The trend of racing-car design

THE 1939 season, until interrupted towards its close by international unrest, contained some truly interesting developments. First, we had the continued development of the 3-litre Formula G.P. cars, which, in 1938, their first season, proved to be almost as fast as the foregoing 5½-6-litre Formula cars; but nothing like so reliable. Then, with every probability that the 1½-litre Formula would. govern the International contests of 1940, 1½-litre racing took on a new importance altogether. Finally, in the sphere of record-breaking the Land Speed Record was raised by a comparatively light-weight car and some remarkable practical engineering work was done when Major Gardner successfully attempted to better 200 m.p.h. in both class F and class G.

In the matter of the 3-litre Formula cars, new speed and general performance was found, but reliability was, if any-thing, less marked than before. Mercedes-Benz, with the V12 cars, proved outstandingly successful, with the V12 Auto-Unions very worthy rivals, both teams continuing to employ the exacting methods of preparation and participation that we who have seen these German teams in action have come to respect. Maserati, with the 3-litre straight-eight, was not in the picture except for a burst of speed at Nurburg. Bugatti and Delahaye featured mainly in sports-car races and Alfa-Corse, scratching from the Eifel meeting, gave up the V16 car and did indifferently with the straight-eights. The supercharged V16 Darracq failed to appear, but the unsupercharged Formula 4½-litre six-cylinder engine in the new chassis, although outclassed by the blown 3-litres, went very nicely at Pau and Rheims. The amazing performance of the 1939 3-litre cars is emphasised by the fact that at Rheims Lang’s Mercedes-Benz broke the former lap record, and in the Eifel G.P. Lang not only beat the former lap record, held by Rosemeyer’s 6-litre Auto-Union, by .43 of a m.p.h., but he established a new race average record, winning at 84.14 m.p.h., as against Rosemeyer’s 82.95 m.p.h. Early in the season Auto-Union was doing nearly 200 m.p.h. flat out, and at Rheims the faster 3-litre cars were clocking 185 m.p.h. along the straight and some 170 m.p.h. past the stands. Definitely temperament has returned to G.P. racing, and the entire Mercedes-Benz team retired at Rheims. Tyre wear is also pronounced, in spite of better road holding qualities.

In the sphere of 1½-litre endeavour, the greatest sensation, and one which will be remembered for ever in racing history, was the debut of the two 1½-litre V8 Mercedes-Benz cars. Built in complete secrecy for the Tripoli race, limited for the first time to 1½-litres, these astounding German cars suffered no teething troubles at all and swept all before them, opposition from the latest Alfa-Romeos not excepted, Lang, the winner, averaging a speed within some 4 m.p.h. of that at which the 3-litre won in 1938. These Mercedes-Benz were later demonstrated at Nurburg during the Eifel meeting, but did not again compete, being retained for purely 1½-litre contests. Had the 1½-litre International Formula come into being this year, undoubtedly Mercedes-Benz would have been in a very well-entrenched position.

The beautifully constructed, straight-eight Type 308 Alfa-Romeos were certainly the runners-up, and demonstrated the potency of modern 1½-litres in the Swiss G.P., when Farina won on general classification and actually ran second to Lang’s 3-litre Mercedes-Benz for four laps, being only 51 secs. behind the 3-litre car at the end of the first, and very fierce, lap.

When the Alfettes were not running, Maserati was up in front with the new four-cylinder, sixteen-valve cars, after piston failures at Tripoli. It is unusual for British drivers to be able to acquire the very latest example of a famous Continental marque, but both Wakefield and Tongue secured these sixteen-valve Maseratis, Wakefield scoring notable successes in Continental 1½-litre events.

Another very High Spot in 1½-litre racing was the appearance of the new E.R.A., very Mercedes in outline and with new frame, suspension and transmission and a modified six-cylinder engine. Unfortunately early misfortunes with the oil-pump drive, piston rings, valves, overheating, etc., rendered it a frequent non-runner, and at Albi it crashed while in the lead, but not before Arthur Dobson had set a new lap record at 98.58 m.p.h. and was leading the sixteen-valve Maseratis.

