The Ejection Site

1- What is the fastest ejection on record?

Although this seems to be an easy question, looks can be deceiving. 'How fast' is an imprecise question as it can be answered in several ways, for example: speed over ground, Knots Indicated Air Speed (KIAS), Knots Equivalent Air Speed (KEAS) and so forth. For example, some SR-71 pilots are rumored to have ejected at speeds of Mach 3 at 80,000 feet. This is a ground speed of around 2000 miles per hour, yet due to the thinner atmosphere at that altitude, the speed is closer to 400 KEAS. That is more like a 460 miles per hour. An F-15E pilot survived an ejection at a very small ground speed as he was traveling almost straight down in a spin, yet he was traveling at 780 MPH. This is over 1.6 times faster in equivalent air speed. Another difficulty with answering this question is determining the exact speed. Since most ejections occur in situations that are changing rapidly, it is difficult to get an exact speed of the ejection. Most ejection speeds are calculated values based on the recollections of the crewman, and what little evidence survives the aircraft's destruction. This can lead to very imprecise numbers. In the first known case of a man surviving a supersonic ejection, George Smith(IIRC will be verified) ejected from an F-100 Super Sabre in a dive. It was known that he ejected supersonically due to eyewitnesses who heard and saw the ejection from nearby based on the sounds of the sonic booms and the visual clues of the crash.

2- Are there any helicopters with ejection seats?

Yes. The Russian Zvezda K-37 seat system was specifically developed for use in the Kaman Ka-50 Black Shark, and is also used in the Ka-52 Alligator attack helicopter. The seat is more of a tractor rocket system than a full ejection seat, but it does provide for escape from the helicopter. The system first fires explosive bolts to jettison the rotor blades then jettisons the canopies and finally tractors the crewmen out. Their parachutes automatically deploy seconds later. In the United States, some work was done on a similar concept using an AH-1 Cobra helicopter, and a crew module system was tested on an H-21. Neither was followed up on.

3- What seat is in xxxxxx airplane?

This is a very difficult question to answer. In many cases the aircraft goes through several different seats in its service career. Often the prototypes will have one seat and the service aircraft a different seat. In other cases the seat may vary either in detail or to a different design over the lifespan of the aircraft as requirements change, and as the seats evolve. The Lockheed F-104 Starfighter had at least six seats (five of which are covered on the attached page). The F-100 Super Sabre had at least four. In recent vintage, the F/A-18 has at least two types (three different designations), as well as the F-14 using two different seats over its lifespan. If you have a specific question as to a particular aircraft, drop me a line, and I will attempt to look it up.

4- Why are some seats gray, and others black?

There are several reasons for the choices, some of which are due to tradition, others due to practical reasons. The traditional rule is that a single seat aircraft will have a gray seat, and a dual seat aircraft will have black ones. This is mainly due to canopy reflection from the gray seats being more noticeable in dual seat aircraft. There are of course exceptions to the rules. Martin-Baker Aircraft seats are normally black no matter which type of aircraft, but even they produce gray seats upon request. The color choice is normally part of the specification for the seat from the customer, be it the military, or the military contractor producing a prototype. Newer USAF aircraft are generally getting black seats for the glare reason mentioned above.

5- What is the maximum G force that a crewman experiences on ejection?

The maximum G-force that is experienced depends on several factors of the propulsion system in the seat, and in the mass of the seat/man combination. As there are many different designs of seats and propulsion systems, it is hard to generalize this. The older purely ballistic seats tended to be higher ranges, from 17-22Gz not being unusual. Later designs lowered the maximum G force as the addition of rocket propulsion allowed for seats to clear the aircraft with less initial force. The newer seats are often in the range of 12-14 Gz. This varies by temperature as well, with the hotter cockpit temperature allowing for a higher impulse from the cartridges.

The other major factor is the mass of the seat/man package. Often referred to as the total ejected mass, this is a measurement of the mass of the seat, the survival equipment, and the crewman and his/her total body mass along with the mass of the gear he/she is wearing. In current issue seats, the amount of force from the catapult and rocket is not variable so the lighter the crewman the higher the amount of force. The reverse holds true for the heavier crewman up to a point, where the total mass of the seat/man begins to cause excessive inertia to build up on the catapult. This would allow gas pressure to build higher and thus provide a higher force when the inertia is finally overcome.

