The Lockheed D-21 drone was a sophisticated attempt by the US to create an unmanned reconnaissance air vehicle that could spy on its Cold War rivals, the Soviet Union and China, without risking the lives of its Air Force personnel. Despite looking out of this world, it was a very real aircraft.
The D-21, constructed without landing gears, was an innovative contraption that could only be used only once and was jettisoned mid-air from another plane that acted as a mothership. It was the product of the tense nuclear stand-off between the US and the Soviet Union that characterized much of the 1950s and 1960s, and the Free World’s desire to be more well-informed about the development of Communist nuclear programs.
The Flight of Gary Powers
Following the Soviet’s rejection of an ‘open-skies’ policy proposed by President Dwight Eisenhower, which would permit both sides to inspect each other’s nuclear facilities, the US government turned to more surreptitious means to gather data on their atomically armed nemesis.
The U-2 spyplane, a manned reconnaissance device, was crafted specifically with this purpose in mind, flying at an altitude of 70,000 feet which was generally believed to be high enough to evade radar detection.
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Starting in July 1956 with a sortie over Moscow and Leningrad, the U-2 carried out its most famous mission in May 1960, undertaken by CIA pilot Francis Gary Powers from an airfield in Pakistan bound for Norway.
He was to make a 2,900 mile diversion through Soviet airspace. When he reached the city of Sverdlovsk nestled in the Ural Mountains, he was spotted and shot down by a Soviet surface-to-air missile.
Powers released his parachute and floated down to the surface where he was detained by KGB agents and interrogated. He was sentenced to 3 years in prison and 7 years hard labour but was eventually swapped for Soviet spy Rudolf Abel in February 1962.
The US scrambled for an excuse, claiming that Powers had been operating a routine weather flight when he had blacked out following a problem with the oxygen delivery system, causing him to unintentionally drift into the Soviet Union.
However, the Soviets possessed clear evidence from the recovered wreckage that this was false, and on May 11th of that year Eisenhower was forced to publicly acknowledge the truth.
He explained that the program was necessary for US defense policy since the Soviets had rejected the implementation of nuclear inspections and that he planned to continue it.
However, realizing his fleet was now vulnerable to Soviet anti-air attacks, Eisenhower discontinued all manned flights over the Soviet Union in favor of a self-operating alternative.
The CIA decided that an unmanned reconnaissance craft that could fly higher, faster, and be less susceptible to detection was now required.
In 1962 they selected the renowned team at Lockheed Skunkworks, a division responsible for developing many of the black-budget aircraft of the Cold War, to design and build for them a suitable replacement for the U-2.
Lockheed would incorporate many of the aeronautical advances of the SR-71 Blackbird into their new project, which was christened Q-21 and later renamed to D-21.
The D-21 was 42.9 feet long, 7.1 feet in height, and had a gross weight of 11,200Ibs. In combination with a titanium body and single vertical tail, the D-21 had a highly swept delta wing with a span of 19.1 feet, engineered with the wing leading edges running the centre of the vehicle made from silicon composite material.
It was propelled by a Marquardt RJ43-MA-3 Bomarc Engine supplied with circumvented air from a mixed compression inlet connected to a titanium duct that ran through the centre of the craft.
The engine had to be air-launched and could only be activated at a certain speed, hence the D-21’s need for a mothership and its notable absence of take-off and landing gears.
While traveling, it had a cruise speed of 3.2 Mach, a cruise altitude of between 65,000 to 90,000 feet, and a maximum range of 3,000 miles.
It was run by JP-7 fuel that was stored in the fuselage and wings, the fuel tanks being separated into 3 sections by bulkheads which could contain a maximum fuel load of 5,900Ibs. An auxiliary power unit provided electricity for the aircraft and the cooling system, and a hydraulic pump generated charge for the control surfaces.
The D-21’s reconnaissance equipment, including the automatic flight control system, telemetry electronics, recovery beacons, parachute system, and a high-resolution camera capable of taking detailed photos from as high as 90,000 feet were all loaded into an ejectable hatch assembly located on the bottom of the air vehicle.
The D-21 was designed to operate in tandem with another transporter plane and was fitted with a rack that allowed it to be attached to the back of an M-21.
As a result, the D-21 was designated ‘Daughter’ and the M-21 ‘Mother’.
The D-21 was released by the M-21 when a speed of Mach 1.2 had been achieved, helping it accelerate to Mach 3 velocity.
