Carburetors are effective, inexpensive, and relatively simple. That’s why they continue to be installed on many light single and multiengine aircraft. Although dependable, carburetors are subject to one major drawback—icing. Knowing how the ice accumulates can lead to a better understanding of how to prevent it.
The same physical principle that lifts our wings also mixes fuel and air in the carburetor. Bernoulli’s principle says that as a fluid’s speed increases, its pressure—and thus its temperature—decreases. As air moves through the thinner throat section of the carburetor, the temperature drops. On days that might seem relatively warm and dry, the temperature may still drop enough, and there might be enough moisture, for ice to begin to form. And as ice forms, power available to the engine decreases.
The best way to prevent ice from forming is to apply carburetor heat. Recommendations on this vary, but you can’t go wrong with the recommendations of the airplane’s pilot’s operating handbook, or in the absence of that, applying carburetor heat anytime the power drops below a standard cruise setting. If while cruising along the power seems to slowly decrease, add heat. Just remember that anytime heat is added, power will decrease because you are introducing warmer, less dense air.
Related Articles
