Forget to ask: 80? or high compression 100hp? (Might be less of an issue on
the
80)
> On Apr 23, 2021, at 3:22 PM, n7188u <chmgarb@gmail.com> wrote:
>
>
> Thanks PeteZ and I think we are starting to get a great conversation going.
>
> First: I don't think you should fixate on the static RPM number, it's
> meaningless
as long as the TO performance is acceptable and you are not overloading the
engine during climb. See the blurb I added at the end of this posting regarding
the CTLS. They call in their manual that once RPM reaches 4800 during TO
roll power is acceptable for takeoff.
>
> Second: I am using a Woodcomp Klassic prop that came out of a Sport Cruiser
> (same
engine I have). I have the maintenance manual for that airplane and it calls
for max. 5,000 100 rpm ground static RPM. The CTLS people I talk to confirmed
today they climb at 4900-5000 RPM all the time. So lets really see in what
context the 5200 RPM recommendation from Rotax comes from (which I am sure is
important but is that for continuous operation).
>
> BTW, as I was writing this I thought of looking at the CTLS operator manual.
Very interesting. RPM during initial TO roll is called to be 4800-5000 RPM.
Climb
RPM 4800-4900. Prop is set to 5500 RPM at WOT in level flight and 4800 RPM
recommended for cruise. WOT static RPM 4900. This is from Flight Design USA web
site.
>
> As the owner of a LongEZ I quickly learned that TO performance must be
> compromised
in order to achieve the speed potential of the airplane (which is still
hard to do). So yes, my takeoff run is longer than if I had finer pitch in the
prop but it must be done to keep the RPM at bay during cruise (I would have to
bring the throttle to idle to not overspeed the prop on that airplane). Yes,
the Europa is that kind of airplane that really needs a constant speed prop but
if you don't have one it is not the end of the world. At least me, I don't
have the $10K needed to put one on mine.
>
> BTW, if your thing is to fly from short unimproved runways then of course set
your prop for that environment.
>
> Best,
> Chris
>
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> Read this topic online here:
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> http://forums.matronics.com/viewtopic.php?p=501481#501481
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