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500 Class Electric Helicopters 500 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar. |
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09-29-2014, 02:48 PM | #1 (permalink) |
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Join Date: Jan 2012
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blade tracking
I've just built a 500 cmt ( my first 500) and have a problem with blade tracking . The blades are balanced,and not tight in the grips, pitch is right but in a hover the blades are about 30mm apart , I landed and adjusted the relevant linkage tried again without success .tried this a few times and then put it on the turntable .After a few more attempts at adjustment I wacked the throttle up and the blades lined up perfectly . So now I'm thinking is my headspeed too low? I have the typhoon 500 motor with 11T pinion. T.C. is 0-60-70-80-100 ,P.C.-10 ,0,+10 . I have no way of checking the speed other than the online calculator. When it's in the air the throttle is mainly between 70 - 80. So I'm thinking maybe I should go with a hhigher /flat throttle curve .Assistance here will be much appreciated
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09-29-2014, 03:02 PM | #2 (permalink) | |
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Join Date: Jan 2014
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Quote:
First check your links to makes sure there the same Right and left. ( check stock specs ) Never try to take it out of one blade. maybe 1 turn longer and 1 turn short on the other link. BUT 30mm I would go though your build and check your links You will never get that from 2 turns ..... Go two turn's on each link longer/Shorter maybe and see where your at. HHMMMMM Check your link setting side to side.... Check where each link is.... Set to stock and start from there. You could have a bad set of blades as well.....
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09-29-2014, 03:51 PM | #3 (permalink) |
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Join Date: Jan 2010
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Head speed is unlikely to be the issue, though personally I have my first point at 70 instead of 60, and then go up gradually from there.
How "not tight" are the blades in their holders? They should be tight enough that they need quite a bit of force to move them -- tight enough that they won't fold if you hold the heli on its side. Assuming one or both of your blades don't have some kind of twist in them, as has been mentioned you need to check your geometry. Starting at the bottom, all servo arms should be at 90 degrees at mid-stick, and the links to the swash should be the right length (they might not be exactly the same if the rear servo is mounted differently from the front two) so that the swash is level; and the swash should stay level at all collective stick positions. Then the links from the swash upwards should all be exactly the same length as their partners. Having said that, having just built an HK500 myself after flying an Align T-Rex 500 for five years, I fear that you may be onto a hiding to nothing: Before even flying it I installed a complete Align tail rotor because the HK slider was notchy -- something I'd already been warned about. But when I did test fly it, with everything set up and balanced correctly, the tracking was so far out and it was shaking so much that I aborted after about ten seconds I never did bother finding what exactly was wrong, for I had a spare Align head, shaft, blades, main bearings, and main gear which I put in. It flew perfect right from the off, and I didn't have to make any tracking adjustments. I guess that the issue with the HK head parts is just an accumulation of poor tolerances and quality. For me it was a cheap way of getting another heli by using parts I'd already got. I wouldn't recommend it for a beginner. |
09-29-2014, 06:46 PM | #4 (permalink) |
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Join Date: Nov 2012
Location: Maryland
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What Abenn said. If you find that making an adjustment does not result in a consistent, expected change in your tracking, then you are most likely dealing with poor HK tolerances, and you need to start replacing head components with Align stuff.
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09-30-2014, 03:54 AM | #5 (permalink) |
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Thread Starter
Join Date: Jan 2012
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All my links are correct length and all the arms line up. when first setting up I found that the mixing arm was sloppy, this has now been fixed. The swash, v. poor quality , has been swapped for Align. My blades are balanced and straight, zero pitch at mid stick they just about hold if you turn the heli side on. I've measured the grips and blade root and have 0.008 thou clearance which could be shimmed if nessecary. The only pat I'm unsure of was linkage rod between flybar cage and washout arm, to level the washout arm I just shortened that link ,everything still moved freely so nothing else was adjusted.
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09-30-2014, 08:25 PM | #6 (permalink) |
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Join Date: Jun 2011
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I once tried some cheap fiberglass blades on a 500 and the tracking never was right. One blade would flex more than the other under load. Switching to decent carbon fiber blades fixed the problem. Just a thought..
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10-01-2014, 02:58 AM | #7 (permalink) |
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Thread Starter
Join Date: Jan 2012
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My FG blades were fine, CG was within 2mm , 2 strips of tape needed to balance .I think I may have found the problem ,a bent flybar ! I stripped the head last night and checked everything . found that the paddle were different weights , and a bearing was tight on the washout arm. I didn't expect a new flybar to be bent ! This will probably explain why the pitch was right at higher revs , centrifugal force straightened it out .Got a few loose ball links also . I've made some shoulder screws for the washout and control arms which should be better than the screws provided . Hopefully with the new parts and a fresh set up my problem will be solved !
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11-17-2014, 02:51 PM | #8 (permalink) |
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Thread Starter
Join Date: Jan 2012
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I thought I'd post an update to my tracking problem and hopefully help others in a similar position. I stripped the mixing and washout arm etc and found incorrect spacers fitted between the bearings , causing bearings to lock up when tightened .New spacers were fitted ,I had to open up the hole in the middle of the arms so the spacers didn't foul. I also found the thread on one side of the wash out base had been drilled diagonally , resulting in washout arms not being parallel swapped this for new align part . so far so good , I had spare good quality main bearings ,so,fitted them . the dampers that came with the kit were'nt very good so align were dampers fitted and anew feathering shaft ,cos I had a spare . blade balance was checked again and everything re-assembled and reset. Tested it on the turntable ,because I had to set the tail and didn't trust hovering it ,blade tracking was perfect . recharged the battery and went for a test flight tracking was out !
I went over the manual again and looked at the feathering shaft sleeve ,you don't get this in the HK kit and my 450 doesn't have it and they work fine ,so I bought one and tried it ,deep joy ! it worked , not perfect but flyable , maybe after few flights everything will bed in , put in a 2nd battery and went again but this time the aile arm broke mid-flight I am now awaiting replacement parts |
11-17-2014, 06:15 PM | #9 (permalink) |
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Yeah that's HK heads If I was you I would get an better head to fly with
If you repair the HK head it will just do it again Taro not that expensive and its quality is generally really good and price not that bad
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