| When I first started power model aircraft flying back in | | | | impractable as the tank has a larger capacity than the |
| the1950s we only had the ic engine generally | | | | bulb filling it. In this case by far the most economic way |
| available,items did appear in the model press from time | | | | to charge the motor is to use the bulk adapter that fits |
| to time in the 1960s about the use of CO2 motors, | | | | onto a `Sodastream' cylinder. These are generally |
| Unfortunately ic engines had a few drawbacks mainly | | | | available in some form worldwide, but do make sure if |
| in the fact they where noisy, there where no silencers | | | | you use a non `Sodastream' cylinder that the pressure |
| for them in those days and as control line flying was in | | | | release valve is on the side of the cylinder and NOT |
| its heyday many complaints about noise started to roll | | | | built into the head valve. |
| in, causing the loss of several flying sites,manufactures | | | | In countries where the `Sodastream' cylinders are not |
| started to produce silencers for many of the bigger | | | | available it is often possible to get 12gm bulbs, usually |
| engines and there where attempts to produce early | | | | used on airguns. In order to use this size of bulb it will |
| electric powered planes, The drawback being these | | | | be necessary to use the deluxe Gasparin charger |
| proved very heavy due to batteries, the size of the | | | | which takes either 8 or 12gm bulbs. |
| motor and the radio gear at the time, | | | | In the UK the `Sodastream' cylinder can be obtained |
| A few CO2 motors had started to appear in the UK | | | | from Boots, Tesco etc, it is only necessary to |
| about this time, Bill Brown in the USA had built he's first | | | | purchase the cylinder once, from then on take the |
| CO2 engine that ran in 1942, apart from The American | | | | empty one back and exchange for a filled one for less |
| Brown the English Shark ,Telco, and the Czech | | | | than the cost of a box of bulbs. Each cylinder contains |
| Modela, became available,and until around the early | | | | 250 gms of gas and can last for ages. Installation of |
| 90s this is how things remained, | | | | C02 motors is quite simple, the tube from the motor to |
| Enter Stefan Gasparin. Until the first 'Interscale' in | | | | the tank can be gently bent to almost any shape |
| Nottingham in 1991, this name was known only to a | | | | required, in the case of Gasparin tube, it can be wound |
| very few people outside of the model fraternity in the | | | | round a pencil to take up unwanted slack. The only rule |
| then Czechoslovakia for whom Stefan made a very | | | | to bear in mind is that the tank must not be mounted |
| few tiny motors for his friends. | | | | more than 45¡ off vertical. It makes no difference |
| The advent of the Velvet revolution enabled him to | | | | to the motor which way up its installed. |
| consider selling his motors to the west and with this in | | | | Filling the tank can be done in two ways. With the filler |
| mind he got together with a small firm which made | | | | nozzle of the motor facing down and the charger |
| instruments for full size aircraft (mostly Russian, this | | | | nozzle up, a `gas' charge is made, this is used for |
| company at that time was suffering from a sudden | | | | trimming and flight testing and also, in conditions of very |
| drop in orders) the idea being for the factory to mass | | | | high humidity. This is to prevent very rapid burning off |
| produce a new design of motor for him. | | | | of the gas which can lead to freezing of the motor |
| At Interscale, Gasparin motors were shown by the | | | | cylinder and hence very poor performance. |
| editor of the Czech model magazine, Otakar Saffek, | | | | The other way to charge is a `liquid' charge. This is |
| also an international F.A.I. judge, to a stunned group of | | | | with the charger facing down and the filler nozzle from |
| modellers who couldn't believe a model airplane could | | | | the motor facing up. Liquid gas is introduced into the |
| fit into a 2oz tobacco tin, let alone have a working | | | | tank and takes longer to burn off than a gas charge |
| motor fitted to it that actually worked. | | | | resulting in much longer motor runs. Beware! It is |
| So today there is now an opportunity to build quite a | | | | possible, if the pin on the piston is lifting the ball in the |
| variety of small, light scale, sport, competition model | | | | head valve at the time of charging, that liquid gas can |
