Dougal Marchant
From your JAP series, I see Dougal Marchant carried out engine design work for them in the late 1930s. Okay, but
I’ve also read he carried out design work for Sunbeam. Did he work for both companies at the same time? Stu Blake, Sussex.
Yes, and others too. While some of his late 1930s design work for JAP went into production, albeit limited and curtailed by the Second World War, his work for Sunbeam only saw the light of day as a prototype.
Although Dougal Marchant had been involved with MAG (Motosacoche Acacais Geneva) during the 1930s, following to an extent in the footsteps of fellow Brooklands ace Bert Le Vack (died 1931), he was involved in other engineering design work in parallel. And it’s perhaps due to his work on the Continent that the 500cc single cylinder engine he designed for Sunbeam, seemingly in unit with its gearbox, looks Continental.
However, rather than MAG it externally has similarities with the Belgian circa 1926 onwards FN M70’s 348cc side-valve engine, which is in unit with its gearbox.
It’s unlikely Dougal Marchant ever worked full time for a factory. Men such as him were free spirits, probably unemployable and when involved with a project, it would be all consuming and, at other times, thinking was the order of the day. There is also evidence to suggest Marchant maintained his Weybridge base during the 1930s when with MAG, spending time at the Surrey town, and that he maintained links with MAG after the Second World War, including designing an openframed 250cc machine for the Swiss factory with twin V belt drive in 1946.