Thursday, February 14, 2008

Supercharged Velocette

I became interested in HC Lamacraft after doing some research on racing Velocettes at Brooklands, and came across these two photographs of his ca.1935 mkV KTT, to which he added a blower in 1938. Supercharging a single-cylinder motorcycle isn't easy, as the intake comes in pulses - by contrast, multi-cylinder engines draw more evenly from a forced-air chamber. They work best when a chamber equal to the engine capacity is added between the blower and the engine; I can't tell whether the large sheet-metal enclosure over the blower is has an air chamber, or is a protective cover for Henry's tender parts! Superchargers spin at very high rpm, and were known to blow up in those early days, so he was certainly being prudent.

I owned a supercharged Zenith for a while - subject for another day.

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