Rumblings, August 1960

Making Comparisons

Deciding on the new car is one of the most difficult of human tasks. The other day we met a methodical approach prepared by someone confronted with whether he should invest in a Ford Consul, Morris-Oxford Series V or Standard Ensign. Although these are not sporting cars, we think the approach may be instructive, as it can be applied by clear thinkers to any competitive group of cars. The problem was resolved in favour of the B.M.C. product by the following argument :—

“The main competitors of the Morris-Oxford are the Ford Consul, Hillman Minx, and Standard Ensign, With the first-mentioned as the main contender. Whilst the Hillman in particular and the Ford have a price differential in their favour, the Oxford offers much more in accommodation, comfort, style, and in engineering quality.

“Features such as the lockable filler cap, separate spare wheel carrier, parcel shelves, rear swivelling ventilating louvres, and topline performance are all to be found only in the Oxford. The car also has wider door openings than any of its competitors, and because of its modern styling generally, wind roar has been greatly minimised to enhance quiet travel at speed. The counterbalanced lid of the largest boot in this class of car appeals.

Cast a glance over the Ford Consul, and note that only three speeds are still offered and the steering-column change is compulsory. The latter remarks also apply to the hand brake, and, again from the driver’s point of view, the instruments are not nearly so easily read. Similarly, economy is not so good and maximum speed is less.

“The Hillman Minx De-luxe and Special are smaller and there is less room inside. The fuel tank is little bigger than would be suitable for a baby car and the brakes are in a like condition. Leather upholstery is not offered. There is no facia compartment, nor is there an ashtray. The boot is small and in addition is cluttered with the spare wheel, and the heater, when fitted, sucks in air at exhaust level.

“Dimension-wise the Standard Ensign is similar to the Morris Oxford but it has much narrower doors. It is also a heavier car with, surprisingly enough, a total brake-shoe lining area which is 26 sq. in. less. At 14 cu ft. its luggage boot is much smaller, and it does not provide the valuable convenience of a facia tray.”

Of course, other aspects of specification and performance were also taken into consideration. Thus a hand-brake lever beside the driver instead of on the facia, a point shared with the Minx and the spare wheel separate from the boot, also found in the Ensign, gave further advantage to the Morris-Oxford. On the other hand, when acceleration and m.p.g. were thought about the Ford Consul scored, but it wasn’t so fast all-out, which is where the Oxford and Ensign tied.

You may care to spend some leisure hours sorting out the cars on your” short list” in this fashion and perhaps an industrious Motor Sport reader will even find time to work out similar comparisons class by class, on a capacity and also price basis.

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Thoughts on rotary engines

In the year 1925. when model-T was on the way out and the side-valve engine was reaching its zenith, Mr. Hilaire Belloc wrote a book called “Mr. Petre.” The only remark able thing about this tit-bit of literary history is the fact that Mr. Petre was the strangely prophetic party to a most important happening, the invention of the rotary engine. He was projected nearly 30 years into the future, to a day in April 1953, when London was abuzz with “the whirring of the mighty little engine,” and every ship, car and aeroplane of that distant world was rotary propelled.

Inspired crystal gazing ? Whatever it was that led hint to assign such an exact place in time to Mn Petre and the rotary engine, it must be admitted that Belloc’s forecast failed to send the motor industry into a paroxysm of rethinking. Indeed, Mr. Petre would have remained securely tucked away between the Trumpet Major and Madame Bovary, happy in his obscurity and his raiment of grey London dust, had not Mr. Alec Issigonis, of all people, forced him into the open.

Now Mr. Issigonis is a car designer of great renown and, in particular. the progenitor of the British mini-car. The last thing that can be said of him is that he is a slave to orthodoxy.

It was all the more surprising, then, to find him quoted, in May 1960, as “seeing no future for rotary engines like the Wankel, now under development in Germany by N.S.U.”

After all, if Mr. Petre were alive today (one suspects that he was run over by a rotary taxicab) he would have been well into his 80s, which gives the much better informed Mr. Issigonis quite a bit of leeway to make up.

