Re: Re: Re: oversize flight cases


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Posted by Rick Denney on September 22, 2003 at 13:16:07:

In Reply to: Re: Re: oversize flight cases posted by In need of disabuse on September 19, 2003 at 14:11:53:

It ain't the middle of the tire that needs to be slick--you don't make as much use of the traction when riding in a straight line. It's the shoulders, just where most tires have some sort of a fine pattern on them. Those are the parts you are using when leaned over at that critical 44-degree angle.

And I've bought a few bicycle tires in the last few years, heh, heh, without discriminating against any of the different makers (except Continental, whose tires attract punctures like no other brand I've ever ridden).

As to the case thing, yes, you'd have to secure the tuba reliably by its body. How to we carry our instruments? When I carry a tuba bell-down, I carry it by the inside of the bottom bow. I can envision swining the tuba by the inside of the bottom bow at several G's with no damage, while the bell would crumple like foil. Thus, I would put a fixture in the case that would fit under the bottom bow and restrain the horn from moving in the bell direction. It would have some foam (that crushes in the range of up to, say, 2 G's), backed by Styrofoam that would protect it (once) up to 8 or 10 G's, backed by a structural brace able to withstand any G's up to the point where the case breaks apart. The saddle of the fixture would fit the shape of the bow perfectly.

Some tubas don't have space for such a fixture, in which case I would use a form-fitting nylon strap with the appropriate strength and elongation properties, firmly anchored to the end of the case.

I like wood for a case because it splinters instead of deforming into an unhealthy shape. If the wood splinters, it's done its job. And a destroyed case with a partly damaged tuba inside it convicts the baggage gorillas far more surely than a pristine-looking case with a destroyed tuba inside it.

You could design the foam around the bell to be so weak that it would never apply enough force to deform it, but then you'd have to secure the body in just the way I recommend above. If the body doesn't have to be secured that well, then it is because the case depends too much on securing the bell. Most cases secure the body in that direction by restraining the upper bow on the outside of the bow. But pulling on the inside of the bow is far stronger than pushing on the outside of the bow.

I would use the bottom bow for restraining the instrument in all directions, and the top bow for restraining it side to side (in two directions). That would put padding all around the bottom 8 or 10 inches of the instrument, and another wall of foam and support that clamps over the upper bow and the bell just above the leadpipe. I don't see the need for padding anywhere else. The leadpipe and valve body, plus the bell, would float in free air.

I might actually do one thing to help guard against the tuba bell contacting the inside of the case. I might build a round pad that is attached to the end of the case that slips inside the bell. It would be structurally strong with the various foams wrapped around a structural member, and would be soft enough to only apply real force when the other supports aren't enough. That would apply pressure to the bell in the way it is most able to withstand it.

Rick "tempted to build one just to prove the concept" Denney


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