INITIAL ENGINE RUNS

by Brad Hood in General Tech Discussion 13 years ago

I have a question about initial engine runs of a new 912ULS. Most engine builders of Lycoming or TCM engines prefer you not ground run the engine more than is absolutely essential to adjust it for takeoff. The danger is glazing the cylinder bores. I can find no reference to this in any of the Rotax guidance. My DAR wants me to taxi test for around 2 hours which is really insane I think. Any idea if prolonged taxi prior to first flight will possibly damage the 912 engine.
Thanks,
Brad

Re: INITIAL ENGINE RUNS

by MARK JACKSON » 13 years ago

MARK JACKSON

12 332 11

Hi Brad

I don't think it matters either way.

I would suggest a 30 min ground run with the aircraft tied down just to prove all the ancillaries are ok and there are no leaks and then go for it.

I you do ground run it for 2hrs, I would suggest that you tie it down securely so you can get full power and then warm the engine up and give it full power for around 1min fairly early and then back off to cruise power for 10 mins or so and repeat. Just keep an eye on your temps. This will be as good as flying it.

The engines are run in at rotax so no problems there.

Cheers mark.

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Re: INITIAL ENGINE RUNS

by Brad Hood » 13 years ago

Brad Hood

3 3 0

Thanks Mark!

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Re: INITIAL ENGINE RUNS

by bill martin » 13 years ago

bill martin

10 757 0

Brad,

I think mark is right. It won't hurt to taxi for a couple of hours but it's not necessary. New four cycle engines, car and aircraft engines alike, don't need the break in periods like they used to do back in the day. Do the purge by the book, sync the carbs, warm the engine, check it for full throttle and cruise operation and go flying.

Bill.

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Re: INITIAL ENGINE RUNS

by Roger Lee » 13 years ago

Roger Lee

131 5.38k 5.44k

I'm with Mark,

Everyone should forget the the words or any comparison of the Continental or Lycoming to a Rotax. Different species all together. That's also why many A&P's make mistakes on a Rotax because they think Continental or Lycoming. Think of a Rotax more like a motorcycle engine, then you will have a better handle on what makes it tick and why. You wouldn't buy a Honda motorcycle and ride in a parking lot for hours before going on the street. Read the Rotax installation manual, do a good oil purge, do what is described in the manual and go fly. The engine has been run at the factory already, too. If you have a factory built plane it was run again at that factory. This engine is not designed to sit around for long hours at slow idle rpms.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Thank you said by: YEN NIEN YU

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