Please note that the amount of air pressure necessary for this check is minimal.
You could damage the gauges with a hearty blow. A method that does not risk
damage is to put your scrap tubing over the pitot, then clamp the other end.
Slowly
roll the tubing up, which will compress the trapped air. Stop when the gauge
reads a number you like.
David (another one - they're everywhere)
A071
-----Original Message-----
Subject: Re: Calibration check of pitot static systems
David
I can lend you a callibration instrument but it's rather bulky.
Checking the Pitot line is easy, use a few feet of Europa's old PVC 5/16
bore sight gauge tube and push it over the end of the pitot. Carfeully blow
into it , watching the ASI reading and get it up to 100kts or so, then
block the end of the tube with your tongue. You could clamp it to close off
the pipe. Wait and watch. The reading should remain constant for an
indefinite time. 30 seconds would be enough to verify there are no leaks.
I used to do this as part of a rigging check .
Checking the static line for leaks is not quite so easy but a similar
method could be used but using suction instead of pressure. You would need
to disconnect the static line from the Pitot assemble, then connect to it.
I haven't forgotten about my offer to you BTW. Still struggling a bit but
dust is slowly settling.
Graham
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