The flying monkeys got me...

Helis and fixed wing

AMA 957918
IRCHA 4345
AMA Intro Pilot Instructor

Tuesday, July 10, 2012

The Gang's All Here!

Spent the day getting my helis back on line. Yesterday I replaced the tail boom on Frankenheli, and ended up also having to change out the tail assembly. The boom that was on there was a remnant of the 450 Stretch project, where for some reason, I guess wanting a bigger heli, I went with the 345mm longer blades, which necessitated using the longer Outrage boom, and a longer belt. I could never get the longer blades balanced right (they balanced fine, but there was always a bad vibration in flight, no matter what I did. This went away when regular blades were put on her. Never figured it out). and gave up on it. So I replaced the boom with a standard sized boom, and rather than take the entire tail assembly apart to replace the belt, I opted to replace it with a new one I had on hand, already with a belt. Loctited it, and as has happened before, when the feathering screws are tightened it would not move. I did the best I could, installed it, and put the entire tail back together. Today I put the Tarot ZYX stabilzation system back on it, rechecked its programming, and replaced the bent main shaft. Took her out for a spin and hovered her in the driveway several times. Eventually, fortunately on the ground, she threw a tail blade, grip and all. I replaced it with a good one I had setup before, and she is good to go.
 
I also installed the Tarot ZYX on the EXI 450 from which I had stolen the BeastX for the HK 500cmt. This was a brand new one, and though the box was a little crushed and the device floating around inside it, it worked fine. Installed it on 3 of the thin foam pads provided, wired it up, then programmed it easily using the USB and my notebook. She is ready for flight testing.
 
Lastly, I put the final touch on the HK500cmt, installing the Tarot FBL head. These are the best inexpensive quality FBL heads out there. Just look at this thing. Solid, well designed and well built. Bolted on in an instant. Did have a little trouble with getting one of the plastic link end thingys on and substituted one from the HDX. The turnbuckle was threaded but on this one particular end would not screw in right. Managed to get it in place and secured but it took a lot of work. Took the head apart to inspect and grease the thrust bearings and Locktite everything, then installed it easily. Programmed the BeastX with the head, having preprogrammed most of it before the head arrived, and took her out to maiden hover in the driveway. She spun up nicely, but as the disc came up to speed, she suddenly leaned over to the right in an uncommanded ground roll. I hit hold and tried again, same thing. Took her upstairs to the lab suspecting a programming error, but she responded exactly as she should to manuevering. Then I decided to remove the main blades and spin her up to see what would happen. This is what I saw:
 
 
There was a vibration that really became evident at certain rpms suggesting an imbalance, and this vibration coincided with a reliably reproducible uncommanded roll. I removed the tail blades and spun her up, and the vibration, as well as the roll, was gone. Inspected the blades, removed a chip, rebalanced them (off by 0.1 gm) with some tape on a blade balancer (I do this for all my helis now). I suspect in the initial spin up a piece of the tail blade came off, the chip. Now that they are balanced, put them back on, spun her up, that vibration was gone and there was no roll command from the BeastX. Put the mains back on, took her to the driveway, and she spun up and flew perfectly on her maiden hover! Perfectly!
 
So all of my helis, save the Erazor which is being replaced with an EXI 450 Sport as I write this, are up and ready to go! Can't wait for the weather to clear to fly them!
 

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