In our fleet of 912ULS engines that typically run at fairly low RPM because of training, we've always made TBO, but that being said, we have significant lead build up issues that typically begin to manifest after the 1000h mark. Valves stop seating properly and our mechanic ends up overhauling the cylinders. On one particular engine on a particular plane that was always run at low RPM due to airframe buffet at high airspeed, we actually had a valve fully stick in flight. When Jamie tore it apart he showed it to me and the lead build up was significant. (Note: We always run TCP but the lead still builds up.)
I own a C172 with an O300 (big brother to the O200) and I have similar but even more pronounced issues with that engine. Like the Rotax, it was not designed to run on gas with the high lead content of 100LL. Advice I have always been given by mechanics for dealing with the problem is to "run it hard and hot." If given the option, and running 100LL, I think that advice holds true for a Rotax as well.
As a side note, due to all the lead issues we've encountered, we are installing a mogas pump. Hopefully that will alleviate the problems associated with running at Rotax at low RPMs.
Helen
I own a C172 with an O300 (big brother to the O200) and I have similar but even more pronounced issues with that engine. Like the Rotax, it was not designed to run on gas with the high lead content of 100LL. Advice I have always been given by mechanics for dealing with the problem is to "run it hard and hot." If given the option, and running 100LL, I think that advice holds true for a Rotax as well.
As a side note, due to all the lead issues we've encountered, we are installing a mogas pump. Hopefully that will alleviate the problems associated with running at Rotax at low RPMs.
Helen
> Posted by: "circicirci" acensor@fastmail.fm
>
> At http://flymall.org/aircraft/docs/FAQs-on-Rotax.pdf
> it says,or at least strongly implies, that cruising at less than 5500
> RPM will wear the engine MORE.
>
> Although we do cruise climbs at 5000 to 5500 we often level cruise ours
> down in the 4300 to 4800 range when not in a hurry to get somewhere.
> We're both lightweight pilots and that's plenty of power to stay aloft
> in level flight at our loading. Uses less fuel, makes less noise, and
> figured for sure it would increase engine life.
> Despite their explaination on that site of why 5500 is optimal, it
> still seems suspicious and doubtful to me that 4600 RPM wouldn't be
> less wear.
>
> Anyone have, thoughts, knowledge, or experience on that?
>
> Yeah, I know the 912 shouldn't be ideled below 2000 RPM -- that's not
> the issue I'm concerned about.
>
> And I'm not talking about an engine that's running at below 5000 RPM
> because it's overloaded (for example if the prop pitch has been set too
> high.)
>
> Any ideas?
> Alex
If it was my engine Alex,
I'd be very happy with it running between 4000 and 4500.
(and that's with a fixed-pitch prop)
Mike
.
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/Sport_Aircraft/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/Sport_Aircraft/join
(Yahoo! ID required)
<*> To change settings via email:
Sport_Aircraft-digest@yahoogroups.com
Sport_Aircraft-fullfeatured@yahoogroups.com
<*> To unsubscribe from this group, send an email to:
Sport_Aircraft-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
__._,_.___
No comments:
Post a Comment