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Old Oct 25, 2012, 03:36 PM
Get to the choppa!
RFDelie's Avatar
United States, PA, Pittsburgh
Joined Sep 2012
358 Posts
Thanks finguz, I have solved the problem atleast for the time being, I changed out the blades and re-applied blue locktite to the feathering shaft. I did not think that I had done anything dofferently, but I took it out and it flew wonderfully. It was late so I had planned to come out the next day. I did preflight everything looked good, I take off and there is the wobble again, it flew well for about 10 seconds. In frustration I took off the training gear and the thing flew perfectly. But every once in a while I will see a much less intense wobble it will last for a second and then stop. I wonder if the training gear was just amplifying a small intermittent wobble. Another observation, Since taking the gear off I can turn the gain up on my gyro. Before I could not go above 25% without getting the tail hunt. But now I can go 60% - 70% before I get the hunt. Training gear = BAD!

Thanks for your help.
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Old Oct 25, 2012, 08:28 PM
Don't take any wooden nickels
finguz's Avatar
United States, CA, San Diego
Joined Mar 2012
1,944 Posts
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Originally Posted by RFDelie View Post
Thanks finguz, I have solved the problem atleast for the time being, I changed out the blades and re-applied blue locktite to the feathering shaft. I did not think that I had done anything dofferently, but I took it out and it flew wonderfully. It was late so I had planned to come out the next day. I did preflight everything looked good, I take off and there is the wobble again, it flew well for about 10 seconds. In frustration I took off the training gear and the thing flew perfectly. But every once in a while I will see a much less intense wobble it will last for a second and then stop. I wonder if the training gear was just amplifying a small intermittent wobble. Another observation, Since taking the gear off I can turn the gain up on my gyro. Before I could not go above 25% without getting the tail hunt. But now I can go 60% - 70% before I get the hunt. Training gear = BAD!

Thanks for your help.
No problem, these machines are touchy sometimes. Have tried to up your throttle curve a little, or try a flat throttle (of like 80%) in idleup. I can't remember if you said anything about if you tried different headspeed. Sometimes low headspeed will get you. Also, try.. just try to run your belt tight, once, if you don't like it you can change it back. Mine seemed like it had to be tight to work right... exi belts are super cheap (I got 7 of them on sale for like $3 or something) but align belts are awesome.

When you get it right it will be worth it though. Just to be nosey, do you let your loctite cure or dry? It takes 24 hours to cure completely.
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Old Oct 26, 2012, 06:54 AM
Get to the choppa!
RFDelie's Avatar
United States, PA, Pittsburgh
Joined Sep 2012
358 Posts
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Originally Posted by finguz View Post
No problem, these machines are touchy sometimes. Have tried to up your throttle curve a little, or try a flat throttle (of like 80%) in idleup. I can't remember if you said anything about if you tried different headspeed. Sometimes low headspeed will get you. Also, try.. just try to run your belt tight, once, if you don't like it you can change it back. Mine seemed like it had to be tight to work right... exi belts are super cheap (I got 7 of them on sale for like $3 or something) but align belts are awesome.

When you get it right it will be worth it though. Just to be nosey, do you let your loctite cure or dry? It takes 24 hours to cure completely.
I did tweak my headspeed a little, oddly, it effected my rudder to I had to go back. I will try to tighten my belt a little more. I am using an align belt. One of the first things that happened to me when learning to fly was the CF tail stabilizer broke and the tail hit the ground hard so I replaed the whole assembly. I am using a plastic tail stabilizer until i am done learning, then I will go back to the CF.

I do like to let the locktite dry, but lately I have been tweaking and flying tweaking and flying while trying to figure this out. I think the added vibration from my training gear was helping walk those screws put because they have not moved at all since I took it off.

Where do you get your parts? I found a great place to buy parts, they have just about every align part out there. Having a pro you probably have an easier time, but very few retailers have all of the sport parts.

http://www.amainhobbies.com/index.ph...rs-Parts-Align
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Old Oct 26, 2012, 02:14 PM
Don't take any wooden nickels
finguz's Avatar
United States, CA, San Diego
Joined Mar 2012
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I buy most of my align parts at amainhobbies as well. Helidirect is another place I've bought from. Price wise they're about the same for align parts. There are lots more out there though.

