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03-02-2012, 02:25 AM | #41 (permalink) |
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Join Date: Feb 2011
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Georgi, I'm thinking perhaps I'm looking for the wrong thing. I've rebuilt the tail will all new parts, I've tested belt tension, tail alignment and tightness. I can't make the belt looser as it will grab, any tighter and it won't turn smoothly. I believe I have it set right.
Now I'm wondering if perhaps there's something wrong with the front pulley or tensioner. I can't access the files at work but I want to look for a lateral vibe at around 4000 rpm - this is where I expect the front pulley to be. Another viable option for a lateral tail vibe could be bad tracking on the tail blades. What do you think? |
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03-02-2012, 12:20 PM | #42 (permalink) |
Join Date: Mar 2007
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=] we are this close Froggy, idler (tensioner) pulley bearing? its on that belt drive somewhere!
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03-02-2012, 01:41 PM | #43 (permalink) |
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I rebuilt the tail a few more times, trying different tensions. I then removed the main gear and pulley, pulled out the tensioners and checked them for play and movement - all fine. I reinstalled it all carefully, checking that I've not missed anything in the assembly.
No change. |
03-02-2012, 07:09 PM | #44 (permalink) |
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Sorry you are having proiblems.
You have the good tail it sounds like. I have the plastic tail case with the plastic balls molded to the grips. When I first saw the assy I thought it l;ooked like cheap junk but it has survived a hard life. The original Mod .7 main gear did strip. I have. Ive been frustrated at times with this FBL install and a couple of things I dont understand but I believe it is ready to test hover. I am going to make a new post listing what I have done and would appreciate it if you guys could look it over and tell me if I forgot something and am in imminent danger of dirt napping it. Hope you find your problem Jimmy
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Compass7HV,Sk720HeliJive120HV Pyro 700 52L allHV Outrage 550: Scorpion 4020-1390,CC125A ESC,WR ESC Logo 5003D Scorpion Sk720 4020-1100, Blade130X MCPX TT E-620 SE x 2: Scorpion 4025-740 200srx, nano qx JR Parkmites x 2 Last edited by Jamesppp; 03-03-2012 at 11:31 AM.. |
03-03-2012, 10:09 AM | #45 (permalink) |
Join Date: Mar 2007
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=] Froggy is that belt ok??!
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03-03-2012, 01:01 PM | #46 (permalink) |
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Yeah, the belt is fine. I took the heli to my Mikado dealer but none of their recommendations worked. I've now stripped the heli to a bare airframe - I'm taking it back sometime next week. They will rebuild it for me and find the issue. I really can't be arsed in this case - I bought the Logo for simplicity and ease of use. Depending on what they find I may just sell the airframe and move on.
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03-04-2012, 01:23 AM | #47 (permalink) |
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Interesting results..
So as per my previous post I stripped the Logo down. Last night I installed all the electronics (servos, ESC, BEC, SK, etc.) into my Trex 550E as this is what the setup was originally for. I maidened the Trex this morning and vibes are ok - motor and tail the main cuprits - vibes peaking at 2.8. Note this airframe hasn't been flown - it was rebuilt after it's maiden crash last year and has been sitting neglected on a shelf.
Anyway, the really interesting thing I noted is that my SK initialised a lot quicker on Trex than on the Logo. It really struggled on the Logo, taking 30 seconds or more. The motor also 'twitched' as the ESC beeped, waiting for throttle signal. I thought this was the Hobby Wing ESC.. Now the SK initialised within seconds and the motor doesn't twitch.. interesting. So we know the significant design differences between Trex and Logo (without pack the Logo is 400g lighter than the Trex with the same electronics!!!!). In particular there is the belt versus torque tube - and this I think could hold a key to the original crash of my Logo. You see, as per recommendation I earthed the Logo tail - to the motor mount. I'm wondering if this was causing electrical noise, even on the ground? In flight was this enough to freak out the SK and induce uncommanded roll and accelerometer errors? While the Trex is a basic and vibey airframe, the system is behaving perfectly - the heli is responding as it should. Hopefully the flights later will prove to be successful. I will email Art now with this bit of insight on the earthing and ask his opinion. The Logo is going back to the dealer tomorrow for an assessment of the mechanical setup. Once we have answers I'd have to decide what to do with the Logo (I'm not stripping the Trex if it flies well) - likely a 10S or 12S 600 monster setup. |
03-04-2012, 11:00 AM | #48 (permalink) |
Join Date: Mar 2007
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=] I would be surprised if static were an issue here? its only an earth to the motor mount after all.
but its great to see you are up and away with the rexy! so we will await your feedback on the returned SK unit & the Logo rebuild
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03-04-2012, 02:31 PM | #49 (permalink) |
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Thanks Georgi - unfortunately the wind was very very strong today. I did three shorts test flights, not enough to even dent a pack. However the 550 did well, registering an average of 1.4 on the vibe scale, clean logs and the motor and esc came down cool. It flew well considering the conditions. I only had it at 2000 rpm in idle 1 and with the gusts I had trouble controlling the heli - it was bobbing like a 450 in wind.
The Logo will remain an ornament for a while as I decide what to do with it and find the money to build another heli. The second SK goes into my Srimok as this was down for major maintenance (~200 flights). |
03-04-2012, 06:53 PM | #50 (permalink) |
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Froggy, it seems like it must have something to do with the belt.
