas F4D-1 Skyray of Marine Fighter Squadron 115 (VMF-115) "Able Eagles" in flight in 1957 | Photo: US Marine Corps)
January 23, 1951 – The first flight of the Douglas F4D-1 (F-6) Skyray. One of the more important spoils of war that the Allies captured from Germany at the end of WWII was a trove of aerodynamic data that had been collected by German scientists and, in many cases, the scientists themselves. Germany was on the forefront of innovative and even radical aircraft design, and the Allies were soon employing many of the German ideas in their own aircraft. Among the materials captured in Operation Paperclip was the work of Alexander Lippisch, who had done a significant amount of research into delta wings, specifically tailless delta designs.
A US Navy reserve F-6A taking off in 1963. After the Department of Defense adopted a uniform scheme for classifying aircraft, the F4D Skyray became the F-6 Skyray. | Photo: US Navy
In 1947, the US Navy issued a requirement for a new interceptor, one that could be launched from land bases and carriers at sea. The new interceptor would have to be very fast and have an excellent rate of climb, as it was intended to intercept bombers flying at 40,000 feet with a speed of 575 mph. With an interception range of 100 miles, the new fighter would have to reach 40,000 feet in just five minutes. Following the inspiration of Lippisch, famed Douglas engineer Ed Heinemann created a relatively small aircraft that had rounded delta wings and no tail. The wings were swept to 52.5 degrees, which had the added benefit of shifting the center of gravity aft, thereby improving the aircraft’s pivot point in pitch. With no horizontal tail, the pilot controlled pitch and roll with the use of elevons, a movable control surface that combines the functions of ailerons and elevators. This arrangement later became standard on most delta wing designs. A hydraulic booster helped activate the elevons and, in the event of hydraulic failure, the control stick could be extended by 12 inches to give the pilot more leverage to work them manually.
US Navy Douglas F4D-1 Skyrays of Fighter Squadron VF-74 "Be-Devilers" on the tarmac at Marine Corps Air Station Yuma, Arizona in 1959 | Photo: US Navy
Heinemann originally planned to use the Westinghouse J40 afterburning turbojet, but that engine wasn’t ready in time for use in the prototype. So Douglas substituted a less powerful Allison engine, which significantly affected the Skyray’s performance. The only engine available at the time that would give the Skyray the required performance was the Pratt & Whitney J57, but using this engine required a complete redesign of the fuselage, which Douglas did. The extra work proved worthwhile, because the Skyray turned out to be everything the Navy wanted in an interceptor, and could easily have been nicknamed Skyrocket instead of Skyray (the unofficial nickname was Ford, for F4D). During a test flight on October 3, 1953, the Skyray established a world speed record of 753 mph, the first carrier-based aircraft to hold the title. And, in another test, a Marine Corps pilot took his Skyray to 50,000 feet in just 2 minutes 36 seconds, setting a world record for the fastest time to altitude.
A US Navy Douglas F4D-1 Skyray from Fighter Squadron VF-23 "Flashers" aboard the aircraft carrier USS Hancock (CVA 19) in 1957 | Photo: US Navy
The Skyray entered service in 1956 and a total of 422 were produced. However, despite the Skyray’s blistering speed, it soon became a victim of its own specialization. Designed solely as a high altitude interceptor, the Skyray was unsuited for the multi-role missions that newer, larger carrier aircraft were designed for. It served for only eight years before the Navy phased it out of service in 1964, though NACA continued to fly four Skyrays for research missions until 1969. In an effort to extend the life of the design, Douglas developed a larger, more powerful, multi-role version with the F5D Skylancer, but it was not adopted by the Navy, and only four were built.
A US Army Air Corps Douglas A-20A Havoc of the 58th Bomb Squadron over Oahu, Hawaii in 1941 | Photo: US Air Force
January 23, 1939 – The first flight of the Douglas A-20 Havoc. The Douglas A-20 Havoc was arguably one of the best medium bombers of WWII, but it doesn’t garner nearly as much attention today as the North American B-25 Mitchell, its closest competitor, even though they both arose from the same 1937 US Army request for new attack aircraft. In response to the Army’s request, North American submitted their NA-40 (which would become the B-25), Douglas proposed their DB-7 (Douglas Bomber 7, which would become the A-20, and was designed by Ed Heinemann), Stearman submitted the X-100, and Martin proposed their 167F (which would become the Maryland). In the end, the Army chose North American’s offering, and showed little interest in the submission from Douglas. However, the French showed significant interest in the Douglas design, and they ordered 270 DB-7s at the outbreak of WWII with their own specific modifications. These included a thinner, taller fuselage, 1,000 hp Pratt & Whitney radial engines, French-made guns, and cockpit instruments that used the metric system. These aircraft took part in a vain attempt to stop the German invasion of France, and the survivors were evacuated to North Africa with the fall of France. In battle, the DB-7 proved to be rugged and dependable, with excellent maneuverability and speed for its size.
