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OPERATING PRINCIPLE
In place of the piston and cylinder of a 
conventional reciprocating engine, the Wankel 
motor has a three-lobe rotor which moves in a 
circular path, while rotating about its own axis, 

THE NSU/WANKEL SYSTEM
Now available in a new and improved 
PI(peripheral inlet) model, its outstanding 
features remain its high specific power output, 
its almost total freedom from vibration, its 
relatively low noise level and its compact 
shape.
This highly successful application of the 
NSU/Wankel System to a power unit of 
miniature proportions, was only made possible 
by the expertise of O.S. research and 
development engineers and by the high levels 
of precision craftsmanship achieved in its 
tooling and manufacture.

within a housing having an epitrochoidal bore - 
i.e. a wide-waisted figure-of-eight 
shape.Planetary rotation is controlled by an 
eccentric shaft, an internally-toothed gear and 
a fixed pinion mounted centrally on the rear 
cover plate. The tips of the rotor are in 
continuous contact with the housing, forming 
three chambers, each of which changes in 
volume, with rotation, to effect suction, 
compression, expansion and exhaust phases, 
as in a four-stroke reciprocating engine. 
Spring-loaded tip seals on the rotor prevent 
gases from passing from one chamber to the 
adjoining one and the rotor uncovers ports, as 
in a two-stroke engine, to control intake and 
exhaust timing.
The engine is fitted with a conventional throttle 
type carburettor that gives smooth and 
progressive control of engine speed from idling 
to full power. It is also supplied with a compact 
matched muffler that very effectively 
attenuates exhaust noise without causing 
undue power loss.

7

Summary of Contents for 49PI

Page 1: ...s instruction manual so as to familiarize yourself with the controls and other features of the engine Keep these instructions in a safe place so that you may readily refer to them whenever necessary It is suggested that any instructions supplied with the aircraft radio control equipment etc are accessible for checking at the same time ROTARY ENGINE 49PI Due to updating and improvement latest produ...

Page 2: ...TRODUCTION BASIC ENGINE PARTS GLOWPLUG MOUNTING THE ENGINE BEFORE STARTING STARTING RUNNING IN Breaking in PRE FLIGHT CHECKING SUBSEQUENT READJUSTMENT ENGINE CARE AND MAINTENANCE GENUINE O S PARTS ACCESSORIES ENGINE THREE VIEW DRAWINGS ENGINE EXPLODED VIEWS ENGINE PARTS LIST CARBURETOR EXPLODED VIEW PARTS LIST 1 ...

Page 3: ...e would respectfully request that these instructions are also passed on to its new owner SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O S ENGINE The advice which follows is grouped under two headings according to the degree of damage or danger which might arise through misuse or neglect WARNINGS NOTES These cover events which might involve serious in extreme circumstances even fatal injury These co...

Page 4: ... head or exhaust header pipe in particular may result in a serious burn Never touch or allow any object to come into contact with the rotating propeller and do not crouch over the engine when it is running A weakened or loose propeller may disintegrate or be thrown off and since propeller tip speeds with powerful engines may exceed 600 feet 180 metres per second it will be understood that such a f...

Page 5: ...aring Such noise is also likely to cause annoyance to others over a wide area Install a top quality propeller of the diameter and pitch specified for the engine and aircraft Locate the propeller on the shaft so that the curved face of the blades faces forward i e in the direction of flight Firmly tighten the propeller nut using the correct size wrench If you remove the glowplug from the engine and...

Page 6: ... wearing of safety glasses is also strongly recommended Discard any propeller which has become split cracked nicked or otherwise rendered unsafe Never attempt to repair such a propeller destroy it Do not modify a propeller in any way unless you are highly experienced in tuning propellers for specialized competition work such as pylon racing Take care that the glow plug clip or battery leads do not...

Page 7: ... sand The propeller may throw such material in your face and eyes and cause injury For their safety keep all onlookers especially small children well back at least 20 feet or 6 meters when preparing your model for flight If you have to carry the model to the take off point with the engine running be especially cautious Keep the propeller pointed away from you and walk well clear of spectators Warn...

Page 8: ...ing having an epitrochoidal bore i e a wide waisted figure of eight shape Planetary rotation is controlled by an eccentric shaft an internally toothed gear and a fixed pinion mounted centrally on the rear cover plate The tips of the rotor are in continuous contact with the housing forming three chambers each of which changes in volume with rotation to effect suction compression expansion and exhau...

Page 9: ...nt Glowplug Drive Hub Spinner Nut Rotor Housing Front Housing BASIC ENGINE PARTS Carefully insert plug with washer fingertight only before final tightening with the correct size plug wrench Installing the glowplug Glow plug Washer 8 ...

Page 10: ...ng events Do not run the engine too lean and do not leave the battery connected while adjusting the needle However plug life can be extended and engine performance maintained by careful use i e Apart from when actually burned out a plug may need to be replaced because it no longer delivers its best performance such as when When to replace the glowplug Filament surface has roughened and turned whit...

