Fig. 1 . Propeller body (A) and plan and side views (B) of the complete `see-saw'
propeller rig. Roman numerals identify parts of the propeller body. i, sting
for attachment to wings; ii, propeller head; iii, smoke chamber (smoke in this
chamber feeds into the hollow shaft and up to the propeller head); iv,
cut-away section showing torque strain gauges (electrical connections run down
the hollow axle); v, strain gauge bridge supply and first-stage amplification
by electronics rotating with axle; vi, electrical contacts on multi-wiper
slip-rings carrying power and strain gauge signal; vii, gearbox; viii, motor;
ix, tachometer.
