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  THE MOTOR CYCLIST ILLUSTRATED ROAD TEST  
 
There have been many excellent British three-wheelers, some have been noted for performance, others for economy and simplicity of upkeep, but few for beauty of line. The plastic-bodied Coronet has a measure of all these qualities, and is certainly one of the most handsome three-wheelers ever built.

A product of Coronet Cars Ltd., it is built in its entirety by James Whitson and Company of West Drayton, Middle-sex, and distributed in the United Kingdom by Blue Star Garages Ltd. James Whitson and Company are an incred-ibly capable group of engineers who seem to he able to produce anything and well.

 
 
 
Since the war they have built more than a thousand fire engines on a variety of chassis, and they are highly respected in commercial vehicle circles for their superb 'bus and coach bodies.

Basis of this handsome three-seater is a robust chassis frame with 14 gauge channel-section steel longerons and tubular cross members.Further tubular outriggers support the bodywork, and a composite structure of round and rectangular box-section members form a bridge at the front of the chassis for the independent suspension.

 
 
  Front suspension is by unequal length wishbones and Armstrong coil spring/damper units. Steering is by forward-mounted worm and peg steering box and three-piece track-rod. A 12-volt battery for lighting and starting is mounted within the front suspension framework.

The single rear wheel is positioned between the extremities of the chassis longerons and is suspended on a massive swinging-arm.

Movement is controlled by a single Armstrong coil spring/damper unit, mounted on a tubular structure to the nearside of the car. All three pressed-steel wheels have 7 in. Girling hydraulic brakes.

The 328 c.c. Excelsior parallel-twin two-stroke engine is mounted behind the seat, and drives to the rear wheel through a three-speed and reverse gearbox, final drive being by roller-chain and sprocket. Cooling is by ducted fan, a stream of air being drawn in from the nearside and distributed over the light-alloy cylinder-heads.

First thing to strike the onlooker upon examining the Coronet is its exceptionally high finish and excellent detail work. The shapely glass-fibre bodywork is produced entirely by James Whitson and Company in relatively large numbers. Since March 1957 more than 250 Coronets have been built, current production being about 15 cars per week.

The body-building process is an interesting one involving in the first instance the construction of a light-alloy proto-type shell from which five glass-fibre moulds were made. The five moulds are bolted together to form the complete body mould.

First operation is the coating of the inside of the mould with a release agent. This is to prevent the treated glass-fibre cloth from adhering to the mould when dry. Gelcoat, to provide the body's exceptional outside finish, is applied by brush on to the release agent.

 
Glass-fibre mat is then built-up on the Gelcoat layer, and soaked with brush-applied polyester resins. Several layers are applied and gradually the body thickness is built up. A hardener is added, normal time for setting being about six hours at temperature of 70-80 deg. Fahrenheit. At this stage the mould sections are unbolted, and the body removed.

Bulkhead mountings are next banded into position with glass-fibre strips, and all rough edges are smoothed. Headlamps are fitted and the body is then fitted to the chassis. Doors, which are produced in separate moulds are fitted with special piano type hinges, Whitson-designed and produced. The glass-fibre dashboard is then bonded into position, and all surface imperfections are cleaned up prior to painting.

An enamel spray finish is used in preference to the dyed resins preferred by some plastic manufacturers. A coat of seal, a coat of primer filler and two of enamel are applied, and then the windscreen, sidescreens, hood, instruments, seats, carpets and trimming are added, resulting in a ,very well-finished and attractive car. It seems incredible that such a well-equipped vehicle could weigh less than 8 cwt., but of course to take advantage of the attractive £5 per annum three-wheeler tax it must not exceed this figure with full equipment. Exact all-up dry weight is 7 cwt. 2 qtr. 4 lb. which provides a power-to-weight ratio of about 45 b.h.p. per ton-comparable to many current family cars.

Through the courtesy of Blue Star Garages Ltd., and of James Whitson and Company, MOTOR CYCLIST ILLUSTRATED was permitted to try a Coronet. Acceleration was found to be lively, and a 40 m.p.h. cruising speed seemed to suit it very well.

In spite of the gear-change mechanism not having received its final adjustment, the shift was found to be easy and the hydraulic brakes very powerful.

The Siba starting equip-ment gave an instant and silent start from cold, and due to its petroil lubrication the Coronet can be briskly driven off at once.

Handling qualities were good, with oversteering charac-teristics, i.e. if corners were taken fast, a certain degree of "pay-off" was necessary half-way through the curve. Driving position was good, although the writer would have preferred a shorter steering column. The 47 in. bench type seat is wide enough to accommodate three adults in reasonable comfort, or two large males in luxury!

A parcels shelf under the dash, a hood tray and door pockets all provide useful accommodation, and there is considerable luggage space in the boot. Fuel tank is under the "bonnet" where it is raised to the Amal Monobloc carburetter by S.U. electric pump.

During our brief run the Coronet excited complimentary comments, and a small throng invariably gathered wherever it was parked.

The exhaust note was suggestive of power, but was pleasantly subdued, and full acceleration could be used without creating attention.

 

The Coronet was tried both in open form, and with the excellent all-weather equipment erected. As an open car it was delightful, the curved windscreen providing good protection. With hood and sidescreens in place it became a snug coupe with its good looks, if anything, enhanced. The uncrushable rear window ensures first-class visibility.

 

With its turning circle of 31 ft. and its ground clearance of 7 in., the Coronet is a thoroughly practical vehicle, besides possessing the advantages of economical operation and upkeep. It should come near to ideal general-purpose transport for many people.