The SL (SL-912-016R1) doesn't say what is being reported in this thread. It
says:
"Continuous use of engine speed below 5200 rpm must follow manifold pressure
graph...."
So a takeoff and climb to 500' @ WOT is not 'continuous'.
'Continuous' might be defined by Rotax's 5-minute rule in relation to continuous
operation at >5500rpm. Cruising at 4000rpm is permitted at <27" MP, for example,
and the SL merely says operation outside of the graph is to be "limited",
not verboten.
Then there is the other hearsay (reported from the secret Rotax instructional
events)
that "resonances" disfavour low (<5200rpm) rev operation, but where is
the published (by Rotax) technical evidence? Other than maybe the fretting of
crankcases in older designs, the cause of which seems also to be hearsay tainted
by vested/misguided interests?
Duncan McF.
> On 24 April 2021 at 04:06 Peter pender <ppen@live.com.au> wrote:
>
>
>
> Hi Chris,
>
> The SL that I referred Griffo to back in your other post states the you should
have 5200 rpm min at take off WOT. It doesn't say what part of TO. It also
doesn't
mention any thing about static revs in regard prop pitch. They now have
a sort of power chart as well but once again, pretty vague.
>
> Pete is probably correct that it doesn't help the gearbox but I think the main
reason is to protect the crankshaft. That SL came out after a crash where an
aircraft with an inflight adjustable prop had been operated for some time at
too low revs for the MAP.
>
> Prior to that most people tried for 4900 to 5000 at TO for a bit of cruise
> performance
and I'm sure a lot of people still do.
>
> It's really what ever people feel comfortable with.
>
> Cheers Peter
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=501494#501494
>
>
>
>
>
>
>
>
>
|