# Asymmetric thrust [closed]

Let's assume we lose left engine on a twin-engine aircraft during a straight and level flight without a side slip. In order to compensate yawing moment to the left from the right engine we deflect the rudder to the right (picture 12.21), however there appears an unbalanced force to the left behind the CG (rudder force). It is said (at least in the book I study about principles of flight) that there are two ways to balance the side force from the rudder: with wings level (picture 12.23) and by banking slightly towards the live engine. At first I would like to consider the first method. It states that yawing to the live engine gives a side slip force on the keel surfaces behind CG opposite to the rudder force. That's fine, however if it acts not through the CG (what is the case in the picture 12.23) there should as well appear a moment from that force which would again yaw the aircraft to the left? Am i missing something?

## closed as unclear what you're asking by fooot, xxavier, Sean, Ralph J, anshabhiDec 7 '18 at 13:44

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• I find your question a little confusing. First, all moments will act "through" the cog, that is, the cog will be the axis along which the force will try to rotate the plane. – TomMcW Dec 6 '18 at 20:56