Comments-20-2

Sir,

May I take this opportunity of expressing my gratification (and, I may add, my surprise) at the interest that has been taken in my views on the post-war sports car, and of thanking those who have commented on my remarks.

Replying to these in the order in which their letters have appeared, S/Sgt. Truscott hrings me down . to earth with a bump, but it must be realised, I am afraid, that there is a good deal of truth in what he says. here I must emphasise that when beginning my remarks, I was careful to say that it was the type of car that I should like to own—whether I am ever to be in a position to own one must be left to the future to decide. Dr. Edisbury’s remarks about the cooling system are most interesting, but I remain unconvinced id’ the desirability of a fan. The extra weight of a radiator with a greater cooling surface. but not necessarily with a larger water eiti.iacity, is, I feel, a lesser evil than the power loss involved in driving a fan at high speeds. Also, 70 b.h.p. should propel 15 cwt.. of

Imam. through the air rapitlly enough lo keep a reasonable flow of air through thin rad i a I or e yen when indulging in Alpinery.”

In reply to Mr. Hambling, the 110 ” Speed Model ” 2-litre AstonMartin and the 160 b.h.p. Type 575 Ilm,atti are examples of engine winch are reliable, and which have piston sizes and si weds comparable to, if not greater than, those that. I have quoted, thus showing, at, any rate, that it. can be done.

The dilRrential is it piece of mechanism which I overlooked before. In place of the lock controllable from the diiver s seat suggested by Mr. Ilambling, I would, personally. prefer to see a self-locking device. I have a bias in favour of the 13allainy hydraulically-controlled differential, which should prove much better than the German 7F one, though I have had no practical experience of either.

The points raised by Sqn. Ldr. C. W. S. Marris are very interesting, and I should like to deal with them one by one.

To say, as I did, that unified bodychassis construction is out of the question in an open car, is a sweeping statement that is not justified. I maintain, however, that in the absence of screen pillars, door pillars and roof to brace the structure, the advantages and, in fact, the whole reason for adopting this construction disappear.

I do not agree that the design of the car has been compromised to the extent that Sqn. Edr. Marris thinks by my requirement that it should be able to perform with reasonable chance of success in not too fearsome trials, though I am hoping that the post-war world will find trials’ organisers with other hazards than rockstrewn tracks and deep mud, though I cannot think what. The bottom gear-ratio was selected with a view to easy control in traffic as much as anything else, as with a small high-speed engine without much flywheel, continued restarting on any gear much higher than that selected becomes a matter requiring continued attention and

delicacy of control. In any case, it. is HOW an exploded fallacy that trials conditions demand an ultra low bottom gear on a car having a good power-weight. ratio. The five-speed transmission was specified to obtain an overdrive ratio in order to improve the car as a road car, which is what Sqn. Ldr. Marris is demanding. I did specify the ground clearance as 7 in., a figure which I consider adequate for the trials which I had in mind, considering the moderate wheelbase of under

8 ft., and that there is nothing liable to damage Underneath the car.

In answer to his third point, re weight distribution, I point to the Type 828 B.M.W. as an example of a car Which is second to none in its class as a road car, and yet is by no means without honour as a trials machine.

I do not think that the third passenger’s ” reasonable ” comfort would be unduly compromised by his having to put his feet on one or both sides of the clutch housing. As regards his solution for all these difficulties that he has raised, obviously Sqn. Ldr. Marris is a front-drive enthusiast and I am not, and therefore it is unlikely that we shall ever agree. However, I should like .him to consider the following points. If he adopts the Citroen transmission arrangement with an all-indirect gearbox mounted in front of the final drive and with the clutchshaft passing over the final drive, as he is bound to do unless he adds about 18 in. to the wheelbase and puts the gearbox between the engine and the final drive, the height of the crankshaft from the ground will be some 3 in. to 4 in. higher than that necessary to give 7 in. clearance under the flywheel housing. This will probably necessitate increasing the bonnet height and also raising the seating position, thus raising the centre of gravity and increasing the frontal area. Also, even if he has the forward gearbox mounting, he will have to increase the wheelbase by some ft in. unless he is prepared to have the cylinder block projecting into the cockpit where I had the clutch housing. I am, Yours, etc.,

R.E.M.E., J. S. MOON (Capt.). Horne Forces.