Escape crew capsule

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An escape crew capsule allows a pilot (or astronaut) to escape from their craft while it is subjected to extreme conditions such as high speed or altitude. The crewman remains encapsulated and protected until such time as the external environment is suitable for direct exposure or the capsule reaches the ground.

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[edit] Escape types

There are two ways to do this:

  1. ejecting individual crew capsules (one for each pilot/crew member) or "capsule ejection", and
  2. ejecting the entire crew cabin, or "cabin ejection".

Some examples of U.S. Military aircraft that have escape crew capsules comprise:[1]

  • The B-58 Hustler and XB-70 Valkyrie had individual encapsulated seats. A cabin ejection for the XB-70 Valkyrie was also tested.
  • The F-111 used cabin ejection where both side-by-side seats were in a single 3000 lb (1360 kg) capsule.[2]
  • Three of the four B-1A prototypes also used cabin ejection. They had a single capsule "roughly the size of a mini-van" [3] for all four crew members.

[edit] Design and development

The first escape capsule designed was for the U.S. Navy F4D Skyray.[1] It was tested in 1951-52 but was never installed in the aircraft. The Bell X-2, designed for flight in excess of Mach 3, could jettison the cockpit, though the pilot would still have to jump out and descend under his own parachute.[4] The first production aircraft with an escape crew capsule was the Mach 2 B-58 bomber. The capsule was pressurized, sheltered the pilot from the airstream, and contained food and survival supplies. [5] [6]

The Mach 3 XB-70's two crew escape capsules did not work well the only time they were needed. On June 8, 1966, XB-70 airframe AV/2 was involved in a mid-air crash with an F-104 Starfighter. Maj. Carl Cross's seat was unable to retract backwards into the escape capsule due to high-g-forces as the plane spiraled downwards. He died in the crash. Maj. Al White's seat did retract but his elbow protruded from the capsule and blocked the closing clamshell doors. He struggled to free his trapped elbow. As soon as he freed the doors, he was ejected from the plane and descended by parachute as planned. However, due to pain and confusion, White failed to trigger the manually-activated airbag which would normally cushion the capsule upon landing. When the capsule hit the ground, White was subjected to an estimated 33 to 44 g (320 to 430 m/s²). He received serious injuries, but nevertheless survived. [7] [8] [9]

In the 1960s and 1970s, the F-111 and B-1A introduced the method of jettisoning the entire front fuselage as a means of crew escape. The crew remains strapped in the cabin, unencumbered by a parachute harness, while 27,000 lbf (120 kN) of thrust from rockets pushes the module out into the air. Multiple large parachutes bring the capsule down, in a manner very similar to the Launch Escape System of the Apollo spacecraft. On landing, an airbag system cushions the landing. In the event of a water landing the airbag acts as a flotation device; on land, the airbag is also usable as a shelter. Only the F-111 retains this feature in service.

Three of the four B-1A prototypes featured a single crew escape capsule for the crew members. For the fourth prototype and for the B-1B, this was changed to use conventional ejection seats. One source gives the reason "due to concerns about servicing the pyrotechnical components of the system,"[3] while another says this was done "to save cost and weight."[10] On August 29 1984, B-1A prototype #2 crashed and the capsule was ejected at low altitude. The parachute deployed improperly and one of the three crewmembers aboard died. [11] [12]

For more information on the advantages and disadvantages of B-58/XB-70 style capsule ejection vs. F-111/B-1 style cabin ejection, see Space Shuttle abort modes.

[edit] Ejection seats vs. escape crew capsules

Kelly Johnson, founder of Lockheed Skunk Works, and developer of the U-2 and SR-71 Blackbird family of spy planes, commented on escape crew capsules when discussing development of the YF-12A (Blackbird) ejection seat: "We set ourselves a very high goal in providing crew escape systems. We were determined to develop a system good for zero escape velocity on the ground and through the complete flight spectrum, having speeds above Mach 3 at 100,000 feet. We did achieve our design goals.... I have never been convinced that a capsule ejection is required for anything other than high velocity re-entry from outer space. Our escape system in a very important sense really provides a capsule, which is the pressure suit, which is surely capable of meeting the speeds and temperatures likely to be encountered in the near future of manned aircraft."[13]

[edit] See also

[edit] References

  1. ^ a b B.F.Goodrich - HISTORY OF AIRCRAFT ESCAPE SYSTEM PROPULSION
  2. ^ Ejection Site - F-111 Aardvark
  3. ^ a b Ejection Site - B-1A Lancer
  4. ^ NASA Dryden Research Fact Sheet - Bell X-2 Starbuster
  5. ^ Octave Chanute Aerospace Museum
  6. ^ Ejection Site - EB-58 Hustler
  7. ^ Area 51 Special Projects - XB-70 Valkyrie Crash
  8. ^ NASA Dryden Research Fact Sheet - XB-70
  9. ^ Labiker XB-70
  10. ^ Global Security's B-1A Lancer
  11. ^ Vector Site B-1B
  12. ^ Ejection Seat Site B-1A
  13. ^ "Some Development Aspects of the YF-12A Interceptor Aircraft", Clarence "Kelly" Johnson, Vice President, Lockheed Aircraft Corporation, Burbank, California, July 1969. As quoted in Miller, Jay, "Lockheed Martin's Skunk Works", Midland Publishing Ltd., page 212, middle of column 2.

[edit] External links

[edit] Popular culture

An escape crew capsule was also incorporated into some of Gerry Anderson's complex vehicles on the Thunderbirds TV series. Also, in the TV series Babylon 5 the Starfury space fighter appeared to demonstrate this capability.

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