In the field of record-breaking the three outstanding happenings were the raising of the 3-litre short-distance records by the specially-streamlined Mercedes-Benz to 248 m.p.h., the setting up of 1,100 c.c. and 1½-litre sprint records at over 200 m.p.h. by Major Gardner’s M.G., and the lifting of the Land Speed Record (world’s flying mile) to 368 m.p.h. by John Cobb’s Railton, the last overshadowed by the threat of world war. The M.G. records were notable not only because this was the first time 200 m.p.h. had been exceeded in classes G and F., but because the same engine was used for both, the cylinders being bored out on the spot after the class G attack, which was an extremely fine tribute not only to British design and construction, but to our ability on the practical engineering side. It is interesting that the two former record-attacks disposed of long-standing historic landmarks, Mercedes-Benz putting some 48 m.p.h. on to the unofficial 200 m.p.h. achieved by the 3-litre Lockhart-Stutz in 1928, and the M.G. disposing of the official 164 m.p.h. 1½-litre record held by Lockhart’s Miller, by over 39 m.p.h. Incidentally, the 3-litre Mercedes-Benz broke the former official records, standing to the credit of Maserati, by over 100 m.p.h. Although C.I. class records have not yet been instituted as we have often requested, a 2-litre diesel Hanomag broke two C.I. records.

At the beginning of the 1939 season interest centred chiefly on the Formula cars and in particular on what Mercedes-Benz and Auto-Union would do. When the latest 3-litres appeared it was seen that Mercedes were even lower in body depth than before, with narrower radiator cowl and longer, squat noses. It was said that experiments with supercharging had resulted in an output of over 140 b.h.p. per litre. They were lighter and faster than in 1938 and now used grouped exhaust branches running into the main pipe. Auto-Union had again redesigned their front suspension, to improve steering and stability, it was said largely under the supervision of Tazio Nuvolari. Mercedes-Benz had new “fretwork” cooling rims on their brake drums, additional to the circular cooling holes on the drum faces, used in 1938. They used the older nose-treatment for the 3-litre which Lang drove at the Vienna hill-climb, incidentally employing stub exhausts and twin rear-tyres in this instance. In this sphere, as in road-racing, the 3-litre demonstrated its extreme potency, beating the 5½-litre G.P. Mercedes-Benz and the short-chassis 6-litre Auto-Union.

