Hewland

Hewland is a British engineering company, founded in 1957 by Mike Hewland, which specialises in racing-car gearboxes.

History

Mike Hewland ran a small engineering business at Maidenhead in the UK with the specialty in gear cutting. In 1959, Bob Gibson-Jarvie, the Chief Mechanic of UDT Laystall racing team running Cooper F2 cars, sought help from Hewland as gearbox troubles were experienced. The result of this request came out as six successful gearboxes being designed and built in 1959, and Hewland was in the gearbox business.^[1]

The first transaxle product, the Hewland Mk.I of 1960, was a minor modification of the Volkswagen Beetle 4 speed transaxle used upside-down with custom made differential housing side plates for the midship engine Lola Mk.III (John Young tuned Ford 105E 997cc pushrod) built for the new Formula Junior rules (1 litre engine with minimum weight 360 kg, or 1.1 litre with minimum 400 kg) in 1961.^[2] Hewland Mk.II was a similar 4 speed transaxle with more modifications for Coventry Climax engined Elva Mk.VI 1.1 litre sports racer in 1961.

Hewland Mk.III of 1962 became the first product for the public, which utilised the magnesium alloy case of the Beetle transaxle to house 5 pairs of bespoke straight-cut constant mesh spur gears with dog rings operated by custom-made brass shift forks. Gear selector shaft was located in the nose housing, unmodified as in the Beetle set up, facing rear-ward at the tail end of the box in the front-side-back position on a midship engine racing cars. The elimination of synchromesh parts provided the space for an additional pair of gears for the 5th speed.

This Mk.III became very popular for small displacement formula cars and racing sports cars, and was the basis on which all the later products were built.

Hewland Mk.IV on 1964 Lotus 32. The product that built the reputation and the dominant market position for Hewland.

Mk.IV had the tail casing made by Hewland, with the selector rod located in the right side lower position, facing forward. This made the shifter linkage design easier on the part of chassis manufacturers. Together with its high torque version Mk.V, Mk.IV became a big seller, putting Hewland on a growing track.

Mk.VI of 1965 was an improved version of Mk.IV, which established Hewland as the dominant volume production transaxle manufacturer in the small displacement midship-engine racing car market, helped by the de facto standard usage in the newly born Formula Ford series. Although Formula Ford engines displaced 1.6 litre, the capacity was not a problem as the 1.5 litre rating was for higher power racing engines as opposed to the single carburetor, production cam and compression ratio regulation of the formula.

The advantages of the series were:

• Dog-ring gear selection made it extremely quick shifting.
• The structure that enabled changing of gear ratios on the 2nd through 5th speeds possible without removing the transaxle from the vehicle, or detaching it from the engine.
• Upside-down usage enabled the dry sump racing engines to be mounted low on the chassis.
• The 3rd, 4th and the 5th gears had the same thickness and drive/driven axis distance, thus were interchangeable.
• Magnesium alloy Volkswagen case made it strong and very light weight.

Hewland was claimed to be the first company that made racing car gearboxes, ^[3] however, a transaxle housed in an aluminium alloy case for racing purpose in midship-engine configuration had been designed by Ferdinand Porsche and built by Horch in 1933 as a part of Auto Union Type A.
Valerio Colotti had been producing gearboxes for racing purposes before 1959, and his transaxle for midship-engine racing cars debuted on May 10, 1959 at Monaco Grand Prix on Behra-Porsche. Colotti 5 speed T.32 transaxle, which weighed less than 35 kg, was in use by Rob Walker in 1960. Lotus Engineering made a transaxle for front-engine Lotus 12 in 1957 designed by Richard Ansdale and Harry Mundy, and this gearbox/differential unit was adopted to midship-engine use for Lotus 18 which debuted on 8 April 1960.^[4]

Hewland dominated the racing scenes in the 1960s, 70s, 80s and 90s, and still is a leading company in racing transmissions with its focus shifted a bit toward custom engineering work for vehicle manufacturers. In addition to the traditional manual transmission products covering almost all the racing and rallying classes, Hewland now offers a complete semi-automatic transmission components including shift actuators, throttle actuators, compressors, shift position sensors and steering wheel paddle systems.^[5]

Transaxle types

The following is the list of the smaller product range housed in Volkswagen case except for LD200.

Transmission capacity is measured by the maximum output torque (not the horsepower), which is the product of the input torque times overall reduction ratio. However, as the output torque is proportional to the input torque with typical gear and differential reduction ratios, and as the input torque (engine output torque) is roughly proportional to the engine displacement, Hewland used to indicate the maximum allowable engine size, and later the maximum input torque measured in Lbs/ft., as the transaxle selection guide.

The following is the list of larger product range up to 1981.

ARV Super2

After an approach from Richard Noble, Hewland were persuaded to design and build the AE75, a 75 bhp aero-engine for Noble ARV Super2, a 2-seater light aircraft. This engine, an inverted three-cylinder water-cooled two-stroke unit with dual ignition and a 2.7:1 reduction gearbox, was developed from Hewland's existing two-cylinder microlight engine. The AE75 was very light at 49 kg (108 lb), thereby contributing to the overall lightness of the aircraft, so that the ARV Super2 weighed 40% less than its competitor, the Cessna 152.

Track day cars

Hewland has been involoved with various track day cars. Most notably the Caparo T1^[6] and BAC Mono,^[7] both of which featured gearboxes designed and manufactured by the company.

See also

• ZF Friedrichshafen

External links

• Official website

References

1. ↑ James, Roger. "The Hewland Story". Retrieved 2007-09-05. 
2. ↑ James, Roger. "The Hewland Story". Retrieved 2007-09-05. 
3. ↑ "Hewland Engineering Introduction". Archived from the original on 2007-09-29. Retrieved 2007-09-05. 
4. ↑ "Stats F1". 
5. ↑ "Hewland Brochure". Retrieved 2013-09-14. 
6. ↑ http://www.autocar.co.uk/car-review/caparo/t1/first-drives/caparo-t1
7. ↑ http://us.bac-mono.com/specs.php