Hi! Graham .
The overall diameter of the prop. is relevant to your statement in that the
tip speed /distance travelled is also to be considered with respect to the
transonic factor.
However you are quite right, that's why my CS prop limits the RPM to 2900
and I therefore have in the region of 25% safety scope for the engine to run
continuously at 2700 rpm and I cruise at 120kts/125kts just fine currently
with a fuel burn of 5 /5.3 galls per hour.
Not withstanding it is cleared to run at 3300 RPM continuously anyway !!!!
Regards
Bob H G-PTAG
-----Original Message-----
From: forum-owner@europaclub.org.uk
Subject: Re: Mods & 120 HP JAB engine
>Second thing the Jabiru 3300 120hp sounds very powerful for a Europa, is
>the weight of it OK.
>Kevin
Unfortunately IMHO the rpm at 120 hp is too high for an efficient
propeller, getting into the transonic zone of Mach # at the tips. a. noisy
and b. inefficient.
Graham
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