In the French G.P. Mercedes and Auto-Union were getting some 190 m.p.h. all out, undoubtedly the highest speed ever achieved by a regular road race car, and in spite of the very high speed the cars were notably steady. On the other hand, as has been said, reliability was not so evident, lubrication and supercharger troubles being not unknown. The pressure built up in the crankcase in V engines still gave some anxiety, and amongst the devices used in practice by the Mercedes technicians was a pressure gauge on the engine crankcase. The scheme of using a decoy car to lap fast from the commencement of a race and so tempt one’s rivals to open up seems to have completely vanished and both the German firms seemed to consider it desirable that their complete teams should finish. Out of seven Formula races Mercedes-Benz managed one hat-trick with the first three places, and in five instances held first place. Auto-Union split things up by taking second place on four occasions, winning once. Mercedes retirements numbered Caracciola’s broken oil pipes at Pau, Seaman’s slipping clutch at the Eifelrennen, Seaman’s terrible accident and Caracciola’s crash at Spa, two engine failures and Caracciola’s wall-encounter at Rheims, and Lang’s and Brauchitsch’s plug trouble and Brendel’s crash at Nurburg. Minor bothers were Lang’s difficulty in re-starting his engine at Spa and Caracciola’s early plug trouble and Brauchitsch’s leaky tank at Nurburg. Auto-Union retirements were Nuvolari’s and Meier’s accidents at Spa, Nuvolari’s engine blow-up at Rheims, Nuvolari and Stuck with mechanical failings and Hasse and Meier through loss of control at Nurburg. Meier’s car went on fire at Rheims, when he finished second, a lap after Muller, and Stuck lost speed. Clearly, in spite of exceptional preparation and splendid road-holding, both engineers and drivers were finding 200 m.p.h. 3-litre road-racing bolides a handful. The increase in performance over 1938 was due mainly to supercharging alterations. Mercedes used two Roots blowers, each absorbing 80 b.h.p., drawing from three carburetters, Auto-Union commenced the season at the Eifelrennen with their single Roots blower drawing from four carburetters feeding via four short separate connecting pipes set one above the other. It will be recalled that the Vauxhall-Villiers (described in MOTOR SPORT, January 1937) had three carburetters feeding thus into the blower casing, to ensure an even mixture entry and this is undoubtedly the reason for Auto-Union adopting four separate delivery pipes. At Rheims two of the Auto-Unions had special rear cowling, a tunnel on the off side of the tail feeding air to the carburetters and an air-scoop behind the driver’s head, merging with the tunnel, taking cool air to the blower. It was rumoured that a very high boost was in use. For the German G.P. at Nurburg Auto-Union came out with two-stage supercharging, using two Roots blowers of differing size, one feeding to the other, drawing from the previous quadruple carburetters. Two-stage supercharging has found a place in aeronautical engineering, but this appears to be its first application to a racing-car engine. The Auto-Union engineers apparently wished to raise the boost appreciably, while retaining Roots blowers on account of their high speed of operation giving reliability with low weight. The comparative inefficiency of the Roots blower pointed to two-stage boost, in which the first blower would deliver mixture under considerable pressure  to the second blower, in which the pressure would be doubled. This points to a boost of some 25-30 lbs. per square inch. There was some suggestion that Mercedes were also using two-stage boost, and if three carburetters were used with twin blowers this may be so, but we rather believe they adhered to one blower per block, probably, with twin carburetters to each supercharger. The I½-litre Mercedes-Benz had one Roots blower drawing from two carburetters, Maserati tried both single and double Roots blowers on their 1½-litre, using two on the 3-litre, the V16 Darracq would have had two Roots blowers, and Alfa-Romeo had a single Roots blower on the near side of the block on the 1½litre. E.R.A. used a huge Zoller vane-compressor blowing at 28 lbs. per square inch on the new car, set beside the block on the off side, and the 200 m.p.h. M.G. had a Centric vane-compressor blowing at 30 lbs. per square inch, and drawing from two 2 inch S.U. carburetters. The M.G.’s supercharger absorbed some 35 b.h.p. and ran at just over half engine speed. The latest Alta used an Alta-Roots blower delivering at 20 lbs. per square inch. The importance of correct gas flow within the supercharger is emphasised in an article by H. Pfau in the May 1939 issue of “Automobiltechnische Zeitschrift,” in which it is stated that at gas velocities below 850 ft. per sec. no error in estimating delivery head and delivery efficiencies arises if gas compressibility is neglected, but over this velocity errors are incurred. Probably referring to experiments with the record-breaking 3-litre Mercedes-Benz, this same author states that the air-intake temperature at 250 m.p.h. is raised 6.1° above atmospheric by the relative speed, and the power loss thus occasioned must not be overlooked. In a paper read before the S.A.E. by Arthur Nutt, last June, the advantages of the exhaust-driven turbo-supercharger for high power aero-motors, over the two-stage and two-speed types, was mentioned, and one wonders whether this type will one day find a place on racing-car engines.

Valve arrangements and constructional details remain largely as in 1938, and four-cylinder (Maserati and Alta), six-cylinder (Darracq and E.R.A.), V8 (1½-litre Mercedes-Benz), straight-eight (Alfa and Maserati) and V12 (Mercedes, Auto-Union and Delahaye) types were all seen. The six-cylinder Darracq had push-rod valve gear and light alloy block with Nitralloy liners and alloy head with bronze valve seats. The b.h.p. per litre of modern G.P. engines is about 130-140 in the case of the 3-litre cars, and around 100 or over from the 1½-litres. The Mercedes runs up to over 8,000 r.p.m., and the 1½-litre to 10,000 r.p.m., but Maserati reduced maximum speed somewhat, to about 7,000 r.p.m„ and the 1½-litre Alfa peaked at 7,000 r.p.m., whereas the new E.R.A. went up to 8,000 r.p.m. or over. Speeds of over 140 m.p.h. were realised from the road-racing 1½-litres. Mercedes-Benz used coolant in place of water for cooling, with a boiling point of 120° C., permitting the engine to run at 100° C. A higher boost and compression ratio was used than was employed for the 5½-litre engines and oil cooling was a problem. The lubricant was fed on the dry-sump system via a radiator having an airflow of 24,000 litres per min. at a rate of circulation of 20 gallons a minute. These 3-litre engines were a thought temperamental over plugs. In sultry weather Mercedes used Bosch Type 450, but cool weather necessitated Bosch Type 420 and wet, cold conditions demanded hotter plugs—Lang’s retirement and Caracciola’s early troubles in the German G.P. were traced to the use of Type 420 plugs which oiled owing to unexpectedly low temperatures. Gardner’s M.G. took its 200 m.p.h. records on a top gear ratio of 3.09 to 1, the engine reaching over 7,000 r.p.m., with a piston speed of 3,250 ft. per second. This represented a reduction in crankshaft speed of approximately 16 per cent. over the earlier form, but as the speed of the car went up by 91per cent., the actual reduction in top-gear peak was 8 per cent. Sodium-cooled D.T.H. 49a valves were used in a Barronia bronze 14 mm. plug head. The rebore carried out at Dessau to convert the car from 1,086 c.c. to 1,105.5 c.c. involved enlarging the bores by .020”. Done as it was on the spot, this constituted a truly praiseworthy example of British practical work. A standard Van Norman boring tool was employed, Type 944  “Per-fect-o.” Aerolite pistons were used, with a .040″ clearance, and the engine was not even test-run before going out after the 1½-litre records. The whole operation reflects immense credit on E. P. Barrus, Ltd., the makers of the tool, on Aerolite, and on S. Enever and Robin Jackson, the chief engineers involved.

