Thursday, March 10, 2011

Velocette's 4 cylinder racer...."The little engine that never grew up"......

The text heading for this blog says it all....
"Velocette's 4 cylinder racer".....
"The little engine that never grew up"......
In the early 1950's despite the Velocette board being divided on the prospect of continuing racing, the then Managing Director, Percy Goodman and his son Bertie hatched the idea of a 500cc 4 cylinder racer to win the 500cc world championship and of course the Senior IOM TT.... something that had eluded the company since its first foray into racing in the 1920's.
The 350cc championships had been theirs on many occasions with IOM TT wins in the Junior class...but never a Senior win, despite coming oh so close.
But Percy's death in 1954 changed all that...the board of Veloce closed the racing shop and any thoughts of the projected 500/4 became dusty artifacts at Velocette.
The two UK motorcycle papers did articles on the project in 1961 and in 1965.
I've scanned them and they illustrate this blog rather than ramblings from me....
The first “The little Engine that Never Grew Up”…The MotorCycle 5 May 1960. pages 552-555, details the project with photos of the 125cc test engine then almost completed and the front brake.
The second followed exciting news at the time, 1965, of a lottery by the Manx people to raise funds to build a 500cc British world beater.
Velocette were to be heavily involved with it...
Bertie Goodman featured in the article...

"Four with a flying start"…Motorcycling Feb.6th 1965 page 8-9.
Read on....
Left click on the illustrations to enlarge them....





