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.

[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.

By 1929, at Ariel, Jack Sangster had Edward Turner and Bert Hopwood working under Val Page in design.

[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.

He added single-tube frames, enclosed valve gear, upswept exhausts, polished cases, new paint designs, and chrome petrol tanks.

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.

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.

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.

[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).

Turner became involved in the establishment of the US-based Triumph Corp. in Maryland, a distribution company created to serve East Coast US markets.

[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.".

In 1956, after a boardroom struggle over power and control, Jack Sangster became Chairman of BSA Group, succeeding Sir Bernard Docker.

He appointed Turner Chief Executive of the Automotive Division (comprising BSA, Ariel, Triumph, Daimler and Carbodies – makers of London taxicabs).

Although quickly mimicked by competitors, eventually Turner relented on this unpopular feature, the 'bathtub' becoming more and more abbreviated until disappearing altogether on the final 1966 versions.

Turner, wary of racing and high-performance options, thought the Bonnie was a bad design and reputedly said to Frank Baker, Triumph's experimental department manager, "This, my boy, will lead us straight into Carey Street (where the bankruptcy courts were).

Bert Hopwood resigned from AMC, and accepted Turner's offer to work for Triumph as Director and General Manager.

Sturgeon decided to streamline motorcycle operations after McKinsey, an international business consultant, recommended treating the two companies as one.

It was to be sold as both the Triumph Bandit and BSA Fury, each distinguished by minor cosmetic changes and paint schemes, with 34 bhp and capable of 110 mph.

The look was very well received and many enthusiasts were looking forward to their arrival but BSA-Triumph was in a deteriorating financial condition (labour disputes, unreliable electrical systems, oil-leaking engines, and ageing styling).

When the Royal Mail issued six postage stamps on 19 July 2005 each featuring a classic British motorcycle, Turner was the only designer cited by name in the accompanying presentation packet notes.

[16] In 2008, an address where Turner lived and worked in Peckham, South-East London was awarded a Blue plaque by Southwark Borough Council, following a popular public vote in 2007.