Copyright of RotorSport UK Ltd
Document number RSUK0288
Page 24 of 55
HTC Propeller
Basic description
See RSDS7066
The HTC propeller is fitted as standard. This is a 3 bladed composite design with an
aluminium 2 piece hub machined from solid. Each blade is a foam filled wet layup
component in carbon and glass fibre. There is a spacer fitted between the propeller and
the engine gearbox flange. Between the spacer and the propeller are fitted 6 torque
bushes, to transmit the engine torque from the spacer to the propeller. Similarly, there are
6 (Rotax manufactured) flanged nuts fitted to the gearbox flange, into which the propeller
bolts are tightened. These carry the torque to the spacer. The function of the six propeller
bolts is to clamp the hub to the gearbox flange. In use, they should carry no torque, and if
the propeller balance is correct, very little tensile cyclic loading – as the driving force is
onto the gearbox flange.
An optional spinner assembly may be fitted. This comprises a composite spinner, an
aluminium CNC machined mounting plate, and 9 M4 screws to hold the spinner to the
plate (with plastic washers under the heads).
Materials used
1,73m diameter 3 blade HTC composite propeller assembly
Hub assembly (always a pair, and matched marked with numbers)
Blade assy (marked at the root with ‘A’ or ‘B’, and a week no./yr of manufacture. If
replacing a blade always ensure the A or B is matched to the original, as this denotes the
blade weight.
Hub bolt and washer set
Hub to engine bolt and washer set
Engine flange nut set
Spacer and bush set
Spinner backing plate
Spinner
Assembly methods
Bolt torque (M6 and M8) 15Nm. Take care not to overtighten, and pre coat M8 centre bolt
threads with loctite 243. Apply paint stripe between the protruding bolts theads and
gearbox flange to allow visual check of bolt security.
Spinner screws. Use loctite 243 sparingly and tighten securely. Ensure a nylon washer is
fitted to each screw.
912ULS Approx blade angle 19.5 deg, 12” from the end of the blade.
914 Turbo Approx blade angle 20.5 deg, 12” from the end of the blade.
Angle measured with respect to the hub face, see photos. Balance propeller after fitting,
unless not disassembled and refitted in original location.
Page issue 2, dated 11.03.13
