Three-Litre - ost.rok (od '25)
Sixteen (od '27)
Twenty (od '29)
Twenty-Five (od '29)
Approximately 315 Three-Litre were made.
In 1930, the Sixteen suspension was changed to semi-elliptics all the way round. Around 3,495 examples of the 1926-1930 type were made.
Production of the 1926-30 the Twenty type ran to around 2560 units. In 1930, the 20 was revised with a new 3317cc OHV six (rating 23.8 hp), Zenith carburettor and a slightly larger chassis. Other revisions included vacuum servo brakes and a silent third gearbox.
In 1930, for Twenty-Five a vacuum brake servo was added and Stromberg carburettor fitted.
Sunbeam made one final attempt on the Land Speed Record in 1930 with The Silver Bullet, built for Kaye Don. Despite it dramatic appearance and supercharged twin V12s totalling 48000cc, it was a disaster and achieved nothing.
W ubiegłym roku Henry Segrave na dwusilnikowym Sunbeamie Golden Arrow pobił światowy rekord prędkości, osiągając 372,5 km/h.
Sunbeam 25 HP is one of four types offered by this famous manufacturer. The six-cylinder OHV engine measure 80 x 120 mm (3619 cc) and develop 70 bhp. Treasury rating is 23.8 HP. The wheelbase is just over 11 ft 5 in, the tyre size 6.00-21. The Rally Weymann Saloon with side-mounted spare wheels cost £1075 and is supplied only to special order.
RATED at 4,000 h.p., weighing four and a half tons and measuring 31ft. lin. from stern to stern, the Sunbeam "Silver Bullet," with which Kaye Don (at the moment of writing) is attempting an attack on the world's land speed record, is the most "special" of all the monsters that, so far, have been built. The earlier giants were, in a measure, hybrids; with the "Silver Bullet," the engines, like everything else in the car, are designed and built specially for their job and the whole vehicle is undoubtedly one of the most interesting things on wheels that has ever been evolved.
The engines have twelve cylinders, arranged in banks of six at an angle of 50°. The bore and stroke dimensions are 140 m.m. x 130 m.m. and the capacity is 24,000 c.c. The cylinders are cast in blocks of three and are of aluminium with Nitralloy steel liners. There are four valves per cylinder, and two camshafts for each bank of six cylinders; one sparking per cylinder is used. At the front of each engine, trains of spur wheels driving the camshafts are housed, and at the back of each there is a multiplication gear to the countershaft beneath the crankcase. The engines are installed in the frame tandemwise. Behind the rear engine is a spur-wheel drive which works a blower. The mixture is supplied by two special Amal carburettors. Lubrication is of the dry sump type and each engine has two pumps. The cooling system is unique; because an ordinary honeycomb radiator would present too much head resistance, an ice chest and cistern is used in conjunction with water pumps. Ignition is by coil and a battery.
Transmission is through a three-speed gear box and two propeller shafts (one on each side of the driver's seat) and then by straight-tooth bevels to the axle shafts and road wheels. From engine to wheels the top-gear ratio is 0.965 to 1.
Brakes are operated on the Lockheed hydraulic principle, and the drums are situated within the wheel discs; they are almost as large in diameter as the rims themselves. There is also an air-brake fitted between the stabilizing fins in the tail of the car. This comprises a 2½ fiit square plate which pivots on a cross shaft.
Springing is by means of straight semi-elliptics and Hartford shock-absorbers are fitted.
Steering gear is a duplicated Marles and a lock of only 15 degrees in each direction, giving the car a turning circle of 130 feet. There is no tie-rod between the front wheels.
The body is very highly stream-lined andnothing projects from the main structure save the four wheels and the Splintex wind-screen.
Motor Sport, April 1930