Just as a tiny datapoint, AFAIK, since my club switched their two BR23s to only SuperPlus or 100LL (I assume at least 90% of which Super Plus, which we get mainly at EDFC), there have have been no issues.
boscomantico wrote:
Just as a tiny datapoint, AFAIK, since my club switched their two BR23s to only SuperPlus or 100LL (I assume at least 90% of which Super Plus, which we get mainly at EDFC), there have have been no issues.
This is in line with all other tiny datapoint 
Yet another confirmation of facts.
gallois wrote:
When air enters the carb, the venturi effect can lower that temperature by as much as 30°
No. It’s not the venturi effect. It’s the evaporation of fuel that cools down the mix.
Maoraigh wrote:
I don’t understand how partial carb heat can make carb ice possible. I understand the carb ice diagrams, but an increase in air temperature will be accompanied by a reduction in humidity unless water vapour is added.
I agree. What I learned during PPL was it’s a procedural thing. Running without heat, then turning on the heat every now and then for 20 seconds you will learn to listen to the engine. If it behaves the same every time, no carb ice. If ice is formed, the engine will behave different when this ice is cleared, and you will notice. No carb heat gives more power.
Rotax installations has at least 3 different ways (5 actually) of dealing with carb ice that I know of.
Which one is best? I don’t know. Carb ice and Rotax in the same sentence is a seldom phenomenon. Obviosly EFI is best of course, but carb ice doesn’t really seem to be a problem from the start.
@Le Sving
A quick Google
Carburetor icing is caused by the temperature drop in the carburetor, as an effect of fuel vaporization, and the temperature drop associated with the pressure drop in the venturi.
gallois wrote:
Carburetor icing is caused by the temperature drop in the carburetor, as an effect of fuel vaporization, and the temperature drop associated with the pressure drop in the venturi.
Yes, but please. Google some more until you find the relative effect fuel vaporization vs pressure drop. Don’t remember what they are, but in the order of 100 to 1 for fuel vaporization.
Some interesting comments on Rotax reliability here from a South African Sling operator with 35,000 hours spread over several aircraft, the highest time of them having over 7,000 hrs TT. This was published over a year ago. He’s had gearbox and alternator stator problems with the injected 912is variant, but reports no problems such as those reported elsewhere with the Bing carb’d engines in those airframes, using whatever auto fuel he is burning in that country.
South Africa with mostly steady dry climate isn’t exactly Northern Europe. These Bings are pressure compensated, but not temperature compensated. The iS, or any other EFI for that matter, is. Manual mixture also
