involves the use of spanwise spoiler on the wings. In
all cases be sure to secure such devices in a manner that
precludes their coming free and causing damage that
they are designed to preclude.
ENGINES
General Information
The Lancair IV is generally fitted with a Conti-
nental engine of 300-350 HP and a constant speed pro-
peller. These engines are FAA certified aircraft power-
plants of 6 cylinder opposed, air cooled design provided
with magnetos for ignition, a starter and alternator.
Since this is your only source of power for flight it only
makes sense to give it that extra bit of care so that it can
take care of you hour after hour.
Engine Controls
All engines are equipped with dual magnetos
which are shorted in the OFF position, generally one
mag fires the lower cylinder plugs, the other fires the
upper plugs however other firing techniques are also
used. It is mandatory that operation of the mags be
checked prior to each flight. An RPM drop of approx-
imately 100 RPM will be experienced from moderate
power settings (1700 RPM) when operating on only
one magneto. The engine speed variation between left
and right mags should not exceed 50 RPM. Operation
on either magneto should be smooth or the flight should
be aborted and the problem resolved. The propeller
should never be rotated on the ground without assuming
that the mags are “hot” and the OFF position should be
checked for operation by briefly switching the mags to
the OFF position while at idle RPM prior to each shut
-
down. Normal shutdown then is accomplished by putting the
mixture control in the cut-off position and running dry of fuel.
All engines utilize a throttle to control the airflow into
the engine, restricting it with a butterfly (throttle) valve in the
intake system. Full throttle allows unrestricted airflow into the
engine.
Controllable propeller engines have a prop control which
controls the engine RPM. Maximum engine RPM at full throttle
settings are required for takeoff. Cruise power settings reduce
engine RPM commensurate with manifold pressure.
Fuel/air ratio is also controlled to compensate for the
large air density changes due to operation at altitude. This
mixture
control reduces the fuel quantity provided to the engine
from “Rich” to “Lean” and is varied by fuel flow versus pow-
er setting curves from the engine handbook to leaning based
on measured engine exhaust gas temperatures or Turbine Inlet
Temperatures. The latter provides maximum fuel economy and
extended engine life. Takeoff is at full rich at all times except
for some high altitude and/or hot day conditions.
Engine Instrumentation
Oil, the life blood on an engine is of prime concern. Oil
quantity is only measurable prior to flight and is a mandatory
item in the checklist. Perhaps the most important measurement
during operation is oil pressure. Oil temperature is another valu
-
able measurement. Proper oil type and viscosity per the engine
manufacturer’s recommendation must be used. This is particu-
larly important for the breaking in of a new engine. This phase
of an engine’s (or a cylinder’s) life requires a mineral oil (non
detergent) and the use of high and variable power settings for the
first few hours of operation. For specifics see the manufacturer’s
engine operating manual for recommendations for
your
engine.
RPM.
Controllable propellers are adjusted ( by changing pitch
of the blades) to keep the engine RPM at the desired setting.
