SIDESLIPS By Baladeur
An “Alfonso” in Holland.
APASSING remark in the course of a recent ” Sideslip ” on the subject of M. Marc Birkigt and prewar Hispano-Suizas has brought me a letter from a reader in Holland, who has recently purchased a 1912 Alfonso XIII model of the famous marque for 75 florins, which used to be just over £6 and is now about £9. This Dutch enthusiast has apparently given his veteran flyer a thorough overhaul, fitted a braked front-axle off a 1926 2-litre Ansaldo, and, so he tells me, in Holland where there are few sports cars about, can usually hold his own with anything he meets on the road. He asks me in his letter for historical details of the Alfonso model and its forbears and in reply I have referred him to the number of MOToR SPoRT for July 1931, in which we described such a car as his as one of the “Veteran Types” series and traced its descent from the racing car which won the Coupe des Voiturettes in 1910.
A Famous Driver—now Forgotten. True sports cars, such as the Alfonso Hispano, were something of a rarity in pre-war days, and the subject is thus perhaps of some general interest. The facts of its descent were responsible as a matter of fact for what is perhaps the most remarkable point about this Hispano engine, at any rate on paper. Its dimensions in fact are 80 x 180 mm , and a stroke-bore ratio of 2.25 : 1 can only be explained by the fact that the engine was directly developed from that designed for a voiturette race run under the limited bore-unlimited stroke regulations. The Alfonso engine was in actual fact moderate compared with that in the car with which Zucarelli won the race at Boulogne in 1910. As a driver, incidentally, Zucarelli is now almost forgotten but in another age his was a name to conjure with. After the withdrawal of Hispano-Suiza from active racing in 1911, Zucarelli joined the Peugeot equipe, and with Georges Boillot and Jules Goux, formed a team which was almost invincible for several seasons. Unfortunately in 1913 while practising for a race, Zucarelli’s car turned over and the driver was killed. I well remember that a good many years ago we were making the most of a wonderful stretch of road which runs nearly due South from Evreux to Dreu.x when we espied on the left a stone monolith. In spite of its being in the days of 2-wheel brakes we stopped and reversed to inspect it ; but ever afterwards I was quite unable to remember where the monument was or in
memory of what driver it was erected. It was not until a couple of years ago that I was motoring, northwards, this time, along the same stretch of road, when I again espied the monument. In the meantime of course front brakes had made their appearance, but speed also was higher, and again we had to reverse to read the inscription. On my Michelin map a cross now marks the spot and a note in the margin informs me that there is the Zucarelli monument.
A Roadside Monument.
This incident reminds me of a friend of mine who some years ago was motoring from Paris to Bordeaux on a sports car which had previously belonged to me. Flat out along a beautiful piece of road he suddenly came upon a long gentle bend which in practice proved much more dangerous than it had looked. For some yards he fought that gallant car which longed to go stern first, and then just as he thought he was round, he nearly wiped the tail off on a large stone monument by the roadside. As soon as he and the motor had recovered sufficiently, he returned to see what was this rock on which he had so nearly foundered. On it he read the words, “To the memory of Marcel Renault, killed at this spot in the Paris-Madrid Race, 24th May, 1903.”
A Record Stroke.
However to return to the engine of Zucarelli’s voiturette racer, this motor had a bore and stroke of 65 x 200 mm., the ratio in this case being 3.08 : 1. Again these dimensions were moderate compared with those of another car which ran in the same race, a V 4-cylinder Peugeot driven by Georges Boillot. This engine, like the Hispano-Suiza had a bore of 65 mm., which represented the limit assigned by the rules of the race for 4-cylinder engines, but in the case of the Peugeot the stroke was 260 rum., and the stroke-bore ratio therefore no less than 4 : 1 ! This ratio must I should think, constitute a record, but actually in the same race there was another car with a longer stroke. This also was a Peugeot which was driven by Jules Goux, and which had a V-twin engine of which the dimensions were 80 x 280 mm. I should think that this also constitutes a record as the engine with the longest stroke ever put into a car. Even the giant 110 h.p. GobronBAUM which competed in Paris-Madrid and which had two opposed pistons one above the other in the same cylinder only had a COMBINED stroke of 220 mm.
A Knotty Point.
