Wednesday, May 5, 2010

B-58 Escape Capsule

Here is a dead end (for now) of aviation evolution. This is an ejection capsule from the B-58 Hustler bomber, designed by Stanley Aviation Company, it was also used on the XB-70 Valkyrie. The idea was that pilots needed specialized equipment if they were going to survive ejection at high altitudes and speeds, to say nothing of the fact, that if you are ejecting, your plane is probably in a pretty bad way and it is likely there are people who want to make your day even worse than it has turned out to be so far. So basically, when your bomber gets hit with a surface to air missile or a bunch of high explosive cannon rounds, or simply decides that it is done flying before you land it, you are in a lot of trouble.

The B-58 was the first production aircraft to be fitted with an escape capsules for the crew. It was added to the design when engineers began to think about the effects of ejecting at 1400 miles per hour. The force of the wind can tear the helmet off the pilots head. Arms have been broken due to the uncontrolled failing that is pretty much assured when you rocket out of a jet flying at Mach 2. Also, when you are above 14,500 feet, there is not enough oxygen to support consciousness. And it is wicked cold. Like 55 below zero Fahrenheit. To increase crew safety and comfort, the capsules were pressurized, contained a survival packet with food and other supplies and gave the pilot protection from the airstream. When the trigger handles were squeezed, the canopy was jettisoned and then the rockets fired, sending the capsule up and away from the airframe. A drogue parachute immediately deployed to keep the capsule properly oriented. The main parachute deployed automatically at the appropriate altitude on descent. The system was designed to land with the crewman on their back, protected from impact by a manually operated airbag.

Each capsule was controlled by the crewman in it. They were activated by trigger handles and automatically restrained and repositioned the airman. Shoulder straps tightened and pulled the crewmen back while a bar underneath the legs raised the knees and then pulled heels back. Any other position than this would not allow the doors to close. There was a large window in the pilot's capsule along with the control stick, the stick mounted trim buttons and other controls gave the pilot some control over the plane while the capsule while it was closed. The other two capsules
had much smaller windows and did not have any way to access their controls. A closed capsule could be opened during flight, although with difficulty. The doors could be unlatched with levers located near the pilots' feet, but it was hard to reach the latches.

When they tested the "Stanley Capsule" in 1962, a black bear became the first living creature to survive a supersonic ejection. I think the bear really deserved 5 minutes in a sealed racquetball court with the design team after that, but that is just me.

Now for the bad news. The escape capsule did not really work as well can be wished. While the capsule was fairly large and comfortable, Those with size 12 or larger boots were at risk of losing their toes on capsule closure. I'm sure you are beginning to see some of the problems here. During the collision between a F-104 and one of the XB-70s on June 8, 1962, the capsule for Major Cross did not retract enough to close due to the high g forces of the plane as it went down. As a result, he was unable to eject and died in the crash. Major Al White's seat did retract, but closed on his elbow, severely injuring it. He descended by parachute as planned, but was unable to manually trigger the airbag and was subjected to 33 to 44 Gs. He was seriously injured, but made a recovery.

And for the curious, this is the B-58 Hustler, the Air Force's first supersonic bomber.

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