A Douglas DB-7 in French service in 1940 | Photo: Les avions de la guerre d’Algérie
With the fall of France, the remaining aircraft were handed over to the British, where they became known as the Boston. The RAF intended them to be used as bombers; however, their range was not sufficient to reach targets on the European mainland, so many were instead converted to night fighters called the Havoc I. In this role, the glazed bombardier’s position was replaced with a solid nose which housed a targeting radar. It was also fitted with forward firing machine guns. Another version, called Turbinlite, was given a 2.7 million candlepower spotlight powered by batteries in the bomb bay along with a targeting radar. The unarmed Turbinlite aircraft illuminated enemy bombers bombers so they could be attacked by other aircraft. A large number of A-20B, G and H Havocs were exported to the Soviet Union through the Lend-Lease program, and the Russians eventually operated more Havocs than the United States. The Soviets appreciated the high speed and maneuverability of the big plane and, when fitted with more powerful machine guns and cannons, it became a potent tank buster for the Soviet Air Force. Havocs were also exported to the Netherlands and Australia, where they saw service in the Pacific Theater.
Royal Air Force Bostons in formation | Photo: UK Government
Though initially cool to the A-20, the US Army changed its mind after seeing how well the bomber served in French and British hands. The Army placed orders for two versions of the A-20: one for high-level bombing (A-20) and the other for low-level attack (A-20A). Douglas also produced a version known as the A-20B, which was intended for high-level bombing, with armor protection and self-sealing fuel tanks removed to reduce weight. Though the Army ordered 999 of these B models, the majority were sent to Russia. The A-20G, which removed the glazed nose in favor of four 2omm cannons and two .50 caliber machine guns, was the most highly produced model with 2,850 built. The G model proved particularly effective in the Pacific against Japanese ground targets and shipping.
US Army Air Forces P-70 night fighter, painted black, with antennae set in the nose | Photo: US Air Force
When the US entered into WWII, their first purpose-built night fighter, the Northrop P-61 Black Widow, was still a year away from its maiden flight, and wouldn’t enter service until late in the war. Following the British lead, the Americans converted the Havoc to the night fighting role. Dubbed the P-70, the aircraft’s glazed nose was painted over and filled with a SCR-540 radar, which was a copy of the radar set used by the British. Four 20mm cannons were fitted in a tray beneath the bomb bay, and extra fuel was loaded in the upper bomb bay. Later conversions of C and G models moved the weapons to the nose and the radar set took its place in the bomb bay.
US Army Forces A-20G Havoc. Note the armament in the nose. | Photo: US Air Force
In the end, the bomber that had initially been turned down by the US Army Air Forces proved to be a rugged, dependable, and extremely flexible platform that saw service in all theaters of the war. By the end of production in September 1944, nearly 7,500 Havocs had been built, with a handful also constructed under license by Boeing. Havocs were retired from US Air Force service by 1949, but a number of surplus aircraft made their way into private hands, where they were flown as cargo haulers and executive transport.
January 22, 2003 – The final communication is made between Pioneer 10 and Earth. Pioneer 10 is an unmanned spacecraft that was launched on March 3, 1972 and designed to study Jupiter. The probe made its closest approach to Jupiter on December 3, 1973, then crossed the orbits of Saturn in 1976 and Uranus in 1979 before finally achieving exit velocity and leaving our solar system on March 31, 1997. After solar power to the radios and antenna had become too weak, NASA received Pioneer 10's final radio message on January 22, 2003, when the probe was 12 billion kilometers from Earth. Pioneer 10's final trajectory would take it in the direction of the star Aldebaran, about 68 light years away. At its current velocity, it will take Pioneer 10 more than 2 million years to reach Aldebaran.
January 22, 1992 – The launch of Space Shuttle Discovery on STS-42 carrying the first Canadian woman astronaut into space. Astronaut Roberta Bondar flew as part of an international crew that also carried the first German astronaut, Ulf Merbold, on his second trip into Earth orbit. A neurologist, Bondar started training to be an astronaut in 1984. During her eight-day Shuttle flight, she served as a Payload Specialist for the International Microgravity Laboratory Mission and performed experiments inside the Shuttles pressurized Spacelab. Following her Shuttle mission, Bondar worked for more than 10 years with NASA, leading an international research team to find ways to help humans recover from the weightlessness of space travel.
