Cruising at high power settings

Rotax engines can run at 5,500 rpm all day long. (5,800 WOT for max 5 minutes gets you 141 hp) At 5,500 rpm you're getting 135 hp all the way to 15,000 feet. Your fuel burn will be higher at 5,500 but you can run it there all day, assuming your temps stay in the green. I have a Magni M16 Plus gyroplane with the 915. I cruise at 5,200 rpm and that usually gets me somewhere around 31" manifold pressure. 51" is max so its certainly not overtaxing the engine. Good call on the Sling TSI. If I flew fixed wing, that's the plane I'd want. Modern, fast, long range, and powerful with the 915.

Thanks for the reply. Do you know at what point the 915iS goes into ECO mode? Is it a certain percent of power or manifold pressure? I couldn't get a precise answer out of the Sling demo guy. (They said that previously ECO would display on their Garmin display, but after a recent engine update, that stopped displaying for some reason.)

Mike wrote:

Thanks for the reply. Do you know at what point the 915iS goes into ECO mode? Is it a certain percent of power or manifold pressure? I couldn't get a precise answer out of the Sling demo guy. (They said that previously ECO would display on their Garmin display, but after a recent engine update, that stopped displaying for some reason.)

Anything over 36.9” of manifold at 5500 RPM will kick it out of Eco mode. Fuel burn at 36.4” and 5500 RPM is 7.8 GPH on the TSi. 

I recently purchased an Autogyro Cavalon with a 915 rotax (I own an experimental Cavalon with a 914 turbo and put over 1000 hrs. on it almost trouble free over the last 5 years) sooooo,,,,,,,,I flew it home about 21/2 hrs with a very good head wind so it was working and also put about 10 hrs. on it over the next week or so. I am now seeing high exhaust temps on 1 and 2 cylinders if I run anything over 5200 rpm also pretty high manifold pressure. Anyone have an idea why this issue would have started all of a sudden. The OAT when I flew it home was very high so I don't think increased local temps are the problem, I live in northeast Pa. Any suggestions? 

Ronald, I think you'd be better served starting a new thread with your question, rather than piggy-backing off Mike's (probably) unrelated question...