The Lotus 49

During last season Team Lotus were without an engine of their own for Grand Prig racing, having relied on Coventry-Climax engines until the end of 1965. When the Coventry firm had to withdraw from racing it left a number of the British Grand Prix car constructors high and dry, the only self-contained Grand Prix team being B.R.M. This situation coincided with the beginning of the new 3-litre Formula for Grand Prix racing, and while B.R.M. were occupied with their 16-cylinder engine, Brabham had made arrangements with Repco of Australia for the supply of a suitable engine, and Cooper had made a contract with Maserati for engines. This left Lotus without a power unit, but at this point the Ford Motor Company stepped in and said they would finance an engine project for Lotus, to the tune of £100,000. The job of designing and building the proposed engine was given to Cosworth Engineering, under the direction of Keith Duckworth and Mike Costin, both of whom were closely associated with Lotus and Colin Chapman.

In Formula Two and Formula Three the names Lotus and Cosworth had been spelling success for some time, so naturally the connection of the two names on a Grand Prix Project, paid for with Ford money, had everyone’s interest. As you cannot design and build an engine overnight the project was aimed for 1967 and Team Lotus had to look or other means of racing in 1966. For this they relied on an old V8 Coventry-Climax 1 1/2-litre engine, enlarged to 2 litres, and a 2-litre V8 B.R.M. unit, these being installed in Lotus 33 single-seaters dating from 1965. As a temporary measure for 1966 two B.R.M. 3-litre 16-cylinder engines were ordered and installed in Lotus 43 chassis, and though Clark won the United States G.P. with one of these cars and went very fast in the Italian G.P., they were not a great success as the B.R.M. engine suffered numerous teething troubles. The works B.R.M. cars were behind on development, so it was not likely that Team Lotus were going to have much success during 1966 and they resigned themselves to being patient and working towards better things in 1967 when they would be self-contained with the Lotus Cosworth combine.

The Ford-inspired engine programme called for the building of a 4-cylinder 1,600-c.c. Formula Two engine based on the Cortina cylinder block, this unit to be a design study for a V8-cylinder 3,000-c.c. Grand Prix engine, and Duckworth designed, and Cosworth built, a twin camshaft cylinder head with four valves per cylinder for use on the basic Ford Cortina cylinder block, this Cosworth FVA engine being extremely successful from its inception, like many of the earlier F.3 and F.2 Cosworth projects. During 1966 the prototype 4-cylinder Cosworth FVA engine was installed in a single-seater Brabham chassis and underwent a serious test programme driven in Club racing by Mike Costin. Cosworth Engineering have a great advantage in that one of the directors is a sufficiently expert driver that he can compete in races and really test an engine, learning far more about the practical usage of a racing engine than any test-bed work or test driving done by a professional driver. By the time the FVA engine was ready to be sold to Formula Two racing teams it had been race proven and the design and development knowledge was already being incorporated in the Grand Prix engine programme. As part of the Ford domination of all types of racing the Formula Two Cosworth engine was made available to teams other than Team Lotus, but the 3-litre Grand Prix engine was to be exclusive to Lotus.

From the beginning of the Lotus-Cosworth Grand Prix project, paid for by Ford, Colin Chapman and his design team worked closely with Duckworth and Costin, so that the projected Lotus 49 was a complete unit from the “clean sheet of paper” stage and there was no question of adaptation or “special building” as on previous Lotus Grand Prix cars. The aim was to design a compact and light car, and the engine was to be used as part of the chassis design, suitably stressed to form the rear part of the car. From experience with the Formula Two FVA engine Duckworth designed his V8 engine so that it was very compact and short, and the cylinder heads, block and sump were all made extremely rigid as the main structure of the car was to be hung on the front of the power unit and the rear suspension was to be hung on the back, suitable pick-up points being built into the design of the various castings. From his experience of engine designing Duckworth almost guaranteed 400 b.h.p. from the new 3-litre engine, and last Easter, before the first V8 had been built, he said that if it did not give 380 b.h.p. in the first runs on the test bed he might as well throw it away, because it would mean he had been wasting his time and Ford’s money for the past twelve months.

It was hoped that the first Lotus 49 would run at Monte Carlo in May 1967 but no-one was unduly surprised or upset when it failed to appear, for racing projects seldom meet their deadline. This is not because of a failing on the part of the people doing the work, rather due to the optimism of the estimates, for in racing “today is only just in time, tomorrow is too late, and yesterday would have been better.” If the production world worked at the pace of the racing world we would never be able to buy anything really new, for by the time we had written out a cheque the product would have been superseded!

