YS 50ST Operator's Manual

OPERATOR'S MANUAL
(Part No.YS0030)
50ST
Fig,1
Main Needle Valve
42.3
Low Speed Needle
37
FEATURES
The YS 50ST Engine features the patented YS regulated
fuel system for positive fuel flow during all types of flight
conditions.
Factory authorized parts and service available worldwide.
CAUTIONS
1. Take care not to touch the engine immediately after shut-
down to avoid painful burns.
2. Do not attempt to fly with engine problems as it can be
dangerous. Fix the problem prior to flying.
3. When starting the engine, do not use full throttle but set
throttle to low speed before applying the glow driver.
4. This engine is intended for helicopter use. Aircraft conver-
sion parts are available from our service department.
5. This engine is intended for use by experienced modelers
only. If you are not properly trained to operate this engine,
please get assistance from a skilled modeler.
6. The user is responsible for operating this engine in a safe
safe manner.
SPECIFICATION
Bore
Stroke
Displacement
Weight
Practical rpm
17.5
37
Fuel Filter
Tube (B)
Check Valve Tube (A)
Tube (C) : 35mm
INSTALLATION
1. The fuel lines should be connected to the fuel tank as
shown in the above diagram. Be careful to install the
check valve in the correct direction. Since the tank is
exposed to high pressures, be sure that all connections
are secure to prevent pressure leakage.
2. Since the engine is sensitive to dirt in the fuel, a fuel filter
must be used.
3. Tube (C) should be set exactly at 35mm between the
engine and the check valve.
4. The check valve is designed exclusively for the 50ST.
Use only YS factory parts for replacement.
MUFFLER
1. Use an expansion chamber muffler intended for 50 size
helicopter engines. If there is a fuel tank pressure fitting
on the muffler you choose, plug it, as it is not necessary
to use muffler pressure with the YS system.
2. Please note that the use of tuned pipes and tuned muffler
systems can interfere with the operation of the regulator
system and result in poor engine performance.
22,0mm
21,5mm
8,17cc
398g
2,000-20,000rpm
HIGH SPEED ADJUSTMENT
High speed is also adjusted with the main needle valve.
Turning the needle valve clockwise will lean the fuel mixture,
and counter-clockwise will richen the fuel mixture.
Adjust carefully as this setting will also affect the hover ad-
justment.
THROTTLE LINKAGE
Set the throttle stick on the transmitter at the center, and
adjust the linkage to put the mark on the carb body and the
mark on the throttle barrel in line. Hovering should take place
with the throttle stick near the center position if the linkage
ratio is properly set. If the ratio is incorrect, the throttle bar-
rel will be too far open at the center position on the stick and
hovering will commence at a lower stick position.
Fig.2
Hover 40%
Low Speed 0%
B
A
High Speed 100%
BREAK-IN
It is not necessary to mount this engine on a test stand for
break-in. However, the engine should be adjusted slightly on
the rich setting for the first few flights to ensure proper break-
in. Always use a good quality fuel which contains 30% nitro
and an oil content of 20-30%.
GLOW PLIG
1. We have found that the glow plugs listed below will give
the best engine performance;
YS #2
OS #8
Enya #3
2. Replace the glow plug when idling or top end performance
decreases.
IMPORTANT!
Silicone rubber is used in many parts of the YS Engine. Use
only glow fuel for cleaning. Gasoline or other solvents will
damage silicone if used.