October 02, 2015      

Breaking the sound barrier…on land!

Additive-manufactured parts are going to break the sound barrier and then 1,000 mph without leaving the ground in 2016. The Bloodhound Supersonic Car, a British effort to set the next land-speed record, will have three and possible four printed components when it is fired up in South Africa next year.

The Bloodhound, which is nearing completion, will be powered by a Rolls-Royce EJ200 jet engine on loan from the military, a 750 British horsepower Cosworth F1 engine that powers an oxidizer pump and a customized rocket engine that will generate 20,233 pound-feet of thrust. Together, they will generate 135,000 horsepower.

Not surprisingly, the team building the car needs to minimize weight while maximizing strength. The steering wheel and nose tip of the Bloodhound were printed from powdered titanium, and the auxiliary air intakes were printed using carbon by graphite. A fourth part, hinges for the air brake, is being considered for printing.

The air brake is pretty important, as the car will have driven from 0 to 1,000 mph in 55 seconds on an 11.8-mile strip of parched lakebed. Indeed, the airbrake will be only the first of three brakes used. After the air brake will be parachutes and friction brakes.

If the record is broken, and the Bloodhound reaches Mach 1.4, it would mark 3D printing’s most significant contribution to manufacturing history to date.

Bloodhound SSC’s team is being led by Richard Noble, who, in 1983 used a single Rolls-Royce jet engine to set a record of 633.047 mph. Royal Air Force fighter pilot Andy Green is the driver. Green set the current record in 1997, driving a car with two McDonald Douglas F4 Phantom engines to a peak speed of 763.035 mph.

A world record in this endeavor would be exciting, but this is not the first time additive manufacturing has been used to build lighter, faster ground vehicles. Printed nylon parts began showing up on Formula 1 racecars around 2005.

Today, every team uses resins and metal powders with stereolithography and selective-laser-sintering, and carbon-fiber materials are growing in popularity.

In fact, there are between 40 and 60 metal printed parts on Formula 1 racers. Among those parts is the life-and-death critical roll bar sitting directly behind a driver’s head.

Four years ago, the first printed roll bar and, to date, the parts (technically called roll hoops) have held up to the stringent standards of Formula 1’s governing body, the Federation Internationale De L’Automobile.

There are rumors that a very few race teams are using trackside printers, but beyond that, work is sent out to contractors.

Formula 1 engineers have tried extrusion methods of additive manufacturing, but the very nature of laying down layered beads of materials makes it too weak. The objects are more likely to break between each layer.

Oil and water coolers are being considered for additive manufacturing, and there are those who want to eventually print the entire gearbox.

But as any good Formula 1 team principal advises the crew, take it one race at a time.

See related: Five-part webcast series on 3D printing