LightAuto

Mainly For Fun

The story of the light sports roadster

Introduction

Light. Sports. Roadster. Looking up these three words in the my dictionary, I find, of light weight, amusement, fun, diversion, outdoor pastime, for sport and use on the road. All the above apply to the type of car, the history of which I wish to relate to you. But to define it further, I look back to a term commonly used throughout the first half of the twentieth century to describe cars with an engine capacity up to 1500c.C. "Light car",. This serves very well to define the size of car I will be describing. "Sports car" as it is used today, is a very broad term, that is why I have chosen to use "sports roadster" to describe the two seat, open, sporting car that was once universally seen as the sports car, in this study. There are various other names to describe this type of car, i.E., "Speedster", "spyder", and others I am sure you will be able to think of, but to me "sports roadster", is the most suitable. The "MG" "T" series of cars is to many people the quintessential light sports roadster, usually associated with young men of spirit, but loved by the young at heart of both sexes. These  cars were not the first and fortunately not the last of the breed, as I will describe in this and following volumes.

 The Beginning 1910 to1920


Early motoring was always an adventure, never being sure when you would break down, or reach your destination successfully. It was novel, with speeds only matched or exceeded by express trains. By the turn of the century, motoring became a more predictable and reliable form of transport and therefore a less exiting pastime. The earliest sporting cars, were created by enthusiasts, lightening and tuning cars so that they may compete against other touring cars with an advantage, in the often illegal and clandestine hillclimbs, speed trials and other sporting events that were staged whenever motoring enthusiasts got together. The open tourer was the most common type of body mounted on cars for the first thirty years of the motorcar, and the two seater tourer usually the lightest. The two seat open tourer, or roadster, in time provided the basis for the sports roadster. These didn't appear as a separate type until the beginning of the nineteen twenties. Previously special models of standard designs with tuned engines had to suffice. Some of these standard designs were very sporting, and if not termed "sports", were sporting in spirit. The period 1910 to 1920 was a time of transition, when the "voiturette type", the earliest form of light car,( The title was used again in the nineteen thirties on a class of racing cars.) Was giving way to the" light car". It wasn't just a change of name but a change in engineering, as significant as the advent of the "mini", and it's affect on car design. There was another development that started about this time, the "cyclecar".

Voiturettes Cyclecars Light Cars

Voiturettes.

Around the turn of the century as mainstream cars got bigger, the "voiturette" type was conceived, a simpler, smaller and cheaper to run light vehicle, mostly with single or twin cylinder engines. By 1912 the type had almost disappeared.

Cyclecars.

This was a motoring side track that started around 1910 and finally expired in the late thirties. The engineering was a hybrid, part motorcycle part car, and cyclecars were produced with three and four wheels. Mostly economy cars but some outstanding sporting machines were made.

Light cars.

The light car of the period shared the technology of the mainstream cars of the day, only smaller, lighter and with smaller capacity engines.In it's roadster form,this was the type that was developed throughout the next sixty years, as the classic sports car.

Abbreviations used in the text.

Engine description.

4.          Number of cylinders.
I.L.       Inline configuration.
"V"twin 2 cylinders in a vee.
W.C.      Water cooled.
A.C.       Air cooled.
S.V.       Side valve.
O.H.V.  Overhead valve.
I.o.E.    Inlet over exhaust valve.
S.O.H.C.  Single overhead camshaft.
D.O.H.C.      Double overhead camshaft.

Chassis description.

1/4 Elliptic.     Quarter elliptic leaf springs.
1/2 Elliptic.             Half elliptic leaf spring.
Cantilever.              Cantilever leaf spring.
I.F.S.       Independent front suspension.
F.W.D.                          Front wheel drive.

Performance.

M.P.H.   Miles  per hour.
B.H.P.    Brake horse power.
R.P.M.   Revolutions per minute.
K.P.H.   Kilometres per hour.

Sizaire Naudin 12h.p. 1912 Voiturette France

Perhaps the unconventional Sizaire Naudin was intended to be an economy car, but the"poke" of it's unusual single cylinder engine gave it no mean urge, particularly in the larger sizes, and the controls were sufficiently complicated to make the driving of it a sporting occupation! The specification embraced a long-stroke single cylinder engine, the speed of which was controlled by altering valve lift, in a wooden frame with the distinction of i.f.s. by transverse leaf spring and vertical sliding members carrying the stub axles,( this several years prior to the first world war ) while there was an exceedingly ingenious change-speed mechanism incorporating a means of pinion sideways and back and fore to mesh with a special multiple crown wheel. Petrol was carried in a cylindrical tank over the engine, and on all grounds the Sizaire Naudin must be accepted as a sports car, apart altogether from it's successes in voiturette contests.

Layout. Front engine/rear wheel drive.

Chassis. Wooden ladder frame.

Engine. single cylinder, 1,584cc.

Transmission. 3 Forward speeds.

Suspension front. i.f.s. coils.

Suspension rear. Live axle with gearbox.

Steering.

Brakes front.

Brakes rear.

Weight. 500 kg.

Wheelbase. 8ft 9in.

Engine output.

@ r.p.m. 2400

Max speed. 50 mph.