Photo: San Diego Air and Space Museum
January 22, 1938 – The first flight of the Heinkel He 100, a single-seat fighter developed in the period before WWII for the German Luftwaffe. Designed by twin bothers Walter and Siegfried Günter, the He 100 was a prototype fighter developed in competition with the Messerschmitt Bf 109. The 100 was powered by a Daimler-Benz DB 601 liquid-cooled inverted V-12, the same engine that powered the Bf 109 and Bf 110 Zerstörer. However, both competing aircraft were already in production, and there was an insufficient supply of engines for production of the Heinkel fighter. The only other engine available, the Junkers Jumo 211, provided insufficient power. A specially prepared He 100 briefly held a world speed record of 463.9 mph in 1939, but was soon overtaken by a modified Bf 109. Ultimately, the German decision to back only the Bf 109 and Bf 110, as well as the decision that Messerschmitt was to focus on fighters while Junkers was to focus on bombers, meant that development of the He 100 was canceled after completion of 25 aircraft.
Photo: Author unknown
January 22, 1922 – The death of Elsa Andersson. The daughter of a farmer, Andersson aspired to be more than just a farmer’s wife. At age 24, she learned to fly and became Sweden’s first woman pilot. Following that achievement, Andersson traveled to Germany to learn how to parachute, and toured as a parachuting stunt performer, often diving head first out of the airplane and performing acrobatics during free fall. Her untimely death came in the third jump of the day at a show Askersund, Sweden. In front of 4,000 spectators, Andersson’s parachute malfunctioned and opened too close to the ground to slow her fall. Andersson was 25 years old.
Photo: Lockheed Martin
January 23, 2007 – The first flight of the Lockheed Martin CATBird (Cooperative Avionics Test Bed), a highly modified Boeing 737-330 developed to test the avionics on the Lockheed Martin F-35 Lightning II. Lockheed purchased the 737 from Indonesian Airlines and began the process of converting the former airlinier in 1986. With a full-sized F-35 lightning nose section on the front of the aircraft, and canards that are the exact size and position relative to the nose as the actual F-35, the CATBird provides an economical way to test the Lightning’s suite of avionics, and can carry engineers and other testing equipment aloft in a flexible system for testing different components and configurations.
Photo: J. Klank
January 23, 1909 – The first flight of the Blériot XI. In the early days of aviation, flying across the English Channel seemed an almost insurmountable feat. The first pilot to make the journey successfully was Louis Blériot, flying a Blériot XI, a plane of his own design and construction. The flight made Blériot an instant celebrity, and his fame was an important factor in the success of his budding aircraft company. Produced in single and double seat configurations, the Blériot XI saw service in WWI, and was the aircraft of choice for many pioneering aviators who used it for racing and record-setting flights. Two restored Blériot XIs exist today, and they are considered the oldest flyable aircraft in the world.
January 24, 1975 – The first flight of the Eurocopter AS365 Dauphin, a multipurpose medium helicopter that is currently produced by Airbus Helicopters. Similar in many ways to the commercially unsuccessful Aérospatiale SA 360, the AS365 improves on the earlier design by adding a second engine and other upgraded components. The Dauphin was originally developed by Aérospatiale, but through a series of corporate mergers it was subsequently produced by Eurocopter, and finally Airbus. The Dauphin was introduced in 1978, serves both commercial and military operators, and remains in production after more than 40 years. More than 1,000 Dauphins have been produced to date.
Photo: US Air Force
January 24, 1961 – A USAF Strategic Air Command bomber flying a 24-hour alert mission crashes while carrying two nuclear bombs. Known as the Goldsboro crash, the accident began when a Boeing B-52G Stratofortress based at Seymour Johnson AFB in North Carolina suffered a fuel leak from a ruptured wing. After flying out to sea to burn of fuel, the bomber was ordered to return to base. Unable to control the aircraft as it descended, the aircraft commander ordered the crew to eject, and the bomber eventually broke up, killing two crewmen, while a third died after ejecting. As the aircraft broke up, two Mark 39 nuclear bombs separated from the fuselage. One came down in a field and was destroyed. The second, though, parachuted to the ground as designed and landed upright, its parachute snagged on a tree. Of the four arming switches, three were tripped, meaning the bomb was one step away from detonating, though some experts dispute the claim that the weapon was close to detonating.
