Today was an interesting day. I decided to try to get my X-Cell .40 (vintage 1985?) flight worthy again. It’s so old it had (what we call now) a wide-band receiver. Around 1997 RC radios went to narrow-band which is the system we all use now. A while ago I bought a new Hitec Eclipse 7 transmitter, a new Hitec 8 channel receiver and Futaba GY401 AVCS gyro. I installed them but never got the radio fully programmed to use them. Also, it hasn’t been flown in 8+ years so I’m not even sure if the engine will turn over! So today I decided to try to see how much work it would take to get it flight ready.
First of all, the container of fuel that I had was (I’m sure) useless. If you leave it too long the nitro escapes through the plastic and won’t run the engine. I’ve had this happen before so I know what I’m talking about. So I replaced the fuel container with a newer one. I don’t know how new it really is, but it was never opened so I’m sure it’s got a much better chance of running the engine than the original container would have. Of course in the process I learned that the old container had leaked (some how) all over the inside of my flight box. What a mess that was to clean out! I’m so tired of nitro engines!!! This is why I moved to electrics. I’d rather wait for the batteries to charge and deal with all of the nitro mess!
After getting the fuel situation all sorted out I started on the radio setup. I disabled the collective channel so I would adjust the throttle without the helicopter trying to take off of my test stand. I got my flight box battery fully charged, tested my starter motor and glow plug starter. So far – so good. But my luck was about to change – significantly. I had just filled the gas tank about 3/4 full. When I removed the filler tube all of the gas just shot right out all over the grass! What was that all about?!?! The tank shouldn’t be pressurized until the engine is running! Something was wrong. Perhaps the muffler line was clogged. So I disconnected it and filled the tank again. This time the gas stayed in. I reconnected the muffler line. I turned everything on, connected the glow plug starter, set the throttle and started to turn the engine over. Nothing. I adjusted the throttle. Still nothing. I pumped some gas directly into the carburetor. I removed the glow plug so I could crank the engine to get the fuel flowing. That seemed to work so I replaced the glow plug and tried to start it again. Miraculously it started! For some reason it revved and slowed over and over again. I’m not sure what that was all about. The throttle servo (and others) seemed to be going crazy; oscillating back and forth. I don’t know why. Without the engine running the electronics seemed to be working properly. I tried several times to get the engine running and stable, but couldn’t. When the electronics wasn’t oscillating wildly the engine seemed to be having real problems. I finally had to pull the fuel line to shut it down. I had been holding the rotor head to keep it from spinning and may have burned out the clutch in the process. Bummer! It was smoking by the time I got the engine stopped! What a mess! I’m not sure if this thing will ever fly again. I’ve been so spoiled with electric copters I don’t know if I could ever go back to nitro. But since this copter has to be so much more stable than my Hummingbird V2 (Fixed Pitch) copter I would love to fly it just one more time to see how much better it handles. Since this was my first RC chopper and I’ve invested so much in it I kind of hate to just walk away from it. The last time I flew it I still had the training gear on it. I did pretty well at hovering at any altitude (up to 50 feet) but I had to keep the tail pointed at me to maintain orientation. Since then I’ve been using several computer simulators to improve my skills. I’ve been using a R/C AeroChopper (DOS program with wire frame graphics) for many many years. The graphics aren’t great, but it’s a pretty good simulator. I’ve become quite a “hot shot” on that simulator. Lately I’ve upgraded to a Real Flight G3, which has awesome graphics including several photo realistic flying fields. My personal favorite is the “sod farm“. It takes a good bit of skill and experience to take off, turn around and run straight into the van parked behind me. So far I can only hit it (directly) 2 out of 10 times. I guess I still need more practice. Anyway, I’ve been flying my FP Hummingbird (in the house) for quite a while now and I’m getting pretty good at keeping it in one place (reasonably under control). I’ve even flown it at work, check out the video on the DreamHost blog! On the Real Flight G3 I’m flying the Bell 222 (modified so the retractable landing gear works) and can keep it reasonably under control. I’m getting pretty good at nose-in flying and disaster recovery. That’s why I thought if I could get the X-Cell airborne again I could probably do pretty well with it because it’s got plenty of power to handle a bit of wind and it reacts very well too. Oh well, we’ll see if that ever happens.
At this point I’m not really sure I want to go to all the trouble to get his nitro chopper back in the air. It’s reinforced my distain for nitro and will probably get me to start work right away on getting my new T-REX airborne.
Oh yeah, I forgot to mention this. I sold my (un-built) Hummingbird V3 (Collective Pitch) chopper with all the upgrades to a colleague of mine and purchased an Align T-REX SE. So far I’ve got the electronics all set up and tested. Now I’ve got to start working on the airframe. More updates on that later.
Here is a link to the FULL SIZE PHOTOS of my X-Cell .40 chopper on my Gallery site. Here are the thumbnails…