Edward Turner (motorcycle designer)

On 16 April 1925 "The Motor Cycle" published drawings by Turner of an OHC single he had designed, using a series of vertically stacked gears to drive the overhead camshaft. A subsequent redesign used bevel gears to drive a vertical camshaft, operating the valves through rockers. The only shared aspects of the two designs were the bore and stroke, 74 mm × 81 mm (2.9 in × 3.2 in), with the barrel being sunk into the crankcases. The head could be removed from either design complete with undisturbed valve gear.^[2]

Turner built his first bike in 1927, using his second design, a 350 cc OHC single. The Motor Cycle published a photograph of Turner's patented engine, mounted in his motorcycle called the Turner Special.^[3] The Special was registered for road use with the London County Council as YP 9286. It used Webb forks, and a three-speed Sturmey-Archer gearbox.^[2]

By now, living at various addresses in Peckham and East Dulwich, in the London Borough of Southwark and running Chepstow Motors, a Peckham High Street motorcycle shop with a Velocette agency, Turner conceived the Square Four engine in 1928. At this time he was looking for work, showing drawings of his engine design to motorcycle manufacturers.^[4] The engine was essentially a pair of 'across frame' OHC parallel twins joined by their geared central flywheels, with a one-piece four-cylinder block (or Monobloc) and single head.^[5] The idea for the engine was rejected by BSA, but adopted by Ariel. Thus it became the Ariel Square Four, and not the BSA Square Four. Turner was then invited by Jack Sangster to join Ariel.

By 1929, at Ariel, Jack Sangster had Edward Turner and Bert Hopwood working under Val Page in design.^[6] Turner, now 28, married Edith Webley.^{[citation needed]}

The first Ariel Square Four 4F^[7] was shown at the Olympia Motorcycle Show in 1930 in chain-driven overhead camshaft 500 cc form. This was heavier and slower than Turner's original prototype due to production changes made necessary by the Great Depression. To make up for the extra weight, Turner increased the engine capacity to 601 cc for the 1932 Model 4F6. Ariel went bankrupt in September 1932, but was bought by Sangster, who promoted Turner to chief designer.^[6]

In 1936 Triumph decided to create separate motorcycle and car companies, and sell the motorcycle company. Ariel owner Jack Sangster bought it and changed the name to Triumph Engineering Company. The Ariel Square Four changed from the 4F 600 cc OHC version to the 4G OHV 995 cc version that year.

Sangster made Turner, now 35, General Manager and Chief Designer. (In this new position Turner received a 5% commission on the company's net profits, and became a shareholder with 4.9% of the equity). The first thing he did was clear space on the production floor for an office and an adjoining drawing office. Val Page had left Triumph four months before and joined BSA. Bert Hopwood came to Triumph as Turner's Design Assistant. Ted Crabtree, who was also at Ariel before, became Chief Buyer, and Freddie Clarke was made Chief Development Engineer: both were motorcycle racers.

Turner examined the line of 250, 350 (3H) and 500 cc Mk 5 singles, and rationalised them into three sports roadsters: the Tigers 70, 80, and 90. He added single-tube frames, enclosed valve gear, upswept exhausts, polished cases, new paint designs, and chrome petrol tanks.

In July 1937, Turner introduced the 500 cc Speed Twin, selling at £75. It was smaller and weighed five pounds less than the £70 Tiger 90,^[8] and proved very successful. The 5T Speed Twin (some say based on the engine design of Turner's Riley Nine car) became the standard by which other twins were judged, and its descendants continued in production until the 1980s. The original 27 bhp parallel-twin was capable of exceeding 90 mph (145 km/h)^[8] and weighed 361 lb (166 kg).

Turner's wife Edith died in a car crash near Coventry on 8 July 1939; the same crash which killed Gillian Lynne's mother and two other friends. Turner kept in contact with Gillian Lynne thereafter.^[9]

Turner's "sprung hub" was supposed to go into production in 1941, adding 17 lb to the weight of a bike. But the war delayed its introduction until 1948.

