Billowing smoke at a German Rocket Bike race 1920's

“When you get up to sixty (mph) or so - you’re thinking - I really don’t want to know how fast it will go.”

The Swedes started working with pulse jet technology attaching these jet engines to bicycles at the beginning of the 20th century. Germany built their own jet engined bicycles in the 20's and 30's racing jet propelled bicycles around velodromes, later in World war II they used pulse jet technology for their V-1 Buzz Bomb programme.

A Bob Maddox rocket bike being propelled at speed along a public road.

First we had the Buzz Bomb and some crazy experiments with Pulse Jet technology then along came Robert Maddox. Running on just about anything the pulse jet is a simple combustion engine. Thrust is created by "Pulses" of mixed fuel and air firing about seventy times per second. Ear plugs are supposed to be mandatory if one of these machines is fired up anywhere. At the bottom of this post I've added a short video of Giacomo Agostini firing up a 350cc six cylinder MV - just for comparison.

Robert Maddox's red SUPER TWIN pulse jet is built to be like a replica of a 1920's Indian board tracker ... the SUPER TWIN has a cro moly frame, basic components are an air tank, 12 volt battery, spark box, air goes into the air tank via the frame, a fuel pump one each side, plus a three gallon tank - enough fuel for a five minute run. There's fifty pounds of thrust with each jet, joined in the middle two jets make 100 pounds of thrust total ... expect to do about 120 kmh with both pumps open -"that's how you throttle it" - moderating the throttle is achieved by switching one of the pumps off. These rocket bikes are pretty light so power to weight favours speed. Robert says "I tell ya it would be a blast to take this up on a banked track of twenty thirty degrees"

In the second video Robert Maddox rides the black SUPER TWIN jet bike at about 120 kmh through the Oregon desert. After the run he said "Today's run we were running about 75% gas and 25% kerosene - you can run whatever you want ...... Anyway this is a really nice bike glad I didn't lay it down since it's paid for, I would have been scrambl'n to get all the scratches out" In an interview with wired.com he said “When you get up to sixty or so - you’re thinking - I really don’t want to know how fast it will go.”

Go to http://maddoxjets.com/ and check out Bob's bikes ... it's a passion and it shows, he hand crafts everything, it's not just about the noise they make and how fast they go, these rocket bikes look sensational too. Borrowing design cues from the fifties plus racing heritage from 20's board trackers, add in rocket power - unique and untamed.