Posted by Joe S. on June 14, 1999 at 00:42:36:
In Reply to: Re: Re: Re: Thayer Valves posted by Carl on June 13, 1999 at 23:49:28:
It seems like these valves would also have to be enormous in size, and that would make for a challenging engineering problem to get all (four?) of them to four lined-up fingerkeys, and to rotate with the speed and lightness required. The nice thing about traditional rotors AND pistons is their compactness. I would tend to think that Mr. Meinl's supposition about resistance is humbug, even though he has "lightyears-to-the-infinity-power" more experience in fabrication than I do. I certainly don't blame him for wanting to think of a good-sounding "acoustical" reason not to want to mess with axial-flow valve systems, though. Also, although trombonists seem to put up with a lot of leakiness it their instruments (their inside and outside playing slides usually have SEVERAL thousandths of an inch tolerance between them), the Thayer valve, by design, has to be a bit leaky (definitely leaker than good rotors or pistons) to be able to rotate, because the huge flat bearing surface is also an air-seal surface. I don't think that we will see these on tubas anytime soon, unless someone overcomes the size problem and the leak problem, both of which I think tuba players would find unacceptable. Personally, I think that well-made pistons offer just about as smooth a flow of air as we can hope to get.
I certainly would like to blow on a tuba rigged up with valves like this, but I don't imagine that I will have the opportunity to do so.
Incidentally, there is a recent Oregon newspaper article on the web about Mr. Thayer's lawsuit with the old underwriter/business partner in Albany, NY...quite a complicated situation.