Compatible with 1953 GMC XP-21 Firebird I Concept Pearl White 1:18 True Scale TSM121806

XP-21 Firebird 1953, the fighter plane that couldn't fly:

The XP-21 in question was presented under the generic and powerful initials of GMC. The giant American industrial consortium presented this futuristic prototype at its own Motorama show, which was held at the Waldorf Astoria hotel in New York at that time.

The XP-21 was one of three experimental vehicles developed with aeronautical engineering by Harley J. Earl, who was responsible for GM's designs for many years. And it was undoubtedly the most extreme development. In fact, it was a scaled replica of the military Douglas F4D Skyray, with wheels and no wings, although with an imposing delta rear fin.

But although the most striking thing about the Firebird was undoubtedly its airplane shape and transparency, its greatest technological interest was its engine. After much research effort by General Motors, the Firebird represented the experimental culmination of applying a gas turbine in the industry.

Its technology, although quite absurd in practice, still amazes today for its avant-garde nature and complexity. Even more so in the current moment when new alternatives to the internal combustion engine are being sought.

It was a two-phase independent technology. The first was a gas generator that operated using a centrifugal compressor and a turbine. The incoming air was compressed to 3.5 bar and kerosene was injected until the resulting gases reached a temperature of 1,500 degrees Celsius. It was then injected into another Whirlfire Turbo-Power turbine, the so-called driving one, which was connected via a two-speed transmission to the rear axle wheels.

The declared advantages of this then-revolutionary technology (let's remember that today almost all transport ships operate using gas turbines) were the possibility of using various types of fuels, some significantly cheaper than gasoline. Additionally, the Firebird, built with fiberglass, had a very lightweight on the scale and eliminated from its transmission the gearbox, the clutch, and numerous heavy moving parts through which a car loses much energy due to friction.

The importance of the project was far-reaching since the chassis was developed under the supervision of Charles L. McCuen, the very vice president of General Motors and head of the research and development division.

The high speeds that the Firebird could reach, along with its high production costs, made the project commercially unviable. Like airplanes, it had air brakes controlled from the driver’s steering wheel, although it also had enormous brake drums located outside the rims to enhance cooling. A detail that says much about its advanced technology is that its transparent hood could already open automatically via an ultrasonic control.