Revision: 4
Date:
09/08/20
RV-12iS Flight Training Supplement
5-8
ENGINE CONTROLS
Throttle, Eco Stop, Friction Control, Choke (ULS only),
Fuel Shut-Off.
Choke (ULS engine only) is used for cold starting. The choke
can be locked in a specific position by rotating the handle.
Fuel shut-off valve is used to permit or prevent fuel from flowing
to the engine. It may be pulled up to the 'OFF' position to
prevent/stop fuel flow, or pushed down to the 'ON' position for
normal operation.
Throttle is used to control the engine RPM. Full-throttle position
is achieved when the throttle lever is closest to the instrument
panel.
The adjustable friction control knob modifies the friction in
throttle control movement. A small amount of friction must be
applied to prevent the throttle return spring at the engine throttle
body from pulling the throttle to full RPM.
The Rotax 912 iS engine has two different modes: ECO mode
and POWER mode. The mode in which the engine is currently
operating is indicated on the EFIS.
The engine generates more power while in POWER mode, but
fuel consumption increases significantly.
POWER mode is engaged when the throttle position is
advanced beyond approximately 97%.
The RV-
12iS is equipped with an “eco stop” which allows the
throttle position to be advanced up to approximately 97% (i.e.
the upper limit of ECO mode). To use the “eco stop”, apply
leftward pressure to the throttle handle while advancing the
throttle. The
throttle’s advance will be stopped by the “eco stop”.
THROTTLE RETURN SPRINGS
– ROTAX 912 ULS ONLY
The strong coil springs attached to the throttle arms of the Bing Carburetors
on Rotax 912 ULS engines serve two purposes:
The primary function of the springs is to assure balanced carburetor
operation. The Rotax 912ULS engine is equipped with dual carburetors, one
serving the right side cylinders, the other serving the left. It is important that
the throttle positions of both carbs remain closely matched to prevent uneven
power pulses (which can result in vibration, power loss, engine wear) on both
sides of the engine. To assure uniform throttle positions, Rotax specifies the
use of semi-rigid throttle cables that rely on the strong throttle-open springs
to offset any slack or free play in these cables.
The throttle arm springs also function to “add power” in the unlikely event of
a broken
throttle cable or throttle mechanism. The constant “Throttle Open”
tension on the throttle cables requires a throttle control mechanism with an adjustable friction device to prevent
“throttle creep.”
The result is that the Rotax 912 ULS throttle requires more operator effort to alter its position than throttles on many
traditional aircraft engines. In an effort to achieve lower throttle friction, throttle arm springs have been supplied
rated at a lower lbs./in tension per displacement than the stock spring supplied with the Rotax engine. Use of these
springs will require a periodic test of the spring functionality as described in the maintenance manual.
FRICTION
CONTROL
FUEL
SHUTOFF
ECO
STOP
THROTTLE
CHOKE
(912ULS
ONLY)
Summary of Contents for RV 12iS
Page 1: ...Revision 4 Date 09 08 20 RV 12iS Flight Training Supplement i FLIGHT TRAINING SUPPLEMENT...
Page 14: ...Revision 4 Date 09 08 20 RV 12iS Flight Training Supplement 4 2...
Page 15: ...Revision 4 Date 09 08 20 RV 12iS Flight Training Supplement 4 3...
Page 50: ...Revision 4 Date 09 08 20 RV 12iS Flight Training Supplement 6 2 ELECTRICAL SWITCHES KNOBS...
Page 56: ...Revision 4 Date 09 08 20 RV 12iS Flight Training Supplement 6 8...
Page 89: ...Revision 4 Date 09 08 20 RV 12iS Flight Training Supplement REAR COVER...
