Thrush Aircraft S2R–T660 Maintenance Manual page 106

A. Record the stabilized outside air temperature accurately and set the altimeter window to
29.92. Record the pressure altitude.
B. Start the engine and allow the instruments to stabilize.
C. With the propeller lever full forward, advance the power lever until 1600 RPM propeller
speed is obtained.
D. Record the engine torque which is indicated on the torque meter.
E. Shut down the engine.
F. Refer to Figure A and read the desired engine torque for the prevailing ambient conditions.
G. Ensure that the beta valve clevis slot is flush with the beta valve cap nut. Remove the
propeller spinner and adjust the beta nuts, if necessary, to obtain the desired engine
torque. To facilitate the adjustment of the beta nuts, scribe a line on the beta nuts and the
low-pitch stop rods as shown in Figure 4-5. Use the reference line to ensure that each nut
is adjusted the same number of flats. Turning the nuts six flats will provide approximately
one (1) PSI change in the engine torque. Standing in front of the propeller and facing the
dome, make the adjustments: to increase turn clockwise and to decrease turn counter-
clockwise. The torque meter should be within +/- one (1) psi of the predetermined value.
Do not perform ground testing of the propeller if the wind exceeds 5 MPH. If any wind at all is
present, head the aircraft to a crosswind.
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THRUSH AIRCRAFT INC - T660 TURBO THRUSH
AIRCRAFT MAINTENANCE MANUAL
*NOTE*
It is not necessary to cap the bleed air line
when checking the 1600 RPM torque setting
**CAUTION**
It is important that each nut be moved the same amount to
ensure that the nuts are not moved out of the relationship
with each other.
Effective: 12/17/03