O.S. Engines FS-120S-E - Manual (Page 5)

8
NEEDLE-VALVE EXTENSION
The needle-valve supplied with this engine is designed to
accept an extension so that, when the engine is enclosed in a
cowling, the needle-valve may be adjusted from the outside.
An L-shaped rod, of appropriate length, may be inserted in the
needle-valve knob center hole and secured by tightening the
set-screw with a 1.5mm Allen key.
THROTTLE LINKAGE
Before connecting the throttle to its servo, make sure that the
throttle arm and linkage safely clear any adjacent part of the
airframe structure, etc., as the throttle is opened and closed.
Connect the linkage so that the throttle is fully closed when
the transmitter throttle stick and its trim lever are at their
lowest settings and fully open when the throttle stick is in its
fully-open position..
Carefully align the appropriate holes in the throttle arm and
servo horn so that they move symmetrically and smoothly
through their full travel.
Install these in the following sequence.
Screw the header pipe into the cylinder head until it " bottoms
", then unscrew sufficiently to achieve the desired exhaust
angle and tighten the locknut securely with a 17mm wrench.
Screw the silencer onto the outer end of the header pipe and
tighten the other locknut.
The application of a heatproof silicone sealant to the threads of
the exhaust system is recommended to reduce the risk of joints
loosening and the leakage of exhaust gases and oil residue.
EXHAUST HEADER PIPE & SILENCER
Reminder:
Model engines generate considerable heat and contact
with the header pipe or silencer may result in a serious
burn.
If you need to tighten the silencer joints, which may
loosen when they are hot, use a thick folded cloth for
protection.
9
The choice of propeller depends on the design and weight of
the aircraft and on the type of flying in which you will be
engaged. Determine the best size and type after practical
experimentation.
As a starting point, refer to the props listed in the
accompanying table.
Slightly larger, or even slightly smaller, props than those shown
in the table may be used, but remember that propeller noise will
increase if blade tip velocity is raised, due to higher rpm or if a
larger-diameter / lower-pitch prop is used.
PROPELLERS
Type Size (DxP)
Stunt planes 13x11-12, 14x10-11, 15x8, 16x6-7
15x8, 16x6-7, 18x5-6 Scale models
Make sure that the propeller is well balanced. An
unbalanced propeller and / or spinner can cause serious
vibration which may weaken parts of the airframe or
affect the safety of the radio-control system.
DO NOT forget the WARNINGS and NOTES on propeller
and spinner safety given on pages 2,3 and 4.
Warning:
PROPELLER & SPINNER ATTACHMENT
Ream the propeller shaft hole to 8.0mm bore with an
appropriate reamer, checking that the hole is exactly
centered.
Install the prop to the engine shaft, followed by the retaining
washer and prop nut and tighten firmly with a 17mm
wrench.
There is a risk, particularly
with powerful four-stroke
engines, of the propeller flying
off if the prop nut loosens due
to detonation ("knocking") in
the combustion chamber when
the engine is operated too
lean, or under an excessively
heavy load.
Obviously, this can be very hazardous. To eliminate such
dangers, the O.S. Safety Locknut Assembly was devised.
Install this as follows:
Lock Nut
Propeller Washer
Propeller Nut
1.
2.
3. Add the special tapered and slotted locknut and secure
with a 14mm wrench while holding the prop nut with the
17mm wrench.