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Ok, Here's a question for you pilots. As many of you may know, alot of LSA aircraft use the Rotax 912ULS 100 HP 4 stroke engine as their powerplant of choice. Can anyone tell me why this engine does not incorporate a mixture control? The only control I've seen is a choke for cold starts. Given the fact that the Performance ceiling for this particular aircraft is 13,000 ft., shouldn't there be a way to lean the mixture?

I haven't flown one in a dozen years, but as I recall the Diamond Katana had a Rotax 912 and it was equipped with an auto-leaning system. No need to have a lever since the plane leaned as needed.

The Rotax 912S is the specified engine for the Vans RV-12 LSA Kit plane.

Here's a quote from the Van's site:

"Operating the Rotax is a very pleasant experience. ... They also feature automatic mixture compensation for altitude changes, so there is no mixture control in the cockpit. The engine starts easier than either a carbureted or fuel injected Lycoming. It is smooth and quiet, both on ground and in flight."

http://www.vansaircraft.com/public/rv-12his_3.htm

No idea how well it works, but it seems like a pretty basic concept.

It has dual altitude-compensating carbs. I have no idea how they work, but it does have them.

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Brad
RV-7: RV7Factory.com
Blog: PilotBrad.com

i would guess it has some sort of diaphram that expands and contracts with altitude to adjust mixture control. seems pretty simple. you'd want to make sure that they were in good shape though! Ive always wondered about the dual carb setup on the rotax's. seems awfully complicated to keep them balanced. trying to get two mechanical devices working exactly the same seems to be a maintenance tweaking nightmare in most applications

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Everyone must believe in something, I believe that I will go flying.

Very good point Tony; I never considered that.

I'm relatively unfamiliar with the Rotax 912. Can anyone tell me how long the engine has been in service? And where they're manufactured?

Looking at an RV-12 kit... the reason I'm asking.

I don't know how long the 912 has been around, but I do know they are made in Austria. The overwhelming majority of LSAs use some form of the Rotax 912.

Check out... http://en.wikipedia.org/wiki/Rotax_912

_________________
Brad
RV-7: RV7Factory.com
Blog: PilotBrad.com

ebrendan,

I don't know if you get Kitplane magazine, but they just did a review of the RV-12. http://www.kitplanes.com/issues/pdfs/1008-0817.pdf

_________________
Brad
RV-7: RV7Factory.com
Blog: PilotBrad.com

I do not; but probably should.

I saw read that pdf and was really excited by the article. It's generally a very positive review of the airplane. The 912 seems to be winning fans.

Thanks for pointing that out.