Carb Icing

[alanmack]

Final deliberations on the content of the September Issue of Microflight Africa saw the Editor's Q&A being moved from the Sept to the Nov issue.

One of the Answers that I researched in response to a Question was that of Carb Icing. Much is available on the topic on the net but the attachment was not found.

The full document is too long for the Editor's Q&A but is a useful guide to Rotax owners. The document is issued by Aviation Engines as an adendum to the Rotax manual with new engine sales.

Niren Chotoki at Aviation answered the following questions:

Do you really believe that all Trikes in SA should be fitted with Carb Heaters? > No, unless they are operated in areas where atmospheric conditions are conducive for carb icing. 2-Stroke engines are less susceptible than 4-stroke engines to carb icing.

How much do they cost? > The most economical carb heating system is the one that uses the coolant system to warm the carb body. However this can’t be used on an air-cooled engine, eg. 503. Prices vary from approx. R2000 for a Rotax 582 to R2600 for the 912 engines.

Why are they not standard with a Rotax? > Rotax engines are used in so many different applications and if they had to supply a standard carb heater, it may not suit most applications. It is the responsibility of the aircraft manufacturer. The latest Installation Manual for 2-stroke engines states the following: “If the aircraft is operated in climatic conditions where carburettor icing is likely to occur, a heating system must be fitted”
As concerns the Rotax 912 engines, the Installation Manual also mentions that the aircraft manufacturer must make provisions for carb heating.

How much do they weigh? > The weight of the systems mention here, is negligible and well under 1 Kg. Conventional heating systems that take warm air from the exhaust may be heavier depending on the design, but these systems do get complex.

Fly safe

PS Apologies for there being no attachment. It is a PDF file and this is not permitted on the forum - email Niren Chotoki at Aviation Engines and request him to send you a copy. His email is:

niren@aviation-engines.co.za