"Michael D. Callahan" wrote:

    After sending that post on EPS foam, I remembered something the two-cycle
motorcycle guys are doing to make chambers, hydro-forming. This takes some simple
figuring for the circumference.

    You lay out the part (as in 180 degree bends) on two pieces of sheet metal a
little longer than you want and allowing 1/4" or so on each side so you can weld
them at the edges when they are stacked. A pipe nipple is welded to one end and the
other is welded shut, so allow a few extra inches on the end too.

    Go to the hardware store and purchase a pressure pump that is used to check
water systems. Hook up the garden hose to the pump, hook the pump directly to the
nipple, turn on the water and start pumping. Stop and weld up the inevitable leaks,
repeat as neccessary as long as water leaks out. when the leaks are stopped, start
getting serious on the pressure.

    The part will start to bulge out and you can stop when it reaches the shape you
like. No it won't explode if a weld breaks because water is incompressible, just
don't hook back up and start again with it half full of air.
    Well, I won't be annoying you guys any more till after Oshkosh. Mike C.

Mike! No annoyance. It has been a pleasure. You are full of good information.
Looking forward to meeting you at OSH.

Paul Lamar
 
The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org