After the success of the initial three GM Motorama Firebirds, engineer Bob McLean's research studio briefly entertained plans to design and build a fourth Firebird.
Plans for a Firebird IV sprang from this
radical overhead-view sketch.
This would have been a large three-passenger "ground-effects" machine, part of a wide-ranging study into automated roadways. It got as far as a full-sized wooden space frame and seating buck, but at that point Design Staff apparently lost interest in the ground-effects vehicle.
Work on the three-seat "ground-effects" car
got as far as this April 1960 frame model.
Maybe GM's designers and engineers realized that turbine-powered passenger cars weren't even the stuff of dreams, much less of reality -- something Chrysler hadn't quite admitted yet.
The chart below provides a comparative look at the stuff of GM/Chrysler's dreams: the GM Motorama Firebird I, II, and III.
| || Firebird I||Firebird II ||Firebird III |
| GM code designation||XP-21|| XP-43 || XP-73 |
| Gas turbine designation||GT-302|| GT-304 || GT-305 |
| Gas turbine type|| Simple cycle|| Regenerative || Regenerative |
| Maximum horsepower|| 400 (rpm NA)||200@28,000|| 225@24,000 |
|Transmission|| 2-speed planetary|| 4-speed automatic|| 4-speed automatic |
| Fuel consumption|| 4-6 mpg|| 8-10 mpg|| 16-20 mpg|
| Wheelbase, inches||100||120||119|
| Overall length, inches||223||235||248|
| Overall height, inches|| 41 (55 at fin)||52.8|| 44.8 (57 at fin)|
| Overall width, inches||80|| 70.6 || 81 |
| Front tread, inches||50|| 60 || 57 |
| Rear tread, inches||54|| 57 || 57 |
| Curb weight, pounds||2,440|| 5,300 || 5,275 |
| Tire size||6.70x16|| 8.20x16||8.00x14/8.50x14|
| Front suspension||Independent|| Independent || Solid axle |
| Rear suspension|| Ind., deDion|| Ind., swing axles || Ind., deDion |
| Body material||Fiberglass||Titanium/fiberglass|| Fiberglass |
The Firebird program's great legacy, of course, was to lend its name to Pontiac's ponycars, starting in 1967. In that sense, it's still alive today, as are the gas turbine engine cars themselves.
Firebird III recently was taken out of mothballs and put back in running order. The fiberglass-bodied Firebird II is also fully operational (it ran alongside Chrysler's famed 1963 Turbine Car at the Straits Area Antique Auto Show in St. Ignace, Michigan), while its titanium-skinned sister is safely tucked away in a warehouse. As for Firebird I, General Motors recently reacquired it from the Henry Ford Museum and plans to restore it, too.
GM also tells us that all three Firebirds might even take to the road again, just as in Motorama days. If they ever come to your town, don't miss them.
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