M.G. GIVES BRITAIN A LEAD
THE NEW R TYPE MIDGET RACING MODEL INCORPORATES TORSION ROD INDEPENDENT SPRINGING FOR ALL FOUR WHEELS, INDEPENDENT STEERING, A Y SHAPED BOX FRAME, GIRLING BRAKES, AND PRE-SELECTOR GEAR BOX. PRICE, READY TO RACE, 1750.
APRIL 25th, 1935, may well rank as a milestone in British automobile history. On that clay a little gathering of racing personalities assembled at a Piccadilly showroom, where Mr. Cecil Kim ber had invited them to inspect the latest product of the M.G. Car Company.
And what a magnificent engineering achievement this new car is ! The Monoposto M.G. Midget Racing Model (Type R.) stood in the centre of the large room, almost submerged by the peering heads of the guests, while those who had already examined its remarkable features stood around and unburdened their enthusiasm on their equally enthusiastic listeners. Dealing first with the chassis, for it is in this respect that the Type R differs radically from all other British productions, we find that the normal chassis frame has been discarded in favour of a Y-shaped frame built up into a box section of electrically welded 16 gauge steel. It is internally braced, and although weighing only 57 lbs. is far stronger than any conciform construction of the same weight. Each road wheel is carried on two horizontal wish-bone brackets mounted above and below the frame, on which they pivot. The lower bracket is connected to the torsion rod, which is placed parallel to the chassis-frame and is fixed on a special bracket at the far end. With this form of springing, of course, it is essential that adjustment of the torsion bars should be possible, so that the car can be held at the correct height from the ground and the angles of the “
wish-bones” be arranged in normal relation to the stops limiting the wheel movement. The M.G. system provides for adjustment of the torsion-bars at their fixed ends. The stops, incidentally, are forged in one piece with the wheel-carrier brackets. Liivax shock-absorbers are used, with exceedingly light fluid-containers made of hiclumini um. In case any of our readers may doubt the safety of the torsion-bar suspension, it will interest them to hear the following experiment which was made at the M.G. factory. For the adequate springing of
Detailed Specification of the Monoposto M.G M.G. Midget 1?acing Model (R type).
rngine : Four cylinder, 67 x 73 mm., 746 C.c., 108 0.h.p. at 0,500 r.p.m. Pressure lubrication, with 8 pints spare oil supply. Z.,ollerM.G. compressor giving 22 lbs. per sq. in. normal boost, and 28 lbs. per sq. in. maximum boost. S.U. carburetter. 14 mm. plugs.
Transmission Wilson pre-selector gearbox.
Ratios : top direct, third 1.3 to 1, second 1.84 to I, bottom 3,09 to I, reverse 4.15 to I. Rear drive ratio 4.125 to 1. Wheel size 3.00 x 18 rims. Tyres 4.75 < 18.
Sundry : Tank capacity 22 gallons. Fuel feed by twin SU… pumps. Track, front 3/1.10 tn., rear 3 ft. 9 in. Wheelbase 7 ft. 6 in. Weight empty 11 cwt.
Price, ready to race : £750 ex works.
the monoposto Midget the bars have only to twist through an angle of 35 degrees, but in an actual test no less than eight complete turns (2,880 degrees) were made before the bar snapped. There’s a margin of safety for you !
The steering-gear, too, is a complete departure from previous M.G. practice. The front wheel steering arms are attached to long drag links which pass alongside the body to a cross-shaft which extends on each side of the chassis and is held in two bearings. This is operated by a twin-steering box bolted to the bulkhead. It will be seen that this system provides absolutely independent steering of the front wheels, the usual track-rod being eliminated. In actual practice the great advantage lies in the fact that the” kick” from one wheel does not affect the steering of the other.
The new Midget carries the highly successful Girling brake drum and brake back-plate assemblies, the former being made of high manganese steel and the latter of elektron. A feature of this system is that the braking efficiency does not fall off at high temperatures.
Turning to the engine, the power-unit of the ” R type ” is really a modified version of the ” Q type.” The latter was sometimes prone to overheating, however, and this has been cured by means of an improved three-branch water manifold, which materially assists the cooling of the head. A Zoller-M.G. compressor is fitted in the usual forward position, and draws the mixture from a large-bore S.U. carburetter. At 6,500 r.p.m. incidentally, the engine develops a b.h.p. of 110, more than any four
cylinder in the world of its size. The blower gives a maximum boost of 28 lbs. per square inch. The drive is transmitted through a disc-type clutch and a pre-selector gearbox manufactured under Wilson patent. The clutch is so arranged that it cannot be operated by the pedal controlling the gear-bands, but only comes into operation should, in changing to a lower gear, the engine revs place a strain on the trans mission in excess of a pre-determined slip-load. The gear-selection is made by means of a normal quadrant mounted on
the steering column, thus eliminating the necessity of removing one hand from the steering wheel. From the gearbox the torque is taken to the rear through a Hardy-Spicer propellor-shaft which is balanced at 8,000 r.p.m. The shaft runs on top of the single chassis-member. The dif ferential assembly is composed of straight cut teeth crown wheel and bevel pinions and a four twin differential. The alu
minium casing is mounted on the chassis member and the cross tube to which the ” wish-bones ” are attached. The power is finally transmitted to the rear wheels by way of short Hardy Spicer shafts. At the price of £750 the Monoposto Midget is an amazing proposition, being a
genuine Grand Prix racing car in miniature. Nothing like it has ever been within reach of motor-racing enthusiasts at the price, either in England or on the Continent.
No description of this outstanding racing car would be complete without a tribute to Mr. Cecil Kimber for his courage in breaking away from orthodox design. The result is a car which will be the admiration of the rest of the world, Is it too much to hope that, following the tradition of the M.G, Company of incorporating in their production cars features tested in racing, that we shall see independent springing on M.G. sports cars ?