Sport Pilot Talk

Hi all, I am new to this forum and this is my first post. I am currently working towards my LSA and having a lot of fun doing it. I have a question about the plane that I am training in. It is an FK lightplanes model FK-9 with a Rotax 912 and it doesn't have carb heat. I have been trying to research about the Rotax and the concensus that I have come up with is that due to the location of the carbs and cowling they are a lot less prone to icing. Just curious to hear anyone elses experience.
Thanks!
MB

Hmm. My Zenith 601 has a Rotax 912 and has carb heat. Other than doing my run up never had to use it.

It seems all of these light sport airplanes have different engine installations. Many that have air filters installed directly on the back of the carburetors do not have carb heat. There rarely seems to be issues with this installation.
Some of these installations do have the coolant based carburetor heat installed. This system provides constant heat to the body of the carburetor, while not heating the air entering the carburetor. With this system it is constant heat, and no controls for the pilot.

3Dreaming wrote:It seems all of these light sport airplanes have different engine installations. Many that have air filters installed directly on the back of the carburetors do not have carb heat. There rarely seems to be issues with this installation.

Yeah, the RV-12 is setup this way, basically "carb heat all the time". Since the Rotax doesn't drop RPM/power with under-cowl air, this works great. In fact on my CTSW the "carb heat" is just a flapper that shuts the outside NACA scoop and opens the airbox to warmer air under the cowl. Seems heavy and complex compared to the RV-12.

First off, welcome to the forum, and thanks for posting!

The Rotax 912 series of engines are relatively tolerant of carb icing (no carbureted engine is ever completely immune), for two reasons

(1) as you previously noted, the location of the carbs on top of the warm jugs helps.

(2) with 2 carbs, each driving 2 cylinders, the chances of engine total shutdown due to carb ice are greatly diminished. Both carbs are unlikely to ice up at the same time. As one begins to be blocked off, the engine starts running rough, which is hard to miss. If you recognize this as an early warning of carb ice formation, and feed in more power (thus generating more heat), you can nip the problem in the bud.

Hence, some manufacturers omit carb heat. I'm aware of very few carb ice related accidents with these engines.

Thanks to everyone for the replies!

Just as a followup I asked about this when I transitioned from the 172 I started training in that had carb heat to a Technam P92 without. The answer the CFI gave was exactly the same as was alluded to above, the intakes are under the cowl and the temp is always a bit warm so it was not an issue. However, I did notice in the POH that the plane does have an option for carb heat, so maybe in more northern latitudes it's extra insurance? Doc, you fly the Evector in Pennsylvania if I remember correctly, so much colder than in Louisiana, does that manufacturer have carb heat as an option???

Yes, Ed - but not as an option. The 912ULS powered Evektors all have carb heat as standard equipment (and I've very seldom had occasion to use it, other than to check that it functions during run-up).