Recently I saw some figures on the above done by John Brownlow. they were in
the range 4400 rpm to 5600 tacho the corrected (for gearbox) figures ran from
4727 to 6046 running on average about 8% high.
I did a shorter series of tests on my rig so I have put all the figures that
I got in.
Tacho Prop Engine error %
2000 900 2045 +45
2.25
3000 1400 3181 +181 6.00
4000 1950 4431 +431 10.8
4500 2200 5000 +500 11.3
The nasty bit about the above is the way in which the error seems to be
heading.
If the increase does indeed follow the curve it seems to be on full normal
revs 5500 on the tacho would probably be around 6200 or 6200 and a quick run
to an indicated absolute max of 5800 would really get you worried.
My checks were done with a tacho sold for the model makers but checked at
vaious veifiable speeds such as mains frequency and computer frame rates and
so fourth it seems pretty good. Any comments please.
Ron S No33.
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