1) Burdens 2) Millstones 
(1) Power loading. The loaded weight of an aeroplane divided by the total power of the engine(s). (2) Span loading. The loaded weight of an aeroplane or glider divided by the square of the wing span. (3) Surface loading. The mean force on unit area carried by an aerofoil under specified aerodynamic conditions. (4) Wing loading. The loaded weight of...