In 1942, Turner designed a generator, using an all-alloy Triumph vertical twin engine, for the Air Ministry. After a heated disagreement with Jack Sangster, Turner quit his position at Triumph and promptly became chief designer at BSA, where he worked on a side-valve vertical twin for the War. Bert Hopwood was made Triumph's new designer and Sangster put him to work on a 500 cc side-valve twin competing for the same contract.

By 1943 Bert Hopwood completed the design, but it was never produced. Triumph's prototypes were released in February, before BSA's planned launch. The design later became the post-war TRW model. In late October, Turner went back to Triumph. Hopwood had been working on a design for a 700 cc inline four-cylinder engine that could produce 50 bhp, but Turner's return to Triumph put an end to that plan.

Turner was Managing Director once again by 1944.

The Speed Twin, Tiger 100 and 350 cc 3T models emerged in 1945. They now had telescopic forks, originally designed by Turner, but modified by Freddie Clarke after it was found that fork oil would spew out on bottoming.

Ernie Lyons won the first Manx Grand Prix on a Tiger 100 built by Freddie Clarke using an alloy wartime generator engine and the unreleased sprung hub in 1946. Turner, away in America, and anti-racing, was furious when he heard, but threw Lyons a victory dinner anyway, and a small batch of replica T100 were made for sale. Clarke resigned and joined AMC as Chief Development Engineer. Bert Hopwood had an argument with Turner over racing, left Triumph, and stayed away for 14 years.^[10]

The Mark I sprung rear hub was introduced in late 1947.^{[citation needed]}

In 1948, Turner was persuaded to allow the entry of three 500 cc twins in the Senior TT, but none of them finished, so the experience only added to Turner's opposition to factory racing.^{[citation needed]}

The 6T 650 cc Thunderbird, as designed by Turner, and further developed by Jack Wickes, was launched on 20 September 1949, when three models covered 500 miles at 90 mph (800 km at 145 km/h) in a demonstration at Montlhery. Essentially an enlarged tourer version of the Speed Twin, the 6T was designed to satisfy the substantial American export market, and was advertised as capable of a genuine 100 mph (161 km/h). The Thunderbird became a favourite of police forces worldwide.

For 1950, Turner went for a "low-chrome" policy, and banned the use of chrome fuel tanks. A chrome tank did not reappear till the 1981 Bonneville T140LE Royal Wedding edition.

Once in production, the first performance improvements came midway through the first year when the carburettor size was increased. This was the year Turner expressed the belief that 650 cc was the practical limit for the traditional British 360° vertical twin. It was the last year for the T100 GP model, although the T100C carried on, and the Mark 2 sprung hub was released.

Turner became involved in the establishment of the US-based Triumph Corp. in Maryland, a distribution company created to serve East Coast US markets. After 1950, America became Triumph's biggest customer.

In 1951 Sangster sold Triumph to BSA for £2.5 million, having previously sold Ariel to BSA in 1939. As part of the sale agreement, he joined the BSA Group as a member of the board. Turner's holdings in Triumph gave him 10% of the sale.

A race kit for the Tiger 100 was introduced, bikes were restyled with new paint and the first dual seat appeared. The Tiger 100 race kit was dropped, and the T100C came with the kit already installed. The T100C had twin-carburettors for this year only.^{[citation needed]}

The first lightweight for Triumph since 1933, a 150 cc OHV Terrier T15, four-speed unit construction single with a sloping engine, was introduced in 1953. As a result, Triumph directors Turner, Bob Fearon and Alex Masters rode from Land's End to John O'Groat's for a 1,000-mile Terrier demonstration and publicity stunt – the "Gaffers' Gallop.".^{[11][citation needed]} .

By 1954 the sportier 200 cc version was available, and called the Tiger Cub.^[12]

In 1952, Turner married Shirley Watts. They had two daughters and a son.

The production 650 cc Thunderbird was a low-compression tourer, and the 500 cc Tiger 100 was the performance bike. That changed in 1954, along with the change to swing arm frames and the release of the 650 cc Tiger 110, eclipsing the 500 cc Tiger 100 as the performance model.