| aircraft, either for free flight or RC, indoor & | | | | get into the cylinder. If this happens and you swing the |
| outdoor. You name it. A safe, clean, and satisfying | | | | prop, the result is a ruined piston ring which will have |
| way to fly. The power produced for their size is | | | | been frozen to the cylinder wall by the sub zero gas. |
| astonishing. | | | | Always make sure that the piston is not at the top of |
| A word about how they work. The CO2 and steam | | | | its travel before filling the tank. |
| engine work on the same principal. They are | | | | Should you be unlucky and freeze the ring, it is very |
| expansion engines. The main difference, the fuel. The | | | | simple to change it, simply unscrew the whole cylinder, |
| CO2 engine uses gas generated from liquid CO2, as | | | | locking ring and all and lift it off the piston. You will see |
| opposed to steam. The gas vapor under high pressure | | | | the ring on the top of the piston, flick it off and fit a |
| is fed through a small tube from the tank to a | | | | new one, don't forget to put a little C02 lube on the ring |
| chamber with a ball and valve seat in the cylinder | | | | before carefully re-fitting the cylinder, remember to |
| head. When the piston, which has a post centered on | | | | slacken off the locking ring before putting the cylinder |
| top, pushes the ball out of the seat (at top dead | | | | back, put a gas charge in the tank and screw the |
| center), gas rushes in, pushing the piston down. The | | | | cylinder down flicking the prop between turns until the |
| gas exhausts through ports as the crankshaft swings | | | | correct speed is set , then lock off with the locking ring. |
| around toward bottom dead center. As the piston | | | | Simple really! BUT! If you attempt to fit a ring to one of |
| comes back up, the cycle is complete. The engine will | | | | the smaller motors, G24 down, I do recommend that |
| run either direction. | | | | you wear a jewellers glass so you can see what you |
| The information presented here is quite general and is | | | | are doing! |
| intended to help the newcomer to CO2 eliminate some | | | | C02 motors are now both reliable and relatively |
| problems that can arise from not following a few | | | | inexpensive to buy. They look good on a model that |
| important procedures. By following these procedures a | | | | should have an engine and, most of all, although they |
| great deal of satisfaction and good old fun will be | | | | are virtually silent, the noise they make is most realistic |
| yours. | | | | and won't cause offence to neighbours or the public |
| Servicing the engine: When there is a need to open | | | | when in use |
| your engine to clean out dirt or foreign matter from a | | | | Engine speed adjustment: RPM can be changed by |
| bad landing, replace a damaged seal, etc., assemble | | | | rotating cylinder. Loosen locknut, turn cylinder clockwise |
| parts just finger tight, lock nut, cylinder head, tank lid, | | | | RPM is increased. Counter clockwise RPM is |
| nozzle, etc. NEVER use pliers or any kind of wrench. | | | | decreased. |
| Lubrication: It's very important to keep your little gem | | | | Selecting engine size for your model: Refer to mfg. |
| well oiled. For the oiling procedure, see mfg. instructions. | | | | operating instructions. However, it is wise to install a |
| Every six or eight flights should do it. A small amount | | | | slightly larger engine throttled down than a smaller |
| with a needle oiler will do. Don't over oil. Extra oil won't | | | | engine that has to be run wide open for desired |
| hurt the engine but will, if done repeatedly, mess up | | | | performance. |
| your aircraft. | | | | Mounting tank in model: Locate the tank on the center |
| Chargers for C02 Motors. | | | | of balance, or slightly forward. The weight of tank |
| There are currently 5 types of charger available. | | | | varies with the amount of liquid and if too far from the |
| In the UK we generally use only 2. The simple `spartlet' | | | | center of balance it can change the trim of aircraft in |
| type which uses the 8gm bulb used for making soda | | | | flight. |
| water is cheap to buy but can be very expensive to | | | | Model weight: Build light. Keep wing loading down. Light |
| run, a box of 10 bulbs only holds 80gms of gas, and | | | | models, especially scale, look better as they fly slower. |
| anyway, for the larger motors the small fillers are | | | | |