An interesting reflection on the cost of racing-car maintenance was given by H.R.H. Prince Chula of Thailand in “The Autocar ” last August, when he stated that running his stable of cars in 1938 absorbed £4,326, of which spares and repairs took £1,376 and equipment only £31. Prize and starting monies, incidentally, set the loss at £1,393. If you consider the number of cars used, that is a creditably low outlay per car for front-line racing.

So far as maximum power outputs are concerned, estimates are far from consistent, but Mercedes and Auto-Union were quoted at 420-450 b.h.p., the V16 Alfa-Romeo 410 b.h.p., the 1½ litre Mercedes at least 250 b.h.p., the new E.R.A. 220-250 b.h.p. (the preceding Zoller-blown E.R.A. developed 200 b.h.p.), the 1½-litre sixteen-valve Maserati 200 b.h.p., the 1½-litre Alfa-Romeo 195-210 b.h.p., the 1,100 c.c. M.G. 196 b.h.p. and the Austin Seven slightly more than its former 134 b.h.p. Crankshaft speeds were raised, strokes being kept short, which tendency is also seen in the 1½ litre class, with the square Maserati engine of 78 x78 mm., the 58 x70 mm. Alfa and the 63 x 80 mm. E.R.A., though Alta retained a 100 mm. stroke. Of unblown engines the 4½litre Delahaye was quoted about 260 b.h.p. at 5,000 r.p.m. and the 4½-litre Le Mans Lagonda 240 b.h.p. at 5,000 r.p.m.

It was revealed during 1939 that the new bearing material, A.C. 9, evolved by Rolls-Royce and used on their production Rolls-Royce and Bentley cars, was first tried out in E. R. Hall’s Bentley which averaged 80.81 m.p.h. in the Ulster T.T. E.R.A. adopted this material in 1937 and the cars in which it was used required no bearing attention during the whole of the 1938 season. The 1939 works cars naturally had A.C. 9 alloy bearings.

Refuelling seems to have gone through more rapidly than in 1938, the average time for a refuel and tyre change being around 33 or 34 secs., while at the Eifel race Brauchitsch kept his engine running while tyres only were changed and lost only 24 secs., and when duelling in the German G.P. Caracciola and Muller, stopping for a second supply of fuel, which would only entail a small quantity, were away in 15 secs. and 18 secs. respectively. Tyres require changing after about 100-120 miles, sometimes lasting only 57 miles if one instances Lang in the Eifelrennen. Consequently, fuel can be put in when the tyre change is made. This raises the interesting problem of whether to start with fuel only sufficient for running until the tyre change, or putting in a full tank of fuel, with the adverse effect on road-holding in the opening stages, but a gain at the pit stop because a wheel change is quicker to accomplish than a half-tank refuel, it being possible to keep the engine running while the car is on the jack, while no hose impedes the mechanics at work on the tyre change. In the Eifelrennen Auto-Union did the 142½ miles without a tyre change or refuel, but Mercedes preferred to attempt this only with Brauchitsch’s car, which, however, needed tyres after 71 miles. Even so, keeping his engine running he saved 8-13 secs. over Lang and Caracciola, who took on some 30 gallons of fuel, having started with half-full tanks. This year’s European Formula races varied in length from the 135.7 mile Final of the Swiss G.P., to the Belgian G.P. and German G.P., both of 312 miles. Using 70 gallon tanks the 3-litre cars would get through the former and need only one refuel in the latter race. Designed with 40 gallon tanks to necessitate refuelling every tyre stop they only need topping up in the shorter race and no time-loss need result at the pit stop, but in the long-duration race two stops would be needed and at both refuelling would outrun the duration of the tyre change, which also might not coincide with convenient  refuelling. So Mercs. were wise to retain big tanks, filling them half full only for the Eifel experiment. In the German G.P. Caracciola refuelled at his tyre stop after 126 miles, indicating some 45-50 gallons at the start, and stopped 18 secs. for a top-up at 256 miles, pointing to another 45 or 50 gallons going in at the first stop, assuming 2½-3 m.p.g. It seems that earlier estimates of the speed at which fuel flows through the hose during refuelling operations with pressure pit-tanks were over-optimistic, as even a 35 gallon refuel takes longer than a tyre change, indicating a refuel flow-speed of around 1 gallon a second. This is a problem on which some knowledgeable pit-attendant might very well expound.