After the D-21 was dropped, it underwent a pre-programmed reconnaissance flight at Mach 3.3. After surveillance, the D-21 maneuvered into an unpowered descent with the hatch assembly, housing all the photos and data, ejecting when it reached 60,000 feet.
At 52,000 feet the D-21 initiated a self-destruction sequence while the hatch assembly glided towards a waiting Lockheed C130 or US battleship to be collected.
Testing with the M-21
The D-21, tested between 1966 to 1971, produced mostly disappointing results. In March 1966, it completed its maiden voyage without any hitches, however, the next two attempts would foster an ominous sense of uneasiness.
The second flight was marred by hydraulic failure, and the third was by a failed electronics module. Concerns were raised by Skunkworks chief Kelly Johnson, who was anxious that the D-21 launch process was too dangerous.
Johnson’s apprehensive analysis was ignored, and in July 1966 the program would be shaken by a horrific accident.
During its fourth foray, the D-21 collided with the right wing of the M-21 upon release at Mach 3.25 speed after experiencing an asymmetric unstart, causing the mothership to break up in mid-air while plummeting towards the Pacific Ocean near Point Magu.
The forward fuselage of the M-21 that contained the two operators were torn off in the clash. Pilot Bill Park was able to escape unscathed, but flight engineer Ray Torick was not so lucky.
His flight suit became damaged and filled with water, and he drowned shortly after hitting the sea.
With one death and both vehicles totally destroyed, the program was temporarily suspended. Lockheed went back to the drawing board, with Kelly Johnson suggesting they should instead use the B-52 Stratofortress as the mounting aircraft.
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The Switch to the B-52
During the top-secret operation codenamed ‘Senior Bowl,’ the Skunkworks crew modified two B-52s so that a D-21 could be fitted onto them. In total, the second phase of the program ran from January 1968 to July 1971.
The new drone, given the moniker D-21B, was re-fashioned with dorsal mounting hooks so that it could bind itself to a pylon from the B-52.
The new prototype was also fitted with a solid rocket booster that was to give the D-21B significantly more acceleration and the ability to reach Mach 2 speed, designed to quicken its passage away from the parent craft, thereby reducing the chance of another mid-air disaster.
This additional component provided an average thrust of 27,300 pounds over 87 seconds, shooting it from 38,000 feet at Mach 0.8 to 80,000 feet at Mach 3.2 in a matter of minutes.
The booster was even bigger than the D-21B, sizing up at 30 inches in diameter, 531 inches in length, and even heavier at a colossal 13,286Ibs.
The D-21Bs flew 4 unsuccessful reconnaissance missions over Communist China, aimed at monitoring a Chinese nuclear weapons testing facility in the west of the county at Lop Nor.
The first D-21B failed after a malfunction with its navigation system propelled the craft past China and into Soviet lands where it was picked up by the KGB.
Later on, after the fall of the Soviet Union, it was transferred back into American custody as a gift from the KGB to retired Skunkworks president, Ben Rich.
The second flight performed admirably until the electronics module recovery system broke down after ejection and fell into the sea. The third mission went very well, but when the reconnaissance module was being retrieved it was accidentally grazed by a US Navy ship, causing it sink to the bottom of the ocean.
The final model, the D-21 #527, simply vanished from sight heading towards the Gobi Desert after launch. It was later found by Chinese authorities after going down near Lop Nor, and is now on display at the Chinese National Aviation Museum.
In 1971 the program was cancelled, and in January 1977, the 17 remaining D-21s were transported into long-term storage and subsequently loaned out to multiple aircraft museums around the USA, with two given to NASA.
In the late 1990s, the D-21s were earmarked to be involved in the testing of the trailblazing Demonstration of Rocket and Air-Breathing Combined Cycle Operation Engine, abbreviated ‘DRACO’.
The plan was to discharge them with B-52s in order to examine how DRACO performed at low-speed flight. Despite the D21s being deemed flightworthy by NASA inspectors, the proposed plan was never approved.
- Wingspan: 19 ft 0.25 in (5.8 m)
- Length: 42 ft 10 in (13.1 m)
- Height: 7 ft 0.25 in (2.1 m)
- Launch weight: 11,000 lb (5,000 kg)
- Cruise speed: Mach 3.32 (2,524 mph; 4062 km/h)
- Maximum speed: Mach 3.35 (3,600 km/h; 2,300 mph) (conversions estimated at the service ceiling altitude)
- Service ceiling: 95,000 ft (29,000 m)
- Range: 3,500 mi (5,600 km)
- Engine: 1 x Marquardt RJ-43-MA-20S4 ramjet, 1,500 lbf (6.7 kN)