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Old Oct 30, 2009, 09:40 PM
Team Wack-a-Mole
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Maryland
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Quote:
Originally Posted by skizziks View Post
techspy you might be a little nose heavy with anything larger than a 3000mah....You can use an A123 battery...They are more expensive but they last longer, safer and take only 20 minutes to charge....http://www.bphobbies.com/view.asp?id...2&pid=D0626122
lasts longer? Everything I looked into A123 told me they were heavier and you got less flight time cause they were smaller for something even heavier than a 3000mAh.
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Old Oct 30, 2009, 10:00 PM
Gone Flying.
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Western NY
Joined Nov 2006
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Originally Posted by MikeHRC View Post
Agreed - and I think that the EXI 500, HK500GT, Flasher 500 and Bullet 500 (that I have) are all made by Skya (actually I don't think that the Copterx is).

I had some tracking issues with mine - it turned out to be a combination of the plastic mixing arms (twisting under high forces) and the wash-out base being over-size on the mainshaft - I replaced the wash-out block with an Align one and the mixing arms with metal Skya ones and job-done.

Mike.
For those of you who have successfully adjusted your blade tracking, I haven't been able to get the blades to track consistently, so I'm not having any luck here. At varying head speeds, the blade tracking goes "off", I could spend all day adjusting tracking and it'll never be perfect under these circumstances. When I run above 60% throttle on 6S, the head speed seems really high, though I haven't tach'd it yet. The higher the head speed, the more the blades spread apart. I wouldn't dare push the throttle up near 90% as a result, and I'm not flying it until the tracking issues are squared away.

Looks like I may have to go the route of MikeHRC and replace that washout base as well as the non-metal mixing arms.
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Old Oct 31, 2009, 01:32 AM
Have a go, it might work!
Melbourne, Australia
Joined Feb 2004
696 Posts
I had a look at my tail and it has a small diameter brass washer under the screw. No chance of it rubbung on the outer bearing race. There goes my theory.

Cheers,

red
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Old Oct 31, 2009, 08:31 AM
Team Wack-a-Mole
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Maryland
Joined Oct 2008
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the bad tracking can also be fiberglass blades or dampers. The stock Skya dampers are rather soft.
Yup,HK and EXI at least are all Skya. Just built to different specs.
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Old Oct 31, 2009, 11:05 AM
Gone Flying.
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Western NY
Joined Nov 2006
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Mel -

I did notice some softness to the dampers. Not sure how the blades could be the cause of the tracking problems, they were balanced and there is virtually no vibration in the heli until head RPMs come up over 65% throttle. At that point, the blades spread out of track and vibration is introduced. I think the symptoms I'm experiencing are indicative of what MikeHRC pointed out earlier in the thread, the non-metal mixing arms aren't holding up at higher RPMs. I checked the washout base, it doesn't appear to be over-sized from what I have observed, though I haven't checked it in any detail.

Does anyone know whether or not the "SF Mixing Arm" Align part is metal or plastic? The part I'm referring to is here.
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Old Oct 31, 2009, 12:14 PM
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Southwest Florida
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Quote:
Originally Posted by rcnewb View Post
Mel -

I did notice some softness to the dampers. Not sure how the blades could be the cause of the tracking problems, they were balanced and there is virtually no vibration in the heli until head RPMs come up over 65% throttle. At that point, the blades spread out of track and vibration is introduced. I think the symptoms I'm experiencing are indicative of what MikeHRC pointed out earlier in the thread, the non-metal mixing arms aren't holding up at higher RPMs. I checked the washout base, it doesn't appear to be over-sized from what I have observed, though I haven't checked it in any detail.

Does anyone know whether or not the "SF Mixing Arm" Align part is metal or plastic? The part I'm referring to is here.
It could very well be your blades. What kind do you have?
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Old Oct 31, 2009, 12:23 PM
Team Wack-a-Mole
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Cheaper fiberglass blades will flex more and the flex can varry with temperature, RPM and the phase of the moon.

There is flex lengthwise and chordwise on fiberglassblades. Most Fiberglass blades will begoodlengthwise (not as good as CF) but will be able to be twisted more than CF.
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Old Oct 31, 2009, 12:35 PM
Gone Flying.
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Western NY
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Quote:
Originally Posted by Melnic View Post
Cheaper fiberglass blades will flex more and the flex can varry with temperature, RPM and the phase of the moon.

There is flex lengthwise and chordwise on fiberglassblades. Most Fiberglass blades will begoodlengthwise (not as good as CF) but will be able to be twisted more than CF.
I am using these blades from helidirect. They are fiberglass, but I had the same problem with the stock blades (I think they are the same with identical design/coloring). I can adjust tracking spot on by adjusting the linkages accordingly, as soon as I increase head speed, the blades go off track by as much as 1-2". They are literally spreading out like a fan at higher head speeds.
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Old Oct 31, 2009, 12:41 PM
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Kyalami, South Africa
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I bought a set of the HK500GT tail grips which arrived recently. I totally dissembled them and put them back together. They have a standard axial bearing as the inner race, and radial bearing as an outer race. This is the same as the T500 arrangement on their tail grip. There are a few small differences:

1/ The GT tial grips have a spacer washer of around .9mm between the inner race half and the grip.
2/ The arms arm 1mm thicker on the GT grips.
3/ The GT grip has a 1mm chamfer between the bearing mount and the start of the blade grip itself.
4/ There was no grease on the radial bearings on both sides.
5/ The grips themselves are machined a littlle too big for the inner axial bearing. The grip dissembles leaving the bearing on the hub not in the grip.

