What I found out about building and setting up a couple of GAS X-CELL's. I
hope that this will help to get a new GAS HELICOPTER owners off to a good start.
The helicopter built just as friendly as any of the other X-CELL's. The instructions are very good and straight forward. Miniature has done there usual good job at them. The only thing we had to change was the pins that held the canopy on at the bottom were a little to long. We had to take off about 1/8 of an inch on both of them. We did add the electronic solid state ignition to the engine. This was about $15 dollars more. That was about it. I could go on into details but there was nothing that could not be found in the instructions and the nice exploded views. Yes the X-CELL's can take a little bit longer to build do to the fact that none of the parts are pre built, but I personally think that this is good because it gives you the ability to rebuild it if necessary.
The first thing that we found in building the helicopter is that the engines had little pieces of metal shavings in the engine. We had to disassemble the engine and remove the shavings. Also check around the ports and edges for pieces that have not come fully loose.
Next we found that the engine fly wheels were out of balance. They were not to bad, but could have better. I would recommend getting them balanced. If you do not then keep any eye on the shaking. We ran the engines on a test bed first and then ran them after the fly wheels were balanced. There was only a slight difference that was noticed.
None of the above was the fault of MINIATURE. I am to understand that since these two kits were produced the engine manufacture has since taken care of the engine problems. I still however would still check to be on the safe side.
Another thing we did, but I personally do not think it was really necessary was to install a better insulated spark plug cap.
The one thing we did do that was not an option for us was to install a solid state ignition. We were not going to take a chance with this. At first they will be ok, but after running for a while you will be more prone to engine RF noise. So we changed this now when the engine was out. There really isn't anything to installing the solid state ignition. If you do remove the fly wheel for balancing, then this will be the best time to install the solid state ignition. This is because it gave us the opportunity to remove the old points from the engine. We did this because we did not want the old points to ware and leave residue in the engine.
Now some people will say to install capacitors on the servo's. One of the two helicopters, did need to have the caps installed, the other did not. What we did to check this is after the helicopters were built, we ran the helicopters with the blades off. DON'T run it much faster than a idle. Then while it was running we did a radio RF check to see what would happen. The helicopter with the need for the caps only needed one on the elevator servo. This servo had the longest lead and is also located over the plug. We used a .01mf cap soldered at the servo motor. This was connected from the signal wire to the ground wire. This stop the servo from "chattering".
This is what we found in the set up.
Unlike setting up a nitro gas engine, the gas version has that big old fly wheel to spin. This gives the engine a longer lag time for the throttle to take effect. For a nitro engine setup in "IDLE UP" we would use a throttle curve setting that looked like a "J". We would have about 50% at low, 40% at 1/4 throttle stick, 50% at 1/2 throttle stick, and 75% at 3/4 throttle stick, and of course 100% at full throttle. In the gas version if we were to use the 40% throttle at 1/4 throttle setting, at the top of loops when we came off the throttle the engine would still be up at the 50% setting, but when the nose of the helicopter is pointing down, and we wanted to come back up with the throttle, the engine's lag time would catch up and then it would go to the 40% throttle, when we wanted it to go up. What we had to do was set it up more like a backwards "L". Instead of using 40% throttle at 1/4 stick, we ended up using more of a flat setting. Also the gas has more torque. What we found out was the engine would hover at about 40% throttle, based on equal 100% end points. Are final settings ended up like this. 40% throttle at low, 38% at 1/4 throttle stick, 40% at 1/2 throttle stick, 75% at 3/4 throttle stick and 100% at full throttle. We also needed more negative pitch for IDLE - UP 1 to do the loops with. This was due to the heavier weight. Normal did not need as much negative to come down with because of the weight, but it did cause us to fly with the throttle trimmer up. This was do again to weight and also the engines lag time. At the bottom of the decent when we came back up with the throttle there was not head speed to stop the weight of the decent and the engines lag time wouldn't bring it back soon enough, so the helicopter would fall farther before we could stop it.
Watch out for the loops. They can be a little bit smaller than the nitro helicopters. Auto rotations also feel heavier and they will come down and need to be stopped a little bit earlier. So do your first ones in the wind, at least till you get used to flying the helicopter.
As for the engine mixture. The stock settings are on the rich side. We broke in the helicopter using a 20 to 1 mixture of gas/oil. We will use this for a while to break in the engine in more. The engine ran a little ruff at first, do to being rich. We left it this way to break the engine in. There are 2 needles on the carb. One is for the high end, and one is for the low. What we did was richened up the high till it would be sluggishly rich. Then we leaned it a little bit at a time till we could fly around with enough power but the engine would not over heat. The we hovered the helicopter but it was still rich there. We then leaned the low end a little bit at a time till the hover smoothed out. This needle was very sensitive so a little bit is enough. It acted like a throttle stop screw instead of a mixture setting. By doing this we then had to reset the throttle end points.
There you have it. That was pretty easy and flying a gas a lot of fun. They are easy on the fuel and and sound just like that leave blower that would wake you up on Saturday morning , but your out flying. You might want to think about taking a fire extinguisher with you to the field, just in case. Gas / Oil does not burn as easy, but its better to be safe than sorry.
Enjoy - now go fly.
But remember - BE SAFE!!!! READ AND FOLLOW ALL THE INCLUDED INSTRUCTIONS!!!!