The flying monkeys got me...

Helis and fixed wing

AMA 957918
IRCHA 4345
AMA Intro Pilot Instructor

Wednesday, February 13, 2013

Rolling Gear and Nacelles Back In Business

I finished up the nacelles, and they look so much better further forward. As I described, I lengthened the wheelbase.
Initial installation
Current Installation

Sunday, February 10, 2013

EXI 450 FBL Repaired

Yesterday I had some issues with the EXI 450 FBL that resulted in a fractured swash follower arm and a displaced aileron ball link.
Today I replaced both swash arms (they have to be the same size and aren't exactly standard, so to keep them the same I had to salvage two spares and replace them). I fixed the displaced ball link, and removed the blades. I test spun the system and found that the main shaft was bent. I replaced it. I also checked the feathering shaft, since a bent main often means a bent feathering shaft, but it was fine. So I cleaned up the bearings and re-greased them, put everything back together. New balanced blades put on, re-zeroed the pitch (whenever I do anything to the rotor head I always recheck the swash. I find that when I make sure both blades are zero at zero pitch I never have to fuss with the blades being off in tracking). Set her up for test spin, everything sweet, tracking fine, balanced and vibration free.
I still don't know for sure if the follower arm failed first or I crashed it through pilot error (I am still a beginner heli pilot, after all), but things were going just fine until they weren't.


Saturday, February 9, 2013

At least I flew something...

30 degrees today, but a light breeze and crystal clear skies. There was no way I wasn't going to fly something. I was a little worried about plastic brittleness in the cold, as I had seen others run into these problems. I was right to be worried, but at least it didn't hurt much.
Wingmasters has changed their keys at the first of the year, but since I am only going to be here for a couple of months I didn't want to go to the trouble to get a key or pay for a year. I had found a place to fly behind Kettering Junior High School in Kettering, Ohio. School is out this being a Saturday, so I knew it would be safe. As I drove up, I saw A guy named Joe who was flying a couple of micro foamies (and doing a pretty good job too!).
I took the EXI450 FBL up first. hovered her for a few seconds, and the tail kicked over a couple of times uncommanded, but she settled down and I walked and hovered out to the field from the parking lot and took her around for a few circuits and figure eights. I began a turn in and she suddenly stopped flying and dropped as I hit Hold. inspection revealed one of the swash follower arms snapped off at its weak point where it Y's onto the swash arm of the FBL head. The aileron ball link on the servo also popped off. One blade delaminated when it hit the ground. I haven't checked the servos yet, tomorrow's project.
The upper line points to the swash arm, and the lower one to the ball link.
Video of the flight. Sorry the heli is so far away...
I put her away and brought out the HK500cmt. This would be her first flight since I put the rolling gear on, and I was curious how that would go. On setting her up I found that despite having rebound her when I reset up the servos and the BeastX when I updated the Airware on my DX8 (in the update you have to rebind and reset all the servos...). So I rebound her, and then had to reset the throttle limits. Spun her up, and she spun herself down. No power... These are all fresh batteries. When I got home I found the cells were all down to 3.84v. Put a fresh set on and she powered up fine. The BeastX was doing some odd things, but they seemed manageable. On flipping into flight mode from normal she pulled hard right and I had to put in and hold a bit of left aileron. When I brought her down, set her down and flipped out of flight mode, she pushed over to the right and then left, a blade struck, and the tail blades touched. The plastic tail blades snapped off clean at the hubs... cold had made them brittle so instead of chipping they snapped clean off.
One of the things I noticed was that the gear were leveraging and twisting against the frame, and it had come loose, making the frame dip down in front. I decided to remove the gear, and thought about putting the skids back on, but opted instead to rotate them forward increasing the wheelbase, and set them up with another wood block this time attaching the gear so that the attachment point is behind the nylon gear, and a second wood bar is in front absorbing the forward leverage forces. I attached a wire tie to this to further stabilize it. I had replaced the base of the frame since the previously repaired landing gear supports had worn and broken and were not repairable. This time I bolted the gear to the frame instead of using wood servo screws I had used previously. This is solid.
I have to rework the nacelles, and this work isn't done. I have to refinish them having refit them to the now forward sweeping struts. I hope this works out as I rather like them.
Joe, if you read this, it was a pleasure to meet you and I should have given you my email address. Hope you grow into the hobby!
Addendum 2/23/13: I read up, and the BeastX, and likely any MEMS based gyro, can operate at cold temps. The key is giving it plenty of time to acclimate. I took the HK500cmt out this afternoon and I think did not give it enough time. It turned on lift off, the tail jerked a couple time, then turn in a slow roll and pirouette out of control. Hit hold, only lost the main blades. Stupid is as stupid does. Tomorrow I may try again, but allow it to sit for half an hour.