RUNNING AND MAINTENANCE INSTRUCTIONS
PLEASE READ THESE INTRUCTIONS BEFORE RUNNING THE ENGINE
Progress Aero Works accept no liability for commercial loss or damage, accident, injury or fatality arising from the use of PAW products.
It is the responsibility of the user to use PAW products in a properly safe manner.
P.A.W. Engines have been designed to give modellers all over the world high-performance motors of robust construction and with good life expectancy.
They have been introduced to meet the ever growing demand for such engines which so far have always been an "experts only" engine because of their high price. We have now perfected a range of engines which are within the reach of all modellers, costing but little more than the mass-produced article, yet offering so much more in power and life.
Each P.A.W. Engine is tested so that all motors sent out are up to the specification indicated. Every engine is backed by our two months guarantee.
1. MOUNTING THE ENGINE
For running-in you will need to mount the motor in a test stand, or bolt the engine to a piece of wood, which can then be held firmly in a vice. Never hold the engine itself in a vice, as this distorts the crankcase, and leads to serious trouble.
2. RUNNING INSTRUCTIONS
Before leaving the works, all P.A.W. Engines are run up to 10,000 r.p.m. and require a minimum of running-in. However, this is the time to become familiar with the running and handling characteristics of your motor. Choose your propeller from the list and run the engines for five-minute spells, allowing it to cool down between runs. A total running time of one hour should be ample.
3. FITTING YOUR PROPELLER
Fit your propeller to the engine so that, as the piston travels upwards, closing the exhaust ports and beginning to compress the gas, the propeller is in the horizontal position. This will give you a good flick as you bring your right hand from right to left smartly, touching the propeller as near to the hub as possible, to get maximum impetus. Your finger passes over the crankshaft. A very smart flick is essential for good starting, achieved by a very loose wristed "whiplash" action, not a stiff movement from the shoulder. Your left hand will be free to prime the engine by placing your left forefinger over the venturi (air intake) for one turn, or to adjust the compression lever.
N.B. Direction of rotation of the engine, as seen from the front, is anti-clockwise.
Fuel tanks are not supplied by us, as there are many different shapes, sizes and types. We or your Model Shop will gladly advise you.
4. FUEL (also see 13)
Never allow fuel to stand open, to be mixed, or to be left in a plastic container for longer than 2 hours, as it can ruin the fuel. Keep fuel in a tightly closed metal can. If you prefer to use commercial fuels we strongly recommend the use of Model Technics D1000 Easy Start fuel.
Use the fuel recommended, or if using some fuels commercially supplied, use Needle Valve settings approximately one full turn further closed than the normal 2-3 turn open, or add 10% Medicinal Castor Oil especially during running-in period.
(a) Fuel level in tank during starting procedure MUST NOT BE HIGHER than in the same horizontal plane as jet. A little lower (up to 1cm) is alright. This means that when starting engines in model, especially C/L models, it will be necessary to hold the model in an attitude that this condition is observed, i.e. generally with the tail and outboard wing slightly down, say 10 to 15 degrees.
(b) Draw fuel to jet by choked flicks of propeller (3). Clear plastic tubing is a help here. When fuel reaches jet, ONE, AT MOST TWO more flicks to prime. You are now ready to actually start the engine, and it will normally be achieved with two or three correctly and smartly executed flicks as described in section 3. If engine fails to start, but flicks over easily, screw in compression screw 1/8 turn at a time, until engine fires. If no result and engine very hard to flick over, re-prime as (b) above. If fuel is obviously present e.g. wet exhaust output, and engine does not respond, it is flooded. Keep on as much compression (screwed in) as will allow flicking over. Flick/Adjust compression up/down as necessary until engine fires. Make sure fuel level in tank is as described above at (a). When started, close needle to 1.5 turns approximately, and unscrew compression to achieve maximum power. Generally, needle will need to be closed to increase speed. If labouring results, unscrew compression. If missing results, screw in compression.
6. HOT RE-STARTS
Hot re-starts are the same procedure, BUT from the last best hot running setting (max. speed under load) it will be found necessary to UNSCREW the compression lever 1/4 to 1/2 turn first. This will become unnecessary when the engine is fully run in, and a really good flick is learnt.
COLD START = HOT RUNNING SETTING PLUS 1/4 TO 3/4 TURN IN OF COMP. SCREW.
HOT RE-START = HOT RUNNING SETTING LESS 1/4 TO 1/2 TURN OUT OF COMP. SCREW.
Engines are all tested and hand started before dispatch. If you lose the original setting of the compression screw (engines are dispatched with compression set at hot running setting), prime the engines as (3) then flick to start, meanwhile with the free hand screwing IN compression 1/8 turn between flicks until the engine fires. You are then within 1/4 turn either way of the cold start setting; proceed as (5).
7. INSTALLATION INSTRUCTIONS
Suction feed should be used whenever possible, although for some purposes, where it is difficult to choke the engines for starting, as in a close-cowled model, gravity feed can be used. This type of feed is best for inverted installation, making priming and choking virtually unnecessary.
