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Post by chipbutty on Oct 3, 2010 15:42:57 GMT -5
Instead of cluttering up the welcome thread I thought I'd start a new thread here and post any queries I have while doing the build ;D Lining up those metal flybar arms so they're level with each other was a pain Any tips on making this easier? I'm sure there's a simple method I must be overlooking. I did see the way Finless did it in his 550 build video but it didn't work for me. Maybe it's easier to do once the head is actually on the heli. I must have struggled for over an hour getting that bit right! An issue I have at the moment is stopping the metal flybar arms from slipping around the flybar. I've tightened the set screws as tight as I can get them but the arms will slip if I grap hold of each arm and twist them. This may not be an issue in flight but it's a bit disconcerting. Any ideas? One final one for this evening ;D One of the pins (Gaui call it a pillar) that goes through the radius arm (think that's the correct term) on the washout arm assembly is really stiff. What's the best way to get the pin out and loosen up the plastic a little? I had the same issue with the elevator assembly but I did manage to get the pin out on that one by putting it in a vice and knocking the pin out with a tiny hex key. So far this hasn't worked on this particular pin. I was surprised there's no set screw to secure the paddles to the flybar but it does seem pretty secure with just the screw in assembly. So far I love how everything fits together so well
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Post by dunkonu23 on Oct 3, 2010 17:20:14 GMT -5
The best thing I've found and I think we've all found for eliminating the guess work behind getting those darn little arms right is to not use them at all. Instead, I think most of us have opted for this: rcdumbthumbs.com/G-204679.aspxIt's expensive but it is so much easier to use and setup. I remembered fighting with those arms on another helicopter and chucked them right away. Cures everything. I haven't had a problem with the washout arms on my helicopter... even when they were plastic. Admittedly, I stick with plastic for long. Why not just work them back and forth for a bit to see if they loosen up. Frankly, because it's a rotational component, I'd want the pins to be way tight in their mounts and I'd work them to free them up. Scott
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Post by chipbutty on Oct 3, 2010 17:31:45 GMT -5
Thanks for the link. They look like the ticket. I've just taken a look on Buzzflyer and they have that cage in stock. Maybe this cage would also grip the flybar better. I wouldn't want to fly it as it is now; it just won't bite into the flybar enough to prevent it from slipping.
I tried loosening them up the washout arms by rocking back and forth but it doesn't loosen up, it's really stiff. Once those pins are in there they don't want to come out. I wish Gaui wouldn't pre-assemble the head. Maybe I'll try and get a little WD40 in there to see if that will help.
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Post by dunkonu23 on Oct 3, 2010 19:00:27 GMT -5
It'll do the trick. Remember to keep the tiny washers!!
On the washout hinge... Maybe try a little heat? I mean a l i t t l e heat...
Scott
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Post by Jerrymac on Oct 4, 2010 1:16:53 GMT -5
I really didn't have a problem with the flybar L arms myself. I adjusted them after I had the head assembled. I have those L arms on both my 425 and my 550.
The one piece flybar cage does look to be much easier to set up though. I will soon find out as I have a complete Gaui cnc head assembly for my new "500" build.
I wouldn't worry too much about a little stiffness in the washout arms. They will loosen up after a few flights. Better to be a little snug, than to have slop in them.
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Post by chipbutty on Oct 4, 2010 7:07:00 GMT -5
Jerrymac, you have the midas touch with those L arms ;D
I decided to fit the washout assembly as it is and just crack on with the build! I didn't get too far before hitting a little issue with play in the main shaft. The play is horizontal. If I grab the shaft and move it forwards and backwards I can feel play. I can't feel any vertical play. Is this normal? I tried tightening all the frame screws as I thought maybe the frame wasn't tight enough and the bearings hadn't seated properly. But no luck. Tried pulling up on the head as I tightened the shaft collar and various other methods. Annoying but maybe it won't be an issue in flight? Though I'm pretty sure it would cause vibes.
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Post by chipbutty on Oct 4, 2010 11:39:10 GMT -5
I must have underestimated how tight the frame screws need to be. I tightened them up more and more and the play is almost gone but not quite The correct torque on the frame screws seems very important on this frame. I'm guessing this is why people like CF frames on helis this size as you don't get the flex and warp of plastic. Would be great if heli kit manufacturers supplied torque settings for screws!
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Post by dunkonu23 on Oct 4, 2010 12:49:19 GMT -5
LOL! I hear you on torque settings. On my Velocity 50, I use a drill with torque settings on it to drive bolts. I've had people at fun-flys stop by and ask me what I was doing because of the noise the drill makes when it reaches the torque setting. Scott
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Post by dunkonu23 on Oct 4, 2010 12:50:40 GMT -5
Is the main shaft rocking in the bearing or are the bearings moving? I must admit, I've never heard of this.