By mid-May the first Lotus 49 was out on test, driven by Graham Hill, the engine giving over 400 b.h.p. at 9,000 r.p.m. and the close liaison between Lotus and Cosworth producing an engine/car unit that set new standards for Grand Prix car design as regards light weight and an overall compactness. It was now just a question of whether it would work. Graham Hill did all the test-driving on 49/1 and by the end of May 49/2 was completed and the two cars were entered for the Dutch G.P. at Zandvoort, to be driven by Hill and Clark. With both engines giving well over 400 b.h.p. (409 b.h.p. maximum), they dominated the meeting, Hill recording fastest practice lap on both days and leading the race until a camshaft drive gear-wheel broke, which wrecked the cam-gear, and then Clark took over the lead and won without opposition. Writing from memory, a Grand Prix car, new in design from stem to stern, has only achieved victory in its first Grand Prix twice before in recent years, the prototype Maserati 250E won the 1954 Argentine G.P. on its first appearance, and in July of the same year the W196 Mercedes-Benz did the same thing in the French G.P. The victory of the Lotus 49 in the 1967 Dutch G.P. stands out as being equally impressive.

The Cosworth V8 engine, designated the D.F.V., was described in detail in Motor Sport last month as far as dimensions are concerned but since that description the ignition system has been changed for the Lucas OPUS or Oscillating Pick-Up System, which utilises a normal 12-volt coil to provide the sparks and has the advantage of providing sparks at lower crankshaft speeds so that a smaller and lighter starter motor can be used, saving 6 lb. on this unit alone, which is typical of the thought that has gone into the overall design of the Lotus 49. It is difficult to say whether the Lotus monocoque cockpit structure or the Cosworth V8 engine is the most important structural member, for one is complementary to the other. The cockpit is within a monocoque structure made from 16 s.w.g. aluminium alloy sheet, with rubber-bag fuel tanks in the hollow sides and behind the driver’s seat. On the front bulkhead of the monocoque a tubular steel subframe carries the front suspension and the steering rack and pinion, the suspension being by upper rocking levers operating inboard coil-spring/damper units, and lower wishbone members in what is now an almost universal layout. On the rear bulkhead of the monocoque the V8 engine is attached by two small triangular duralumin plates at the top and two lugs at the bottom, one large Allen screw sufficing to grip each of the upper alloy plates in a slot. At the back of each cylinder head is attached a tiny tubular structure that forms the inner mounting of the top transverse link of each rear suspension, as well as the top anchorage for each coil-spring/damper unit, and the anti-roll bar mounting. A similar small tubular structure attached to the lower part of the crankcase, on each side, forms the mounting of the pivot of the apex of the lower wishbone member. The 5-speed gearbox is over-hung from the rear of the engine, and carries supports for the low-mounted exhaust pipes. The ZF gearbox has the latest differential with sliding roller splines inside so that the drive shafts are without joints, all lateral movement as the rear suspension works being taken up by the sliding movement within the differential unit. All the ignition equipment, including an electronic r.p.m limiting device, is mounted on a plate attached to the top of the gearbox, the electrical controller being by Lucas and fixing maximum engine speed to 9,200-9,300 r.p.m., with a “fade out” – “fade in” range of about 160 r.p.m.

The 15-inch diameter cast magnesium wheels are located by four pegs each, with a single large hexagon centre-lock nut, the hubs being carried on magnesium uprights which are so arranged that the 12-inch brake discs, although attached to the outer ends of the hubs, protrude inwards clear of the wheels and are well in the airstream. The discs are very wide and profusely ventilated, there being four pads to each disc in special Girling calipers. Each rear hub carrier is located by twin radius rods running forwards to the monocoque structure. The Iong nose cowling is made of glass-fibre, as is the cockpit surround to which the ducted air-flow windscreen is attached, but there is no attempt to cover any of the mechanical components aft of the cockpit.

The Lotus 49, with V8 engine by Cosworth, paid for by Ford, is not new in conception, as regards principles and layout, but it is entirely new in overall design and has set new standards for Grand Prix cars, especially from the point of view of b.h.p to overall weight and compactness. A great deal of the detail design work also sets new standards, which many other designers will no doubt endeavour to copy. – D. S. J.