At this time of year speculation is rife concerning prospects for the coming racing season. Certainly they are brighter than they have been for some years. However, the many races and speed events that we are destined to see during 1949 may seriously aggravate last year’s difficulty of making aged racing machinery hold together through so many spells of highly-competitive speed work. It may be that one of the season’s more absorbing features will be the incursion into the headlines of comparatively slow but reliable cars that have out-lasted their faster rivals. Certainly Formula II racing will be intensely competitive and immensely worth following.
Down at Tolworth a lightened, shortened H.R.G. is in course of preparation under the care of Marcus Chambers for this form of racing, the power-unit being a 2-litre Standard Vanguard, complete with its steering-column-control gearbox, and the body an aerodynamic single-seater. In the same field the Hutchison/Poore stable has the imported B.M.W.-engined Veritas, while Horsfall’s Aston-Martin, Heath’s Alta and the O.B.M. should constitute worthy rivals. The Alta, by the way, will be new, with a chassis devised by Heath and Abecassis for their four-carburetter engine, of short wheelbase and with i.f.s. and 1/4-elliptic rear springs. The body will resemble that of the Ferrari.
Sports-car racing will obviously be well to the fore and we believe the R.A.C. has already made enquiries as to whether sufficient support from manufacturers would be forthcoming to justify holding the T.T. Allard has had to say no, but if Aston-Martin, Lea-Francis, Frazer-Nash, Riley, M.G., Healey, Jaguar and H.R.G. would play, what a race we should see! Certainly we must not allow the prestige built up at Spa and Paris to lapse. The great Le Mans 24 Hour Race is being revived this year, in any case. Class I racing to the 500 Club Formula is clearly going to expand in 1949, for amateur constructors seem quite resigned to competition from such factory-built cars as the Coopers, Marwyns, Bonds and Iotas, and the R.A.C. will quite likely again stage a long-distance classic for the “little fellows” at Silverstone. C. A. N. May is known to have disposed of his trials Ford V8 in order to concentrate on racing the Cooper 500 that 18-year-old Stirling Moss used to such good effect last season, and the Swiss, Hubert Patthey, has ordered a new Cooper. Several drivers have Cooper 1,000s with V-twin Vincent-H.R.D. engines, which those of you who have read the 1949 edition of the “Motor Sport Racing Car Review” know to be quite something (approx. 80 b.h.p. and 600 lb.), and Moss a J.A.P.-engined Cooper 1,000, which will presumably fluctuate between sprint meetings and Formula II races. In the 500-c.c. field, too, Lones has been busy converting the rear suspension of his fearsome Tiger Kitten to reversed 1/4-elliptic, while the Frys intend to stick to a J.A.P. engine in their very light Iota, their interest in the Cross rotary valve having concluded.
Grand Prix Formula I racing will doubtless resolve itself into a fascinating struggle between Alfa-Romeo, Maserati and Ferrari, with subsidiary interest in what the B.R.M. will achieve in its first season and whether the French will get the C.T.A. Arsenal to perform properly. Whether Maserati will pull out a surprise and cause Alfa-Romeo to bring out their rear-engined, flat-twelve Type 512 remains to be seen, although our personal guess is that the Type 158A Alfa-Romeo will remain supreme. Certainly we shall hope to see a team of such cars at Silverstone before the 1949 season is over. What Britain will do in this, the most exacting motor-racing of all, it is difficult to predict, despite all our hopes. The B.R.M. will be new, very new, and unless more than one car is run it is difficult to see how it can fend off the best that experienced Italy will put in the field. We can merely extend Raymond Mays our very best wishes and go on hoping . . .
Incidentally, in a recent review published in a popular weekly, Mays spoke of retiring from driving so as to act as manager to the B.R.M. team; but we believe he was looking forward to the year 1951 or 1952 and that he will presumably handle the first of the B.R.M. cars. Rumour, fickle jade, also speaks of Gerard in this capacity and, teasingly, points out that he has released Frank Woolley, his invaluable racing manager, from his stable. More definite is the news that one Englishman, at least, should be well up in the Grand Prix sphere, Reg. Parnell having joined the Scuderia Ambrosiana, with Villoresi and Ascari as his team-mates. He intends to use his own 4 CLT/48 Maserati, but hopes to fit it with the latest blowers and brakes. Parnell was potent enough as an independent and now we shall see him as a member of a leading Continental team — it should be worth watching! Moreover, Fred Ashmore may join them, also with a 4 CLT/48 Maserati. Then Leslie Johnson is doggedly persevering with the E-type E.R.A. These unlucky cars will have a good chance of retrieving their bad reputation, for “Taso” Mathieson has bought Johnson’s GP2, a new car is being built for Johnson, and Peter Walker’s GP1 is being rebuilt, although not at Dunstable. We have heard of no further G.P. Altas being built, but must hope that Abecassis has got over the teething troubles in his. car
Sprint events will have to meet competition from Goodwood and Silverstone, but support for Prescott and Shelsley Walsh, etc., will probably be not too drastically affected. We imagine that Raymond May’s famous D-type E.R.A. will again be in evidence. It is the most effective sprint car in this country today, and if it could carry Mays to a hat-trick — winning the R.A.C. British Hill-Climbing Championship for the third year in succession — well, in view of this ace-driver’s remarks about retiring, what a very fitting climax this would be to a long and brilliant career. The opposition will be stiff and Mays would be the last to wish it otherwise. Kenneth Hutchison has acquired the ex-Dobson, ex-Brooke 2-litre B-type E.R.A. (R7B) and intends to have it completely revamped by Robin Jackson, who looked after Hutchison’s Alfa-Romeo last season. Independent front suspension, ZF differential, probably new bodywork, and perhaps two-stage supercharging, may be expected to make this E.R.A. a very exciting sprint car indeed. As a matter of fact, the older cars of this make will need to look to their laurels, for Peter Walker has a 2-litre E.R.A. engine that he intends to put to good use. Hampshire will have his effectively modified 1 1/2-litre A-type out again and hopes, too, to share Murray’s ex-Parnell Maserati and the ex-“Bira” E.R.A. “Hanuman.” Then Butterworth has been carefully going over his four-wheel-drive Steyr-engined A.J.B. this winter and contemplates circuits as well as sprints, while Sydney Allard’s Steyr-Allard single-seater is being expanded from 3.6 to nearly 5 litres, and he is said to have on the stocks another Allard in which he intends to install a V8 engine having water-cooled blocks and Steyr air-cooled heads. Busy time ahead!
