Following on the article on the Adler in the February issue of Motor Sport, we now publish some notes by A. F. Carlisle on the Volkswagen, based on our contributor’s personal experience of one of these interesting, Dr. Porsche-designed cars, bought new in Germany in early 1947 and since driven 20,000 miles, mostly in this country. The technicalities of the Volkswagen render it of considerable allure, apart from the “political” implications of its challenge to our own cars in the export market. — Ed.
The Volkswagen is a strange mixture of very advanced and unorthodox design (which should appeal to readers of Motor Sport) and utilitarianism. At best it is a modern saloon, with independent suspension of all four wheels, an air-cooled o.h.v. flat-four engine mounted at the rear, built-in heating, and possessed of a high cruising speed. At worst, it is a light-gauge tin box, in the construction of which self-cutting screws, cardboard, and rubber solution feature.
The cars are manufactured in a specially-built factory put up at lavish expense near Brunswick, just inside the British Zone. Post-war production, I believe, has been 2,000 a month or about half full capacity.
The chassis is made in two types, the Type 51, which was the German Army’s “Jeep” (known to us as the V.W. 82), and Type 11, which is the “People’s car.” With the exception of a few fittings both are the same and their chassis consists of a central backbone, which is a large-section built-up tube with a fork at the rear to pass either, side of the gearbox. Built inside the chassis tube are control wires, brake-rod and cables, petrol pipe and gear-change rod. At the front end two cross-tubes are bolted on one above the other, and inside each of these is a three-leaf spring making a small square torsion bar. Each of these bars is fixed in the centre, and the extremities are attached to the trailing arms (four in all) of the Porsche i.f.s. system.
The trailing arms are very short and like so many components seem very light and small for the size of car.
Rear suspension is by swinging half-axles located in the centre by the engine-gearbox unit and sprung by torsion bars located inside a cross-tube and acting through trailing arms. The Type 51 has a small reduction-gear unit on the outer end of each half shaft which gives increased ground clearance and a wider track; the front-end is similar, with a modified stub-axle unit incorporating an anti-shimmy device. The springing of both versions of Volkswagen is firm and completely unbreakable, there is no roll on corners and tyre scrub at the rear greatly assists the shock-absorbers in damping rebound; in fact, a hump-back bridge can be taken at 50 m.p.h. without bottoming or bouncing. The brake drums and wheel hubs are cast in one: the brakes are a bit disappointing and are liable to fade when applied hard.
The engine is a flat-four, built up as a unit with its accessories and mounted just behind the rear-axle by four bolts which attach it to the transmission case. The drive passes through a dry-plate clutch to the gearbox ahead of the rear-axle and then back again to the final drive.
Bore and stroke are 75 by 64 mm., and the compression ratio is 5.8 to 1. The very short stroke greatly reduces the size of the engine, and its components, notably the crankshaft and connecting rods, appear to belong to an engine much smaller than 1,131-c.c., which is the actual capacity. Owing to staggering of the cylinders the crankshaft is also very short in spite of the big bore; it has four throws and three main bearings, with an extension bearing behind the timing gear wheel. Each cylinder barrel is separate and clamped between the one-piece aluminium cylinder head and the crankcase without gaskets by means of long studs. Like so many air-cooled units this one is mechanically noisy, although I think a lot might be done to reduce the noise by fitting split-skirt pistons and a better means of tappet adjustment than the method actually used, in which the adjusting screws bear on the valve tops and soon wear a groove. The overhead valves are parallel and operated by hollow push rods (which also pump oil to the rocker boxes), the camshaft being set low underneath the crankshaft.
Carburation is by means of a down-draught Type 26 V.F.J. Solex and a rather small T-shaped induction pipe incorporating a hot-spot. The engine is said to develop 25 b.h.p. at 3,800 r.p.m.