A propos of Goux’s Peugeot I was amusing myself the other day by trying to calculate the minimum overall height of an engine with a stroke of 280 mm. Not being an internal combustion engine designer or anything like it I am sorry to say that I do not think I ever reached a conclusion. One can of course add the stroke to the same number representing twice the length of a crank throw ; but supposing that the bore is limited I presume that the centre line of the crankshaft is necessarily a certain distance below the bottom of the cylinders to allow for clearance of the connecting rod in its extreme angular position, and that tested my mathematics a bit. Incidentally I think that the angle between the cylinders was 15°, which makes it more difficult. Perhaps my technical readers will enlighten me. For the benefit of the others I may remark that this Peugeot engine had overhead valves operated by a camshaft beside them, and the top of the bonnet was about 5f t. from the ground.
Piston Speed.
The exaggerated dimensions of these Peugeot racers of 1910 led to the suppression of the limited bore regulations and its replacement by the capacity limit. The origin and rejection of the old limit is however, of some interest. The earliest motor car engines had quite large strokebore ratios, the dimensions of the 3i h.p. Daimler engine fitted to the Panhard et Levassor car of 1894 for instance being 75 x 140 tam. and the ratio thus 1.87 : 1. This engine attained a crankshaft speed of 750 r.p.m., and a piston speed, therefore, of 210 metres per minute. During the next seven years designers of racing cars were given a free hand to increase the power of their engines without any limitations. The first and most obvious method was to increase the number of cylinders from two to four. Next crankshaft speeds were pushed up to about 1,000 r.p.m., and while strokes remained at 140 ram., piston speed went up to 280 metres per minute. This done, designers set about seeing how far they could increase the bore of their engines without making the reciprocating parts so heavy that crankshaft speed was reduced. To take as an instance Patthard et Levassor, which was the most successful marque during this period, the bore of the 4-cylinder engine increased from 80 mm. in 1896 to 130 mm. in 1901 ; but during these years no engine had a stroke in excess of 140 mm. and piston speed remained around 280 metres per minute.
In 1902 came the weight limit of 1,000 kilos for the car, and designers were stung by it even into putting up piston speed. The bore of the 70 h.p. Panhard et Levassor built in that year was, it is true, increased to 160 mm., but for the first time the stroke was increased to 170 mm. Piston speed must have reached about 340 metres per minute, a triumph for the engineering skill of the period. This done, however, designers once more concentrated on seeing how far they could increase the bore, and up to and including 1907 engines with strokes in excess of 170 mm. were extremely rare and probably were only used where the crankshaft speed was comparatively low. In the meantime, however, the bore had reached as much as 190 mm.
An Increase to 432 per minute.
Then in 1908 came the Grand Prix regulations limiting the bore of engines to 155 mm. Now in order to increase the capacity x time product of their engines, designers had to increase piston speed, either by giving their engines longer strokes, or else by increasing the crankshaft speed. Rather naturally the former method was adopted in most cases, although by this date crankshaft speeds had risen to about 1,200 r.p.m. De Dietrich, for instance, whose engine for the 1907 Grand Prix had had dimensions of 180 x 170 mm., and a stroke bore ratio of .94 : 1, produced a motor for the 1908 race with a bore of course of 155 mm., and a stroke of 180 mm., giving a ratio of 1.16 : 1. At 1,200 r.p.m. the piston speed therefore, was 432 metres per minute. Unfortunately, however, owing to the suppression of the Grand Prix in 1909 the later stages of this development, as applied to large cars, was never witnessed.
A Win for the Single Cylinder Peugeot.
Nevertheless the development of the process was to be carried on most effectively in the series of voiturette races organised by our contemporary” l’Auto.” The 1908 race, like the Grand Prix, was run under the limited bore regulations, the maximum cylinder diameters being 100 mm. for singles, 78 mm. for twins and 62 mm. for fours. Light car design was already much more daring than that of larger vehicles. Small engines were already being made to turn at speeds up to 1,800 r.p.m., and yet the designers of single-cylinder motors were employing strokes as long as those used in the larger cars. The 1908 single-cylinder racing Aries, for instance, had a stroke of 180 mm., giving a stroke-bore ratio of 1.8 : 1 and a piston speed at 1,800 r.p.m. of no less than 648 metres per minute. The strokes of the two and four cylinder engines were of course not so high, and the revs, were probably not materially higher either. In these circumstances it is hardly surprising that the first half dozen places in the race went to singles, the first twin was seventh and the first four eighth. In 1909 the organisers of the race turned to what was in reality a capacity limit, but the rules were considerably complicated by the fixing of a maximum stroke bore ratio for of 2.5 1
and various provisions which aimed, unsuccessfully, at levelling up the changes of singles, twins and fours. Peugeot, however, cheerfully adopted the highest permissible ratio with a single cylinder of 100 x 250 mm. Crankshaft speed had by now reached 2,000 r.p.m., and the piston speed in this case must have been somewhere near 1,000 metres per minute. The longest stroke used for a 4-cylinder engine, 140 mm. was that of the HispanoSuiza, but owing to the small bore of 65 mm. makers were still unable to overcome excessive frictional resistance and the crankshaft speed of the fours was little or no higher than that of the singles. The piston speed in this case was thus only about 560 metres per minute—and as was to be expected the single-cylinder Peugeot proved the winner.
