We think it goes without saying that military aviation is fraught with hazards. Actually, it is a great deal safer today than in days past. But even so, it is still quite hazardous. It is not at all unusual for 10 percent, or even 25 percent of a given fleet of tactical aircraft produced to be lost to maintenance, operational, or combat losses over the course of a type’s service life. For instance, Canada lost 110 of the 235 CF-104s it operated in 25 years of service, or 46%.
Right up to the end of World War II, when an aircraft was in distress, the crew left by bailing out, that is, simply stepping out of the cockpit or fuselage. But the speeds of aircraft by the end of the war, and the speeds of jets soon after the war, increasingly made that a very hazardous proposition. A pilot bailing out was quite likely to strike the empennage with fatal results.
And so, the ejection seat was born.
Early ejection seats were mostly of the “gun” type. A cartridge much like a huge blank shotgun shell was fired into a closed, telescoping tube attached to the pilot’s seat. The shell filled the tube with expanding gasses, causing the tube to extend, and forcing the seat up the rails it was mounted on. Also called a catapult, this gun mechanism was sufficient to force the seat and pilot high enough to clear the vertical stabilizer of the stricken craft.
The gun type seat wasn’t without its drawbacks. First, it imposed very high g-loads on the pilot. Spinal injuries were to be expected. Second, getting the seat over the tail was about all the early ejection seat accomplished. The pilot still had to separate himself from the seat and manually pull a ripcord to deploy his parachute. This complication actually raised the minimum safe bailout altitude, as it took time, time in which the pilot would be falling to earth.
While a great deal of development of ejection seats early on focused on safely egressing at supersonic speeds and high altitudes, it turned out that most emergencies tended to happen at lower speeds and altitudes. What was really wanted was a seat that could safely allow a crewmember to escape at very low altitude. Simply using a larger gun charge wouldn’t work. That would merely exacerbate injuries to the crewmember’s back.
And so, the British firm, Martin-Baker opted to use a rocket motor. The catapult was still there, to give the seat its initial impetus. But a rocket motor would then loft the seat to a higher level. As an added bonus, the combination of the gun and rocket gave a greater total vertical vector, but a imposed a lower g-load on the pilot.
Other advances included automatic separation of the pilot from the seat, and automatic deployment of the parachute.
As time has passed, ejection seat designers have added improvements to seats to continuously expand the envelope of where and how a crew can successfully eject. First, there are “zero/zero” seats, where a pilot can be at zero airspeed and zero altitude and successfully eject.
Other improvements include not just automatic deployment of the parachute, but ballistic deployment, where pyrotechnics are used to speed up the deployment of a parachute.
At one time, the US Navy was working on a vertical seeking ejection seat that would allow ejections inverted from very low altitudes.
A modern ejection seat in a high performance fighter such as the F-35 is quite sophisticated.
Speaking of sophisicated, Martin-Baker isn’t the only manufacturer of ejection seats, but they do have one of the best PR departments in the business. If you use a Martin-Baker seat, you are eligible for induction into their Tie Club.
The primary objective of the Club is to provide a distinctive tie to be worn with civilian clothing which therefore provides a visible sign of the members’ common bond. Every Club member is given a certificate, membership card, patch, tie, pin or a brooch for the women. All the Tie Club memorabilia depicts a red triangle warning sign which is the recognised international danger symbol for an ejection seat.
Every good company knows that your best salesmen are your customers.
The Russians, by the way, are no slouches in the bang seat business. Their excellent K36 series seat was forced to put on a convincing display at the Paris Air Show a time or two.