Turning to chassis design, Mercedes-Benz contrived to offset the engine across the frame in their I½ litre, as in their bigger cars, placing the driver’s seat to the off side of the propeller shaft. They also had central tanks on this car, around the scuttle, whereas the 3-litre with tanks before and behind the cockpit still relied on driver-control of the shock-absorbers to compensate for change of weight distribution as fuel level fell. Auto-Unions scored here by their use of central frame-level tankage, though it is wrong to describe these cars as truly rear-engined. The new E.R.A. was extremely low built in spite of relying on a seat placed above the straight transmission line. Alta retained their double reduction rear axle, with dropped propeller shaft, on their latest cars. 1½-litre cars had a fuel range of about 200 miles, but Reggie Tongue’s Maserati was hampered by small capacity. In spite of weighing only about 18 cwt. the 3-litre Formula cars sat down on diverse circuits extremely well, even at nearly 200 m.p.h. The 1½ -litre Maserati was said to weigh about 11 cwt., the latest Alta under 13 cwt. and the new E.R.A. about 14 cwt. Brakes were in most instances hydraulic, and Mercedes-Benz and the new E.R.A. had the Lockheed Two-Leading-Shoe brakes, E.R.A. dropping Girling actuation. Mercedes and Auto-Union made use of hydraulic shock-absorbers, several times altering the detail layout. Mercedes had vertical coil spring front suspension, Auto-Union transverse torsion bars, Alfa-Romeo coil springs on the 3-litre, the 1½-litre Alfa which rode very well in 1938 later had the former transverse leaf spring replaced by transverse torsion bars and swing links, Darracq and Delahaye used transverse leaf springs, the 3-litre Maserati parallel torsion bars, the new E.R.A. transverse torsion bars and trailing links, and Alta brought out a new system of parallel torsion bars and box-section swing links damped by Luvax shock-absorbers. All, of course, sprung the wheels independently. So far as rear suspension is concerned, the de Dion axle held the fort. Mercedes used parallel torsion bars, Auto-Union a similar layout with the bars within the tubular side members, Alfa a transverse leaf spring, Delahaye a transverse leaf spring, the new E.R.A. parallel torsion bars within the tubular side members damped by De Ram hydraulic shock-absorbers, the 1½-litre Maserati had a normal axle, splayed out quarter elliptic springs located conventionally and underslung, the 1½-litre Alfa a transverse leaf spring and torsion bar stiffener, and Alta the now enclosed torsion bar system. Dodson’s 1,100 c.c. Maserati had a curious rear suspension system employing a curious coil-spring cum torsion-bar rear suspension with fully underslung chassis, and Freddie Dixon used tie-rods to combat brake torque on the conventional half-elliptic suspension system of Rolt’s E.R.A., which benefited materially on the Donington circuit, winning the Empire Trophy race. Darracq used hydraulic and frictional shock-absorbers in combination, and the new E.R.A. used long tie-rods locating the rear axle outside the frame. Tubular frames were general, including that of the new E.R.A. and the steel tube Alta, but Maserati used a closed box section and Alfa, Maserati and Delahaye had box side members. The oil tank materially stiffened the rear of the 1½-litre Maserati frame. Mercedes and Auto-Union used five-speed rear axle gearboxes, E.R.A. replaced the Wilson box by a sliding pinion box, but Alta retained the preselector box. The I½-litre Mercedes-Benz used 17″ x 5.00″ front tyres and 17″ x 7.00″ rear tyres. Bodywork was even more streamlined than before. At Tripoli Villoresi used a fully streamlined body with many cooling louvres on his Maserati, with fairing over the wheels, designed by the man responsible for the record-breaking Mercedes. He made fastest lap in practice at 134 m.p.h. but retired on the line with gearbox trouble.

