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Tuesday Morning
7/15/03
Jeff,
After fabricating a new door for a friend of mine, we pressure
tested the door and airplane by renting a portable compressor with a
capacity of somewhere around 80 - 100 SCFM and hooked it to the mixing valve on
the firewall. We used a ball valve at the compressor to
SLOWLY open to pressurize the airplane. You have
to remember that the compressor could over pressurize the plane and cause
damage, so this procedure calls for slow and deliberate work with the ball
valve. Have someone guard the valve while opening it and don't let anyone
else fiddle with it.
The idea is to place enough air in the cabin to bring the
pressure up to the 5-7 PSI for testing and stop there - don't go any
further. If you did a good job of sealing the leaks, the compressor won't
have to work very hard to fill the cabin. If the compressor stays loaded
(pumping air), you have some leaks to find. <grin> You need to read
the manual on the Dukes valve to figure how to "fool" it so you can pressurize
the plane on the ground.
Hope this helps.
Ed Smith
Chesapeake, VA
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