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Post by Cluemeister on May 21, 2016 11:14:34 GMT
When I was training in Florida in the P92 Echo with a Rotax 912ULS, the carb heat knob was taped over with a "do not use" note on it. While poking around the CT forum, many there have rarely to never used carb heat on their 912ULS engines. In the Skycatcher, (Continental engine) I apply carb heat every time I land. Is it really rarely needed in the Rotax?
So a second question in respect to Tecnam. Do they provide a carb heat knob for both the 912ULS and the 914 equipped aircraft? I know the 912is Rotax does not have to worry about this.
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Post by jetcat3 on May 21, 2016 20:28:18 GMT
I think with the way the carbs are mounted (on top) it does eliminate much of the risk of carb ice, but it certainly doesn't mean it can't happen. That is strange to me that the carb heat was taped over with "do not use". I think it is rarely needed in the Rotax 912 UL and ULS engines, but I'd sure still want a n operable carb heat knob. On the 914 UL, I heard that they way the turbo operates eliminates the possibility of carb ice but I could be wrong. Also, if the turbo goes out now you're in the exact same position as a 912 UL 80 HP engine. Mark will have to chime in here!
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Post by Cluemeister on May 23, 2016 10:20:59 GMT
Flew in the 914 this weekend. No carb heat needed. And of course no mixture control on any Rotax. Nice!
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Post by MarkGregor on May 29, 2016 15:15:13 GMT
The turbo on the 914 preheats the air before it enters the carburetors so its basically impossible to get carb ice on the 914. The 912ULS pulls the intake air from inside the cowl which I am told is somewhat preheated from the engine and exhaust. I have never experienced or heard of carb ice on the 2008 or Astore but that does not mean it is not possible.
Mark
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Post by ChrisConnor on Sept 2, 2016 14:22:51 GMT
There is no carb heat on my P92 Echo Classic or my buddy's P92 Echo Super.
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Post by jetcat3 on Sept 6, 2016 22:10:25 GMT
Hey Chris, have you ever had any issues or hints of carb ice before? I wonder how effective having both carbs mounted on top of the engine is for minimizing this potential issue.
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Post by ChrisConnor on Sept 6, 2016 22:18:20 GMT
I've never had even a hint of carb ice. I am familiar with how that acts, being an old Continental man. I wouldn't say it's impossible on the 912ULS, but with the air cleaners nestled nicely behind the engine, and inside the cowl, I'm comfortable with almost impossible.
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helen
New Member
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Post by helen on Sept 7, 2016 19:43:12 GMT
There are two different engine set ups for the Rotax 912, one that draws air from inside the cowling (so it is hot and carb heat is essentially always on) and the other that draws air from outside the cowling (that is cold). Only the latter requires carb heat. During the preflight it should be simple to see which engine set up the plane has. It is possible the plane in question had the set up changed if the engine was replaced at some point leading to the placard.
A Rotax which draws air from the outside is much more likely to develop carb ice and hence will have a carb heat knob installed. I have about 4000 hours behind 912s and have probably had carb ice with such a set up about a dozen times. I have only had carb ice once with the "always on" set up and that was right after start up and quickly cleared itself as the engine warmed.
Helen
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