We take a brief detour and look at the other Javelin, the glamorous Jupiter.
You’re part of the plan.
At the 1949 London Motor Show, Jowett exhibited a low-slung tubular steel chassis featuring the Javelin flat-four engine and a modified form of the saloon’s torsion-bar suspension. It was the culmination of months of frenzied activity by a distinguished Austrian designer and four other engineers at Five Lane Ends, in pursuit of a promising but haphazard joint venture between the Yorkshire car firm and the revived ERA (English Racing Automobiles) company.
By early 1949, it was becoming clear that the Javelin was not meeting sales expectations in the USA. Ordinarily, this would have not been a concern, with production of around 6000 per year, and plenty of interest from the home market and from Jowett’s traditional sales territories in Europe and the former British colonies and dominions. However, the UK’s trade strategy was asymmetrical. The US dollar was the post WW2 world’s paramount currency, and British manufacturers who could bring in hard currency would be best favoured with material supplies.
As Gerald Palmer departed Bradford in mid-1949, Jowett’s new management were presented with an extraordinary opportunity which seemed to fit comfortably with the germ of an idea already being considered. The far from indolent Idle board had a notion to use the Javelin powertrain and chassis components in a two seater sports car of a more modern design than the MG Midget which was selling well in the USA despite its antiquated design. Logic suggested that there was a broad, readily exploitable gap between the primitive MG and the all-new, recently launched Jaguar XK120.
To recapitulate briefly, the plan was required to provide a specialised sports-racing car which would build on ERA’s and Jowett’s competition reputation, and a stylish and up-to-the-minute two-seat open tourer which would bring in US dollars and secure all-important material allocations for the company.
That makes two purposes already, but there was a third, as a blank canvas for coachbuilders. This was far from unusual in the late 1940s, with specialist bodybuilders able and willing to provide small-run bodywork for discerning individualists who wanted something different from the stock design. There was a further raison d’être for rolling chassis sales, as some high-tax export markets levied a lower rate of duty on incomplete vehicles.
The unlikely partnership of Jowett and Leslie Johnson’s rescued ERA was established with only an informal agreement over a lavish and convivial lunch also attended by the project’s matchmaker, no less a person than Laurence Pomeroy, Technical Editor of The Motor. Johnson was a successful furniture manufacturer and amateur racing driver, noted for his charm and boundless enthusiasm.
ERA’s most important contribution was the services of Dr. Ing. Robert Eberan-Eberhorst, an Austrian development engineer with a reputation established by work on the pre-war Auto Union Grand Prix cars. Post-WW2 he was a high-grade jobbing engineer, working in his homeland on the Porsche flat-four engine, and in Italy on the Cisitalia GP car, with fellow expatriates Rudolf Hruska, Erwin Komenda, and Karl Abarth.
Eberan’s contribution to the project was defining but finite. He arrived from Italy in the summer of 1949, and the chassis he produced for Jowett while employed by ERA was ready by October of that year. In 1950 he left ERA to work for David Brown on the Aston Martin DB3 sports-racing car. Design work for Jowett had scarcely started when their ERA partnership disintegrated.
Eberan relocated from ERA’s Dunstable base to Bradford, where he was allocated an assistant, and eventually a team of four to realise his chassis ideas. Palmer’s suspension components were used in a complex tubular chrome-molybendum steel alloy frame, with extensive use of triangulated bracing for strength and lightness. Anti-roll bars were added front and rear. By decree of Jowett’s management, any alteration to the flat-four Javelin engine was ‘off limits’ to Erberan and his team.
In his biography ‘Auto-Architect‘, Gerald Palmer wrote “Von Eberhorst’s steel tube frame was an idealistic layout for a limited production sporting car but it was not easy to manufacture.” Read between these lines and the implication is that the chassis was optimised for the six sports-racing cars Jowett were to provide ERA with under the Pomeroy-brokered Gentleman’s Agreement rather than for the series-produced sports-tourers intended to conquer America.
Reg Korner, Jowett’s body designer since 1936, was given the task of designing the coachwork for the racetrack and touring cars to meet an April 1950 New York show deadline. On top of the demanding timescale, Korner found a further challenge in the flexibility of Eberan’s chassis. Although inherently strong, torsional movement had been built in.
This presented no problem in a narrow racing body with no openable apertures, but meant that Korner’s drophead coupe bodywork had to be self-supporting, with a substantial steel-section frame clad in aluminium panels. The body was fixed to the chassis at six strategically chosen points, with resilient rubber bushes preventing flexure in the chassis from distorting the superstructure. The unwelcome result was a 2,100lb (955kg) kerb weight, still 158lb (68kg) lighter than the Javelin saloon, but well adrift of the 1500lb design target.
To provide increased power the Jupiter had larger Zenith carburettors, gas-flowed cylinder heads, more freely-flowing exhaust manifolding, and a higher compression ratio than in the Javelin installation. Power output was 60bhp at 4750rpm in early cars, increased to 62.5bhp at 4500rpm after January 1953, in each case 10bhp more than the equivalent saloon.
The Jupiter story continues shortly.