-4-
11. 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) Open the main needle 1 turn from full close.
(3) Power on the ignition system.
(4) 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.)
(5) Apply the starter to the prop and activate for about 5 seconds to start the engine.
12. 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.
Thereʼs no need to adjust the slow needle at this step as itʼs 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 11 and run it for 10 sec in low speed.
Fig.8
From
Breather nipple
Exhaust
Muffler outlet
Aluminum pipe
From
Breather
nipple
Tissue
Small
case
To outside
fuselage
Baffle
Cowling
Cool air
9. Engine mounting, muffler attachment, and breather waste disposal
Inverted installation of the engine is recommended for lubrication however normal or side mount-
ing are possible.
Either way, make sure to use SAITO standard engine mount attached. As a gas-engine generates much
heat, SAITO standard mount is designed to release heat effectively and vibration as well. Any other
mount which is not enough robust and heat release, might cause troubles by vibration and heat.
Make the firewall robust enough because this part has to endure vibration and torque caused by
prop rotation. However, a test bench made of steel that doesnʼt absorb any vibration can concen-
trate vibration on the engine and engine mount and there is possibility to break the engine
mount in a worst case. Especially with a low load prop, engine tend to generate large vibration that
is very dangerous.
Therefore please use a wooden bench robust enough, never use a bench made of steel.
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 and muffler, the cowling should be devised.
Also make the air flow outlet larger than the inlet. Building some baffles inside the cowling appropri-
ately will enhance the cooling efficiency. Insufficient cooling may cause engine trouble such as
overheat or muffler looseness.
The muffler should be securely tightened up using two spanners.(Adhesives, such as a screw lock
agent, are effective against looseness and leakage.)
Muffler right angle manifold (Option) allows muffler to set to the position as you like. Regarding the
treatment of the muffler, please refer to Chapter 14.
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.
And one of the effective way of disposal is to set a brief filter made by a small case and a tissue
inside as the Fig.7 shows.
(Please be noted that it might be too much to accumulate for the small case depending on size of the engine.)
10. 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 immo-
bile.)
(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 100-200cc 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 thereʼre no leakage at all the connections.)
(6) For fuel, prepare a mixed gasoline with a volume ratio of “gasoline : oil” = “20 : 1” or richer than that.
(7) Prepare a well balanced APC13”x 7” (Approx 8800rpm).
(8) Prepare an electric starter, also attach a spinner. (This is the standard way of starting engine.)
(9) As it is difficult to judge clearly the peak condition of 4-stroke engines, prepare a tachometer to prevent over-throttling or overheat.
(10) Prepare a fuel pump for gasoline. (Be sure to attach a filter to the intake port. It is available as an option.)
(11) In order to check discharge of the breather, attach a heat-proof and gasoline-proof transparent tube.
(12) Prepare a thin (-) screw driver for carb adjustment.
Caution: If thereʼs 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.
Note: Please tighten up the prop regularly at least once in ten flights. Especially for a wooden prop, it tends to be
compressed so that the nuts are rather easy to be loosen so please confirm carefully that the nuts are tightened adequately.