What of the reality? It cannot be denied that either Belloc or Felix Wankel was slightly awry in his timing. It was, perhaps, inconsiderate of N.S.U. to delay the announcement of the rotary engine until 1959, six years after the date when it was supposed to be propelling the air, sea and road transport of the world. All the same, it was made to work by N.S.U. in 1954.

Even now, some sceptics of the 1960s believe that it is not practicable or, with the kind of reservation adopted by the libel litigant, they plead that if it does work there is no advantage in its doing so, anyway.

Just as any new development is greeted by a wide measure of scepticism, so at the other extreme it attracts unbridled optimism. “Will oust its piston opponent,” “May change car design,” “An engine which cannot go wrong,” are some of the claims which have been made for it—not by N.S.U., it should be added—whilst other commentators have actually seen or heard of test vehicles speeding along jungle roadways, darting incognito through city streets or hiding, in multi-cylinder versions, beneath the bonnets of top-secret racing cars.

The rotary engine, proven beyond question as a power unit of extraordinary performance, has if nothing else demonstrated the existence of some widely held illusions.

Many enthusiastic technicians have questioned the capacity rating of the new engine. The rotor describes one-third of its full path in effecting one complete revolution of the output shaft But the engine works on the four-stroke or Otto system. Therefore, say the “experts,” its capacity must be three times that of the single chamber involved in producing the power stroke to allow for the cylinder volume used in the processes of induction, compression and exhaust. In other words it must be regarded as a three-cylinder engine. The fact is that unless tax is assessed on the basis of capacity the argument has not the slightest relevance to anything. The only thing that matters is the specific amount of fuel consumed in producing a given power output. And published figures show that for approximately the same output as a highly developed twin-cylinder four-stroke engine (in fact, the Triumph twin) the N.S.U. rotary unit has an almost identical specific fuel consumption. If a last word can be said on such an uncontroversial subject, it may as well come from an independent engineer who has inspected the engine closely and driven a car powered by it. In the Automobile Engineer Richard Ansdale, A.M.I.Mech.E. comments:

“From the beginning it has been difficult to decide whether the N.S.U.-Wankel rotary expansion engine should be considered as a single-cylinder engine, as claimed by N.S.U., or a three-cylinder unit. It may, therefore, be pertinent to attempt to clarify the position. The late Professor Joad would undoubtedly have proclaimed, ‘It all depends on what is meant by the number of cylinders’: indeed it does because, based simply on a count of the number of cylinders or pistons, the N.S.U.-Wankel engine is without doubt a single-cylinder engine. Another approach might be to consider a three-node cylinder with a four-sided rotor, which has one extra phase. This phase may fie used either to supercharge the engine or make it into a double expansion unit, in the manner of a compound steam engine; clearly this would remove all basis of comparison unless it was still considered. as equivalent to a single cylinder unit.

“Since in the N.S.U.-Wankel engine there is one rotor and one induction, compression, expansion and exhaust phase per revolution of output shaft, it may safely be concluded that it is a single-cylinder unit. The capacity of the engine is, of course, the volume contained between adjacent apex   als, the cylinder bore and the rotor flank when a straight line through the points of contact between these seals and the bore is parallel to the minor axis.”

Another illusion which discussion of the rotary engine seems to have thrown up is the idea that engine capacity is in some way a determining factor in fuel consumption. Naturally, the bigger the swept volume of the cylinder the higher the consumption is likely to be and, usually but not inevitably, the higher the power output. In fact, the frontal area of a vehicle has much more to do with actual, as opposed to specific, fuel consumption.

What is the official verdict on the future of the engine? The verdict of the people who know, the sdentists and engineers who have worked on it? The verdict is, as it has always been: the N.S.U. Wankel rotary engine, in one of its many possible trochoidal combinations of rotor and cylinder, has been shown to give at least the performance of the most highly developed reciprocating piston engines, while weighing about a third as much, occupying, about a third of the space and, probably, costing something like half to a third as much to make. When will it appear? When all the tasks connected with testing, tooling-up and assembly have been completed. And that takes quite a long time, even with new piston engines of the orthodox kind.

Many people have asked for comment on the assertio,. attributed to Mr: Issigonis, that neither the turbine or the rotary engine is a practicable proposition.

Doubtless Mr. Petre would, if he could.