The stick had none of the "play" of the conventional Detroit steering wheel. It translated the smallest motion into action at the wheels, and a steady hand was needed to keep the car from zigzagging at low speeds. Any degree of play can be put into the system, however, and a slower response would be better for beginners. Sensitive as it was on the Chevy, the system was fairly easy to control after a few minutes' experimenting. It was a singularly exhilarating experience. On Firebird III the stick is mounted between the seats. As on the Chevy only hand pressure (and not very much of that) is required; the forearm rests on a ledge behind the stick. If the stick's handrest is turned 20� to the right or left the car is in reverse, but the stick functions as before.
That is how it works. Why it does 50 is a bit more complicated. Here is what GM says (best taken with aspirin and a little water):
"Having complete freedom of motion with a four-inch sweep, the stick can produce any possible combination of driving operations. It does this by positioning either or both of two electrical potentiometers attached to its base. One...feeds a voltage to an electronic analog computer in the steering system, the other to an electronic system which controls the throttle and brakes.
"The principle of operation is essentially the same for each control channel: for example, the steering system computer receives a signal from the hand control potentiometer, another from a tachometer generator showing car velocity, and a third from an indicator showing front wheel position. From these three signals it computes a stabilizing signal that it flashes to an electrohydraulic control valve on the front wheel servomechanism. This valve regulates the flow of high pressure oil to a power piston that turns the front wheels. The throttle and brakes are similarly controlled by individual computers and servomechanisms."
Check. We now go on to the hands-off guidance system. Given a roadway with a special electrical cable embedded in it, the car is so equipped electronically that it will travel directly above the cable with no steering from within. The driver may accelerate or brake as he desires. Or, by pressing a button, he may order the car to maintain a constant speed.
It is, then, a very clever car, and it has two very interesting engines. The 225-hp gas-turbine engine is asked only to turn the rear wheels. In operation its gear noise is like the sound of a jet-prop Viscount airplane—a rather piercing whine. It is smaller, simpler, lighter, more economical and more powerful than its predecessor on the Firebird II of 1955. It is not expected to replace the piston engine on passenger cars any time soon, but it may be used on trucks before long. Theoretically, it can move the very heavy (5,275 pounds) Firebird III at a maximum speed of 150 mph. About 90% of the exhaust heat is recovered and used to preheat incoming air (the "gas" of the gas turbine), and this recovery system is what makes the car roadable in ordinary traffic. A straight exhaust system would scorch anything in its way, because the temperature in the combustion chamber goes as high as 1650� F.—hot enough to melt silver.
A WASTEFUL SYSTEM
Of more immediate interest than the turbine engine, however, is the Little Joe engine, because of its obvious possibilities for conventional cars. The multitude of power accessories on today's cars must be able to operate at the standard engine's idling speed, an inherently wasteful system. Little Joes would permit as much driving oomph from much smaller engines and would operate the power accessories at a constant, efficient speed.
The Firebird's Little Joe is a 20-cubic-inch, four-cycle, opposed-piston, 53-pound aluminum engine (the first without liners), with a 2�-inch bore and 2-inch stroke, developing its 10 hp at 3,600 rpm. It can be time-set by the driver against his return, by the way, to warm or cool the car to a comfortable temperature via heater or air conditioner.
Other innovations from the labs of GM's research chief, Lawrence R. Hafstad, who was responsible for the technical side of Firebird III, cannot be dealt with at length here. Not to be overlooked, though, are the light-sensitive electronic system which turns driving lights on and off as required; a very advanced air-oil suspension and car-leveling system; a unique wheel-braking system in which the aluminum drums are cast as integral units with the wheels; and air-brake flaps at the rear which are reminiscent of those used on the Mercedes 300SLR racing cars at Le Mans in 1955.