Engine bearers should be substantial; not less than 8mm square for the 55 up to 16mm square for the 60 when using prime hardwood bearers. Softwood bearers should be enlarged pro rata. Always support bearers to body sides for extra rigidity.
8. TANK POSITION (Control Line)
Tanks should be positioned horizontally on the centre line of the JET, except when using an inverted mounted motor, when the tank should be displaced by 3mm. downwards. This allows for the effects of fuel accumulation in the cylinder during upright and inverted flight, inside and outside loops, and contributes greatly to the smooth running of the engine. This does NOT apply to side-mounted engines.
In the plan view, the tank should be mounted on the centre line of the JET; for constructional reasons a displacement of 6mm. either way is permissible, provided that the tank is not more than 45mm. wide.
9. TANK POSITION (Free Flight)
Free flight tanks should be mounted as close to the engine as possible, especially in high-performance duration models having a quick acceleration from launch. An excellent position to mount the tank in a side-mounted free flight installation is on the bearers opposite to the air intake, leading the fuel pipe back to the cut-out mechanism, and forward again to the jet.
10. ESTABLISHING THE SETTINGS IN THE MODEL
If in flight, your engine misfires continually, it is under-compressed. Over-compression is readily recognised by hard running and a serious lack of power.
If your motor lays a vapour trail, and revs up and down it is set too rich, and the needle should be closed further. If it misfires at the beginning of the flight, and continues running in that manner to the point where the engine slows down and stops, it means that the needle setting is too lean, and the needle requires to be opened further. This will also be confirmed by the engine being hot, and difficult to re-start. This is most important in control-line flying, but also applies to long free flight runs, such as in radio controlled flight.
Adjustment to the needle and compression should be made 1/8 turn at a time, until the correct setting is established.
Too lean a setting, over compression, or too "hot" a fuel will also cause hard running particularly on hot days.
R/C Settings:- start engine on full throttle, set to maximum r.p.m., allow to warm up, then adjust slow running to correct safe speed.
Airscrew sizes for running-in and all uses. These are not intended to be instructions, but only a very general guide as to the general sizes of airscrews required. Airscrews vary greatly, but it is a good idea, before using a new one, to measure it exactly, and to balance it on a knife blade, correcting in-balance. very large diameter airscrews should be avoided as far as possible, as these impose severe strain on shaft, connecting rod and gudgeon pin.
12. RECOMMENDED AIRSCREWS
|MAX||RUN IN. ON||MIN|
13. FUELS FOR BEST RESULTS
|Commercial||Running in||Fully run in||TBR only|
14. HOME MIXED FUELS (mix oil-ether-paraffin and additive)
|Med. Castor Oil||Paraffin||Ether||Iso Propyl Nitrate or similar ignition improver|
|Fully run in||25%||40%||33%||2%|
|Fully run in - BR Models||20%||48%||30%||2%|
|Fully run in - TBR only (Racing and Speed)||15%||50%||32-33%||2-3%|
15. AFTER USE (All Engines)
Run to full operating temperature, stop by cutting fuel supply, NEVER by throttle or choking. Leave piston at BOTTOM of stroke for three days to allow escape of acid combustion residues. For longer storage, inject oil into inlet and flick over a few times. Discard any fuel that has been in plastic container - ALWAYS store in well sealed metal can.
Minimal maintenance is required, if you adhere to these instructions. Externally, an occasional check of the tightness of the headscrews is all that is necessary. This is particularly so in the early stages during running-in, but great care is advised to use a good fitting screwdriver, and not to over-tighten the screws. Engines used regularly at speeds over 15000 r.p.m. must have con rods checked every 3-5 hours and replaced if wear is apparent. This precaution is advised after crash or similar violent stopping.
If you should be so unfortunate as to "bury" your motor in soft soil, sand etc., send it to us with a Service Charge to be cleaned; unless you feel thoroughly competent to tackle the work yourself, and have the appropriate equipment.
Always check the pitch of your propeller after such an accident.
It is emphasised that parts removed from any engine must be marked in order that they may be replaced in exactly the same position.
No matter how much care is taken, however, the dismantling of mated parts invariably results in some degree of re-mating and consequent wear, and it is therefore never advisable, and should be done only when absolutely necessary. NEVER dismantle an engine in order to "decarbonise" it. Excess carbon is ejected by the engine automatically as it accumulates.
For spares and service quote tel/fax (+44) (0)1625 423891 or enclose a stamped addressed envelope with your enquiry.
P.A.W. Engines are guaranteed for two months from the date of purchase. If you adhere to the instructions, we will service your motor, should that become necessary, immediately, subject only to the prepayment of a return postage and handling fee of £4.00.
LIMITATION OF GUARANTEE
All motors are guaranteed against defects in materials and workmanship for a period of two months from the date of purchase. Dismantling, the use of abrasives of any kind, and the entry of instruments and of foreign matter via exhaust or intake shall be deemed to be a contravention of the terms of the guarantee, and in such circumstance, any repairs free of charge will be at our sole discretion. Crash damage and Accident damage is not covered by guarantee; repairs of such damage may be charged at the Service charge plus the replacement parts. Fair wear and tear, such as the bore of the motor, is guaranteed for two months; thereafter the appropriate fee will be charged.