Over and above which Miss Betty Haig hopes to compete again in the Rallye Feminia Paris-St. Raphael and Lt.-Col. Goldie Gardner intends to attempt to recapture his Class I records from Tarruffi and Frank Kennington talks of having his 150-b.h.p. M.G. Magnette engine installed in an Italian Nardi and Darrese chassis, while Robert Baird, hopeful of completing an 1,100-c.c. and a G.P. 1 1/2-litre car before the end of the season, has sold the straight-eight Duesenberg engine from his Emeryson to Hardy, who intends to use it in a hill-climb car. Rivers Fletcher will continue to drive his non-supercharged M.G. Magnette in sprint events, but is having the chassis shortened and the engine bored out and fitted with a longer-throw crankshaft to put the car in the 1 1/2-litre class.
Amongst enthusiasts there are many who were brought up, as it were, on the long-stroke low speed type of sports car, so well the represented byt the 3-litre Bentley, or the “Alphonso” Hispano-Suiza of a slightly earlier era. To such persons, it must be sad to say farewell to the long-stroke engine. Even in the past year, bore/stroke ratios have decreased, on British cars, from about 1:1.45 to 1:1.2. In 1912 increasing the stroke was a recognised method of putting up the power output under the prevailing taxation basis and race regulations. Even in those days, however, the late Mr. L. H. Pomeroy was advocating the shorter stroke, as “Baladeur” showed in an entertaining “Sideslips” in the November, 1947, Motor Sport. Robert Brewer, too, in his 1912 edition of Motor Car Construction, began to doubt whether inertia loads and cylinder wall friction might not soon put a limit on piston speed and therefore piston stroke.
Incidentally, in those days the friction set up by the obliquity of the connecting rod was considered one of the disadvantages of the long-stroke engine and led to the use of offset cylinders, but later it was decided that, providing good lubrication was maintained, this source of power loss and bore wear was negligible. After the Kaiser war, despite the tax on bore size, technicians began to call for shorter strokes and in Grand Prix racing, the capacity limit having replaced bore-size restrictions, short-stroke engines able to turn at high speeds by reason of light reciprocating parts and rigid construction, ruled supreme. With the recent introduction of the £10 flat rate of taxation on new cars in this country, all the old arguments against the long-stroke power unit were trumped up with double emphasis. The short-stroke engine, then, claims to score in the following respects:
(a) Higher crankshaft speed in relation to piston speed.
(b) Larger area of valve space.
(c) Lighter, less costly construction.
(d) Smoother running due to shorter crankshaft webs.
(e) More space for bearings and a better length con.-rod.
(f) More efficient piston rings and longer area of piston contact.
Other arguments in favour of short-stroke engines concern the tendency of long-stroke engines to overheat, to show a drop in m.e.p. at low r.p.m. due to heat loss to the cylinder wails and to call for a comparatively high bonnet line or, conversely, loss of ground clearance. To those stalwarts who crave the slogging power in traffic and uphill of the long-stroke engine, coupled with a delightful ability to work leisurely on high gear-ratios, the case is a black one indeed.
