THE HEWLAND GEARBOX

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THE HEWLAND GEARBOX

THE RISE OF THE REAR-ENGINED RACER WAS THE CATALYST FOR A WORLD RENOWNED OFF-THE-SHELF GEARBOX KEITH HOWARD CHARTS THE BIRTH OF HEWLAND’S TRANSAXLE ne of the biggest problems facing the new breed of small racing car constructors who blossomed in Britain after World War II was sourcing a suitable transmission. For the big-budget BRM and Vanwall teams, as well as the established continental equipes, there were resources aplenty for designing and manufacturing powertrains from scratch, but Cooper, Lotus, Lola and their ilk lived in a different world where funds and facilities were much scarcer. Engines could be bought off the shelf from Coventry Climax and later Cosworth, but the ready-made racing transmission didn’t yet exist Modification of

road car gearboxes was therefbre rife.

When the Cooper-inspired move to the rear mid-engined layout took hold in the late ’50s and early ’60s, the number of suitable donor transmissions effectively dwindled to three. For a rear mid-engined configuration a transaxle was required, lifted from a rear-engined road car and turned through 180 degrees. Although Cooper achieved its Fl championship successes in 1959 and 1960 using a modified Citroen ‘box, others turned to the Renault Dauphine, Volkswagen Beetle or (less so) Hillman Imp units, particularly in the lower formulae where budget and regulatory restrictions were at their tightest. Take as an example the cars con testing the 1962 British Formula Junior series, which required that the gearbox casing be from a production car. Cooper used its Citroen unit; Ausper and Gemini used the Renault; Brabham, Elva and Lola used the VW; and Lotus hedged its bets by offering either Renault or VW Of the two, the VW unit was undoubtedly the better. As well as being stronger it was also a relative lightweight because of Volkswagen’s use of a magnesium diecasting for the Beetle’s gearbox casing as well as its crankcase. Although the move to rear mid-engined layout was occasioned principally by the superior traction afforded by its rear-biased weight distribution and I he reduced variation in weight distribution as fuel was consumed, there were other spin-off benefits. firiplification of the transmission was an obvious one: it was no longer necessary to have a propshaft

and somehow route it around the driver, which in turn facilitated improved aerodynamics through a reduction in frontal area. Meanwhile a transaxle transmission offered unprecedented access to the gearbox, the contents of which because they hung off the back of the engine and final drive could be got at without major disassembly of the povvertrain.

Colin Chapman, although not best remembered as a transmission innovator, had seen the potential back in 1956 when conceiving the Twelve. Although the Twelve was a front-engined car, Chapman nonetheless equipped it with a purposedesigned transaxle which both improved the car’s weight distribution and allowed easy access to the internals of the gearbox, permitting gear ratios to be quickly and easily optimised for each circuit. It was the following year, 1957, that the man whose

name would become synonymous with the off-theshelf racing transaxle first set up in business, initially from a 20 x 30 foot shed, complete with leaking roof, beside railway arches near Maidenhead station. Mike Flewlancl had been working for local company ML Aviation when he took the decision to go it alone, but the move into motorsport transmissions occurred by invitation when in 1960 Eric Broadley commissioned Hewland Engineering to design a VW-based transiude for the first rear mid-engined Lola, the Mark 3 Formula Junior. Eleven cars were built in total and 12 transmissions. Although the little Lola was not a success, Hewland’s gearbox subsequently named the Mk1 had made its mark and other commissions followed. A more extensively modified Mk2 version was used by Elva in 1961, followed in 1962 by the five-speed Mk3 the first

version to use a complete set of Hewland gears. But the Mk4 of 1963 was to be the gearbox that really established the company. Again based on the VW casing it incorporated first a Ford and then a GI(N differential together with Hewland sideplates. In MH’s own words: “We hit the jackpot with the Mk4: we sold up to 500 a year of them. In total we must have made over 10,000 of the VW-based ‘boxes.”

From the outset Mike Hewland had designed his gearboxes for easy disassembly, in recognition of the fact that racing engines were becoming more highly tuned and hence more peaky in their torque delivery, requiring not only a much closer set of gear ratios than any road car ‘box but the requirement to fine tune the gearing. It was all part of the trend towards increased adjustability within racing cars. In 1973 the VW-based transaxle would reach its

zenith in the Mk9, a transmission which remains on the price list today. Long before that, though, the company began making ‘clean sheet’ transmissions, designed entirely in-house, beginning with the HD (Heavy Duty) of 1963 which debuted on the 2:7-litre Brabham. For the first time a Hewland transmission now incorporated a limited slip duff to improve traction. Three years later unexpected success at Indianapolis with Graham Hill’s Lola T90 which was fitted with a hastily created two-speed version of Hewland’s mighty LG 500 Can-Am ‘box got the company noticed across the Atlantic. It was Lola’s first victory at the Brickyard but not, by a long chalk, its or Hewland’s last.

Success in Formula One came via the FT200 Formula Two, 200bhp gearbox of 1966, which proved to work well on an Fl car but for the final drive being too weak to take the increased torque. So the FT200’s gear train was mated to the final chive of the tougher DG300, creating the FG400 of 1968. It rapidly became the standard accompaniment to the Cosworth DFV and “must have been on the back of about 200 winning cars at one time or another.” Today Hewland finds itself increasingly involved in creating bespoke transmission systems. To mark its 40th anniversary it moved, for the third time, to new, purpose-built premises in White Waltham a far cry from that original leaky shed and constructed, symbolically, on the site previously occupied by Mike Hewland’s erstwhile employer ML Aviation. Oa www.hewland-engineering.co.uk