Guest Post by Ajlr

Staying in Trim 

Ever wondered how the captain of a big loaded cargo or passenger aircraft knows that it will be able to take off – that is, that the lift given by the wings and other aerodynamic surfaces at take-off speed is greater than the force of gravity holding it on the ground? Or why it doesn't either topple onto its nose, or one wing, or drag its tail in the dust? It's all to do with the payload and 'trim' – and by that I don't mean what colour the seat cushions are. 

Many years ago I ...