January 24, 1961 – The first flight of the Convair 990. In 1959, Convair became the last major manufacturer to enter the civilian jet airliner market with their 880, a four-engine, narrow-body airliner positioned to compete with the Boeing 707 and Douglas DC-8. However, the 880 was never able to capture much market share due to its smaller size, so Convair stretched the 880 by 10 feet to create the 990 Coronado. The new airliner could now seat up to 121 passengers, though still fewer than the 707. Unable to compete in passenger load, Convair bet that both the 880 and 990 would appeal to airlines due to their speed, which was about 40 mph faster than their competitors. However, the penalty for that speed was increased fuel burn. The 990 never caught on, and only 37 were built from 1961-1963. Despite its failure in the commercial market, the 990 remains the fastest non-supersonic airliner ever to enter production, having set a record of speed of Mach .97, or 675 mph, in 1961.
Skyfire77 last edited by
Vickers Type 161
CarsOfFortLangley last edited by
@ttyymmnn KOFL and I are off to the Canadian Aviation Museum this weekend, I'll report back with some pics!
They have a Vampire, which I've always kinda liked.
a box containing approximately USD $265,000 in jewels.
Note that it's apparently unclear whether these jewels are form the Air India 101 crash, or the 1950 Air India 245 crash which in a seemingly absurd improbability was in nearly the same spot, also at the summit of Mont Blanc.
ranwhenparked last edited by
@ttyymmnn I dont think Howard Hughes helped Convair's position, either. He didn't want TWA to just buy the same jets as everyone else, and searched around for someone that would give them a degree of exclusivity.
As I recall, Convair wasn't going to be allowed to deliver 880s to any other airline for like 12 months, and Hughes was able to dictate changes to the design, which kept going back and forth and delayed things (at one point, he wanted the aluminum skin to be made shiny metallic gold colored, so they could market the plane as the 880 Golden Arrow, which proved unfeasible). Also, TWA couldn't afford to pay for the order, so they worked it out where Hughes Tool would buy the planes and lease them to the airline, but the terms were not terribly generous, and it all got caught up in a lawsuit filed by minority shareholders against Hughes, which caused deliveries and payments to be halted for a time.
There is a 1954 British film titles Conflict of Wings, also known by the much more folksy title Fuss Over Feathers, that portrays the conflict that arises when the RAF, preparing for the Malay Emergency, want to use a bird sanctuary for a bombing range. Kind of a dumb movie, but there are some great shots of early postwar RAF jet aircraft, including brief shots of the little-known Supermarine Swift.
siennaman last edited by
Vickers Type 161
An interesting mix of old and new for the era.
An interesting mix of old and new for the era.
Definitely thinking outside the box. While the use of a pusher prop was certainly not new, I'm not aware of any other attempts to integrate it into the fuselage.
@ttyymmnn You'd think they'd have done better to just ditch the rear fuselage section and end up with something more like a WWI Saab 21:
I assume they thought routing the control cables off the centerline was too tricky or something along those lines.
Darkbrador last edited by Darkbrador
The pilot was seated to the left of the centerline
There is something about brits putting the pilot off center. And punishing the navigator for failing his pilot tests and putting him in a closet somewhere below... Case in point :
I believe they were still firmly rooted in a WWI mindset.
ttyymmnn last edited by ttyymmnn
Those are the only two that come to mind. The original F4H Phantom, while keeping the pilot and RIO on the centerline, buried the radar guy in a position they called "the hole." Redesigns gave the guy a better seat with a better view.
@ttyymmnn The YB-35/49 offset the cockpit:
ttyymmnn last edited by ttyymmnn
Then there was the C-74 Globemaster, that put the two pilots under separate bubble canopies on either side of the centerline. That got redesigned into a traditional side-by-side cockpit.
@ttyymmnn Great one! It's hard to believe that the Convair still holds that speed record, 60 years later.
Although not, strictly speaking, asymmetrical, the F-82 Twin Mustang should be mentioned. It had two of the general idea of a Mustang fuselage joined by a center wing section and a common horizontal stabilizer. Depending on the mark and the mission it might have a pilot in the left cockpit and either a relief pilot/navigator or a radar operator in the right one.
The guns were in the center wing section. I've never looked closely at how they handled the gunsight offset.
I've never looked closely at how they handled the gunsight offset.
I never thought about it either.
The unarmed Turbinlite aircraft illuminated enemy bombers so they could be attacked by other aircraft.
Well, that was the goal anyway. My (mis)understanding is that there were several attrition losses during the tricky co-ordination of the Havoc and the night fighters, but actual shootdowns consisted of one Heinkel 111 and one friendly fire incident at the expense of a homeward-bound Shorts Stirling (fortunately the latter made a good landing, supposedly followed by a frank and open exchange of views between its crew and their tormentors).
The experiment was pursued enthusiastically but briefly, retired in favor of better radars that could be carried by a night fighter.