Bugatti Type 13. 1910-1920 Germany/France

The Type 13 of 1910, the first car to carry the Bugatti name but not the first of his design as he had designed cars for other people starting in 1900 was very much a representative of the new breed of light cars. While most people think of grand prix cars or what today would be called super cars when the name Bugatti is mentioned, he also produced an outstanding series of light cars, from 1910 until the beginning of the 1930's, all with that unmistakable style and quality expected of him. It was also the first car to be produced in his new factory at Molsheim in Alsace then part of Germany, becoming part of France after the first world war. It was of conventional layout with a four cylinder water cooled engine at the front, this drove a multi-disc clutch running in oil and paraffin, a separate four speed gearbox with a foot operated transmission brake at the rear of the box, then a propeller shaft and a live axle. The chassis frame was of pressed steel with semi-elliptic springs all round and brakes only on the back wheels. What made the car special was the rest of the specification, an engine with an overhead camshaft with curved tappets operating the valves in the eight valve cylinder head. The camshaft was driven by a vertical shaft and bevel gears. It was free revving for it's time and was built to the exacting standards that became expected of a Bugatti. By 1913 the rear springing was changed to the reversed quarter-elliptic layout that was used on all Bugatti's from then on.

Layout. Front engine/rear wheel drive.

Chassis. Pressed steel channel.

Engine. 4 I.L. W.C. S.O.H.C. 1327cc.

Transmission. 4 speed & reverse.

Suspension front. Beam, 1/2 elliptic.

Suspension rear. Live axle, 1/2 elliptic.

Steering.

Brakes front. None.

Brakes rear. Drum & transmission brake.

Weight.

Wheelbase. 2 metres.

Engine output. 20 bhp.

@ r.p.m.

Max speed. 100 kph.

"GN" Grand Prix 1913 Cyclecar England

Out of the many cyclecar manufacturers, one of those that made an outstanding sporting car was "GN". It was the creation of H.R.Godfrey and A. Fraser Nash, who had opened a factory at Hendon in 1911 to produce economy cyclecars. By 1913 now in a new factory they had discovered the formula, that if you use a very lightweight form of construction with an engine of normal output, high performance is bound to follow. This was the secret of sporting cyclecars and can be found today with the "Caterham Super Seven" and the "Lotus Elise". They had moved on from using motorcycle engines to producing their own cyclecar type engines. It was an air-cooled "v" twin, set across the wooden chassis frame, with the exhaust valves facing forward to assist cooling. The dry single plate clutch was incorporated in the external flywheel and the primary drive was taken through a shaft and bevel gearing to a cross shaft. Twin chains running on different diameter sprockets to provide two gear ratios, took the drive to a second cross shaft which carried the pulleys for the final drive to the rear wheels by belts. Some of the 1913-14 models had four chains providing three forward speeds and reverse or four forward speeds. This model was the type used in the 1913 Cyclecar Grand Prix at Amiens an was capable of 60 m.p.h. Apart from the standard production model, in 1914 two special high performance models, known as "Kim" and Bluebottle", which had various advanced features such as bronze cylinder heads with inclined valves of large diameter, a hemispherical combustion chamber and ball bearings for the main shaft. This type of engine developed 30 h.p. at 3400 r.p.m. an gave the GN cyclecar a maximum speed of 80m.p.h. The model which was designed for the 1914 Cyclecar Grand Prix had a developed standard engine with deep cylinder fins, and was capable of 55 m.p.h. Production stopped during the first world war, and the only car work carried out during the time was the design and building of the chain driven prototype which was to become the post war model.

Layout. Front engine /rear wheel drive.

Chassis. Wooden ladder frame.

Engine."V" twin. A.C. I.o.E. 1087cc.

Transmission. Shaft. Chaingang. Belts.

Suspension front. Tubular beam 1/4 elliptic.

Suspension rear. Axle shaft & 1/4 elliptic.

Steering.

Brakes front.None.

Brakes rear.Drums.

Weight. 230 kg.

Wheelbase.

Engine output.

@ r.p.m.

Max speed. 55 mph.

Morgan Aero 1913-1930 Three wheeled cyclecar England

The other cyclecar manufacturer to make an outstanding sporting car, or to be correct, an outstanding line of sporting cars still with us today, was “Morgan”. Starting with a three wheeled cyclecar, the”Grand Prix”, “Aero” of 1913,that was evolved from his economy cars by H.F.S. Morgan, from the beginning based in Malvern Links, just south west of Worcester. “V” twin cylinder air and water cooled J.A.P. engines of 996c.c. capacity were initially fitted, but soon other units of the same general type were also used,including the M.A.G. Precision and Green designs. The chassis consisted of a single central propeller tube acting as a backbone, a tubular front frame with the sliding pillar and coil springs front suspension. From the engine that was set across the frame and the clutch, a propeller shaft inside the frame tube led to a bevel gear and cross shaft and two secondary chain drives, providing two forward gear ratios which were selected by dog clutches, transmitting the power to the sprung rear wheel. In addition to proving itself to be an excellent touring cyclecar, as was shown by its successes in long distance trails such as the London-Edinburgh and London-Exeter, it was also very successful in sprint races, hill climbs and track and road racing. In December, 1912, H.S.F.Morgan established a cyclecar record by covering nearly 60 miles an hour at Brooklands, for which he gained the Cyclecar trophy. The three-wheeled class of the Cyclecar Grand Prix race at Amiens in June, 1913, was won by W.G.MacMinnes on a Morgan at an average speed of 42 m.p.h. against a strong field of continental competitors. Although essentially simple, particularly when compared with the later light cars of the 1920s, the Morgan continued in favour for some forty years, during which time about 20,000 were built.

Layout. Front engine /rear wheel drive.

Chassis. Tubular backbone.

Engine. “V” twin various.

Transmission. Shaft & chain final drive.

Suspension front. Sliding pillar & coil springs I.f.s.

Suspension rear. Trailing fork & 1/4 elliptic.

Steering. Direct.

Brakes front. None.

Brakes rear. Contracting band, hand & foot.

Weight.

Wheelbase.

Engine output.

@ r.p.m.

Max speed. 60 mph.
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