User Manual
-4-
Cut out
Fig.8
From
Breather nipple
Exhaust
Muffler outlet
Aluminum pipe
Baffle
Cowling
Cool air
Fig.9
8. Engine mounting, muffler attachment, and breather waste disposal
As the carb comes out from back of the firewall, cut out the firewall as adequate size.
Make the firewall robust enough because this part has to endure vibration and torque caused by
prop rotation. Especially with a low load prop, engine tend to generate large vibration that is
very dangerous.
It is preferable to apply some adhesives (such as screw lock) on the tip of each cap screw to
avoid looseness when you install the engine.
To ensure that cooling wind passes through the engine, the cowling should be devised. Also
make the air flow outlet larger than the inlet.
Building some baffles inside the cowling to flow the cool air through the surface of the engine
effectively that is highly recommended. Insufficient cooling may cause engine trouble such as
overheat, percolation, or muffler looseness.
The mufflers should be securely inserted deeply into the adopter and tightened up using
spanners. (Adhesives, such as a screw lock agent, are effective against looseness and leakage.)
Make sure to fix the outlet of the flexible mufflers outside of the cowling using the bracket
included.
For breather treatment, attach the gasoline proof tube to the breather nipple and fix the other
side of the tube on outside of the cowling. Fix a thin aluminum pipe to the outlet of the tube
and bind it to the muffler outlet to diffuse the hot air together with exhaust gas into the air.
9. Preparation for engine start (assuming break-in)
(1) Mount the engine on a robust and parallelized test bench or on the fuselage. (Either way, the
engine should be fixed and immobile.)
(2) Check whether the throttle valve becomes fully closed and opened certainly.
(3) Check whether each code of the ignition system is connected certainly.
(4) Use about 1000cc tank for the test bench, or a tank which has appropriate capacity for the
fuselage.
(5) For piping, only connecting the carburetor with the tank is needed.(Make sure there's no leakage
at all the connections.) In order to check discharge of the breather, attach a heat-proof and
gasoline-proof transparent tube to the breather nipple.
(6) For fuel, prepare a mixed gasoline with a volume ratio of gasoline : oil = 1520 : 1.
(7) Prepare a well balanced 17x 8 prop (APC is recommended). As it should be started with a electric
starter, the prop can be attached as you prefer.
(8) To start with an electric starter, attach a spinner to the end of the shaft.
(9) As it is difficult to judge clearly the peak condition of 4-stroke engines, prepare a tachometer to
prevent over-throttling or overheat. You can also use digital tachometer (Option).
(10) Prepare a fuel pump for gasoline. (Be sure to attach a filter to the intake port. It is available as an
option.)
Caution: If theres anyone stand in front of the engine, be sure to have them move behind the airplane before starting the
engine. Also keep in mind that the exhaust smoke is harmful for health. Keep away one of your arm holding the airplane away
from the prop. Once the engine starts, move behind the airplane. Make needle adjustment or other control from rear. If the
airplane cannot be fixed, ask your assistant to hold the airplane for safety.
10. Method of starting the engine
The following is the procedure with the engine mounted on the airplane. Fill up the tank with fuel.
(Be sure to turn off the switch of the ignition system until just before trying to start up the engine.)
(1) After confirm that the throttle stick is located at the full-close position, turn on the transmitter switch. Then turn on the receiver
switch to check throttle valve and other operation. After that, fully close the throttle valve.
(2) Power on the ignition system.
(3) Open the throttle valve about 1/4 from the full close position by using the throttle stick. (Starting with excessively opened
throttle is dangerous since the airplane jumps forward.)
(4) Apply the starter to the prop and activate for about 5 seconds to start the engine.
11. Break-in
As Break-in is an important procedure to pull out the maximum performance of the engine, it must be cautiously done.
The purpose of break-in is initial lubrication and adjusting of the mobile parts under the condition with rich fuel mixture.
Never make the fuel mixture lean. Lean fuel mixture could cause seizure even during idling or low speed running.
Theres no need to adjust the slow needle at this step as its already set adequately, so you will adjust only the main needle
during break-in.
Procedure;
(1) After filling up the fuel tank, start the engine as described in the above Chapter 10 and run it for 10 sec in low speed.
(2) Opening the main needle gradually and open the throttle valve to full open. If rich air-fuel mixture cant be obtained, open
the main needle additionally. Then continue running for 2 tanks.
During this initial operation, contact of each part inside the engine will be matched. So make the fuel mixture rich as much
as the engine doesnt stop. Do not care about running smoothness at this step.
(3) Refill the tank and run the engine at full throttle for 1 tank.
(4) Refill the tank and run the engine. Open the throttle full and turn the main needle to achieve peak and less speed (richer)
alternately about 5 times. And then maintain the peak condition long gradually. When it gets stable, then operate the
throttle stick to vary slow speed to high speed several times to check the response. After that run it for 1 tank keeping high
speed. When it comes to run smoothly at peak, break-in on the ground is completed.
(5) Then tighten up the whole screws and adjust the tappet gap referring to the next chapter. After that, fly it for about 20
times in rich condition to finish break-in in the air.Also after break-in, please run the engine in rich condition as long as it
doesnt affect to the flight.