A six-volt Bosch generator with AVC is placed high and belt-driven and on the forward end of the generator spindle is the cooling fan. Throughout the car the electrics are first-class, and although I have added a radio and fog lamp, starting has always been very good and I have never had to use the handle. Headlights are not too good, but I blame the crinkled glasses for dispersing the beams to too great an extent. Cooling has obviously received a great deal of careful thought and development. No attempt has been made to use a scoop, all the air being delivered by a centrifugal impeller enclosed in a large semi-circular case which straddles the engine and connects with the fully-baffled cylinders. After the cooling air has passed through the engine it is either expelled through a variable aperture or ducted to the interior of the car for warming the occupants and windscreen demisting. Inside the blower case is an oil cooler with a viscosity by-pass valve, which enables the engine to warm up rapidly and yet maintain reasonable temperatures on a capacity of five pints of oil.
In practice the cooling system has been most satisfactory under all conditions and I would not willingly revert to water cooling. The absence of worry and the saving of expense by dispensing with anti-freeze, the quick warming up, and the simple interior heating are really worth a lot to me.
Accessibility of the engine for a routine check over is good, but for anything more it is advisable to drop it out of the frame; it is just possible to remove a cylinder head in situ, but the cooling baffles make the operation very awkward.
The petrol system is normal except that the 9 1/2-gallon tank is under the bonnet, feeding via a dirt trap and a reserve tap which is controlled from inside the car, to a mechanical pump. No petrol gauge is fitted and this was also the case on the export models I saw recently in Switzerland; however, on my own car I adapted a Jeep gauge with success.
The gearbox has four speeds and reverse, without synchromesh. Gear changing is straightforward if a double de-clutch change is made both up and down. A snag is the noisy top gear, owing to the indirect drive which is actually an overdrive with a ratio of 0.8 to 1; the other ratios are 1.25 to 1, 2.07 to 1, 3.6 to 1. The final-drive ratio is 4.43 to 1 in the Type 11 with a further reduction of 1.4 to 1 in the Type 51.
Also, in the case of the Type 51 a cam-differential is used and I couldn’t resist buying one of these most ingenious little units, although not strictly as a spare, for my Type 11. Briefly, each half-shaft is driven by a cam wheel with the cams facing inwards. These cam wheels are odd, one having nine cams and the other eight. Between them is the driven cage in which 17 plungers are set transversely with their ends bearing on the cams. The different number of cams on each side — putting it crudely — ensures that all the plungers don’t go over t.d.c. together, but there are complications and the overall gear ratio on corners must be higher when turning one way than when turning the other! In unit with the differential are modified cardan-type universal joints which allow for suspension movement.
The Volkswagen saloon body may not be beautiful, but it is a fairly good streamline and very roomy. The seating is set well forward, the back seat being well ahead of the wheel arches and comfortably wide enough for three people; there is also a good stowage behind it on top of the transmission. Left hand drive is standard and although the steering box could be changed to the other side and the halves of the split track rod reversed, the foot pedals which sprout from the chassis tube could not easily be switched over. The interior is austere and typically Continental, with cloth upholstery, but it is completely rain and draught-proof, to the extent that the doors cannot easily be shut unless a window is open to permit air to escape.
When driving one is first aware of the forward driving position and remoteness of the engine, then of the very high top gear, which gives 21.7 m.p.h. per 1,000 r.p.m. As speed rises acceleration improves, until the happy cruising speed of 80 kilometres (50 m.p.h.) is reached. Unless the car is driven fairly fast it is noticeably overgeared and third gear, in which 40 m.p.h. is available, must be used freely. A round 100 k.p.h. (62 m.p.h.) can always be attained in top, even quite a bit more under advantageous conditions. The well-balanced engine becomes perfectly smooth at speed and a lot of the “ticking” disappears. Petrol consumption is fairly reasonable and works out at 37 m.p.g. on my car, taken over 50 gallons. The low weight (14 cwt.) and the clean body lines must contribute to this.
On the straight there is a lack of precision in the steering and a tendency to wander; on gentle curves the car understeers, but on tighter curves she begins to oversteer — a characteristic result of having swinging half-axles at the rear. However, as soon as one has come to anticipate the change-over from understeer to oversteer it is possible to get round corners quite quickly.
In Germany any number of “specials” have been based on the Volkswagen chassis and spares and service are available in every town. The car was on sale to the Forces in Germany for a short while and quite a few have been brought over to this country. I hope some of these will become the basis of further “specials” and I would be interested to hear from anyone contemplating such a car. A good example of a sports Volkswagen is the Porsche, now being sold in Austria.