In the field of record work both the 200 m.p.h. M.G. and Cobb’s Railton had Reid Railton-designed bodies extending out to enclose the wheels, and. totally enclosed cockpits. The record-breaking 3-litre Mercedes-Benz, however, reverted to wheel-spats and had an open cockpit, albeit the spats were well faired, extending well round the wheels and the small nose was very carefully merged into them. The 368 m.p.h. Railton again used ice cooling for the two 23,400 c.c. Napier “Lion” motors.

In sports-car racing Bugatti won at record speed at Le Mans with a supercharged 3.3-litre in spite of a long pit-stop, used modernistic streamlining enclosing the wheels, and many enclosed cars competed, while the amazing 1,100 c.c. Simca Fiats also made use of effective wind-defeating carriagework. Honours were fairly nicely divided between Bugatti, Alfa-Romeo, Darracq and Delahaye. Bugatti won at Le Mans and was second at Comminges, Delahaye took the lap record at Le Mans at almost 97 m.p.h., Alfa-Romeo finished first and second at Antwerp with new six-cylinder cars, and Gerard’s unblown 3-litre Delage was second at Le Mans and Le Begue’s 4.5-litre Darracq took the lap record at 101.4 m.p.h. and won at Comminges. The Le Mans V12 Lagondas made a very fine debut at Le Mans, and later lapped Brooklands, stripped, at about 140 m.p.h. In British races assorted E.R.A.s and M.G.s were prominent, and the little 750 c.c. twin o.h.c. Austins did extremely well, notably on the Crystal Palace circuit. Maclure used the blown Riley Six engine from Mrs. Peter’s Riley in certain races and various sized unblown Riley engines in other events, and Staniland’s Multi-Union II with Considerably modified 3-litre Alfa-Romeo engine went very well and only just missed the Brooklands Lap Record on account of stretched valves. Alta built the long tubular-chassis car for Beadle and did well in sports-car races.

Apart from the outstanding record attacks, Hanomag took the C.I. standing mile record and 5 miles and 5 kilo C.I. flying start records at over 96 m.p.h., using a 2-litre four-cylinder diesel engine and saloon, wheel-enclosing body. Jenkins took Class A long-distance records at around 170 m.p.h., Lurani did 108 m.p.h. on 492 c.c., and the 350 c.c. speed went up to over 91 m.p.h.

It seems that when the war clouds roll away racing will be largely a matter of individual effort. It is interesting, therefore, that several promising ventures were nearing completion when Nazi Germany intervened. Thus Parnell had built a special I½-litre car with tubular frame, independent suspension and de Dion rear axle, and a new six-cylinder single o.h.c. engine with two-stage supercharging, trying it out with an E.R.A. engine at Prescott. Lord Howe had decided to install an ambitious Jameson two-stroke engine of 1½-litres capacity in his E.R.A. Alta had completed a new 1½-litre with torsional independent suspension for Lady Mary Grosvenor, and Major Gardner’s 754 c.c. six-cylinder M.G. was all ready to tackle Class H records at Dessau, a speed of 150 m.p.h. being designed for and 180 m.p.h. hoped for. There was talk of a l½-litre Auto-Union and a new 1½-litre Alfa-Romeo, Cobb was believed to be courting the idea of 400 m.p.h., Eyston would likely have taken the  “Thunderbolt ” out to Utah again, and Peter Clark had designed and planned a fully streamlined H.R.G. for the 1940 Le Mans race, after doing extremely well in the 1939 event with his slightly modified Meadows H.R.G. America had built three six-cylinder rear-engined four-wheel drive turbo-supercharged Millers of Formula type.

When Peace comes again to Europe, such endeavours may take root in broken countries, but it is a very moot point whether International Grand Prix racing will ever again reach present standards. Racing car development on this scale will probably slow down. Very probably the 3-litre Mercedes-Benz will live down the long years as the most remarkable and fully developed racing car ever built. Our generation should be eternally joyous that it has seen this car in action.