At what mixture and carburettor heat setting is a take-off normally carried out?

The correct approach for take-off in reciprocating engines generally involves setting the mixture to fully rich and the carburettor heat to fully off. Setting the mixture to fully rich ensures that the engine receives an optimum fuel-to-air ratio, facilitating maximum power output and performance necessary during the critical phases of take-off. A rich mixture is particularly important because it helps prevent engine knock and ensures adequate fuel reaches the engine under the increased demand for power.

Having the carburettor heat fully off is also crucial during take-off because carburettor heating can introduce warmer air into the engine, potentially leading to a leaner fuel mixture. This can cause a decrease in power and performance, which is undesirable when maximum thrust is required for a successful take-off.

In summary, using a fully rich mixture and turning off the carburettor heat allows the engine to perform at its best during take-off, where every bit of power is critical for ensuring a safe and effective ascent.