Lancair Legacy, Pilot'S Operating Handbook And Flight Manual

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VII-12 February 2008
Legacy
VII-13 February 2008
Legacy
this warmed air a power reduction will be noticed due to the less dense air being
supplied to the engine. Upon clearing of the ice the heat should normally be re-
turned to full cold. If a carburetor air temperature probe is installed (downstream
of the throttle valve) the heat can be modu- lated to maintain the fuel/air mixture
at slightly greater than freezing. Conditions prone to carburetor icing are high
humidity air at temperatures of 20°F to 70°F. Since we seldom have humidity
gauges, an indication of humidity should be obtained from the preflight weather
briefing and from the clouds as seen enroute. Ice can be an insidious visitor,
forming slowly, almost imperceptibly slowly or rapidly requiring an equally fast
response to preclude engine stoppage - beware. Carburetor heat operation should
be checked before every flight during your engine run-up just before takeoff. A
noticeable rpm reduction will be experienced with the application of heat while at
the mag check power setting.
Fuel injected engines spray the fuel into the intake manifold or near the intake valve
and are far less prone to form ice in the intake system since there is no temperature
drop due to the fuel vaporization at the throttle valve. These installations however
generally have an equivalent valve termed “alternate air”. This also utilizes an
alternate source of air for the intake system which is somewhat warmed, but is pri-
marily for protection from the formation of ice on the intake air inlet, screen/filter,
or passageways. This valve may be spring loaded such that it opens automatically
upon loss of intake air pressure or simply manually controlled. Know your system
and check its operation often.
Engine Starting
Starting of the Lancair is simple. The aircraft is equipped with an electric starter
which cranks the engine to provide the fIrst of the three basic requirements (air,
fuel, and ignition). Fuel is introduced by priming prior to cranking the engine.
After the engine starts adjust the RPM to approximately 1000 rpm and monitor
the oil pressure. If no oil pressure is indicated within 30 seconds, shut down and
determine the cause. This time may be slightly longer under abnormally cold
conditions or with the improper grade of oil in the engine. Under these conditions
it is highly desirable to wam the engine and its oil prior to starting to minimize
engine wear and ease starting. Very cold temperatures will increase the normal
oil pressure and following starts the engine rpm should be kept at idle or slightly
above until oil pressure starts returning towards normal.