“The little Engine that Never Grew Up”The MotorCycle 5 May 1960. pages 552-555


It may be under a workbench, interred in a cellar or hidden away in some rarely visited loft-but somewhere or other in almost any motor-cycle factory there lies a ghost engine around which quite a tale can be woven. Thickly overlaid with the dust of years, it is probably of a type far removed from the firm's standard products. A rotary-valve job? Could be. Or a two-stroke flat twin, or four-in-line touring six-fifty-some design for which high hopes were once held but which, when translated into metal, failed to live up to the first, shining promise.
But when the factory is one with a long and honourable racing history, then the engine under the bench could equally well represent a tentative bid for championship honours which, perhaps for financial reasons, was never carried through. And this is no fairy tale. Gathering dust in the Velocette works at Hall Green there is indeed such an engine. Its capacity is 125 c.c; but that is the least of its many intriguing and surprising features.
    It has, for instance, a liquid-cooled cylinder barrel and head. The twin overhead camshafts are driven by a train of gears, one of which also serves to drive the coolant impeller, while another provides the take-off for the magneto drive. That engine was never fitted into a frame and, in fact, was deliberately so designed that the temptation to try it on the track was stifled from the start. Nor was it ever finished, although a further week or two of tool-room work might have seen it ready for the test bench. But interesting though it undoubtedly is, the one-two-five is only part of the story-only a quarter of it, indeed.
In a way, the project began following a leg-pull. One day in 1949, in a hotel lounge in Berne, Switzerland, Bertie Goodman (now Velocette sales director, but at that time racing and development manager) happened to meet Norton's Joe Craig. Understandably, the conversation switched round to motorcycle matters and, in particular, to the progress the Italian stables had made with their fearsome four-cylinder mounts. "And how," asked Bertie, tongue in cheek, "is the new Norton four coming along?"
    Now Joe Craig certainly had planned to complete a four-cylinder Norton-but he wasn't the man to disclose race-shop secrets. "Well," continued the Velocette man, "just wait untii you see ours. That will give Bracebridge Street something to think about!" It was a joke, of course, for until that moment no thought of a Velocettc four had crossed his mind. But later, back at Hall Green, Bertie got down to some serious thinking.
   In the famous overhead-camshaft KTT single the factory had a completely reliable, world-beating three-fifty. Yet victory in the Senior T.T. had always eluded the marque and however satisfying it might be to win the Junior Race-or the 350 c.c. World's Championship, come to that-there was not the same glamour or kudos as for success in the major-capacity class. Perhaps, after all, it was time to turn away from the traditional single.
   Well, there was always the "Roarer," that fabulous supercharged parallel twin, the development of which had been halted by the outbreak of war. An up-to-date version- unsupercharged, of course-might be the answer. Bertie placed his problem before his father, the late Percy Goodman, who began to sketch a possible power unit. Like the pre-war twin, it had separate, contra-rotating crankshafts parallel to the frame axis to facilitate the use of shaft drive and to cancel out torque reaction. But it would have liquid cooling, for distortion would thereby be reduced; hence there would be more efficient oil control and, indeed, a better overall performance.
Moreover the coolant would be pressurized so that its boiling point would be raised above normal (the principle is simply that of a domestic pressure cooker) and glycol, which in any case has a higher boiling point than water, was the coolant in mind. Accordingly, then, the engine could run at temperatures in excess of those obtainable with water cooling; but the higher the temperature of the coolant, the quicker would its heat be dissipated by a radiator of conventional size. It followed therefore that only a comparatively small radiator would be needed-a splendid point since frontal area would be reduced.
   Yet even before the general-arrangement drawing of the revived twin was completed the Goodmans, father and son, were considering still more exciting possibilities. Potentially, more power could be wrested from four small cylinders than from two of medium size. A four, with its squatter overall height, would fit more neatly into a frame. And if that four, like the proposed twin, were to be liquid cooled then it would not be abnormally wide-no large fins to project into the air stream, no air passages between the individual cylinders. It was an attractive and intriguing proposition.
    The decision was taken to go ahead with design, not only of the four-cylinder power unit but also of the necessary cycle parts. (And if at this point we can leap ahead of the main story for a moment, the 8]in-diameter, twin-leading shoe front brake introduced by Velocette for the 1952 racing season was intended for the new four; it was the only part of the design to go into production.)
    But back to 1950, when Percy Goodman began work on the project, setting as his target the 1953 Senior T.T. By 1951 the initial layout was ready and detailing was under way, but Percy was in failing health and so Bertie took over, to finish the work in 1952 and to put in hand construction of the experimental 125 c.c. engine from which test-bench data were to be gained.
    The little single was virtually the right-hand cylinder of the projected four, complete with the full-scale drive to the overhead camshafts. The reasoning was clear enough for if, say, 15 b.h.p. could be wrung from the single then theoretically there would be 60 b.h.p. from the complete engine-more, indeed, for although power losses in the camshaft drive had to be taken into account in the one-two-five, that did not apply in proposition to the remaining three cylinders. As for making it unsuitable for fitting to a frame-well, if they had done otherwise there was always the temptation to try it on the track; that could have led to a Velocette entry into 125 c.c. racing and a consequent splitting of forces.
   But within a week of completion of the experimental unit there came a sudden change of fortune. With the death of Percy Goodman, the managing director, the company totted up costs and decided, most reluctantly, to withdraw from the racing scene. By this time racing could no longer be justified as an economical form of advertising, and it was certainly becoming a most expensive hobby. Possibly a racing stable could have been maintained with assistance from outside sources, but Velocette had been a family business right from its foundation and, sturdily independent as always, wanted to retain control of its own destinies. So that was that.
   Still, what a machine that four-cylinder would have been had the plans come to fruition! In the Italian manner, the engine was transversely mounted in a welded, duplex-tubular frame, to obviate a lengthy wheelbase and to nullify the effects of torque reaction ("Ever watched a car engine start up?" asks Bertie). But there was also shaft drive, effected through a short primary shaft to the gear box and by a longer final-drive shaft to the rear-wheel bevels.
  The crankshaft was of built-up type, with pressed-in crank-pins (as in the current 499 c.c. Venom) and with a large-diameter middle bearing. Total capacity was 498 c.c. and bore and stroke were equal at 54.1 mm. And since the lengthy camshafts were driven from one end they were particularly robust, to overcome any tendency towards twisting; each, too, had a hefty bearing in the middle.
   Pressed into the cylinder block were wet liners (in which the outer wall of the liner itself is in direct contact with the coolant fluid) and the coolant entered the cylinder block by a cored tunnel across the front, whence it was sprayed against the wet liners.
   Hairpin valve springs are the accepted practice where a single-cylinder engine is concerned, but when there are four cylinders the problem of space arises and so, like the MV and Gilera fours, the Velocette was to have coil springs. But these were unusual in that they were conical, the varying rate thus obtained tending to damp out surge. And, borrowing a tip from the successful Jaguar car engine, the springs were encased in large-diameter tappet caps running directly in the light-alloy cylinder head.
The four carburettors were provided with a cross-shaft to operate the throttle slides and the magneto which, as mentioned earlier, was driven by one of the camshaft-train pinions, lay transversely at the rear of the cylinder block. Projecting rearward from the right of the crankcase assembly was a very large replaceable-element Purolator oil filter. No separate oil tank was specified and the oil was carried in an integral crankcase compartment.
   Most unorthodox of all was the transmission, for obviously the necessary bevels could not be fitted at the extreme left-hand end of the crankshaft. And so, instead, there was to have been a short countershaft geared to the crankshaft and lying behind and parallel to it. The countershaft would carry the driving bevel and so the primary shaft to the clutch assembly could be brought inboard. It could also serve to drive, through skew gearing, a gear-type oil pump suspended in the oil container.
   Parallel to the frame axis, the gear box was offset to the left and in line with the transmission shafts; it had two shafts, as in the LE and Valiant gear box, with the input to the forward end of the lower shaft and the final drive taken from the rear end of the upper shaft. A constant-velocity coupling, with its promise of a smoother
drive, would probably have replaced the orthodox universal joint initially proposed for the forward end of the final-drive shaft.
   Yes, the design was all there, even to the line of the four closely tucked-in exhaust pipes and megaphones so that there would have been a theoretical angle of lean of 47 degrees; and all credit to Velocette for taking the project so far as they did.
   And here is one final point to provide food for thought. The design was such that supercharging could have been added later without too much bother. For racing? No, there seemed little prospect of the F.I.M. relaxing the no-supercharger ruling in the foreseeable future. But wouldn't a crack at the world's maximum speed record have been a tempting prospect!
 On reading my blog, Dai Gibberson kindly forwarded this photo, above, with the caption..."Velo Rally 1976 4 cylinder prototype...", I await with interest any more information....
Bo Eklund from Sweden a good Veloman, has sent me this following photo, taken in Ralph Seymour's shop between 1988-1990. I would hazard a guess that the items on the display board above were from Seymour's as they likely had a display at the Velo Rally in 1976.
Perhaps the parts are still with the Seymour family?
The 125cc test engine items....
Four with a flying start…Motorcycling Feb.6th 1965 page 8-9.

