1951 Jowett Jupiter
1951 Jowett Jupiter
Photo: Bill Vance

by Bill Vance

One of the rarest sports cars to reach North America was the British Jowett Jupiter. Its heritage went back to 1906 when Benjamin and William Jowett of Bradford, Yorkshire, expanded from bicycle repair into automobile building. They built their first prototype car that year, but commercial production didn’t begin until 1910.

The first Jowetts had flat, twin-cylinder engines, and this horizontally opposed layout would become a Jowett trademark. Two-and four-passenger models were produced, and in 1936 a flat four engine was introduced.

After the Second World War Jowett introduced their all-new Javelin sedan in 1947, a nicely styled, aerodynamic, unit construction fastback inspired by the American 1930s Lincoln Zephyr. Under the clean lines was a mechanical design that was out of the mainstream of British automotive engineering.

The Javelin’s overhead valve, horizontally opposed, 1.5 litre (90 cu in.) four-cylinder, 50 horsepower engine had twin carburetors, and was located ahead of the front wheel centre line. The radiator was behind the engine with the fan carried on the end of a rotating shaft that passed over top of the engine, similar to early two-stroke Saabs and DKWs. A two-piece driveshaft transmitted power to the rear wheels.

Suspension was via torsion bars all around, longitudinal in front and transverse at the rear. Brakes, originally hydro-mechanical, were switched to full hydraulic in 1951.

In 1950, in an attempt to cash in on the burgeoning post-war sports car market, Jowett produced the Jupiter two-seater using many mechanical components from the Javelin sedan. The main difference underneath was the use of a tubular frame with a sturdy space-frame type bridge section over the rear axle. It was designed by ex-Auto Union engineer Eberan von Eberhorst. Engine power was increased from 50 to 60.

The stylish, modern-looking body had wind-up windows, an almost unheard of luxury for a sports car at that time.

A Jupiter was entered in the 1950 Le Mans 24-hour endurance race and won the 1.5 litre class, a feat it would repeat in 1951 and 1952. It also won other significant races.

This should have made the Jupiter an immediate success, but when it arrived in North America, the prime market for British sports cars, it got off to a poor start. Tom McCahill of Mechanix Illustrated magazine (9/51) panned its handling in his road test.

In Tom’s inimitable style, he wrote: “Testing the English Javelin Jupiter left me with mixed emotions. I didn’t know whether to spray it with an aerosol bomb or give it a friendly pat on the flank.”

Tom’s prose then got more flamboyant. “The outstanding feature of this bug is that it corners and steers worse than any Detroit family bus I have driven since the advent of those dangerous blubber tires. This reluctant torpedo dives into corners like a porpoise with heartburn and the steering is like winding up an eight-day clock with a broken mainspring.”

Tom expressed disappointment at his findings because he had so often extolled the handling and steering of English sports cars.

On the bright side, he liked the comfort, roominess and four-speed transmission, in spite of the column shift. He called the engine a “baby wildcat” that would make the Jupiter “walk away from an MG or Crosley Hot Shot like a jet plane passing a balloon.”

He recorded a zero to 96 km/h (60 mph) time of 15.3 seconds, which he called “terrific performance for a 1-1/2 litre sports car.” Tom’s summary was that, like a bride’s first cake, the Jupiter had all the right ingredients but was taken out of the oven too soon.

When Road & Track (3/53) finally tested the Jupiter it found itself in friendlier hands. As “The Motor Enthusiasts’ Magazine,” R & T felt obliged to address the Jupiter’s criticisms by “one of America’s best known car testers.”

Road & Track was not as critical of the Jupiter’s handling as McCahill was, and suggested that there must have been something awry with the car he tested. They described the Jupiter’s cornering as “modern” rather than “traditional,” meaning that its forward weight bias caused it to understeer rather than oversteer.

Road & Track’s testers saved their criticism for the West Coast Jowett distributor who, they said, should have been campaigning it much more vigorously in competition.

The Jupiter certainly seemed to have all the virtues of an enthusiast’s sports car, but perhaps McCahill was right in his opinion that it was brought to market too soon. It could be competitive, as evidenced by its three class wins at Le Mans.

The Jupiter never reached its apparent potential, and only an estimated 850 were built by the time the bank brought an end to the activities of Jowett Cars Ltd. in 1954, and sold the Bradford plant to International Harvester.

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