All in all they look quite good quality. I will try one out and see how it works. For $11 they seem a better bet than the Align part.

http://www.hobbycity.com/hobbycity/s...il_rotor_grip_
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Old Oct 31, 2009, 01:20 PM
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Southwest Florida
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Quote:
Originally Posted by rcnewb View Post
I am using these blades from helidirect. They are fiberglass, but I had the same problem with the stock blades (I think they are the same with identical design/coloring). I can adjust tracking spot on by adjusting the linkages accordingly, as soon as I increase head speed, the blades go off track by as much as 1-2". They are literally spreading out like a fan at higher head speeds.
Check your feathering shaft to make sure it's straight. PUt a piece of tape on the blades and test hover the heli. Adjust the blades one turn at a time on your ball links. If that still fails, try another set of blades. It can be a frustrating process at times but you'll get it. Jim
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Old Oct 31, 2009, 03:20 PM
Gone Flying.
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Western NY
Joined Nov 2006
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Jim -

Thanks for the info - feathering shaft is brand new, an Align T-Rex 500 shaft (I bent the stock part earlier in the week when I put my HK-500GT into the ceiling), and I tested it out by rolling it on a flat metal surface, it's perfectly straight. Main shaft spins true, no wobble in the gears. No vibration in the heli when spinning up without the blades attached, and almost no vibration when the blade tracking is spot on at around 1900-2000 RPMs. At lower head speeds, I can get the tracking spot on by linkage adjustment. At higher speeds, the tracking goes way off.

Perhaps the blades are the culprit, though I ordered a set of metal mixing arms and a metal washout base (Align parts) - anyone have recommendations for a vendor in the US that sells 425mm C/F main blades real cheap (i.e. around $40 or less)? If I'm gonna get new blades, I'll just go with C/F for the additional rigidity.
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Old Oct 31, 2009, 04:09 PM
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Kyalami, South Africa
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A common problem on the T500 is the balls loosen slightly on the grips after a crash. Check the ball tightness to see if this is not the problem. I had plastic mixing and washout arms on my T500 for 1 year and 400 flights, and never had any issues....
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Old Oct 31, 2009, 10:16 PM
Gone Flying.
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Western NY
Joined Nov 2006
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Quote:
Originally Posted by kyalamikid View Post
A common problem on the T500 is the balls loosen slightly on the grips after a crash. Check the ball tightness to see if this is not the problem. I had plastic mixing and washout arms on my T500 for 1 year and 400 flights, and never had any issues....
I hear you on that one, the first thing I did after that crash earlier in the week was to re-tighten all ball links on the head, to be honest nothing loosened up. This wasn't a typical crash either, I mean how often does a heli punch upward into a crash (well, I guess it would be similar if a heli was crashed during inverted flight from too much positive pitch). I'm not really sure what is causing the blades to go out of track at varying head speeds. I've ordered c/f blades as well as the metal mixing arms for the head, I will swap off the blades first, if the tracking issues remain, I'll replace the non-metal arms on the head. I'm determined to pin this problem down...
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Old Nov 01, 2009, 04:09 AM
Team Mulikow 3D
Oxfordshire, UK
Joined Jan 2007
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Quote:
Originally Posted by kyalamikid View Post
I bought a set of the HK500GT tail grips which arrived recently. I totally dissembled them and put them back together. They have a standard axial bearing as the inner race, and radial bearing as an outer race. This is the same as the T500 arrangement on their tail grip. There are a few small differences:

1/ The GT tial grips have a spacer washer of around .9mm between the inner race half and the grip.
2/ The arms arm 1mm thicker on the GT grips.
3/ The GT grip has a 1mm chamfer between the bearing mount and the start of the blade grip itself.
4/ There was no grease on the radial bearings on both sides.
5/ The grips themselves are machined a littlle too big for the inner axial bearing. The grip dissembles leaving the bearing on the hub not in the grip.

All in all they look quite good quality. I will try one out and see how it works. For $11 they seem a better bet than the Align part.

http://www.hobbycity.com/hobbycity/s...il_rotor_grip_
My tail wouldn't work properly with the non-thrust-bearing set-up, as soon as I changed to the Align thrust bearing grips all was good.

Mike.
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Old Nov 01, 2009, 07:10 AM
Vertical Unlimited
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Mandurah, Western Australia
Joined Mar 2007
522 Posts
Bad blade tracking

I had this problem on my T-Rex 450V2 a while ago, and it was driving me CRAZY. I couldn't even get the blades to track - every adjustment (even on the "fine" (long) arms) caused the tracking to overshoot. I stripped down the head in desperation, and it turned out the see-saw arms were loose. I removed the bolts, added RED Locktite, and resecured them, and finally I achieved consistent tracking. I couldn't see this without stripping down the head due to the mixing arms obstructing the view. [hope I got the names of the components right].
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