Another force that is often involved in this calculation is the amount of G force the aircraft, and its occupant are experiencing when the seat fires. This has an additive effect similar to that of the higher weight occupant.

Since all these forces vary from one ejection to another, a range of force is often specified for a particular seat based on the average crewman on the average day.

6- Does the crewman land in the seat?

A common misperception reinforced by some movies. A full function ejection seat includes some form of seat separation mechanism. Since the early nineteen-fifties the separation mechanisms also would deploy the parachute for the crewman. In some cases, the parachute deployment is actually what causes the separation by allowing the drag of the parachute to remove the crewman from the seat, which continues on its inertial path. Other methods of separation included an inverted 'Y' shaped strap which ran from the front of the seat pan under the survival kit, behind the parachute and into a roller system at the base of the headrest. This roller system is gas operated and at the appropriate time, hot gas would cause it to rapidly spool in the 'Y' strap. This would force the survival kit, parachute and the crewman off the seat. The parachute is connected to the seat by a lanyard which would actuate the automatic opening device. Another type of separation system is a rocket system. The small rocket, often called an 'ear-burner', is located over the crewman's shoulder. When the separation gas reaches the rocket, its thrust forces the seat away from the crewman. The thrust is aimed up alongside the crewman's head, hence the nickname.

7- Why not let the crewman land in the seat?

An ejection seat is a large object which has a certain mass. If the crewman was to descend in the seat, the parachute would have to be larger, or there would have to be another deceleration device to make the landing force acceptable to the human occupant. This is the case in terms of ejection capsules such as the B-58 capsule, and the XB-70 capsule, as well as the F-111 family crew module. For an open seat, the problem is larger as the seat would make landing hazardous to the crewman. In water the seat would act as an anchor and drag him under. The capsules and modules mentioned used flotation devices to prevent this.

8- What happens to the seat?

The seat falls to earth restricted only by its air resistance. The seat which can weigh upwards of 100lbs (45kg) simply tumbles to the ground as does the canopy or hatch the crewman ejected through. Often this leads to damage or destruction of the seat on impact. You might see some footage of a seat falling with a parachute deployed on it. In that case, it is either a drogue chute (small, five to ten feet {two and a half to three meters}) On rare occasions, the seat has been known to land on something or someone and do damage. See the anecdotes page for some examples.

9- I just found a seat in the woods, can I keep it?

Well, if you like having unexploded ordinance in your house, that could injure or kill you... Actually, the first thing that you should do if you find a seat is to stay away from it, and mark its location. Then you should contact your local authorities as to its location so that it may be safely dealt with. It is not only dangerous, but also evidence in an accident investigation. Moving it, or taking parts off of it, may make it difficult or impossible for the investigation crews from answering questions about injuries to the occupant. Those answers might save the life of a crewman later on. As tempting as taking it home may be, an ejection seat is a dangerous piece of material. Collectors often own seats, which should be thoroughly checked by a person familiar with the seat before it is accepted. Virtually every seat is designed to have backup systems to allow the crewman to manually override some of the seat functions if there is a failure. These devices are often cartridge activated devices and they do pose a danger to the unwary. If someone has restored a seat, it should not have any active cartridges on it, but even so, a seat should be treated like a firearm. If you don't know the situation, treat it as if it were loaded.

10- O.k., then where do I get one?

Ejection seats are sold as surplus by the DMRO on occasion. Often they are demilled (intentionally damaged to prevent re-use) and almost always missing parts. They are large, and bulky items which makes shipping expensive and difficult. That said, there are a few places where collectors, or sim builders can look for seats. Click here to go to the Wandered and Pondered pages for surplus merchants. These merchants have been buying seats from the DRMO and other places for a long time and may have the seat you are looking for. Since ejection seats are United States Department of State classified as Munitions, export regulations are involved in shipping seats out of the US. Shipping on a seat may be in the hundreds of dollar range, so keep that in mind when looking. Another source is on-line auctions where often seats are available.

11- Why can't you give a simple answer to a simple question?

I have spent many years researching the field of egress systems, and spoken to many experts on the designs of them. One thing that has impressed me, and stuck with me, is that in most cases there is no simple answer. Each situation is different from the next in some way. Sometimes, the difference is so minor that it has no effect on the outcome, other times, the difference that seems minor has major effects on the outcome. If I were to give a short answer to many of these questions, I would be doing a disservice to the person who asked the question.