JP

The Scottish 500, by Joe Potts of Bellshill, Lanarkshire. Joseph Potts' first business, in the 19th century, was hiring out horse drawn carriages which in turn lead to a move into the funeral trade, which still continues to this day. In the 1930's, the youngest Joseph branched out into engineering, supplying motorcycle parts. During the war, they diversified further including producing parts for Barnes Wallace's Tall Boy bomb. After the war, Joseph Potts established a leading motorbike racing team and became Norton engine tuners of some renown so it was a natural progression to develop their own 500.

The cars were designed by Joe Potts III and Willie Rogerson and were similar to Coopers Mk IVs although the chassis was a little more advanced with two longitudinal tubes on each side, a feature which Coopers did not adopt until the Mk VI of 1952. Two prototype cars were completed in 1950, one short and one long wheelbase and were used by Joe Potts Junior himself.

Joseph Potts III in the 1950s

The first very similar production cars followed soon after several Scottish drivers, including Comish Hunter and David Blane followed purchased them. Joe and Willie realised immediately that copying the Cooper would never work, especially as the JPs were a little heavier so a weigh reduction programme was instituted for later Mk 1 cars.

However the cars were ultimately not quite as quick as the latest JBS and Kieft cars. The 1952 version featured upper and lower wishbones at both ends with coil springs instead of the transverse leaf. From late 1952, Joe began experimenting with De Dion suspension in an attempt to improve on the wishbone arrangement of Coopers and the swing axle of Kieft. Several J.P.s were fitted with an unusual form of de Dion rear which used two parallel tubes about ten inches apart. This adaptation did not prove especially successful. Around 30 cars were built up to 1955. Some success was achieved in Northern England and Scotland, especially in the hands of Ron Flockhart (with Vincent V twin) and Ninian Sanderson, who went on to win the 1956 Le Mans.

Joe at Winfield October 1951. Photo courtesy Hugh Langrische 

The 1952 version reviewed in Iota.

G.A. Brown at Silverstone in 1954.

Bare J.P. Chassis:

Reviewed in Motor Sport, November 1950

Rear view and engine bay details.

The Vincent twin powered Mk I J.P. of Ron Flockhart © Hugh Langrishe

John Porter poses in 2007