Scott
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Post by chipbutty on Oct 4, 2010 13:59:45 GMT -5
It feels like the shaft rocking rather than the bearings moving. It's better since I tightened up the frame screws but it's still there and it's not going to go away. It is really annoying me. Thinking of stripping down the frame completely and reassembling it
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Post by dunkonu23 on Oct 4, 2010 14:25:00 GMT -5
You know, what you describe is almost impossible unless the bearings are loose in their mounts or the ID's of the bearings do not match the shaft. I have never, ever seen this. Perhaps it has something to do with the teflon tape?
Scott
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Post by chipbutty on Oct 4, 2010 14:46:17 GMT -5
Well a downside to tightening up those frame screws is it puts lots of preload on all the bearings! I found that out when I tried to turn the blades. So they're obviously not designed to be that tight. Tightening those screws was probably just masking whatever issue is causing the play. Anyway, I'm back to the knocking shaft.
I checked the ID of each shaft bearing and they're both 7.9mm. Shaft is 8mm. Puzzling. I wouldn't have thought it could be the teflon tape. I mean that stuff is so thin it's like human skin! It could maybe be one of the bearing blocks is a fraction out causing a misalignment?
Definitely looking like a strip down.
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Post by dunkonu23 on Oct 4, 2010 15:12:10 GMT -5
I would say the bearings are floating in the mounts, from what you describe. I would do what you're doing and put a finger on the main shaft under the top main bearing. If you feel play there you're pretty much certain it's the top bearing. If the whole main shaft is wobbling, then it's both bearings. Is there a way you can video what you see? Scott
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Post by chipbutty on Oct 4, 2010 15:32:05 GMT -5
Thanks Scott. I don't want to count my chickens just yet but I think I've made progress. It was definitely the top bearing causing the problem as I could feel it knocking by like you say putting my finger against the shaft and moving the shaft. After noticing earlier that all the gears became very stiff if I tightened the screws around their bearing blocks I decided to tighten the two screws around the top bearing block on the main shaft. This seems to have removed the play. Earlier I was just tightening all the screws without thinking about which ones I was tightening. It seem that tightening the screws around bearing blocks will remove play or if you wish tighten/loosen the gears? I didn't realise that it would load the bearings in this way. Does that make sense? It's the first time I've put together a heli of this type so I'm learning all the way.
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Post by billmay on Oct 4, 2010 16:15:59 GMT -5
Don't know if you watched the Finless Bob H550 build videos but he made a point of mentioning that you should tighten the plastic frame screws around the main shaft first. Get them as tight as you can while still allowing the main shaft to rotate freely. Then work your way outward from the center of the frame to the front and back tightening the rest of the screws. If you tighten the outward screws first you might end up with some flex, or buckle, in the center of the frame that is allowing the bearings to wobble a bit. Good luck with it and let us know what you find.
Bill
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Post by dunkonu23 on Oct 4, 2010 17:28:50 GMT -5
What Bill wrote.... It's dead on. I do this on all frames I build. Start with the bearing blocks and work your way up/down then out with the main shaft in. Sorry I missed that, but Bill is right there for the save!! I remember building mine and tweaking with the screws. It's a good learning platform. Try to get the main shaft to drop straight through. Thanks, Bill! Scott
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Post by Jerrymac on Oct 5, 2010 0:33:12 GMT -5
I am always the late one to reply since I don't get home till midnight. I put both of my plastic frames together just as Bill explained above. Never had any issues with mine.
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Post by chipbutty on Oct 5, 2010 7:11:16 GMT -5
Cheers folks. Yes, I followed Finless's advice for tightening the frame screws when I first put it together. It's a lot better since I tightened the screws around the main shaft but I still have a tiny knock. The knock only occurs at one particular point of the bearing/shaft. In this orientation when moving the shaft nose to tail: Anyway, it's been stripped down and put back together. I may just leave it as it is. I suspect the problem is with the upper bearing or shaft. The knock is very subtle now and I could probably hand it to any of you and you'd probably struggle to find it unless you knew where to find it! I don't know how it would manifest itself after flying or in flight. Maybe I'm just being too anal! You can see here how much tighter the screws are around the shaft bearings than elsewhere:
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Post by dunkonu23 on Oct 5, 2010 12:31:49 GMT -5
At this point, I'd just fly it! Heck I've got a notchy top main bearing in T-Rex 450pro and I'm gonna fly it until it affects something! It may not be the "right" thing to do, but it's working. Scott
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Post by chipbutty on Oct 5, 2010 15:09:45 GMT -5
Yep I'm thinking the same. For whatever reason it's as good as I can get it. On to the next stage!
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