It's funny because when I shop for my exi pro I have to shop half in the pro section, and half in the sport section, because of mybelt driven tail (Align didn't make a 450 pro w/belt tail).

As far as the loctite, I've had decent results flying a couple hours after loctiting and nothing ever came loose, but I really try every time to put off flying (it's hard) until 24 hours. Or now I fly my mcpx. But also I was gonna say about your screws backing out, everytime now I clean the threads of the bolt by screwing it into a rag or my shirt with a driver, I'm amazed how much stuff comes off everytime. I do it to all my bolts now. I guess it's old loctite, but it's got a grey-brown color to it, on the rag, so maybe some grease gets in there too or something. Loctite and grease don't mix well. I also try to clean the hole with a toothpick best I can, and get the old stuff away. Your blade grips loosening might also be a sign of something not being totally smooth in the grip. I'm sure the vibration didn't help it though.
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Old Oct 30, 2012, 03:21 PM
Umm what just flew off my ship
GhostFlyer1's Avatar
Joined Jan 2010
1,016 Posts
Question have you balanced your blades. Another thing you may want to do is pull off the main and tail blades and spin it up holding the tailboom *be careful not to get hit by the flybar* what your looking for is how much vibration there is .... I would also check and make sure the flybar paddles are exactly the same distance on each end. You may also want to just replace the main shaft for general principle. I had that happen to me athough it was 20' up I managed to land it on is gear, however the sudden change in weight on the main shaft of only 1 blade actually bent the main shaft.
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Old Oct 31, 2012, 11:07 PM
Get to the choppa!
RFDelie's Avatar
United States, PA, Pittsburgh
Joined Sep 2012
358 Posts
Thanks Ghostflyer. I think I finally figured it out this evening. I got rid of the MAJOR wobbling, but there was still a small wobble detectible in this FP video I shot:

First Helicopter Flight With POV Camera (1 min 13 sec)


This wobble does not look so bad when you are on the ground looking up at it, but the camera catches every movement. So I hit the internet with renewed determination. I noticed someone with the same problem fixed by lubricating their the thrust bearings and head dampers. So I took my head apart and did that, when assembling everything I happen to notice a small amount of slop in one of the rotor blades. Turns out one of the linkage balls on the blade holders was coming loose [facepalm]. So I took them off and applied locktite.

I took it out for a midnight test flight and it is as smooth as can be. It is now so rock solid that it looks like it is hanging from finguz's ceiling.

Thank you all for your help, this one is a wrap.
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Old Nov 01, 2012, 01:44 AM
Don't take any wooden nickels
finguz's Avatar
United States, CA, San Diego
Joined Mar 2012
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Originally Posted by RFDelie View Post
It is now so rock solid that it looks like it is handing from finguz's ceiling
Ha, did it turn into a 3ch coaxial capable of inverted flight too?
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Old Nov 01, 2012, 07:18 AM
Get to the choppa!
RFDelie's Avatar
United States, PA, Pittsburgh
Joined Sep 2012
358 Posts
Its not how many rotors you have, its how you use it them that counts. 8)
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Old Nov 01, 2012, 12:42 PM
Don't take any wooden nickels
finguz's Avatar
United States, CA, San Diego
Joined Mar 2012
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I want to see someone build a coaxial collective pitch helicopter, like the Kamov Ka-50. It would be way cool.
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Old Nov 01, 2012, 07:47 PM
Get to the choppa!
RFDelie's Avatar
United States, PA, Pittsburgh
Joined Sep 2012
358 Posts
I never got into the co-ax helis. Never owned one. Not sure shy, they just never caught my eye.
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Old Nov 01, 2012, 11:23 PM
Don't take any wooden nickels
finguz's Avatar
United States, CA, San Diego
Joined Mar 2012
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I bought some, but I hated them because I'd crash constantly, not enough control. Around the same time I tried FMS and Helisimrc and liked that much more though it was harder. Though coaxials are one of the things that got me interested in helis in general.

I would like to build a coaxial cp heli and I've been thinking of how recently, but instead (and much easier) one day I'll settle for an Apache scale 450-700.
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