User Manual

ManualsBrandsOS Engines ManualsAirplanesFF-320 Pegasus 4-Cylinder Ringed 4-Stroke Engine

18x10-12, 20x8-10, 22x8

PROPELLER

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.

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:

Type

Size

(

DxP

)

Sport/Scale

PROPELLER & SPINNER ATTACHMENT

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:

To be equal

Ream to 12mm dia.

Fig. 8

Use a propeller that has a

hub of more than 40mm dia.

Fig. 9

Ream the propeller shaft hole to 12mm 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. (not supplied).

Add the special tapered and slotted locknut and secure

with a 12mm wrench while holding the prop nut with the

14mm wrench. (not supplied).

Propeller washer

Propeller nut

Locknut

Drive hub

Back-plate of spinner

The Safety Propeller Locknut can

be used provided that the width is

between 21.5mm and 26mm.

Fig. 10

Make a habit of always checking the tightness of the

propeller before starting the engine. Remember that,

especially with wooden propellers, there is a tendency for

the material to shrink, or for it to be reduced by the

serrated face of the drive hub. Retighten the propeller nut

if necessary after loosening the Safety Propeller Locknut.

The locknut should be tightened firmly after retightening

the propeller nut.

NOTE: