Harnessing the beast

On paper, there really wasn’t a lot wrong, chassis-wise, with the standard Vincent-HRD package.

Cantilever rear suspension controlled by twin spring and damper units, the innovative Girdraulic front end that gave the torsional rigidity of a girder fork combined with the compression and rebound damping control from the long hydraulic units, with both ends simply bolted to the main chassis member allowing rapid disassembly. The engine/gearbox was a fully stressed component of the overall design, with a box section that linked the front and rear components and doubled as an oil tank. In a straight line, a Black Shadow or Lightning was a projectile, but throw in a few corners, particularly fast ones, and a separate personality emerged. Those who eyed the Vincent as a race track weapon, learned to cope with the handling vagaries, and the big twins racked up plenty of wins in Australia in basically standard form. One of the greatest exponents was the spectacular and extroverted Tony McAlpine (known universally as The WOP due to his swarthy features – a term that would be totally unacceptable in today’s socially-correct society), who became virtually unbeatable in Unlimited class races in the late ‘forties and early ‘fifties. McAlpine’s technique was to unleash the power of his heavily tweaked Rapide for as long as possible in a straight line, then throw the machine sideways and drift into corners, before grabbing a massive handful of throttle and power-sliding out, getting the machine upright again as quickly as he could. Sound familiar? Look at today’s MotoGP riders – the technique is identical. Few riders however could match McAlpine’s brute strength and sheer courage, and many came undone trying. Even such talents as Jack Forrest lost a considerable amount of skin trying to tame the Vincent package. Solos, of course, were one kettle of fish, and sidecar outfits another. In three-wheeled form, the Vincent’s handling foibles were more easily overcome, although the lateral forces stressed the chassis components to – and beyond – their limits. It wasn’t long before thoughts began to turn towards harnessing the potential in a different form – utilizing the wonderful one-litre v-twin in a chassis of more conventional design.

At the time, there wasn’t a lot to choose from. In the late 1940s, rigid frames were still the norm, and the alternative was usually only a plunger rear end – itself an inherently flawed design that suffered from all sorts of in-built gremlins. Then, along came the McCandless brothers – the genius Irish pair who conceived and built what became known as the ‘Featherbed’ frame, and even more remarkably, convinced the notoriously difficult board of Norton Motors to adopt the chassis for their works team, which had previously used the prewar ‘Garden Gate’ plunger frame with their BMW-copy telescopic front forks. Suddenly every other chassis, at least in racing terms, was obsolete. The McCandless design –