>> As a further provision against the static head falling off the pitot
unit, I have a tap on the line between the wing and the dash which can
be turned to allow the cabin air to be the static pressure..
It may be of interest to note that, having now completed the first batch
of flight tests on ZK-RJL, the owner has advised me that he has
disconnected the wing static and is using cabin pressure as his static.
His ASI now tracks speed correctly right through the entire operational
range to within a couple of knots whereas he was seeing a larger
variance with the under wing static.
If you want an excuse to go do some test flying it might be worth going
out and doing a series of ASI calibration tests with the static vented
to cabin and see how the figures compare to the calibration tests you
did for the wing mounted static.
Tony
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