ANOTHER "IDEAL" DESIGN

ANOTHER ” IDEAL” DESIGN

M. E. Nixon outlines what he wants after the war—and how he is actually building something approaching it.

INSPIRED by the invitation extended by the Editor at the end of Capt. Moon’s excellent article in the September MOTOR SPORT, I have ventured to set down my requirements for a postwar sports car and how I am trying to meet them. To my mind the first question to be answered in designing or buying a car is, “For what is the car to be used ? ” In my case the answer is : (1) for an everyday home to work and business running ; (2) for evening and week-end pottering round country lanes and field tracks ;

(3) for social occasions ; (4) for occasional read-burning expeditions to Scotland, Cornwall, etc. ; (5) for mild competition work, M.C.C. trials and club race meetings.

Now this specification can be met by practically any car with .pretentious to being 6 sports model, and the important thing is the emphasis placed upon each of the above items. In my ease the pottering about the countryside, on and off the road, and the road-burning expeditions come first, although I must always have an answer to the press on the starter button on Monday morning. What sort of car meets these requirements? My answer is a 2/4-seater roadster body, on a compact chassis, with an engine of moderate size, giving 100 m.p.h. whenever required, 75-80 cruising, and good acceleration. The whole to be reliable and easy to maintain, and light on the pocket. Dealing first with the body, as this will naturally affect the size of chassis and the b.h.p. to drag it • along. If I am to drive for 400 miles off the reel at high Speed, as I dared to on occasions before the war, I must have a really ‘comfortable seat. There is the possibility of my finding someone mug enough to make a practice of coming with me, so there must be two comfortable seats. As I found the T-type M.G. Midget really comfortable over long distances, the front seat dimensions are taken from this. The two rear seats are for the people who insist on a lift home, and the A.C. hammock-type of occasional seat seems to fill the bill, especially as it. could be made to fill the gap behind the front seats when the roof is down. The body should be wide enough to obviate the necessity of a cutaway, as low body. sides are a nuisance when driving through rain. The roof should go tin and down very quickly, if possible without the need for stopping the car, as I have found that one always says, ” It’s only a drip, it will leave off in a minute,” and it never does. Winding windows help on social occasions in the winter and may make all the difference between a car being possible or impossible. In this connection I think a great deal can be learned

by studying the latest American roadsters, as they do this style of body Very Well, although they spoil it by putting it on a glorified cinema organ. Still, this is the type of body I have in mind, scaled down to a 2/4-seater, with all seats under the roof, said roof folding out of sight.

To proceed to the chassis. To accommodate the body outlined above a wheelbase of 9 ft. and a track of 4 ft. 3 in. would Seem to be the minimum. The next question is what sort of chassis, and quite frankly I don’t mind at all so long as it gives good results. Just before the war there were many different ideas on the subject, but there were no signs that any one idea was vastly superior to the rest. My own personal preference is for a chassis composed of two parallel box-section side members, perfectly straight, with a fiat undertray to join them, dished to prevent drumming, tubular cross members and a propeller shaft housing strengthening the structure in the centre where the door space comes. For both front and rear suspensions I like the Porsche type suspension as applied to E.R.A. ; steering by divided track rod. This chassis design is simply what I consider to give the best results, according to my calculations. But I would like to stress that I am ready to be convinced, by practical tests, of the merits of any other system. I have still to be convinced that, for British roads, the normal “carriage-type ” suspension is out of date. IN ith regard to the De Dion rear suspension, I don’t think it has any merits for touring car use, and until the GerMan technicians can he made to talk, I still doubt that it is essential to a racing car. If a car is to go into quantity production I favour a Bugatti rear-axle and central gearbox, with Porsche front suspension. For a quality car, Porsche suspension all round with gearbox and back-axle in one. If it is to be the beat in the world let M. Bugatti design the chassis and take his word for it. Coming next to the engine, there are many good reasons for making a standard chassis and back-axle ready to take any engine and gearbox the customer may want. It should be possible to make the type of car I have in mind weigh not more than about 20 cwt., and with moderate streamlining 100 b.h.p. should take this along at 100 m.p.h., and give real acceleration. But what sort of engine should one fit ? An American with 8-speed box, a touring 3-litre engine with 3-speeds and synchromesh, a ” hot ” unblown 2-litre, or a blown 1 i-litre with crash box ? How many cylinders, and what about a pre-selector gearbox, Cotal or Wilson ? I think this question of engine depends on many things, such as where one lives,

how much money one can afford, etc. While the type of body and chassis I have in mind may appeal to a great many people, sticking to one type of engine might cut down it supporters considerably. My own personal preference is for a 111-litre 6-cylinder with twin camshaft mounted high in the block and operating the valves through rockers direct. This gives a hemispherical head, plugs accessible in the top of the head, and permits of lifting the head without disturbing valve timing. The blower should deliver at 10-12 lb./sq. in. pressure and be of the Boots type in order to give power low down. It should be possible to make the engine almost entirely of light alloys, and use wet liners. The gearbox could be of the Wilson selfchange type, or a crash box, to suit individual preferences ; I personally prefer the 1Vilson. The lubrication should be of I he dry-sump type with the intake passing through the top cylinder coolant take-off pipe to give rapid warming up. The oil tank could be alongside the sump with an oil radiator forward with the coolant radiator.

The specification listed above comes down to a 1i-litre 6-cylinder supercharged engine, with twin high camshafts. Wilson box, independent suspension all round, hydraulic brakes, and a normal 9-ft. chassis carrying a 2/4-seater roadster body. The whole weighing about one ton. Ground clearance and turning circle to be adequate for trials’ work. This is what I decided would be an adequate compromise for my post-war motoring needs, and at the end of 1931, as my T-type M.G. was beginning to show signs of “three years’ bard,” I asked myself what I should do about it. I tried a number of motor-cars, but either they were too expensive (all the I3.M.W.), or. like a lt-litre blown An, too ” vintage ” to be good post-war motors. Then I came across the Atalanta-Talbot already described in MOTOR SPORT. This seemed to provide the answer, although the thought of the tax on ’21 h.p. was not so good. Still, it joined the stable, and after a certain amount of running to get the hang of things, went into the garage for stripping and rebuilding. I was hoping to find time to do this myself. but have had to call upon E. H. Nicholl in my hour of need.

All this time I had the idea of substituting a smaller blown engine for the Talbot, but it was not until a recent visit to Nicholl’s shop that I found the solution. It was a 2-litre supercharged Lagonda. and I fell for it right away ; it had just the type of valve-operating gear I wanted, and is apparently the essence of reliability. Here was the solution to my problem. A 0-Ft. Atalanta chassis, strengthened at the back to overcome the weakness of the frame aft the axle line, a blown ‘2litre Lagonda engine, a Talbot preselector gearbox and the Abbott drophead coupe body converted to a 2/4seater with hammock-type rear seats. The tail has to be lifted to give a better streamline, and I have laid out a front,: end on the lines of the “Le Mans Bugatti. It only remains to put all the bits together !