Is it possible that your belt could be contacting the screw that you are using to ground(earth) the boom. I used a screw to lock the boom on a heli and had that happen I saw on the Mikado thread where someone asked if the belt had an extra twist in it. If it did and the tail was spinning in the right direction, it would have to have a complete rotation and even that would definitely cause your problem it isnt likely that you would have wound it up that much. I dont have the tail that you you have. I have older, less desirable, all plastic, enclosed tail that came with the Logo 500 3D kits. I use some Graphit 33 spray on my belts for static protection and my tail is as smooth as butter. The vibe logs may say differently but just from look and feel. I dip an artist brush into some Graphit 33 that I spray into the cap that comes on the can and hold it against the belt as I rotate the head. I read continuity from one end to the other with my DVM.. I know that it is frustrating but that should be a smooth, quiet running ship.
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Compass7HV,Sk720HeliJive120HV Pyro 700 52L allHV Outrage 550: Scorpion 4020-1390,CC125A ESC,WR ESC Logo 5003D Scorpion Sk720 4020-1100, Blade130X MCPX TT E-620 SE x 2: Scorpion 4025-740 200srx, nano qx JR Parkmites x 2 |
04-11-2012, 03:34 AM | #51 (permalink) |
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An update at last. I just got word that my controller was delivered to my house earlier this morning - I shipped it late February. The Skookum team say they replaced the sensors and recalibrated the unit. Hopefully all is well.
Regarding the airframe and the vibes, I am convinced it was more a gain issue that a pure vibe issue. My LHS (a Mikado dealer) rebuilt my airframe and it's come back almost identical in setup - even the belt tension is the same. The only significant difference is the boom is not pushed all the way into the frame - it's centred between the frame and tail case. I've already installed all the electronics and the power bus so It's a case on mounting the SK and connecting the three cables and two Rx sats. So hopefully this weekend I'll try the maiden v2. |
04-11-2012, 04:39 AM | #52 (permalink) |
Join Date: Mar 2007
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=] Froggy, its great to see it all coming together now!!,
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04-11-2012, 09:59 AM | #53 (permalink) |
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Good deal Froggy.
How tight is your belt? Is there actually 3 mm or so of "slack" or is it tight and you can deflect it 3mm You can check it at your tail but I didn't install the open tail box yet. You don't get much in that carbon tail upgrade bag for $80 usd lol Everything inside my tail case is new and the hub and rotor ,shaft,yoke and lever is brand new Good luck. When I started out and had high vibes, tightening the belt to what I thought was too tight, lowered vibes considerably Jimmy
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Compass7HV,Sk720HeliJive120HV Pyro 700 52L allHV Outrage 550: Scorpion 4020-1390,CC125A ESC,WR ESC Logo 5003D Scorpion Sk720 4020-1100, Blade130X MCPX TT E-620 SE x 2: Scorpion 4025-740 200srx, nano qx JR Parkmites x 2 Last edited by Jamesppp; 04-11-2012 at 11:17 AM.. |
04-11-2012, 02:48 PM | #54 (permalink) |
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This is really funny.. so I set up the Logo this evening and do a bench run without main or tail blades; lift the heli into the air by hand so it would generate a log. The vibes are off the scale... I was previous chasing a lateral spike around 7, with overall vibes around 1.4. Tonight I got spikes at 31, with overall at 18... motor up/down and tail lateral. So the same spikes as before but much much worse. Must check my SK mounting; it's either touching something it shouldn't or the rebuild by the LHS wasn't so hot. Anyway, I'm not even slightly annoyed, it's just a joke by now.
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04-11-2012, 03:19 PM | #55 (permalink) |
Join Date: Mar 2007
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=] that would kill me after what you have been thro' Froggy, its a great heli with an equally great FBL controller, they do merge perfectly.
my EFL straight out the box has less than point .8 vibes, with blades.....
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04-11-2012, 03:54 PM | #56 (permalink) |
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I'm thinking it's just a mounting issue with the controller - after all I did the motor install and that's one of the vibe sources. Also, the entire vibe range is elevated. I'll fiddle with the foam and cable routing tomorrow, should get it sorted.
At least my wife has been incredibly supportive - she says it's completely my own fault that it's worse as I'm OCD and should never let anyone touch my stuff. |
04-12-2012, 01:09 AM | #57 (permalink) |
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So I hovered the heli this morning. Vibes are a more manageable 13, but there's a visible vibe even though the heli sounds smooth. I remounted the SK last night to be sure so I think it wasn't rebuilt properly - specifically the tail.
Log attached. |
04-12-2012, 12:09 PM | #58 (permalink) |
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How tight is your belt. Mine has to be very tight. I'm not crazy about the fact that neither the tail or the mounting block "key" into the boom in any way.
I'm pretty sure, from bench testing that if I put a lite ply piece across the rear battery tabs in the frame and mounted my Sk under the boom,I would have very low vibes. I don't have to lift my heli off the bench to get a vibe log. Is that how OT is supposed to work? Thanks, Jommy
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Compass7HV,Sk720HeliJive120HV Pyro 700 52L allHV Outrage 550: Scorpion 4020-1390,CC125A ESC,WR ESC Logo 5003D Scorpion Sk720 4020-1100, Blade130X MCPX TT E-620 SE x 2: Scorpion 4025-740 200srx, nano qx JR Parkmites x 2 |
04-12-2012, 12:38 PM | #59 (permalink) |
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Jimmy, I got the vibes down to 10 on the tail - once again it's only lateral. I found the 'rebuild' by the LHS had left some lateral play in the output shaft. They had removed the second shim in the shaft so I added another (am one short now because they took one out). It helped a little and so did tightening the boom down more (it's properly square now).
The belt has been tested loose to tight - I think it's spot on - I have very low vibes from the belt ~1. |
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