T WENTY THOUSAND POUNDS to spend, a world-beater to build- and no strings attached in terms of engine size or type! Many would urge that, with this financial incentive and freedom of choice. Britain would plunge headlong into a development programme for one of the smaller capacity classes, where success in ultimately beating foreign competition might bring greatest kudos. But the sum estimated to be available is not big and much of it could well disappear in exploring new design fields with which we, on the whole, are not familiar. Therefore, I would go for a 500. First, because it catches the greatest international publicity - this is a prestige exercise, remember-and fires the imagination equally of the motorcyclist and the man-in-the-street. Short cut Secondly, because I know a short cut to a new 500 in the shape of an up-to-date engine design, the preliminary work on it already completed at the Velocette factory. It is a liquid-cooled four. All the detailed drawings have been done-and that alone represents a saving of up to £2,000. Things have gone even farther with a 125 cc unit- effectively, one quarter of the complete engine-for bench development work. For this "pilot rig", all the pattern equipment and some castings have been made - another £3-4,000's worth of work already done.
Why a four ?
Why the choice of a four by a factory already making four-stroke singles and twins and a two-stroke twin? Let's look at the alternatives we had to .consider. A single? No. Super-tuning to reach the absolute ceiling of "Venom" performance would not fill the bill-though, as all providers of TT works machinery know so well, £20,000 or more can be whittled away in a season or two simply in extracting a couple more bhp from an old design. True, the single is still responsive to further development. But we are very near to the limits of piston speed, and the necessarily great distance from the centre of the piston to the cylinder wall slows down heat dissipation.
Valve point
Further, there is the need to use more than two valves to a combustion chamber to get the best filling. And torque is not smooth because of the relatively long period between firing strokes. So the single is out. Then what about twins in their various forms? Our experience is that the conventional vertical twin on a common crankshaft creates a bad "couple" and, for other reasons, is an engine rather seriously out of balance. Consequently excessive vibration has to be absorbed by using a heavier - than - necessary frame. The 'Roarer' Far better balance is obtained in the vertical twin with two crankshafts geared together-in effect, two single engines running in opposite directions. This was the layout used on the 1939 Velocette "Roarer", which was ridden in practice for the 1939 TT but never raced because the war stopped all further development (and supercharging, for which it was designed, was banned by the FIM after the war). The geared twin is heavier than its single-crankshaft equivalent, but, thanks to its smoothness, can be carried in a lighter frame. The horizontally opposed twin is an extremely smooth engine. But if its crankshaft is parallel to the frame axis it gives a torque reaction which impairs the handling of the machine as a whole, while if the shaft lies across the frame it is difficult to accommodate the gearbox. Finally, all large-capacity twins share, though to a lesser extent, two of the problems of the single-the distance from the centre of the piston is a little too great for maximum heat dissipation and more than two valves per cylinder may become necessary for effective breathing. If twins are rejected, there remains the engine of four or more cylinders-if it is to be a four-stroke, and that is the type of unit with which my company has the greatest experience.
Complication
More than four cylinders introduce costly complications. So-a four it should be. And that is the line of thinking which led Velocette logically, as long ago as 1950, to start planning this in-line four of 54.1 mm more and stroke (495 cc). The unit is set across the frame, but the frontal area of a liquid-cooled four is not detrimental. Using wet liners permits the cylinders to be grouped more closely than if they were air-cooled. Total width of the unit is, in fact, about 141 inches, and the radiator is even narrower.
A vane-type pump circulates coolant through a pressurised system, which permits a small radiator to be used—the pressure raising the operating temperature of the coolant, of course.
Other advantages of liquid cooling are even temperature control, eliminating hot spots and distortion, and the ready availability of the right sort of cooling for supercharging, should it be adopted later.
Valve operation is by twin camshafts acting through thimble-type tappets on to the eight valve stems, the drive being by spur gears from the nearside of the crankshaft.
Ten-millimetre sparking plugs are thought to be best, in order to obtain a spark point as near as possible to the centre of the hemispherical combustion chamber and so derive optimum power.
The crankshaft of the prototype is of pressed-up construction, allowing the use of caged roller-bearing big ends and centre roller main bearings.
Transmission layout is governed by the decision to use shaft final drive—which, unlike a chain, maintains its efficiency constantly throughout a long race, as well as reducing the risk of oil being flung on the tyre.
To provide direct drive to the shaft, the gearbox, which can house five or six gears, is set parallel to the frame axis. Power is taken off the nearside mainshaft and the drive turned through 90 degrees by bevel gears to a conventional multi-plate clutch mounted in front of the box.
The driving bevel is, in fact, on a countershaft and faces inwards to bring the clutch centre-line farther inboard.
The choice of five or six speeds would depend on the finalised characteristics of the engine-if a wide power range is forthcoming, then five speeds will suffice.
But in either case, in order to reduce power loss, lubrication is by jet feed from the engine, which maintains a film of oil on the gears in a "dry" box.
Considerable development work would, of course, be necessary. It is here, in particular, that large sums of money can be spent.
There is undoubtedly room for experiment in fuel-injection, with its theoretical advantages, but for the time being I would stick to the well-proven carburetter, with one per cylinder.
Transistorised ignition, currently used on Grand Prix racing cars, will eliminate magneto-drive power loss and be more efficient than coil ignition at high speeds.
My company has experimented with rotary valves of two different types-in both cases on four-stroke engines-without   deriving any benefit. Though it may be feasible for rotary valves, with improved sealing, to be used in the future, one would have neither time nor money to devote to development of this nature.
The four can, of course, be considered as a multiple of 125 cc. If in the future an attack on the 125 and 250 cc classes should be envisaged, then here would be a ready-made single or twin of the appropriate size and potency.
In any case, to reduce cost, development work on the "four" would be carried out on a single 125 cc component, consisting essentially of the timing side of the four-cylinder engine.
Indeed, one of these 125s was put in hand by my company and nearly completed before our withdrawal from racing in 1952. Another two weeks of finished machining work, and it could be running. .
Materials
Maximum use would be made of modern materials such as titanium and magnesium. The frame- drawings for which have also been completed-is of duplex construction, with bottom leading-link front forks, swinging-fork rear suspension, hydraulically operated disc brakes at the front and conventional drum-type cable-operated rear brake. The complete machine should scale at 300-325 lb when carrying approximately four pints of coolant and six pints of oil. The engine should develop between 70 and 75 bph at 12,000 rpm, giving the machine a maximum speed of approximately 170-175 mph when fitted with a dolphin type fairing.
Would this be a world beater?  I think it could.
The 1952 2LS (internal operation) works front brake compared to the Velocette Thruxton 1965- 2LS front brake.

