Part 20 (1/2)

=Pitot Tube=--A for of a tube with open end facing the wind, which, combined with a static pressure or suction tube, is used in conjunction with a gauge for ram_)

=Pitch, Propeller=--The distance a propeller advances during one revolution supposing the air to be solid

=Pitch, to=--To plunge nose-down

=Reaction=--A force, equal and opposite to the force of the action producing it

=Rudder=--A controlling surface, usually hinged to the tail, the operation of which turns an aeroplane about an axis which is vertical in norht; causes an aeroplane to turn to left or right of the pilot [22]

=Roll, to=--To turn about the longitudinal axis

=Rib, Ordinary=--A light curved wooden part mounted in a fore and aft direction within a surface The ordinary ribs give the surface its camber, carry the fabric, and transfer the lift from the fabric to the spars [23]

=Rib, Co the stress of co wires [24]

=Rib, False=--A subsidiary rib, usually used to improve the caht and Left Hand=--Always used relative to the position of the pilot

When observing an aeroplane froht hand side of it is then on the left hand of the observer

=Remou=--A local movement or condition of the air which may cause displacement of an aeroplane

=Rudder-Bar=--A control leverthe rudder [26]

=Surface=--See ”Aerofoil”

=Surface, Detri the propeller, but excluding the (aeroplane) lifting and (propeller) thrusting surfaces

=Surface, Controlling=--A surface the operation of which turns an aeroplane about one of its axes

=Skin-Friction=--The friction of the air with roughness of surface A for-tip

=Stagger=--The distance the upper surface is forward of the lower surface when the axis of the propeller is horizontal

=Stability=--The inherent tendency of a body, when disturbed, to return to its normal position

=Stability, Directional=--The stability about an axis which is vertical during norht, and without which an aeroplane has no natural tendency to reitudinal=--The stability of an aeroplane about an axis transverse to the direction of norht, and without which it has no tendency to oppose pitching and tossing

=Stability, Lateral=--The stability of an aeroplane about its longitudinal axis, and without which it has no tendency to oppose sideways rolling

=Stabilizer=--A surface, such as fin or tail-plane, designed to give an aeroplane inherent stability

=Stall, to=--To give or allow an aeroplane an angle of incidence greater than the ” a fall in the lift-drift ratio, the lift consequently becoht of the aeroplane, which must then fall, _ie_, ”stall” or ”pancake”