The flying monkeys got me...

Helis and fixed wing

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IRCHA 4345
AMA Intro Pilot Instructor

Friday, December 16, 2011

Waffly Warthog

Took the A-10 Warthog up yesterday. She really didn't have enough thrust to takeoff from grass without a good head wind. She rolled fine on her big wheels, but she just didn't have the thrust. I did manage to takeoff once into a gust, but otherwise I hand launched her.

The pic in the manual that sets the CG at 80mm from the tip of the pylon is incorrect, as one might imagine. I set it about a third back from the leading edge, which put it over the spar, and it was spot on. I had set my low rates for elevator at 50% with 25% expo. She porpoised a lot, so I ended up setting it at 35% and it settled down. Elevator authority is no problem! She is marginally powered with the two 64mm fans on a 3S. She has 40amp ESCs, so she could handle a 4S, but I would have to chisel EPO, and I don't know if the extra weight would bog her down more than the 4S would improve her power. She hand launched easily, but her size and power require she be launched by a flying buddy. Once she waffles up to speed and is truly airborne she flies fine. She is no speed demon, but she is quick. She trimmed out easy, and once I got her elevator expo set she flew quite stably. On landing with power off she loves to float, and her gentle stall behaviors let her come down nicely.

I did have problems with the retracts. They bind, and it took some surgeries on the case to resolve that. The cheap stock servos on the mains burned out, one yesterday, and another today. I replaced them with Tower Pro SG-90mgs. Yesterday's went in no problem, but today's was "reversed" so the left main was out of sync with the nose and right main. The servo was moving correctly, but the installation would not let me put it in "backwards" to get it in sync. I don't know why this servo was different than the stock one, but it is, even though its installed the same. I ended up getting a servo reverser, and its all set now. I didn't get to fly her today due to this retract issue...

Tomorrow I hope to take her out and see if I can takeoff from the ground. Hopefully the grass will be cut before then so I can get her rolling!

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