Lockheed D-21

Kelly Johnson called it "the most dangerous maneuver we have ever been involved in, in any airplane I have ever worked on."

The D-21 itself crashed after a flight of a few hundred kilometers."

^{[Vous devez être inscrit et connecté pour voir ce lien]} As a result, the CIA and the Air Force were still not very enthusiastic about the program. Kelly Johnson conferred with Air Force officials to see what he could do to tune the project more closely to the service's needs.

Among other things, Johnson suggested launching the D-21 from a larger aircraft and using a solid rocket booster to get the drone up to speed.[Vous devez être inscrit et connecté pour voir ce lien]

A second successful launch took place on 27 April 1966, with the D-21 reaching its operational altitude of 90,000 feet (27,400 m) and speed in excess of Mach 3.3, though it was lost due to a hydraulic pump failure after a flight of over 1,200 nautical miles (2,200 km; 1,400 mi).

A third successful flight took place on 16 June, with the D-21 flying 1,550 nautical miles (2,870 km; 1,780 mi) through its complete flight profile, though the hatch wasn't released due to an electronics failure.[Vous devez être inscrit et connecté pour voir ce lien]

However, the fourth and final launch from a M-21 on July 30 ended in disaster. Unlike the three previous launches this one was performed straight and level, not in an outside loop to assist in the separation of the drone from the aircraft.

The D-21 suffered engine problems and struck the M-21's tail immediately after separation, destroying both aircraft.

The two crewmen ejected safely and landed at sea.

The pilot, Bill Park, survived, but the Launch Control Officer (LCO), Ray Torick, drowned.

The tragedy accelerated plans to deploy the D-21 on the [Vous devez être inscrit et connecté pour voir ce lien].[Vous devez être inscrit et connecté pour voir ce lien]

The drone was modified by adding attachment points on its spine to mate with the carrying pylon on the B-52 and its belly attachment points were adapted to accommodate the rocket booster.


Its vertical stabilizer was increased in size by about 20%.

The modified drones were designated D-21B (although there was no -21A version).

Two B-52Hs were modified to carry a pair of drones each by means of two large underwing pylons that replaced the smaller pylons used for the B-52's [Vous devez être inscrit et connecté pour voir ce lien].

Two launch control stations replaced the [Vous devez être inscrit et connecté pour voir ce lien]'s and [Vous devez être inscrit et connecté pour voir ce lien] officer's stations and command and telemetry systems were added.

High-speed cameras were installed to track the drones as they separated from the pylons.

The B-52Hs could communicate with the D-21Bs, which had remote control and telemetry links so that the LCO could order it to self-destruct if necessary.[Vous devez être inscrit et connecté pour voir ce lien]

"The booster was a [Vous devez être inscrit et connecté pour voir ce lien] with a length of 44 feet 4 inches (13.5 m) and a weight of 13,290 pounds (6,028 kg), making it longer and heavier than the drone itself.

The booster had a single small [Vous devez être inscrit et connecté pour voir ce lien] on the bottom to ensure that it flew straight.

The tailfin folded to ensure ground clearance.

The booster had a burn time of about a minute and a half, and a thrust of 27,300 pounds-force (121 kN)."

^{[Vous devez être inscrit et connecté pour voir ce lien]} A discharge of static electricity could have ignited the booster and everybody within 25 feet (7.6 m) were required to wear anti-static straps to prevent any discharge.[Vous devez être inscrit et connecté pour voir ce lien]

"Initial testing began in September 1967 and went on until July 1969.


The first attempted launch of a D-21B was on 28 September 1967, but the drone accidentally fell off the B-52's pylon.

Its booster fired, but the D-21B went straight into the ground. Kelly Johnson called the incident "very embarrassing".

Three more launches were performed from November 1967 through January 1968.

None were completely successful, so Johnson ordered his team to conduct a thorough review before renewing launch attempts."

The next launch was on 10 April 1968, and was also a failure because the engine did not ignite.

On 16 June the D-21B finally made a completely successful flight as it flew at the specified altitude and course for its full range and the hatch was recovered successfully.


