SYSTEM DESCRIPTION
AutoGyro_FOM_MTOsport Revision 5.0 – Issue Date 01.04.2011 7-3
7.5 Pneumatic System
Aircraft trim, rotor brake and activation of the pre-rotator is controlled by a pneumatic
system, consisting of an electrically driven air compressor with dry cartridge, a pressure
gauge in the cockpit, solenoid valves, air lines, pneumatic actuators, and the respective
cockpit controls.
Trim function
Trimming is effected by varying trim pressure in the pneumatic trim actuator which is
installed in parallel with the rotor head tilt for pitch control. Aft or nose-up trimming activates
the electrical compressor and increases trim pressure, causing the actuator to retract, and
tilting the rotor disc aft. Forward trimming opens the pressure relief valve to reduce trim
pressure and allows the rotor disc to flatten, due to the spindle head offset and the
gyroplane’s weight. The actual trim condition is indicated on the trim/brake pressure gauge
in the centre panel of the cockpit.
Rotor brake
With the pneumatic mode selector in BRAKE position the operation of the pneumatic trim
actuator is reversed so that increased pressure causes the actuator to push the rotor head
up (or level) and presses a brake pad against the rotor head disc. In order to increase brake
pressure, move the 4-way trim switch to aft. Note that this action will also push the control
stick forward. At full brake pressure the control stick will be maintained in its full forward
position.
Activation of the pre-rotator
The pre-rotator is activated as long as the respective switch on the control stick head is
depressed, provided the following pre-conditions are met:
pneumatic mode selector set to FLIGHT
control stick in full forward position, controlled by a micro switch installed in the
control linkage at the bottom of the pilot’s control stick
When activated the pneumatic actuator at the pre-rotator belt clutch is pressurized, lifting
the smaller pulley out of its brake position and tensioning the belt at the same time. Engine
torque is then transmitted through the lower pre-rotator drive, a 90° gearbox and upper drive
to the pinion which is engaged by another small pneumatic actuator into the geared ring of
the rotor head. The drive pinion is sliding on a helical gear to provide automatic lock-out in
case of rotor RPM overrun. In order to allow necessary changes in length both pre-rotator
drive shafts feature a sliding sleeve coupling.
Activation of the pre-rotator in BRAKE position
The pre-rotator can be activated in BRAKE position to park the rotor blades fore-aft for taxi.
To do so, the pre-rotator switch and the overdrive/override switch in the cockpit panel have
to be pressed simultaneously. Avoid prolonged activation of the pre-rotator with rotor brake
engaged.
To Next Page
Loading...
