No carb heat in my trainer

This forum is for safety-related discussions. Be safe out there!

Moderator: drseti

Ecoloqua
Posts: 28
Joined: Fri Feb 10, 2017 10:08 am

No carb heat in my trainer

Postby Ecoloqua » Fri Feb 10, 2017 11:15 am

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

rcpilot
Posts: 249
Joined: Fri Jul 03, 2015 4:32 pm
Location: Mastic, NY

Re: No carb heat in my trainer

Postby rcpilot » Fri Feb 10, 2017 1:46 pm

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

3Dreaming
Posts: 2304
Joined: Sun Jan 10, 2010 6:13 pm
Location: noble, IL USA

Re: No carb heat in my trainer

Postby 3Dreaming » Fri Feb 10, 2017 1:55 pm

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.

User avatar
MrMorden
Posts: 1936
Joined: Fri Aug 17, 2012 7:28 am
Location: Athens, GA

Re: No carb heat in my trainer

Postby MrMorden » Fri Feb 10, 2017 2:05 pm

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.
Andy Walker
Athens, GA
Sport Pilot ASEL, LSRI
2007 Flight Design CTSW E-LSA

User avatar
drseti
Posts: 5754
Joined: Sat Nov 28, 2009 6:42 pm
Location: Lock Haven PA
Contact:

Re: No carb heat in my trainer

Postby drseti » Fri Feb 10, 2017 4:24 pm

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.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
fly@AvSport.org
AvSport.org
facebook.com/SportFlying
SportPilotExaminer.US

Ecoloqua
Posts: 28
Joined: Fri Feb 10, 2017 10:08 am

Re: No carb heat in my trainer

Postby Ecoloqua » Sat Feb 11, 2017 12:23 pm

Thanks to everyone for the replies!

foresterpoole
Posts: 228
Joined: Thu Sep 22, 2016 12:28 pm
Location: Alexandria, LA

Re: No carb heat in my trainer

Postby foresterpoole » Mon Feb 13, 2017 10:37 pm

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???
Ed

User avatar
drseti
Posts: 5754
Joined: Sat Nov 28, 2009 6:42 pm
Location: Lock Haven PA
Contact:

Re: No carb heat in my trainer

Postby drseti » Mon Feb 13, 2017 11:25 pm

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).
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
fly@AvSport.org
AvSport.org
facebook.com/SportFlying
SportPilotExaminer.US


Return to “Safety Corner”

Who is online

Users browsing this forum: No registered users and 1 guest