In a mass of technical literature published since the Kaiser war I have found only one advocate of the long-stroke. Who is he, and what are his arguments? He is Flt.-Lt. Bagnall, R.A.F., who, in 1944, wrote a letter to the Motor pointing out that in the motor-cycle world, where capacity limits in racing have encouraged short strokes, such notable manufacturers as J.A.P. and A.J.S. scrapped “square” engines in favour of longer-stroke units with direct improvement and that, despite the capacity classes, a bore/stroke ratio of 1:1.25 was usual. Bagnall suggested that if the stroke of a square engine be doubled but the overall gear-ratios of the car in which it were installed be halved, then, while performance would be unaffected, inertia stresses would be halved, so would valve speeds, while bore wear should be lower, because while piston speed would be unchanged, cylinder area would be doubled. Larger valves would not be required, weight would be about the same in view of the lower inertia stresses, while gas leakage past the piston rings would be reduced because the ratio of piston circumference to cylinder volume is halved. Bagnall emphasised one of the long-standing claims of the long-stroke engine, namely that a high compression ratio is simple to achieve, and generously admitted that his proposed re-design might result in a more bulky power unit. Now his motor-cycle engine argument is convincing, for the highest possible efficiency is required from racing versions, while, as ultra-rapid foot-change gearboxes are universal even on production motor-cycles, the slogging-on top-gear properties of the long-stroke engine are hardly likely to outweigh its alleged shortcomings. Let us, then, analyse Bagnall’s other theory. The Standard Vanguard, for instance, has an 85 by 92 mm., 2,088-c.c. engine and a top gear ratio of 4.6 to 1. Bagnall would re-design it as an 85 by 184 mm., 4,176-c.c. unit pulling a top gear of 2.3 to 1. Now the Vanguard gives 68 b.h.p. at 4,200 r.p.m. and reaches a piston velocity of 2,540 ft. per min. at that speed, or at 67 m.p.h. in top gear. There is every reason to believe that our new 4-litre engine would give the same power at 2,000-2,500 r.p.m., for the 1912 15T Hispano-Suiza, with a T-head engine of 80 by 180 mm., developed 64 b.h.p. at 2,300 r.p.m.
This being so, there would seem to be solve case for the long-stroke engine, and it is not without interest that, amongst modern British cars, the two extreme advocates of the long-stroke principle, the Healey and Riley (for a stroke of 120 mm. in an 80-bore engine is extreme for this day and age) are renowned as very fast cars.
Originally the most obvious claim of the short-stroke school, that piston speed was reduced for a given crankshaft speed, was ignored so far as touring engines were concerned, for they seldom ran much above 2,000 r.p.m. When Pomeroy challenged Coatalen’s long-stroke tendencies he criticised weight and lack of rigidity, not piston speed. This was entirely logical, for a 150-mm.-stroke engine turning at 2,000 r.p.m. will not appreciably exceed 2,000 ft. per min. piston speed, and apparently even in those days bearing loads were not deemed critical until some 2,500 ft. per mm. was reached by the pistons. To-day, of course, the tendency to employ shorter and shorter strokes is due to a desire to reduce piston speeds, in order to reduce loadings and check bore wear, besides taking advantage of the factors set out tabularly above, particularly items c and d. While this same requirement at first resulted in shorter-stroke racing engines, it was hardly maintained, for it can be shown, for instance, that the piston speed of the 1927 1 1/2-litre Delage, with a stroke of 76 mm., was 4,000 ft. per min. at peak r.p.m. Bore wear is of little consequence in a racing engine while its bearings, of great size and copiously lubricated, can withstand the loading implied by its piston speeds, which sound so shocking to designers of ordinary cars. In the more recent racing engines, built to a capacity limit, the individual factors which cause the designer to lop off the stroke are the need for the largest possible valves and bearings and a rigid crankcase and crankshaft, to withstand the loadings involved by very high crankshaft speed as distinct from a long stroke, together with the necessity to reduce as far as possible the weight both of moving parts and of the engine as a whole, not to mention a desire for compact dimensions.
One more paragraph before we leave this fascinating topic. We talk of a long-stroke engine if the bore/stroke ratio is extreme. Thus, a 63.5 by 95 mm. engine is definitely “long-stroke,” as against a 72.6 by 72.6 min. engine of identical capacity. The former engine will be credited with all the disadvantages of its type. But if we go outside the capacity limit we must be careful to discriminate between the apparently long-stroke engines and those whose stroke is actually excessive. For example, an engine of 95 by 95 mm. will be “short-stroke” compared to one of, say, 75 by 152 mm. Between these two engines, all the aforementioned short-stroke advantages are with the first-named. But compare it with our smaller capacity 63.5 by 95 mm. unit and, at a given crankshaft speed, the piston speeds of the two engines are identical. It may be argued that the smaller long-stroke engine will be run faster, but that depends on what output its designer seeks, and the fact remains that, whether or not either or both these engines exceed 2,500 ft. per min. piston speed at peak r.p.m., at any given crankshaft speed they will be stressing their bearings and ovaling their bores to an equal extent, if we discount the detriment of probable greater weight of the larger “short-stroke” engine’s reciprocating parts. Unless the related stroke-length is known, the advantages in respect of crankshaft to piston speed cannot be dogmatically asserted, when engines in different capacity divisions are being compared.
The long-stroke engine, it appears, is doomed — unless our designers “do a Bagnall” overnight! The fact remains that 80 by 149-mm. Bentleys and 80 by 180-mm. Hispano-Suizas will continue to charm their owners, who, confronted with convincing arguments in favour of “square” engines, will doubtless imply that they couldn’t care less. . .
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