S
Scale Model—A miniature aëroplane exactly reproducing the proportions of an original.
Spar—A mast strut or brace.
Side Slip—The tendency of an aëroplane to slide or slip sideways when too steep banking is attempted.
Stability—The power to maintain an even keel in flight.
Starting Platform—A runway to enable an aëroplane to leave the ground.
Surface Friction—Resistance offered by planes or wings.
Slip—The difference between the distance actually traveled by a propeller and that measured by the pitch.
Soaring Flight—A gliding movement without apparent effort.
Sustaining Surface—Extent of the wings or planes which lend support to an aëroplane.