O.S. engine GT120THU, Instruction Manual

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Note 1: The engine outputs 70 – 80% power at a half throttle position. Adjust the throttle stick position of
transmitter at around neutral for hovering using throttle curve and pitch curve setting functions.
Note 2: The needle adjustment of the engine in aircraft is closely related to the adjustment of throttle
curve, pitch curve, and governor functions of transmitter. So the total combination of these adjustments is
important.
Note 3: Applying spark plug ignition system to the engine, you can see rich adjustment symptoms relatively
easily and the engine hardly stalls because of stable ignition timing, on the contrary, it is hard to notice lean
adjustment and the engine sometimes stalls and overheats, so always start the adjustment with the needles
on rich side.
19. INSPECTIONS BEFORE FLIGHT
Check the following items after starting and warming up the engine.
GT120THU inspection contents
items contents Inspection Method
idling
Check if the engine runs stable at idling. hearing/ using
tachometer
response
Move the throttle stick up and down during hovering to see if the
aircraft responses and if the speed of engine goes up and down. Visual /hearing
inspection
Engine stop
switch Check if the engine stops switch works.
Visual inspection
ignitor switch
Check whether the engine stops when the ignitor switch is turned
off.
Visual inspection
noise Check if you hear unusual noise. Hearing the sounds
smell Check if you smell abnormal odor. Smell the whole engine
radio control
system
Check if all the equipment work correctly when the engine is
running. (do the distance test and also see if it is working
normally during pirouetting)
visual inspection
Check and follow the instruction of UAV for inspection before flight.
20. FLIGHT
(1) Be prepared for unexpected troubles such as engine stall during flight.
(2) Using the engine management system ‘EM-100’, which is sold as an option by us, is recommended for
monitoring the engine speed, temperature, fuel level, the power supply voltage of igniter by the telemetry
function during flight.
(3) Cooling is more vitally important to gasoline engines than to a glow engines. If overheating symptoms
(loss of power at full throttle or the stick position of throttle goes up when hovering) are observed during
flight, immediately stop flying and carry out the following measures.
① Adjust the slow needle and high needle to make the air/fuel mixture as rich as possible within the range
you can continue flying.
② Set the throttle curve or pitch curve to make the overall engine rpm going up.
③ Prevent the air leakage from a cooling shroud if the engine is equipped with it.
④ Enlarge the cooling fan size.
(4) When an interval between two flights is short and the engine is still hot, although the overheating
symptoms could not be observed right after the first flight, the high temperature created by the former
flight can be transmitted all over the engine before the next flight, so the engine might show overheating
symptoms during the next flight. In this case, leave the engine until it is fully cooled down (in hot weather,
it may take more than one hour.) or run the engine for 4 to 5 minutes at idling.
21. INSPECTIONS AND TIGHTENING SCREWS AFTER THE FIRST FLIGHT
Check the following after the first flight of mounting the engine in an aircraft
(1) Tighten the screws of silencer again