Hi Ron.
It seems that this is quite normal. Mine has a linear error which also measures
as:
Indicated RPM = 5000 / RPM measured from prop 5330.
I agree that it is a very unsatisfactory instrument. I am sure that it is not
impossible to calibrate them at the factory. If it was in a car then someone
would sue the manufacturer if his engine blew up!!
Mine was measured during the noise test that every homebuilt has to have in
Germany. It was at that time measured using a Conrad Electronics instrument used
for models. I wonder how accurate they are as I seem to recall reading somewhere
that they are only suitable for 10000 RPM plus. This one was accepted by the
aviation authorities in Germany.
I will check directly on the engine soon with an auto unit and report if there
is any discrepancy.
Best regards
Barry Tennant
D-EHBT
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