Posted by Greg Crider on May 06, 2002 at 13:29:05:
Willson tubas use Rotax rotary valves, and are said to feature "geometrie compensation" and to have their own patent. Does anyone know what's special about these valves? Everything I can find about them on the Web either repeats their advertising text or is about their small engine products. If they're a superior product, does anyone else use them?