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View Full Version : Rotax 582 Flying Best Practices



jsimmo97
11-25-2009, 11:17 AM
Folks... anyone out there have some best practices they can share regarding flying the Rotax 582 engine?

I am new to my beast and came across an article that points to cylinder head versus piston temp differences as the root cause for engine failure.



Is suggests that you should never pull the power back to half throttle and descent at a high airspeed. The half throttle condition creates a very lean mixture/high temp delta situation that is certain to cause piston ring failure or other issues.

In flying my Kitfox last week I noticed that the EGTs went up (not down) when pulling the throttle back to certain RPMs. The article point out that its really not high EGTs that is the problem but more the difference between the piston temp and the cylinder head temp.

Would love your thoughts and dialogue.

jrthomas
11-25-2009, 06:41 PM
In my experience with 2 stroke Rotaxes and the advise of the best Rotax man I know (factory trained) is leave the factory jetting alone and fly it. There's 2 main reasons for not pulling back to an idle on decent. One is shock cooling but a 582, since it's water cooled shouldn't be a factor. #2 reason is a 2 stroke gets its lubrication from the oil that is mixed with the gas. If you cut the fuel flow you're also cutting the oil and with the wind spinning your prop your engine may be turning at 3500rpm with no oiling. To decend, I usually cut back to 4500rpm or so and decend gradually. You can go to an idle but just don't push it too hard. I'd keep an eye more on exhaust gas temp than cylinder head temps which should not be a problem as long as the cooling system is right. The exhaust gas temp should never exceed 1200 degrees and if it does, the jetting is too lean. Some people change the clip on the midrange jet needle with the change of seasons to keep temps in the ideal range. 2 strokes exhaust temps will run hotter in cold weather and cooler in warm weather. I usually just leave mine alone year around. One more reason I can think of for not cutting the throttle. Some 2 strokes have hot spots, usually in the 4000rpm range. In my experience, the only Rotaxes I've seen this happen to is 447's with a single carb. 582's are good engines but they need to be run regularly. I talked to a pilot recently with 700+ hours. Run a good synthentic oil and maintain it like Rotax says and you should have good service. James Thomas

Hey Brian, Probably a blue head.It's on a trike that's flown regularly for training. If your gray head has ever been overhauled by a Rotax service center it should have been brought up to blue head specs. I think that's standard practice now. James Thomas