Sensational Bmw Three - Wheeler
SENSATIONAL BMW THREE - WHEELER
PETER HOWDLE
MOTOR CYCLE NEWS
BRITAIN'S LEADING Britain's leading sidecar racer, is building a sensational threewheeler for international racing. Although revolutionary in conception, the machine complies with existing FIM regulations and, subject to satisfactory tests, will be raced in this year's world championship. First public appearance will be at Snetterton, Norfolk, for an international meeting.
The new three-wheeler has a steering wheel, a 500cc BMW engine driving Austin Mini front wheels, and one wheel at the back. The passenger lies flat on a fiberglass deck. The driver reclines in a chair, his left shoulder near the back wheel.
The Flying Deckchair is far from complete but Chris Vincent has made good progress in little more than six weeks. He began his new project soon after visiting the Racing Car Show at Olympia. Thanks to Cassius, a lively 18-month-old Alsatian dog, the master's secret has been well guarded!
A winter association with car racing types sparked off the fascinating 500cc international three-wheeler Chris is busy completing in Birmingham. Rumors have been rife for weeks. Now the secret is out.
His ex-Scheidegger BMW Rennsport engine, with new flywheel and car-type clutch, is coupled, via a flanged plate, to an inverted Hewland six-speed gearbox with limited-slip differential. The power pack sits in the front of a tubular space frame, of Reynolds "531" tubing, with the cylinders ahead of the front wheels.
A manual left-hand gear lever will be used, with foot clutch, brake and accelerator pedals on the right of the enginegearbox unit. With suitable gearing, Chris estimates a 120 mph top speed. One advantage of the robust Hewland close-ratio box, normally seen poking from the back of Formula II cars, is the availability of a wide choice of ratios for different circuits. Needle bearings are used throughout. Magnesium alloy front wheels (10 in. x 5.00), with Mini-Cooper disc brakes, are driven through Metalastic flexible couplings. These couplings (known as "doughnuts" in racing car circles) are also fitted to Hillman Imps.
Unequal wishbone suspension, with antidive design for the lower wishbones, incorporate Vincent's own ideas. The rear arms of the lower wishbones are pivoted normally but the other three pivots (each side) are flexible, being mounted on Rose all-steel ball joints.
Rack and pinion steering (not finished when the pictures were taken) will be controlled by an eight-inch steering wheel. The column has a universal joint to bring the height down. Steering box is from a Mini. Eccentric adjusters at the lower ends of the Girling hydraulic dampers provide compensation for different loads. The rear wheel (10 in. tire on 5.30 rim) has an alloy drum brake, with Lockheed compensator, and is pivoted on a Mini swinging arm, actually lighter than the BSA fork on Vincent's famous 650 twin. A wheelbase of 5 ft. 6 in., with 4 ft. track and only 22 in. overall height (top of engine), makes a very compact layout. Fiberglass bodywork and underfloor fuel tank has yet to be tackled by Bill Jakeman. Since international regulations prohibit streamlining exceeding a four-inch front wheel overhang, the engine may have to remain exposed.
Chris does not anticipate many snags. In his reclining position, only his head should protrude above the engine height. The back wheel will be cowled, with a dished passenger deck extending alongside for passenger Terry Harrison to lie, head forward, almost as on a normal sidecar platform. "He should have a comparatively easy time," says Chris. Front wheel valances, possibly of transparent Perspex, will protect the crew from dirt and spray.
Chris has fitted the original BMW oil sump (removed from the engine he raced in last year's world classics). Ground clearance is 4 in. "If this lot doesn't work, I can put the engine back in my old frame," he says philosophically. But if his Flying Deckchair behaves as well as it looks, inv ventive Chris could revolutionize international three-wheeler racing. The prospect
will certainly add glamour to the coming racing season.
Chris Vincent, who has been racing twelve years, is a former national grass track sidecar champion (1960), who won the 1962 Sidecar TT on a 500 BSA. Now 31 years of age, he has won the British national sidecar racing championship four times (1961-63-64-65). He holds lap records for most British short circuits, racing his famous 650 BSA, on which he won the first sidecar race of the 1966 season, at Mallory Park.
