Fwiw, I was told by the rotax folks that the slipper clutch was added to avoid
spline damage during start-up/shut-down with heavy (high rotational mass)
propellors.
(Not prop strikes as commonly thought)
Cheers,
PeteZ
> On Dec 26, 2022, at 4:33 PM, rparigoris <rparigor@hotmail.com> wrote:
>
>
> Hi Area 51
> 2 Questions below:
> I'm having a bit of a hard time following your thinking?:
> "I am at a total loss as to why rotax have employed a slip dog coupling in the
912 gearbox without torque pulse damper springs"
> I'm not too familiar to the set up without slipper clutch, but with the
> slipper
clutch you in fact have a torque pulse damper spring in the form of Belville
washers. When cylinder fires, it "winds up the spring" In reality it is not
winding up, it is flattening the Belville washer that is in fact a spring which
absorbs some power. Then when no cylinder is not firing, the spring unwinds
and puts some power back to the prop shaft.
>
> 1) Please explain how you would better make a torque pulse damper? I'm pretty
certain if all that would be needed is a compression spring plate as is often
seen in an automotive clutch that Rotax would have used that instead of a high
parts count dog solution. A propeller spinning is a pretty darn good gyroscope,
it really doesn't want to accelerate or deaccelerate.
>
>
> As far as operating at 3,800RPM, I have been interested in the loitering power
setting. I have asked several folks in the know and all thought it is not an
issue for the gearbox. That said it is an issue if you are running on 100LL as
even with TCP or Alcor, you are not making enough power to get rid of the as
much lead as compared to pushing more BTUs through the engine. On Mogas or no
lead think things will be fine.
>
> 2) Rotax want's oil temperature to get to boiling during flight. I thyink at
sender 190F will give hot oil 212F. I'm pretty sure loitering flight will not
allow oil temp to get to 212. My question is why do you need to get to 212F
during
flight? The real reason I ask is on most of my cars rarely do I see 212F
and haven't ever seen anything happen because of it.
> Thx.
> Ron P.
>
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>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=509798#509798
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