Bob Stuart and the Car-Cycle

Styling model for the new CarCycle

The Car-Cycle X-4 was built as an experimental prototype in 1986-87. In '88 it won two second places and one third place in the IHPVA Practical Vehicle Championships in Visalia, California. In '96 it won that event outright in Las Vegas.

The X-4 was built with minimum investment to test its general configuration and proportions. Many minor features help to make it as car-like and convenient as possible. The goals of the overall packaging were to allow room for an adult, child and two grocery bags, to make it narrow enough to go through a standard door, to be tall enough for confident riding in heavy traffic and to keep the shape streamlined .

The major technical innovation also tested is the frame and suspension made of continuous fiber composite parts providing many functions. Just six moldings of Kevlar (tm) fiberglass, and epoxy resin comprise the seat, frame, springs and suspension arms. By incorporating suspension in the frame members the number of parts was almost unaffected, and the total weight was actually reduced since less strength is needed to withstand impacts. Much thought went into the suspension geometry and frequencies, and the test riders have all found the ride amazingly comfortable, even when going fast over a speed bump.

Steering is by side sticks which have about two feet (60cm) of travel, so the action is not twitchy even at high speed. The right hand grip has a lever connected to both front brakes. The left has many functions. Starting from the top are the turn signal switch, the horn button, a lever to mist water onto the rider's legs, shift levers for the wide range derailleurs, and the rear brake. Reversing is accomplished by gripping the right tire through a slot in the fender and pulling.

The height and width specifications made the trike likely to fall over in hard cornering, so the doors were arranged to allow the rider to lean to the inside for better balance. With the brakes on, trikes with two front wheels gain stability and use up some traction, so they will slide rather than roll. In two real-life traffic emengencies, handling has proven adequate to avoid an accident. Many of the features added to make the Car-Cycle more civilized are electrical gadgets run off a 12V motorcycle battery. Lighting includes a powerful headlight, a brake light, turn signals on the roof visible to front and rear, and three lights in the "Safety Sail" tail fin which flash up and down in time with the pedals, imitating pedal reflectors on bikes.

There is also a fan for cooling the rider and/or clearing condensation from the windshield. A manual windshield wiper clips over the top of the polycarbonate windshield when needed. The overall ventilation is regulated by removing or replacing a panel in the nose. With the panel on, it is shirt sleeve temperature inside when freezing outside. The next version will have a convertible top for hot weather riding. On rainy days, the fairing is most welcome.

The "Safety Sail," a large tail fin, is intended to replace the flag sometimes used on bikes. The fluorescent stripes and lights substitute for eye-catching flapping while keeping drag low. In a crosswind, the fin can swing into the wind and act as a sail, as well as keeping the trike balanced to keep going straight.

The main door uses the windshield for a hinge and allows reasonably easy access. A rear view mirror is mounted to the inside of the windshield. A standard bike speedometer is used. Behind the seat you can have either a cargo box or a standard bike child seat. About half the kids encountered would not get in when first offered a ride. Most of the others would not get out afterwards. Both occupants are protected by a roll bar extending up from the main seat back and providing a head rest. Currently only the child has a seat belt, but two could be used.

The bodywork around the rider is made of fiberglass and Kevlar (TM) for crash protection and ease of molding. Coroplast, an extruded polypropylene material resembling corrugated cardboard is used for the front and back body sections. This is not much stronger and stiffer than it needs to be to smooth the airflow, but is very light and tough, shrugging off casual blows.

The overall performance is quite exhilarating. The speed advantage over a regular
bike is about 20% with the vent open, and 30% with it closed. Construction expediencies added about 40 lbs (18kg) to the target weight of 60 lbs (27kg) so it always feels like a production version with lots of luggage. The extra weight, plus the streamlining lead to very interesting riding in rolling terrain. Momentum will carry you up a hill about three times farther from a preceeding descent than it will with a bike, so average speeds are much the same as on the flats. On the other hand, in city traffic, the rider tends to put out short hard sprints followed by long periods of coasting. An electric booster is planned to even out these efforts and keep the speed more constant among hills. ESPN, the sports network produced a very popular show on the IHPVA Championships in '88, and devoted five minutes to the Car-Cycle, calling it the BMW of human powered vehicles. It was also featured on several other TV shows. Of the extensive press coverage, the best was a two-page spread in Bicycling Magazine in April '93.

None of the coverage led to the hoped-for partnership with an established manufacturer or major investor. The opportunities offered led to work on pedal boats, which is now approaching profitability for the second time after loss of a facility. The designer, Bob Stuart, is willing to help with any serious attempts to produce more efficient vehicles.

 For more information about the Car Cycle look at an article that first appeared in the proceedings of the fourth annual Swiss Velomobile Symposium.

You can see more pictures of the Car Cycle here

How to Use Coroplast for HPV bodywork.

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Bob Stuart

Bob Stuart


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