Posted by Rick Denney on September 19, 2003 at 11:23:59:
In Reply to: oversize flight cases posted by Mary Ann on September 18, 2003 at 09:49:38:
As Chuck says, we've discussed this before. In the message linked below (which I know you've seen), I mentioned just what you suggest: That the horn be supported where it is strong and allowed to float in free air where it is weak. I include the valve body in the parts that should not be directly padded, because any force applied to the valve body can cause worse damage than a wrinkled bell.
I believe this could be done with blocks of foam rather than having to make a mold. When I made my own hard case for the Cerveny (which fit the Miraphone), I used blocked floam to hold the body at the bottom bow and at the top bow. But it didn't have sufficient space around the bell, and it was not space-efficient, and I would not use that design again.
Also, most cases are designed such that the tuba outer branch is parallel to the bottom of the case, and this makes the case big. TubaRay used to have a hard case that held the tuba at an angle, such that the tuba pointed down at the bell. The edge of the bell was aligned with the edge of the bottom bow across the top. This added about an inch or two to the length, but reduced its height off the floor by four or five inches at least. It was a clever design, but in my opinion his case was marginally supportive for flight protection, though he used it for that for several trips at least.
I absolutely agree that any ground-up engineering of a custom case would suspend the bell in free air. The problem is that cases made for sale have to meet the expectations of the buyers, and most folks would not believe that such a design would be the most effective. It's a little like bicycle tires with tread patterns. Unlike car tires, bicycle tires of reasonable dimension cannot hydroplane--they are too narrow and the pressure is too high. Thus, a slick tire with no tread pattern provides the best traction, wet or dry. But the tires designed thusly won't sell, because people refuse to believe that a smooth bicycle tire provides the best traction on wet pavement. So, tires with tread patterns--and with reduced traction--continue to be sold because that's what people are prepared to buy. (If you want good bicycle tires without this problem, try Avocet Fasgrips if you can find them. They have smooth treads.)
The post linked below provides my cut at a list of needs and requirements that would feed the design of a proper case, and soome thoughts on how I might construct one. But since I don't fly with my tuba, I haven't seen the need to attempt the project, especially considering the backlog of projects for which there is at least some need.
By the way, the approach posted many times by Charlie Krause has essentially the same effect. He suggests putting an inflated soccer ball down the bell such that it lifts the edge of the bell away from the padding. This has the effect of allowing the bell edge to float while supporting it in a way that makes best use of its strength.
Rick "recognizing that not all engineering TRVTH is plausible to non-engineers" Denney