Genius Innovators

Zero/Zero and the Complete Opposite

Zero-Zero-Sign

Along the way to the modern ejection seat systems from companies like Martin-Baker, other systems have been developed or talked about. Among these sidetracks in the world of pilot safety are some really great ideas (zero/zero ejection seats) and some really bad ideas (Downward Track ejection systems).

To call the Downward Track ejection system a really bad idea actually unfair. It wasn’t until fairly recently (since about the 1970s) that ejection events were considered for low altitude/low speed. Until then, the basic premise of ejection systems was to get the pilot out at altitude and above a certain minimum speed. On some aircraft, due to the aircraft or crew configuration, the reasonable thing to do given that basic premise was to drop the pilot or crew members out through the floor. Early versions of the F-104 were equipped with such a system because engineers were concerned the pilot wouldn’t clear the tall T-tail. In the F-104’s system, the pilot wore spurs that would allow the ejection system to pull the legs to the seat before ejection. In fact, many ejection systems do this to control center of gravity and to keep limbs from being too akimbo. The B-52 will eject the pilot, co-pilot, EWO and gunner up, but the navigator and radar navigator are on a lower level than the other four crewmen. Because of this, it’s necessary to eject them downward. Explosive charges open the ejection hatches and gravity pulls their seats out.

In the 1960s, the US was embroiled in some little war in the jungles of Southeast Asia. After pilots reported that gravity caused them to fall towards the earth behind enemy lines when they were shot down, the US military began looking for a system that would allow the pilot to fly his seat a safe distance away from the aircraft-turned-flare to try and avoid detection. Air Crew Escape/Rescue Capability or Aerial Escape and Rescue Capability (AERCAB) systems were considered from several suppliers, including one involving small turbine engines on small wings. When the US finally began planning the pullout, the AERCAB program was dropped.

When the speeds of aircraft began to get ludicrous, engineers were concerned about the affects of supersonic velocities on pilot bodies. Several pod systems were developed, including the one we saw last weekend on the B-58 Hustler as well as on the F-111 Aardvark, XB-70 Valkyrie, and Apollo crew module. Some of these, like the F-111’s, would actually be the entire cockpit. This had the added of advantage of giving the pilot and co-pilot someone to talk to on the way down.

The greatest leap in ejection seat technology is pretty much the exact opposite of where we started this post. The zero/zero ejection system is designed to allow the pilot and co-pilot to eject even if their aircraft is sitting still on the ground. Non-zero/zero system have some minimum altitude and speed, mostly having to do with the parachute deployment. Zero/zero systems can be very simple — rockets on the bottom of the seat to get it away from the plane and on the parachute to ensure full deployment — or very complex, like Goodrich’s ACES II system. ACES II is one of the newest ejection systems in the world. A computer monitors aircraft attitude, speed, altitude, and a host of other factors and decides when to deploy the drogue chute or the main chute, if there’s enough time to jettison the canopy or if the pilot will be sent through the glass, and what type of beverage to serve with the inflight meal. My recommendation would be The High Smolder from Zero Zero in San Francisco.

I hope you enjoyed this little series. It’s incredible to see the progression of technology, as evidenced by the ejection seat, over the last century.

[Image Credit: Joshua Lurie of Food GPS]

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