Geoff's e-jet

Feb. 20, 1999


At the Feb. 20, 1999 EV1 Club meeting, Geoff Sommer unveiled a surprise EV1 "accessory" project he'd been working on. This is a trunk-mounted, twin jet engine subsystem (for model planes) meant to assist the EV1 when cruising on the freeway, creating a unique kind of hybrid vehicle. Here's his tour of his "e-jet" car for those who missed the meeting...

I prop the trunk lid open (rather than buy a new lid & cut holes in it) mostly because of the no-modification clause of the lease. Disadvantages include higher drag and the fear that one day I'll forget to open the trunk before firing up!! Benefits of the propped-open trunk include less concern about foreign object damage ("bug strikes") to the engines, and less worry about people vandalizing the exhaust nozzles when parked. And I didn't have to worry about fabricating inlets.

Here you can see the engines inside the stainless steel shrouds. The shrouds serve primarily as insulators, but may also actually entrain cold air in an ejector/jet pump role (although not optimized for that). The high temperatures are localized to the jet core - nothing on the car gets even warm.

Forward of the jets are the two fuel cells - 23 gallons total of kerosene/jet-A/diesel. Note the convenience charger is still in the car - this was a point of pride for me! Everything can come out of the car rapidly, with no sign that the car was ever a hybrid. Not a single hole drilled anywhere.

The control panel is press-fit into the space formerly occupied by the cupholder. The LCD displays came with the engines, and show rpm, exhaust gas temperature, and system status. Below is an overtemperature warning light. Switches (left to right) read ARM, BOOST, RUN, RUN, BOOST, AIR. The system uses four fuel pumps: 2 boost-primers, and 2 for thrust control. AIR is wired to a 210 cfm auxiliary fan that I use to evacuate vapors after static tests - not necessary on the road.

This shows the behind-the-seat air supply. The engines need compressed air for starting and auto-cooldown. Ideally, I would use a 12V, 240 W blower to provide air - but I couldn't find one. Note the Loren Neilsen-designed storage box: largest one in the EV1 fleet! Beautiful piece of woodwork.

The engines provide 85 lb of thrust, enough to cruise at 67 mph on the level if my calculations are right. Mileage should be about 4 mpg, which gives a range of about 90 miles/tankful. Before you recoil in horror, that's actually incredibly good for a jet-powered car, and is only made possible by the EV1's efficiency. Anyway, I'm not advocating this for the masses - if I had my druthers, I'd use a small, non-recuperated turbogenerator, which could be quiet, clean, and get about 15 mpg instead: with a deadweight penalty of maybe 20 lbs with no fuel. Which is the OPPOSITE DIRECTION from that taken by automakers currently working on hybrids. Their hybrid approach cripples the EV. Mine doesn't.

For more info on the engines themselves, see


Photos provided by Marc Zorn and Dave & Jean Kodama

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