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W-h-o-o-o-s-h -- supercycles rev up for land speed record

Faster than a galloping thoroughbred.

More powerful than any two-wheeler yet built.

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Able to leap into the record books in a single bound.

Look . . . . It's supercycle! That's the plan, anyway.

A superhuman effort - more than 6,000 man-hours - has gone into a 40 -foot-long bicycle designed and built by Massachusetts Institute of Technology (MIT) students to break the human-powered land speed record.

Five cyclists, enclosed in a machine that looks like a giant pencil on wheels , hurtled down Runway 11 at Hanscom Air Force Base in Bedford, Mass., Sept. 28 in pursuit of the 62.93 m.p.h. record. But just as the vehicle hit 55 m.p.h., an outrigger wheel broke, sending the bike careening to a halt.

''The riders were just starting to sprint, when the wheel snapped. I have no doubt that they could have broken the record,'' says the Group Velocity team leader, Bruno Mombrinie.

The record attempt was part of a last-ditch effort to get sponsors to transport the cyclists and support team to the Eighth International Human Power Vehicle race being held in California, Oct. 2 at Irvine, and Oct. 3 in Carson. There, more than 35 human-powered vehicles (HPVs) of all shapes, sizes, and multiples of riders are to compete. However, race officials say there has never been a vehicle with more than three riders. The record was set by a two-man vehicle in 1980.

One of the more unusual features of this four-wheeled contraption is a donated fiber-optics system. The driver straps on a pair of goggles attached to the end of nine-foot-long bundle of optical fibers. The bundle pokes through a half-inch hole in the opaque nose and offers an amazing wide-angle view.

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Apart from this feature, and the hand cranks used by four of the riders, Mr. Mombrinie says they've stuck to off-the-shelf technology. ''We've avoided new technology to keep it simple. We could have actually built this or something fairly close to it five years ago or even 50 years ago.''

The project has cost an estimated $20,000, including more than $5,000 in parts and materiel donations. Since no sponsors had stepped forward by Sept. 29, it was decided that as many of the riders and support team will go as can personally afford to.

The core of the Group Velocity team is made up of about 6 MIT engineering students. Mombrinie, who graduated in June, says more than 100 people have drifted in and out of the project as interest, time, and money have allowed. The riders are top-notch New England-area cyclists.

When the Group Velocity team arrives in California, they'll find their competition waiting. One of their chief rivals wil come from a school across the river from MIT. Northeastern University has its own 40-foot-long version of the superbike, but with only three wheels and powered by only four riders. This vehicle, too, was constructed by engineering students and their friends.

The Northeastern team has approached the land speed challenge somewhat differently. ''Our strategy has been to put our time into design, not building, '' says team leader Wayne Kirk.

After almost nine months of planning, recruiting, building models, and raising funds, they began construction. The machine was built in about a month and packed off to California without a test run. Tests are going on now.

Mr. Kirk predicted before he left that ''MIT will go over 60 once they get their fairing on. But we'll go over 70 m.p.h.''

Unlike MIT's machine, the Northeastern vehicle, named ''Tensor'' (a mathematical term relating to the relationship between force and velocity), incorporates numerous technological advances.

''There is no way this could have been built five years ago. The parts didn't exist. We're using state-of-the-art bike components and tubing. The shell is made of Kevlar and carbon fiber - both are being used in the latest jet aircraft ,'' says Kirk.

The vehicle looks like a Brobdingnagian javelin with wheels. The long oval shape is based on the cross sections of two airfoils and is aerodynamically designed to reduce drag. What further sets this vehicle apart is the composite shell of lightweight materials. The shell is a sandwich of Kevlar (lighter than fiberglass and used in bulletproof vests) and Nomex (a honeycomb core plastic material) donated by DuPont. The shell alone weighs about 45 pounds. The total vehicle weighs just under 170 pounds - as compared with 250 pounds for the MIT vehicle.

The other significant feature of the Tensor is its 30-inch height above ground. It is the first HPV built this high off the ground; the purpose is to reduce ground effect. (Ground effect is an aerodynamic phenomenon that produces drag when a vehicle is moving close to the ground.) Raising the vehicle, they calculate, will reduce ground effect almost entirely. The benefits of this design are uncertain. As far as the Northeastern designers can tell, there has been no research on ground effect at this height.

Among those who also wonder about ground effect and the like is Eric Edwards, team manager of the Vector Team, fielded by the Versatron Research Corporation in Anaheim, Calif. The two-man Vector Tandem holds the land speed record. Mr. Edwards says Northeastern's aerodynamic design gives it an edge over the MIT vehicle. But he's bothered by its height and its two fairingless front wheels.

''Putting the two front wheels of their vehicle outside of the fairing will create more drag than ground effect. I wouldn't be surprised if ground effect created 10 percent of the total drag, but I doubt if it is over 20 percent.''

Ultimately, the deciding factor, says Edwards, may not be the machines but the riders. Edwards was impressed by Northeastern's stable of four Olympic-class sprint cyclists.

Then there's Edwards's own Vector Team. They aren't about to pull over for the East Coast university upstarts.

''To beat a two-man machine, you need five riders as good as the two in order to come out with more horsepower per man,'' says Edwards. The Vector team has five nationally rated cyclists waiting in the wings for the opportunity to fly the single and two-man Vector machines.

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