This is actually my 2nd Ling Cat. The 1st one met with an unfortunate ending when the ESC overheated and shut down not only the motor, but radio as well. The glide path took it into a chain link fence that turned the forward fuselage into mush. It doesn’t change that it’s really a great flying little plane once you figure out what’s wrong with it. If you’re contemplating getting one, or already have one that seems “un-flyable” read on.

My 1st trim flight (with model balanced at the recommended location) resulted in an “oh **** it’s tail heavy” coming from my mouth after it pointed it’s nose straight up at about 2/3 throttle with absolutely no elevator command given. Not sure of just how I got it back down in one piece but did and removed the lead I’d placed in the tail to achieve the recommended balance point. A second attempt resulted in yet another nose high departure and very hairy test flight before finally getting it back to the ground. (luckily, again with no damage). Time to regroup and looking the model over a bit closer decided that maybe the motor angle was wrong. It did look like it was angled up in a fashion that would push the tail down and in turn kick the nose up. With the problem being worse with more throttle that made sense to me so abandoned trying it again until I could change the angle. Rummaging around in the hardware collection found a small washer that I added underneath the top motor mount. This was enough to bring it to about a zero incidence. I also moved the battery pack and ESC forward to move the balance point more forward.

Test flight number 3 still resulted in a model that went nose high but this time was able to put enough down trim in the elevator to counter it, at least at half throttle. Increasing throttle still made it balloon badly. Though I wish I could take the credit for it, a fellow modeler spotted the problem before I did. He had picked the model up and said look at your elevator. Sure enough, with the wings in a level flight position you could actually see a downward rake in the front of the stab. Since the stabilizer assembly plugs into precut slots on the tail booms and rest on top of more “popsicle stick” screw down mounts I’d never even thought about checking it. Since I didn’t really trust the screws for holding it, I had glued my stab in as well just for insurance. Still with a bit of patience and a sharp blade in the hobby knife was able to cut through the leading edge of the stab where it plugged into the booms. With the leading edge free raised it up and made myself a couple of shims from real popsicle sticks. (They were just the right width, a hard wood, and even pre rounded on the ends to match the existing stab supports) These were attached with epoxy between the front stab support and stab itself. Holes were drilled through and the screws were reinstalled. Eyeballing the assembly looked pretty darn close.

Test flight number 4 went much better. It still had a touch of climb with throttle effect but was able to trim it out with just a few clicks of down. It was a little nose heavy since I hadn’t re-arranged the balance point since the 3rd flight. But it was comfortable. You might note here that the manual that came with kit 1 showed CG @ 175mm back from wing leading edge. Kit 2 had the 175 mm scratched through and 157mm penciled in underneath it. I would suggest using the 157 mm reading. After about 3 minutes of cruising around and getting the feel of it landed and checked the battery. It was barely warm and hooking it up to the charger showed the cells to still be around 3.8 to 3.9 volts.
Flight number 5 was really an enjoyable experience (other than the very end of it). After putting a fresh charge on the battery and shifting it back a little went up again. This little thing is actually fun to fly. Cuban 8’s that looked sloppy with my electric Sportster were right on with this one. It has a good roll rate, and flies well at half throttle. Tracking through a loop was excellent and at full throttle will probably hit the 40-60 mph mark. It also slows down well in a nose high attitude. I guess that I was enjoying flying it so much that I just flew it a hair too long. I was actually getting ready to turn onto final when the ESC must have overheated and shut motor shut off. That might not have been such a bad thing except that it also shut down the receiver for the radio and the glide path carried it into a mixture of mother earth and chain link fence at the same time. (It appeared to have struck both simultaneously.) At this point in time I’m thinking that the 6 servo load and lack of air flow around the ESC caused the failure. For more on that, you will still need to do some more reading.

This isn’t meant to be a replacement for the manual either, just a supplement/correction to it. I’ve shot a handful of photos that will be useful (with more directions) too. It didn’t take me long to decide that a bit of epoxy on all the wing connections would be a good thing as well. The popsicle stick (what they look like to me) joiners are a little too short and can easily split when installing the screws to hold them together (even after drilling a pilot hole). I removed the covering in areas that had wood underneath it. (see photos ) A coat of epoxy will be applied to these areas just before sliding the pieces together.

July 15, 2007
I managed to trim/test fly my second LingCat ARF today, and even managed to get someone at the site to shoot some video. It's not all that great but one that actually has me working the controls for a change. That's a very rare occurrence since it's about impossible to shoot video & fly at the same time. So rare that I’m going to go ahead and publish the page “not quite done”. If you missed the link “(see photos)” for the rest of the instructions, click HERE