LATEST DEVELOPMENTS IN TRANSMISSION

LATEST DEVELOPMENTS IN TRANSMISSION

A NOTABLE NEW FLUID DRIVE.

IN view of the great attention that has been given to the fluid flywheel, undoubtedly one of the greatest advances in recent years in the field of the motor vehicle, considerable interest attaches to the advanced type of car Singer & Co., Ltd., Coventry, have now placed on the market in the shape of their new 11 h.p. model, which costs 2240 at the works, as a four-door fourseater saloon. This car is equipped with the new Vulcan-Sinclair ” Fluidrive,” which is claimed to be an improvement on the fluid flywheel, both types of drive having been evolved in connection with the ” Vulcan-Sinclair” infinitely variable speed gear, the inventions of Harold Sinclair. The ” Fluidrive ” is of the greatest ‘ interest in the whole field of motor traction, that is net only for motor cars, but also Diesel locomotives and rail cars, as well as mechanical excavators, pumps, and portable Diesel engine compressors. In the fluid flywheel, consisting essentially of a driving and driven unit, each with vanes, and not touching one another, operating in oil, the amount of the latter in the coupling always remains

the same. The valuable properties of the drive are due to the fact that the power transmission increases very rapidly as the engine speed rises, that is according to the cube of the speed. Thus when a petrol engine runs at 300 revs, per minute, as when idling, the power transmitted is not sufficient to drive the car. At a higher speed, however, say 3,600 revs, per minute or twelve times the idling speed, the power transmission is 1,728 times as great (12 cubed), being practically a positive drive. A fluid flywheel, however, has to be in practice a compromise between two opposing tendencies, high power slip when the engine is idling, to avoid the car “creeping,” and low power slip, that is high power transmission, at ordinary running speed. The ” Fluidrive” has been designed on most ingenious lines to overcome these difficulties. Essentially the new design is a fluid flywheel with the addition of an oil reservoir chamber at the back of the runner or driven unit. When the latter is stationary, with the engine idling, a portion of the oil passes by transfer ports into the reservoir so

as to reduce the amount of oil in the coupling, and therefore the drag or creeping tendency of the car. When the engine accelerates and the speed of the runner increases, the oil in the reservoir is passed back to the coupling by centrifugal force, resulting in minimum slip, that is high-transmission efficiency. By varying the amount of oil in this way automatically the nett result is a great improvement, especially in acceleration and petrol consumption, as compared with the fluid flywheel.

In the ” Vulcan-Sinclair ” coupling, primarily intended for constant speed power driven unit in the industrial field, such as an A/C electric motor, and largely used for fans and centrifugal pumps, it may be stated the amount of oil in the coupling is varied according to the speed required of the driven unit. Some other prominent features of this 11 h.p. Singer are ” Gordon-Armstrong ” independent front wheel springing, special improved design of chassis .frame. 4-speed helical gear, II Perm-mesh pre-selective clutchless gear change and Splintex ” safety glass.