Bugatti Type 41 – the golden bug

Everyone is so Bugatti-conscious nowadays that we have pleasure in presenting this account, by Cecil Clutton, R.A.F., of one of the patrons rarest and most idealistic models – “La Royale: – Ed.

How many, even the most elect of Bugattisti, can immediately place the Type 41? It is that rarest of motor-cars, christened by its designer “La Royale,” and known familiarly as “the Golden Bug.”

“La Royale” it might well be called, for even a V12 Hispano-Suiza becomes cheap beside it, and Rolls Royces, by comparison, almost two a penny. The chassis price, when introduced in 1926-7, was half a million francs, then equivalent to some £4,000 of English money. That such a king of cars should come from Molsheim seems fitting, for le Patron ever thought in terms of magnificence and for him to be unconventional was normal. In the Type 13 he gave us the first high-efficiency light car. In the bebe Peugeot he produced the first genuine baby car, in the tradition that Austin was to follow so successfully ten years later. The last war saw him producing the first practical straight-eight engine, in the modern tradition, and Monsieur Henri, who worked under him, put his ideas into car practice in the 1919 and 1921 straight-eight Ballots, which set the pace for practically all subsequent racing design. It is known that the Type 41 represented some ten years of consideration and research, and it is therefore clear that its inception dates back to his period of aero-engine design in the last war.

When the type was presented to the public in 1926-7 it was no single, handmade tour de force, but a plant was rigged up for full-scale production, the intention being that 25 should be built. In point of fact, it appears that only about six were made, and the remaining engines were kept in stock for many years until purchased by the Chemin de Fer de l’Ouest for rail work. One car, at least, came to this country.

A peculiarity about this model is the disparity of opinion among experts as to the engine dimensions. The Bugatti Owners’ Club handbook gives them as 125 x 130, which makes a total capacity of 12,760 c.c., but The Autocar quotes 125 x 150 and 14,726 c.c. As the engine was stated to develop 300 b.h.p. at less than the maximum of 2,000 r.p.m., which, even with 15 litres, represents a m.e.p. of over 130 lb. per square inch, it seems probable that the longer stroke is correct. The rated horse-power is 78.

The construction of the engine was altogether remarkable. To begin with, the head, block and crankcase were all one piece; the bottom of the engine was only a lid to keep out the mice and hold up the oil. Curiously enough, the bebe Peugeot was similarly devised.

The crankshaft was held in the block and the nine main bearings were watercooled. The webs were circular and all bearings were white metal, bronze backed. Lubrication was dry sump. The overall length of the block was 4′ 7″ and its total weight the remarkably low one of 240 lb.; the crankshaft alone weighed almost as much. The rods were I section and the pistons aluminium alloy with split skirts. Valves followed the usual Bugatti plan, with an overhead camshaft, two inlet and one exhaust valve per cylinder, set vertically in the flat head. Dual ignition was by coil and magneto. Gas was introduced to the cylinders via two carburetters.

The fact that the engine had to be taken out and the crankshaft removed before a valve could be ground was quite simply laughed off by M. Ettore, who pointed out that, owing to the special materials and design, the valves would not require any attention.

The engine was fixed on to the chassis by the remarkable expedient of three hollow bronze bearers which passed right through the block in one piece from one side member to the other. To this arrangement was attributed the remarkable stiffness of the front end of the motor-car and the entire freedom from vibration of the engine.

The power curve peaked at around 1,700 r.p.m., having regard to which the development of 300 b.h.p. was highly creditable. Maximum permitted revolutions were 2,000 per minute. Equally, the power-weight ratio of the engine was altogether remarkable for the date, for the entire engine turned the scales at only 7 cwt., which is about 2 1/2 lb. per b.h.p.

Turning to the chassis, the track was 5′ 3″ and the wheelbase a trifling matter of 15′ 4″, which is about the same as an L.P.T.B. bus. The 3-speed gearbox grew on the back axle, and the middle ratio was direct. The overdrive was silent and final drive was by spiral bevel: 2,000 r.p.m. gave 95 m.p.h. on direct drive and 125 m.p.h. on the geared-up ratio. The tyres were specially made, being 980 x 170, or roughly 38 1/2″ x 7″, which was a remarkably wide section for the period. This suggests that the upper two ratios were about 1.8 and 2.4 to one, in which case bottom gear would probably be about 4 to one, giving a maximum of about 57 m.p.h. Despite these high ratios, the car could be slowed down to a steady 3 m.p.h. on direct drive. – barely one revolution per second! It could also be started from rest on this ratio.

The road wheels were the splendid pressed aluminium affairs, which also grace the Types 46 and 49 and afford such superlative braking. The brakes were rod-operated and the rods all worked in roller bearings. There was also a transmission brake which, being in front of the gearbox, must have been simply devastating in effect.

The front axle was the usual Bugatti hollow-beam pattern, through which the springs were passed. The rear springs were also the customary reversed quarter elliptics, but there were additional quarter elliptics in front of the axle, which came into operation when extra heavy loads were carried.

The weight of the complete car was again astoundingly low having regard to its immense size; without passengers it scaled only 45 cwt., giving 6 2/3 b.h.p. per hundredweight; which suggests adequately brisk acceleration.

People who rode in the car remarked on the fact that, once in motion, they were no longer aware of its great size, even when driven at high speed on narrow, twisty roads. Silence, comfort, brakes, flexibility and roadholding alike came in for high praise. I am not aware of any published performance figures, but they would doubtless be exceedingly interesting.

Such is a sketch of a car which can, with much justification, claim to be the world’s greatest. It is clear that the 5 litre, Type 46, is an almost exactly scaled-down edition of it, so that those who are fortunate enough to have ridden in that magnificent motor-carriage presumably have some inkling of what it feels like to go about in a “Royale.”

One cannot help thinking what fun it would be to cut a Type 41 down to, say, an 11′ wheelbase and even supply a mild boost of about 5 lb. pressure. An overall weight of about 35 cwt. and 400 b.h.p. should provide an ensemble altogether out of the ordinary.