I've noticed that Axi use flat spacers of various thicknesses in between the bottom bearing and shaft clip to eliminate up and down play in their motors. I took apart two motors and noticed the spacer in one motor was slightly thicker than the other motor's spacer...obviously one motor had more play than the other after assembly and they corrected it with these spacers. One spacer seemed to be no thicker than a sheet of paper...seriously! This could be one method to eliminate up and down play...just gotta find the spacers
The guys here: http://www.helifreak.com/showthread.php?t=51378 are discussing the Axi method of motor shimming to rid up and down play. Looks like they found some shims at McMaster Carr. They also mention a shim kit "Infinovation t-rex 600 damper shim kit" Could be a very cheap solution.
Just an update on my changed Boca bearings... so far on my X8 I changed only one 3515 to the #7's and have flown two days with about 12 flights total on it and there is no horizontal play at all. Maybe just tiny bit of vertical play which is acceptable for me but it hasn't changed. I am lifting a fair weight (11.5kg) as well with bigger props (16")which should expose issues pretty quickly. My flat 8 has three sets of them in and it has flown maybe 25 times with similar results. I had to snug the vertical play on all of them as I replaced them, like I described earlier, but I am not seeing issues yet. So far so good... maybe just lucky. Hows everybody else going with the #7s ?
Well im really REALLY not happy with mine. My copter is shaking all over the place. I was only able to snug down a few of the motor shafts as the others would budge. I do have a lot of up and down play on motor 1 and some side to side on a few of the others. I think I will be ordering the original replacements and trying to get my money back on these. GRR Josh
Wow. That's not good news, Josh. Those are the APEC #7 too, aren't they? Hmm. You'd think for that kind of price... Andy.
Very strange... sorry to hear about that Josh. The stock replacements worked fine but I had to change mine a few times. They are cheap so if you get some mileage they would be worth it. I am going to order another full set of Boca #7's if I go another outing without issues
Reading about Josh's issues I feel there are a few problems all rolled together causing poor flight performance: 12c converter, motors, castle speed controllers. I bet the motors are the lowest offender...ESCs coming in 2nd and the converter in 1st place. 3 options: swap MK flt board for something non-12C or purchase 12C speed controllers (Herkules) for the MK or wait for FF's control board/esc solution. The least expensive option would be to swap the MK flt board and see how that goes.
Josh, prior to installing the Boca bearings, were you getting any of the shaking behavior and sloppiness in the play of the motor shafts?
So it seems to come with time of use and yet I think you said the BOCA's were sloppy, maybe even worse, out of the box when you installed them, correct? Just doesn't make much sense to pay $16/bearing since you would expect it to be same or better than what was standard on the copter, at least according to their website. Maybe a bad batch?
Hey Guys, Thought I would update you all on my bearing issue. I ended up purchasing the stock bearings for my motors and replaced all of them right before leaving for NAB. I had my first shoot/flight with them yesterday and it is a night and day difference. The stock bearings sound super smooth. There isn't any loud lawmower noise (i should have shot a video of how 2 of my motors sounded before replacing the bearings) and after watching the footage back all of it is pretty much usable without any post. I haven't adjusted any other settings on the copter or the radians. Before i had a bad roll twitch and even a little bit of rolling shutter. It's all gone. Now if I can just get my copter to fly smoother in wind that would be awesome! Guess I will just have to sit tight for the Synapse FC... Josh Oh and I rebalanced my props again. I should note that you should balance your balancer also! My balancer was actually pretty far out of balance which surprised me.
Could you give us details of where you got the "stock bearings" please Josh? Also, what technique did you use for balancing the balancer? Thanks Andy.
Bearings were ordered from ClubHeli.com. To balance the balancer I spun the balancer with the prop stoppers and let it spin till it stopped. Marked the top then spun it again. It landed in the exact same spot each time. I then added some thick CA glue to it, hit it with some kicker so it would set then did the spin test again. I kept adding to it till it would land in a different position each time. Then I marked them so I made sure they stayed oriented the same each time I added the prop to it. Josh
Hi Josh: You don't happen to recall any of the dimensional details of the bearings do you? I'm chasing my tail with Google -- I've some Boca Bearings, #BMK-080C-OS, but they don't say on the packaging anything about the sizing -- nor do they on the web site. So just measuring the Boca's I have, they are 4x11x4mm. But I don't see any bearings like that on clubheli.com now. There are these but they are 5x11x4: http://clubheli.com/Gaui-X5-Ball-Bearings-Pack-5x11x4-X4-208760.html Thanks Andy