Original "MotorCycle" photos of the front brake and wheel, used in 1952 and earmarked for the ill fated 500/4 project.

Bertie Goodman was no slouch on a motorcycle... he'll form the basis of a future blog...and was a manufacture who tested and road his products throughout his life...

Pictured below testing the Velocette designed telescopic forks on a modified KTT  possibly in the IOM and in 1950-51 and of course coming up on the 18-19 March this year 2011 is the 50th anniversary of the successful Velocette world record 100mph average for 24 hours and which still stands for the 500cc class.
Bertie was completely involved in this attempt...including riding more than the alloted riding stints for the record due to difficulties experienced by some of the riders when they believed fog had descended onto the circuit and their lap times slowed, putting the record in jeopardy. It hadn't, they were dazzled by the stroboscopic effect of lights used to illuminate the bends of the Montlerey circuit in France as you passed them at speed.
Bertie's wartime experience flying enabled him to overcome the effect.
The poster released at the time says it all.....



3 comments:

occhiolungo said...

Hello Dennis. Do you know if the 125cc motor still exists? It would be fun to finish the machining and assembly, then test the motor on a dyno. Or maybe even mount it in a period chassis... !

Pete

The Velobanjogent said...

Pete, the 125cc engine was never completed and so as parts seemed to have disappeared.
I haven't heard of where it is today....
Dennis.

Anonymous said...

Seymour lived in Thame, near Oxford, my brother moved there and spotted his workshop and stopped-off for a chat, being an MOV-fan of old, had many a chat with him. Like the other Velo-specialists who did great work Seymour wasn't keen on the Goodman's anymore, as, with the others, he realised they had just been used ...and not paid for it either! He's dead years ago now, the shop disappeared, what couldn't be sold-off was probably scrapped by people who didn't know what it was.

Engine looks good, but, why-oh-why do they insist with the stupid shaft-drive! Complicated, expensive, more weight, rotten handling. Money was the problem, they didn't have any to waste, and as such, had no chance against MV anyway, so why bother. Better do as Ethel Denley told me, spend it on the 350 parallel-twin based on V8 car technology, designed by a relative in Detroit to slot into the LE, instead of the crap sidevalve-boxer which had no future even when new and expensive and unreliable to boot. The Yank engine was anvil simple and cheap to make, with bags of potential left. I'd love to get hold of the drawings he showed her and make one, just to prove a point.