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, until I read that site, I figured for sure it would _increase_ engine life.
Despite that site's brief explaination 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 (like if the prop pitch has been set too high.)
I know the factory engineers are very sharp folks but the idea that I could wear it significantly by cruising level at 4600 is SO counterintuitive.
What's more I know dozens of 912 owners and NONE of them cruise at what APPEARS to be the factory recommended 5500 RPM. Most cruise at 5000 on cross country.
Finally, if it WERE damaging to run at medium RPM everytime a 912 is operated in setting up its approach it would be doing excessive wear.
Any ideas?
Al
P.S., I know a 912 owner with a Eurostar with more hours on it than any other I know - just under 4000 without an overhaul or, according to the owner,without need for any mechanical repair. And it is pitched for a max static of 4600. According to him runs just as sweetly and delivers just as much power as a new one.
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, until I read that site, I figured for sure it would _increase_ engine life.
Despite that site's brief explaination 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 (like if the prop pitch has been set too high.)
I know the factory engineers are very sharp folks but the idea that I could wear it significantly by cruising level at 4600 is SO counterintuitive.
What's more I know dozens of 912 owners and NONE of them cruise at what APPEARS to be the factory recommended 5500 RPM. Most cruise at 5000 on cross country.
Finally, if it WERE damaging to run at medium RPM everytime a 912 is operated in setting up its approach it would be doing excessive wear.
Any ideas?
Al
P.S., I know a 912 owner with a Eurostar with more hours on it than any other I know - just under 4000 without an overhaul or, according to the owner,without need for any mechanical repair. And it is pitched for a max static of 4600. According to him runs just as sweetly and delivers just as much power as a new one.
