r similar material. Usually
used in connection with wood joints and wire cable splices.

Slip, Propeller--The pitch less the distance the propeller advances
during one revolution.

Stream-Line--A form or shape of detrimental surface designed to produce
minimum drift.

Toss, to--To plunge tail-down.

Torque, Propeller--The tendency of a propeller to turn an aeroplane
about its longitudinal axis in a direction opposite to that in which the
propeller revolves.

Tail-Slide--A fall whereby the tail of an aeroplane leads.

Tractor--An aeroplane of which the propeller is mounted in front of the
main lifting surface.

Triplane--An aeroplane of which the main lifting surface consists of
three surfaces or pairs of wings mounted one above the other.

Tail-Plane--A horizontal stabilizing surface mounted at some distance
behind the main lifting surface. Empennage.

Turnbuckle--A form of wire-tightener, consisting of a barrel into each
end of which is screwed an eyebolt. Wires are attached to the eyebolts
and the required degree of tension is secured by means of rotating the
barrel.

Thrust, Propeller--See "Air-Screw."

Undercarriage--That part of an aeroplane beneath the fuselage or
nacelle, and intended to support the aeroplane when at rest, and to
absorb the shock of alighting.

Velocity--Rate of displacement; speed.

Volplane--A gliding descent.

Weight--Is a measure of the force of the Earth's attraction (gravity)
upon a body. The standard unit of weight in this country is 1 lb., and
is the force of the Earth's attraction on a piece of platinum called
the standard pound, deposited with the Board of Trade in London. At the
centre of the Earth a body will be attracted with equal force in
every direction. It will therefore have no weight, though its mass
is unchanged. Gravity, of which weight is a measure, decreases with
increase of altitude.

Web (of a rib)--That vertical part of a rib which prevents it from
bending upwards.

Warp, to--To distort a surface in order to vary its angle of incidence.
To vary the angle of incidence of a controlling surface.

Wash--The disturbance of air produced by the flight of an aeroplane.

Wash-in--An increasing angle of incidence of a surface towards its
wing-tip.

Wash-out--A decreasing angle of incidence of a surface towards its
wing-tip.

Wing-tip--The right- or left-hand extremity of a surface.

Wire--A wire is, in Aeronautics, always known by the name of its
func