Today in Motorcycle History

Unibus Scooters

The Unibus was a scooter designed by Harold Boultbee, built by Gloster Aircraft Co and produced from 1920 to 1922.

This machine was one of the best and most advanced designs of that era and, unlike most others, had the modern-styled enclosure and a flat floor behind the apron. The body sat on a channel-section frame with leaf-spring suspension for both 16-inch pressed steel split-rim wheels.

It had a single-cylinder, 269cc two-stroke, air-cooled engine fitted just behind the headstock, with the crankshaft on the machine axis. The magneto went in front and a clutch and two-speed gearbox behind, this then driving a shaft running back to an under-slung worm at the rear wheel. The worm wheel housing incorporated two sets of brake shoes in the rear hub.

It was advertised as 'the car on two wheels' and was marketed at 95 guineas (£95.75) - a whole year's wages for most working folk - and as such did not attract many orders. This was a shame, because the Motorcycling Magazine of 28 June 1920 said, " From whatever standpoint the Unibus is viewed, it stands as an engineers job from start to finish. The design marks a new era in the march of progress of the two wheeler." Gloster's attempt to diversify from military aircraft even looked like a Vespa, with a starting handle on the dashboard. Pressed aluminium panels hid the mechanical portions and the steel frame even incorporated a parcels compartment under the seat.

Although the Unibus was an advanced design, it proved to be too expensive for its market and was short lived.

Unibus 1920

Shaft drive on British machines is found on two extreme types - the miniature and the fully developed three-wheeler. Above is seen the worm-driven rear wheel of the Unibus.

Olympia Show 1920

Unibus. (Stand 26.)

2½ h.p.; 70x70 mm. (269 c.c); single-cylinder two-stroke; drip feed lubrication; B. and B. carburetter; C. A. V. chain-driven magneto; two-speed constant mesh gear; shaft and worm, drive; Dunlop 16x2½ in. tyres. Price ninety-five, guineas.

Gloucestershire Aircraft Co., Ltd., Sunningend Works, Cheltenham.

One of the most interesting exhibits in the miniature line is the Unibus chassis, which shows distinct originality. The motive power is a 2½ h.p. two-stroke engine set across the frame, which drives through a single dry plate clutch to a two-speed gear box built car fashion across a channel steel frame. From gear box to rear wheel the transmission is by propeller-shaft, on the end of which there is an enclosed worm drive. On the inside of the worm are the two internal expanding brakes, one controlled by hand and the other by foot. The rear wheel of the machine is sprung on quarter-elliptic springs, the wheel being carried in a separate frame. The forks are also provided with leaf springs, which extend from the fork crown to the fork links, and both wheels are of the disc variety. The engine is started by means of a free-wheel hand starter mounted on the dashboard and connected to the engine by a chain. Ease of cleaning and weatherproofing are keynotes of the design.

Olympia Show, 1920

The Motor Cycle, December 2nd, 1920.

Gloster Aircraft Co

The Unibus was built by the Gloster Aircraft Co.

Sources include Graces Guide

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