Forgotten makes, No 80: The Constantinesco

A Romanian in London

George Constantinesco, the son of a professsor of mathematics, was born in Romania in 1881 and emigrated to England in 1910. He became a naturalised British subject and is probably best remembered for his hydraulic synchronising gear, which enabled a gun to be fired between the blades of a rotating aeroplane propeller and greatly increased the effectiveness of our fighters during World War One. His wartime inventions should have brought in £99,000 but, as with WO Bentley, tax problems intervened.

He developed the Constantinesco light-car partly to demonstrate the efficiency of his torque converter (which worked on the principle that liquids can be compressed and release energy on their expansion) but also as an effective car in its own right, giving 100mpg at the 35-40mph speeds common at the time of its introduction.

The transmission was but one of many ingenious and successful Constantinesco inventions. It worked on the pendulum principle, and gave an infinitely-variable, clutchless drive at a time when gearchanging and smooth engagement of the clutch were a nightmare to many beginner motorists.

The working of this torque-converter was the subject, as I well remember, of a Meccano model which could replace the sliding-gears on the 1920s Meccano chassis. It was demonstrated in May 1923 in a Sheffield-Simplex chassis whose original 45hp engine had been replaced by a 10hp Singer unit and its radiator — ten adults standing on a platform on this chassis being driven about London by George Constantinesco. The set-up was capable of riding smoothly over 6in wood blocks placed before its wheels, and of towing a lorry up a steep hill.

The Editor of The Automobile Engineer became interested and, to silence any disbelief that his torque-converter would not work, Constantinesco offered £100 to the first person to prove his mathematics wrong or his formulae not in strict accordance with logic. There were no takers . . It is interesting that his first model of the converter emerged from a purely mathematical analy sis of the problem, translated into a working drawing. The model performed as predicted, without trial-and-error or modification.

I do not intend to explain fully how the converter worked, because that will be described and illustrated in a book which George Constantinesco’s son Ian is writing about his father’s life. Suffice it to say that, having proved his torque-converter to be astonishingly effective in the Singer-powered SS, the inventor set about his small-car project. A single-cylinder air-cooled two-stroke engine was coupled to the converter and installed in a chassis which was exhibited at the Empire Exhibition at Wembley in 1924— where Constantinesco had a stand on which were displayed other products stemming from his ingenuity and engineering prowess.

This chassis had previously been shown at the 1924 Paris Salon, but it was realised that there were cooling and engine-balance problems with a single-cylinder engine, so a new design was prepared for the production car. This used a two-stroke engine with two vertical cylinders, well spaced out so that the torque-converter could be placed between them.

The engine was water-cooled, with a bore and stroke of 67mm x 70mm giving a capacity of 494cc, using a carburettor of Constantinesco’s patented design. It was a professionally-made power-unit, whose pot-like water jackets were coupled by a large-bore water pipe extending forward to a shapely radiator. The carburettor was on the offside, two separate exhaust pipes running fore-and-aft on the nearside of the engine and converging just ahead of a large silencer.

Construction of the car was undertaken at Constantinesco’s works at 130 Wilton Road, Victoria, London (he also had offices at 7 Grosvenor Gardens), with some work also being done at 27 Rue La Boetie in Paris. The power-units were installed in an equally professional-looking chassis whose side-members were swept high over a back-axle which had two sliding bevel pinions, to provide a reverse gear via dog-clutches (a system used on very early Panhard and Daimler cars, involving slight offsetting of the universally-jointed propshaft in reverse, engaged by a separate lever). No differential was used, the drive going only to one back wheel; it was claimed that as the propshaft rotated anti-clockwise it gave the driven wheel ample grip, especially as the converter produced five times more torque than normal . . .

Centre-lock wire wheels were fitted, as were four-wheel brakes. The engine, which had lubrication additional to the “petroil” mix of the usual two-stroke, inclined spark-plugs and no gears (a dynamotor starter was fitted), moved the car off from about 1200 rpm, after which driving was fully automatic. Running back on hills was obviated by sprags, and even against a wall with the throttle open it was claimed that the engine could not stall.

This two-cylinder Constantinesco was shown at the 1926 Paris Salon as a chassis; there were two saloons also on the stand, each weighing less than 10cwt and priced at £315. The inventor demonstrated the car in neat two-seater form priced at £215, the original aim of selling it at 100 Guineas having proved too optimistic. In England, where it was hoped to produce the car, HP-rating was 5.58, making the tax only £6 a year.

Constantinesco publicised the project by demonstrating that his eight-year-old son Ian could drive the car, and that the famous sculptor Antoine Bourdelle, who had never driven a car before, was after a few minutes tuition able to drive the Constantinesco about the streets of Paris. The inventor also got his wife Sandra to lead the car by a string attached to the throttle lever! When tried in this country by The Autocar, smooth running at 25mph was reported, with a top speed of about 35mph from this 16cwt, 500cc car.

In its final form in 1926, the Constantinesco had a wheelbase of 8ft 6in, half-elliptic springs front and back, and 715×115 tyres. The four-seater cost £250.

Unfortunately finances ran out, and only six were built. Of these, four have disappeared (probably going to Romania between the wars, when George Constantinesco went there to promote his torque-converter for railcar purposes) but a complete car is in London’s Science Museum awaiting funds for restoration, along with a power-unit which probably came from a demonstration chassis.

The Constantinesco was a remarkable little car, foreshadowing today’s two-pedal automatic-gearbox cars and Ford/Fiat’s infinitely-variable CTX transmission. I am indebted to Ian Constantinesco for his help and wish him well with his book. He would be interested to hear from any reader who has owned one of his father’s cars. WB