Flight of the Phoenix!

Well, I've been trying to fly my Carl Goldberg Tiger 2 electric conversion for a while now, but keep finding reasons not to. For one thing, it is a 5lb model with a 61" wingspan and capable of speeds over 80mph. That isn't something you just take to your local playground park. I went out to the local flying club last weekend, despite a strong 10-15mph wind. There were a ton of folks out there having a fun fly. I watched for a while and asked about what it took to join and stuff. $60 AMA membership dues and $60 for BARKS fees and runway costs. Don't get me wrong, it is probably all worth it (they have a great runway and good pits, despite my not liking to have to try to dead stick in all the sagebrush out there), but I just don't have much time to fly the big models, and mostly the park fliers work great right here by my house.

Anyway, I FINALLY decided to try it again today. Went for a pretty long mountain bike ride this morning, and the weather was very nice and calm (of course). Wind came up this afternoon and I got tired of waiting for it to maybe let up. So, about 5PM, I headed out to give it a shot, again, despite the 10-15mph gusts. I had a 4S1P and 5S1P lipo, each 3000mAh and I've given up on the Hitec Mini 6S rx's that are SC, and have a Neutron 6S in everything now. Got to a local soccer field that was currently empty and assembled the craft. Checked all the surfaces one last time and gave it some gas. As a tail dragger, this wants to lift the tail and push over in tall grass, but if I just give it full up elevator and hit the throttle, it pulls through very nice. ROG was VERY fast with the 5S lipo. Got it up and behavior was very nice and fairly balanced right out. Just needed a little right rudder trim.

Took it through some slow turns, a loop, tried some inverted flight and waterfalls, everything checked out. Did a snap roll, and WOW, completed 1 and three quarters before I could stop. Very responsive snaps. Roll isn't as commanding as I would like, but it isn't bad (need to work on the binding and throws more). The rudder really doesn't command it like I expected it too, despite it having pretty good surface area. I need to look at that more. This thing will got straight vertical and keep on climbing with the 5S and 12x8 Master Airscrew. Looking at the power charts for this Turnigy AerodriveXP 35-48 900kV outrunner, I had forgot that I was going to swap to a 12x6 (I already got it and everything) to dial the current back a little. Well, about 8 minutes into the flight, the 5S 3000mAh lipo was done. And I had been doing mostly half throttle and coasting in the down draft with only limited bursts of full throttle. WOW. That shocked me. It died so fast that I didn't even have any warning to bring it around for a full landing sweep and pretty much turned it dead stick and got it lined up for a quick feathered landing. It settled great and rolled out nice.

Popped the lid off the front hatch and it was H-O-T. The motor was pretty warm too, but not sizzling, nor was the ESC. But the battery was puffy and very hot (uh-oh). I definately need to get the smaller pitch prop. 60A is right at the 20C limit of those 3A lipos. I'm still shocked at the time and how hot it was. I need to cut some air exhaust holes in the aft part of the fuse to allow air to flow. I'm guessing nothing goes through because it is a dead space. That should help.

Let everything cool for 5 minutes and then put the 4S lipo in. Ran the motor up a little and just let it feather at quarter throttle to fan some air. Checked controls again and throttled up. Little longer run up, but not much. This thing leaps in the air. Played a little more, keeping an eye on the time and being a lot more conservative on the power. It ran up past 11 minutes before it started showing laggard response and I brought it right in. Perfectly well behaved landing again and again, the lipo was a bit puffy and pretty warm.

Overall, this plane is very fun. Flies inverted VERY well with the fully symetrical wings and the CoG seems just about right and it will elevator in fairly stable. Just a couple changes (prop and air vents) and I think the next outing will be great. Though, any one that you don't wreck is a great one. LOL.





Update (9/29/2009):I’m sure I’m getting like 4x more power than my easy star (actually, charts for this new motor with that prop shows almost 6x the “thrust” of the easy star). Yes, the plane is that much heavier. It is just under 5lbs with motor, and lipo AUW. Thrust with 5S1P lipo is just under 3000g (or 6.6lbs) and burns through >950W. And it can go straight up pure vertical and accelerate. LMAO. The inrunner in my easy star is max 250W motor (but cranking out almost 400W at max with that 5.5x4.5 prop I have, which is probably why I keep melting wires on it, LOL).