Jet-Powered ATV

Popular Science photographer John Carnett builds a four-wheeler with a screaming Garrett turbine jet engine

Built around a Polaris RZR all-terrain vehicle, John Carnett's homemade machine tops out at just over 60 mph powered by its 87-pound Garrett GTP 30-67 tubine jet engine. The project took Carnett 10 months to build at a cost of more than $15,000.

The beast gets seven miles to the gallon on a mixture of three gallons of regular gas to one gallon of diesel, and it roars at a rock-concert noise level of about 114 decibels.

To build the Whirl, Carnett replaced the RZR’s original engine with a gas turbine connected to a custom gear-reduction box, which is then connected to a pump that controls a hydraulic motor and the transmission. The turbine runs a consistent 8,000 rpm at an output shaft mated to the gear-reduction box, which drops the rpm output to 3,650 (the speed required by the Eaton piston pump to which it’s connected).

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