Hispano versus Peugeot.
By 1910 the scene had entirely changed. The rules once again merely limited the bore, but all the fastest cars in the race, with the exception of Goux’s V-twin Peugeot, were fours. The winning Hispan.o-Suiza had a bore and stroke of 65 x 200 mm. and ran at 2,300 r.p.m., giving a piston speed of 920 metres per minute. Here, however, is where the interest lies. Boillot’s 4-cylinder Peugeot had the same bore as the Hispano and a stroke of 260 mm. instead of 200 ram. Yet both are stated to have developed 45 h.p. Now the Peugeot had 4 overhead valves per cylinder, the Hispano 2 side valves ; the Peugeot engineers had more experience of building first class racing voiturettes than had Marc Birkigt. Therefore I conclude that if the larger Peugeot engine only developed the same power as the Hispano, it cannot have turned so fast. In other words Marc Birkigt had seen that the way of further progress in the matter of getting power from a limited bore engine lay not in increasing the stroke but in crankshaft
stroke but in increasing crankshaft speed. A 3 litre Limit.
Unfortunately the sight of Goux’s Peugeot with the top of its bonnet five feet from the ground so terrified the organisers of the voiturette race, that for 1911 they abandoned the limited bore rule and substituted for it a capacity limit of 3 litres, together with the seemingly quite pointless stipulation that the stroke bore ratio was not to exceed 2 : 1. (Peugeot, I may say, lived up to their reputation by building engines of 78 x 156 mm.) By this means the Hispano-Peugeot controversy did not get a chance of being fought out to a final conclusion, as makers were now only allowed to try and increase the power developed by their engines by increasing the crankshaft speed.
The Limited Bore Regulation.
From all this I draw the somewhat surprising conclusion that the limited bore regulation, which we have all laughed at in our time for producing Goux’s Peugeot, is really a better formula than the limited capacity rule, which we have all doted on for the last twenty years. The former sets makers the problem of increasing piston speed EITHER by
increasing the stroke OR by increasing crankshaft speed. The latter ONLY allows the end to be obtained by the second method. Goux’s Peugeot was admittedly a monstrosity ; but if the rules had been left alone it would almost certainly have died anyhow at the hands of Zucarelli’s Hispano and its descendants.
Further I reach the conclusion that the R.A.C. formula for assessing h.p. for taxation purposes is more scientific than a formula based on cubic capacity. (That ought to sting someone into objecting.) Incidentally why has no British motor manufacturer risen to the problem of the h.p. tax by building a long-stroke engine instead of concentrating exclusively on crankshaft speed ? I suppose the only answer is that they are all sub-consciously so powerfully influenced by racing (pace Sir William Morris) that the alternative never occurred to them.
An Interesting French Car of 1910.
One other gibe. A good modem straight-eight 2i-litre racing engine with a stroke of say 95 min. at its maximum speed of 6,000 r.p.m. attains a piston speed of 1,140 metres per minute, or exactly 14% more than the 1909 racing Peugeot engine. I had finished writing these “Sideslips “when I received a most encouraging letter from a correspondent in France, who after various kind remarks about former articles in this series, goes on to say :—
1 An interesting little car to write about is the little Coupe des Voiturettes Hispano, of, was it ’10 or ’11? Not the 80 x 180 ram. type, but the racer, 65 x 200 mm. Only about 6 of these were made ; I never owned one, but drove one that Charles Faroux, the writer in Piltuo. etc., had. A marvellous little car with 4 brass-bound port-holes in the bonnet that registered with the r exhaust pipes. You could tune in the evening by watching the colour of the 4 exhaust flames that belched from the bonnet, but even the French police of ’10 or ’11 began to object to this ; one called it ` echappement un peu trop libre.’ ” !