Page 11: ... the glowplug on the left i e when viewed from astern The engine should receive a free flow of cooling air Do not obstruct airflow with an oversized spinner If the engine is cowled make sure that the air entering at the front is able to escape easily the outlet area for the cooling air should not be less than the entry area and should preferably be larger MOUNTING THE ENGINE Position the fuel tank...

Page 12: ...might ignite it Do not smoke or allow anyone else to smoke near to it The suitability of the prop depends on the size and weight of the model and type of flying Determine the best size and type after the engine has been run in Check the balance of the propeller before fitting it to the engine Unbalanced propellers cause vibration and loss of power Wooden propellers are to be pre ferred Some nylon ...

Page 13: ...ank Fuel bulb Manual Electric Fuel pumps Resistance coil nichrome wire Adjust applied voltage by changing the position of clip on resistance coil until glowplug element is glowing bright red Battery leads Raise voltage to increase brightness Lower voltage to reduce brightness Warning Very hot Never touch the nichrome wire while the battery is connected 1 5 volt heavy duty dry battery or 2 volt rec...

Page 14: ...prevent entry of foreign matter into the fuel tank Fuel Can Filter Silicone tubing This is required for the connection between the fuel tank and engine Plug wrench Used for tightening glowplug The O S long plug wrench is available as an optional accessory For tightening glowplug 13 ...

Page 15: ...or starting An alternative priming procedure that some users may find preferable when an electric starter is being used is to simply finger choke the intake throttle fully open while turning the prop for six revolutions Now close the throttle to between one quarter and one third open connect glowplug lead and apply electric starter After starting allow the engine to warm up for 5 6 seconds then re...

Page 16: ...will ensure that the engine does not become overheated and damaged during this critical period The break in should be split up into periods of not more than 5 minutes allowing the engine to cool between spells of running After about 30 minutes running time have been accumula ted the needle valve may be gradually closed on each succesive run until continuous full power is being delivered This is wi...

Page 17: ...ls properly set up it should be unnecessary to alter the mixture settings except to make minor adjustments to the Needle Valve occa sionally to take account of variations in climat ic conditions The use of a different fuel however particular ly one containing more or less nitromethane and or a different type or proportion of lubricat ing oil is likely to call for some readjustment of the Needle Va...

Page 18: ...engine with an electric starter for 4 to 5 seconds while the engine is still warm Finally inject some after run oil into the engine Rotate the engine a few times by hand to make sure that it is free and then with an electric starter for 4 to 5 seconds to distribute the oil to all the working parts Do not inject after run oil into the carburetor as this may cause the O ring inside the carburettor t...

Page 19: ... 71531000 71521000 23024009 1 4 28 L 73101000 41651010 O S GENUINE PARTS ACCESSORIES SPINNER NUT EXHAUST PIPE ASSEMBLY LONG PROPELLER NUT SETS SUPER FI LTER NON BUBBLE WEIGHT LONG SOCKET WRENCH WITH PLUG GRIP 18 ...

Page 20: ...4 97 cc 0 303cu in 2 500 18 000 r p m 1 27bhp 17 000 r p m 335g 11 8oz THREE VIEW DRAWING Displacement Bore Stroke Practical R P M Power output Weight SPECIFICATIONS Dimensions mm 19 ...

Page 21: ...p 1 M 3 24 C M2 6 8 6 M 3 24 M 3 23 9pcs N 3 5 5 C M3 10 C M2 6 8 C M2 6 5 EXPLODED VIEW Type of screw C Cap Screw F Flat Head Screw N Round Head Screw S Set Screw 20 o ...

Page 22: ...r Type 49PI RN Rear Bearing Thrust Washer 2pcs Seal Spring 6pcs Rotor Housing Assembly Eccentric Shaft Front Bearing Retainer Crankshaft Ball Bearing F Front Housing Housing Assembly Screw Set Shaft Spacer Woodruff Key Drive Hub Spinner Nut Description Code No Rotor Gear Retaining Screw Engine Retaining Screw 3pcs Engine Mount Rear Cover Retaining Screw 6pcs Rear Cover Rear Counter Weight Retainin...

Page 23: ...Gasket Ratchet Spring Nozzle Assembly Needle Needle Valve Assembly Carburettor Body Throttle Stop Screw Carburettor Rotor Throttle Lever Needle Valve Holder Assembly No Description Code No Specifications are subject to alteration for improvement without notice Type of screw C Cap Screw F Flat Head Screw N Round Head Screw S Set Screw CARBURETOR EXPLODED VIEW PARTS LIST Throttle Lever Retaining Scr...

Page 24: ...eserved Printed in Japan 110100 TEL 06 6702 0225 FAX 06 6704 2722 6 15 3 Chome Imagawa Higashisumiyoshi ku Osaka 546 0003 Japan URL http www os engines co jp U N E Q U A LLED QUALITY PRECISION PERFOR M A N C E E S T A BLISHING THE STANDARDS OF EXCELLE N C E ...

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