^{[Vous devez être inscrit et connecté pour voir ce lien]} "The troubles were not over yet, however.

The next two launches were failures, followed by another successful flight in December.

A launch near Hawaii in February 1969 to simulate an actual operational flight was a failure as well, but the next two flights, in May and July, were both successes."

Operations

Four operational missions took place under the codename of Senior Bowl, from 9 November 1969 to 20 March 1971, over the People's Republic of China to spy on the [Vous devez être inscrit et connecté pour voir ce lien] nuclear test site.

They were flown by the 4200th Support Squadron, based at [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien]; the missions were usually launched from [Vous devez être inscrit et connecté pour voir ce lien] in [Vous devez être inscrit et connecté pour voir ce lien].<sup>[Vous devez être inscrit et connecté pour voir ce lien]

[Vous devez être inscrit et connecté pour voir ce lien]</sup>The Chinese never spotted the D-21B, but it failed to turn around and continued straight, crashing somewhere in the Soviet Union.

Another test flight was conducted on 20 February 1970 in a successful attempt to correct any problems.

The second operational mission, however, was not until 16 December 1970.

The D-21B made it all the way to Lop Nor and back to the recovery point, but the hatch had a partial parachute failure and was lost at sea.

^{[Vous devez être inscrit et connecté pour voir ce lien]} "The third operational flight, on 4 March 1971, was even more frustrating. Once again, the D-21B traveled to Lop Nor and back, and properly discarded the hatch.

The hatch deployed its parachute, but the midair recovery failed, and a destroyer that tried to retrieve the hatch from the sea ran it down.

The hatch sank and was lost. The fourth, and last, flight of the D-21B was on 20 March 1971. It was lost over China on the outbound leg."


^{[Vous devez être inscrit et connecté pour voir ce lien]}According to recent information out of China, it malfunctioned and crashed in a forest.

It is said to be largely intact and the wreckage was collected by the Chinese military.[Vous devez être inscrit et connecté pour voir ce lien]

On 23 July 1971, the D-21B program was canceled, due to a combination of the poor level of success and the introduction of a new generation of photo reconnaissance [Vous devez être inscrit et connecté pour voir ce lien], as well as President [Vous devez être inscrit et connecté pour voir ce lien]'s rapprochement with China.<sup>[Vous devez être inscrit et connecté pour voir ce lien]

[Vous devez être inscrit et connecté pour voir ce lien]</sup>"When Ben Rich, Kelly Johnson's successor at the Skunk Works, visited Russia in the 1990s after the fall of the USSR, a contact gave him a package that contained parts of the D-21 that had disappeared on the first operational flight.

It had crashed in Siberia.

The Soviets had apparently been puzzled as to what it was, but it appears that they also obtained the wreckage of the D-21 lost on the fourth operational flight.

The Tupolev design bureau reverse-engineered the wreck and came up with plans for a Soviet copy, named the "Voron (Raven)", but it was never built."

"In the end, 38 D-21/D-21B drones were built with 21 expended.

The other 17 were put in mothballs at the [Vous devez être inscrit et connecté pour voir ce lien] "boneyard" near [Vous devez être inscrit et connecté pour voir ce lien] and re-designated as GTD-21B.


Since the base is open to the public, the exotic D-21s were eventually spotted and photographed, leading to speculation as to their nature, speculation that was inflamed by misinformation from the Air Force.

For example, they were described as test machines used in development of the A-12/SR-71."[Vous devez être inscrit et connecté pour voir ce lien]

"The mothballed drones were passed off to [Vous devez être inscrit et connecté pour voir ce lien], which took four. In the late 1990s, NASA considered using their D-21s to test a hybrid "rocket-based combined cycle (RBCC)" engine, which operates as a ramjet or rocket, depending on its flight regime.

This idea was abandoned, with NASA preferring to use a derivative of the agency's [Vous devez être inscrit et connecté pour voir ce lien] hypersonic test vehicle for the experiments.

Other D-21s have been released to museums for display."^{[Vous devez être inscrit et connecté pour voir ce lien]}