550sx v2 tail wag problem Solved

[Pj1969]

So after 6 months no flying and building a couple of Helis up over the winter,I took my 550 logo to test fly and set up as I bought it (2nd hand) and noticed a slow tail wag from side to side and can't seem to dial it out. Using a scorpion 4025-1100kv, It has mod1 gearing, 10t / 106 main gear, I've tried gov mode, 1850-2050 HS, taken gov off and run 85% flat line TC, adjusted the gain in gyro up and down, but still get the wag. I was told that the HS was too low, but I'm sure logo's run fairly low HS anyway and that 1850-2050 wold be fine??? It has a CC TALON 90 and MSH BRAIN with 550 Zeal blades. Can anyone shed some light or tell me what head speed you are running on your 550sx v2's before I pull my hair out buying different size pinions and reverting back to standard gearing.

[crash-test-tomo]

I gain too high beaut?

[philipjdall]

Logo should run fine with low headpseed (1850 isn't low for a logo) so I certainly wouldn't go changing your gearing. I run 1700 - 2100 fine.

It could be your gain I guess, but a slow wag is more likely mechanical. I'd rebuild the tail hub with care, check no loctite on the tail hub binding the thrust bearings. Also the link balls sometimes have excess flashing from the casting process so you can sand that off. It needs to be free.

Other things to check are... Belt could be too tight, gear mesh could be too tight.

What tail servo?

[Roger_Salmon]

So after 6 months no flying and building a couple of Helis up over the winter,I took my 550 logo to test fly and set up as I bought it (2nd hand) and noticed a slow tail wag from side to side and can't seem to dial it out. Using a scorpion 4025-1100kv, It has mod1 gearing, 10t / 106 main gear, I've tried gov mode, 1850-2050 HS, taken gov off and run 85% flat line TC, adjusted the gain in gyro up and down, but still get the wag. I was told that the HS was too low, but I'm sure logo's run fairly low HS anyway and that 1850-2050 wold be fine??? It has a CC TALON 90 and MSH BRAIN with 550 Zeal blades. Can anyone shed some light or tell me what head speed you are running on your 550sx v2's before I pull my hair out buying different size pinions and reverting back to standard gearing.

My experience with a range of Logos says that the wag you are seeing has a mechanical origin. The tails on logos seem to need a lot of attention to get the mechanism smooth. Eg., I polish the shaft with fine wire wool, clean up and lubricate the plastic balls on the tail grips, reassemble the bearings in the grips, clean out the slider.

[Pj1969]

Went through up and down, didn't really make any difference.

[Pj1969]

Logo should run fine with low headpseed (1850 isn't low for a logo) so I certainly wouldn't go changing your gearing. I run 1700 - 2100 fine.

It could be your gain I guess, but a slow wag is more likely mechanical. I'd rebuild the tail hub with care, check no loctite on the tail hub binding the thrust bearings. Also the link balls sometimes have excess flashing from the casting process so you can sand that off. It needs to be free.

Other things to check are... Belt could be too tight, gear mesh could be too tight.

What tail servo?

Phil took the tail slider apart as it was binding a little, cleaned it up and it looser than a hookers clacker now, belt I can pinch between thumb and forefinger firmly, meshing seems fine, using a ds655.

[dszabo]

Phil, I had a friend who had the exact issue you describe. Turned out to be a small shim missing from the tail blade grip bearing assembly, and it only started to bind when the heli was spooled up and running.

Worth checking all is assembled correctly in the tail grips.

Dean

[Nick B]

Check for cracks in the lever.

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Tail-rotor-lever-for-ball-bearing-02449_b_0.JPG

[Pj1969]

Phil, I had a friend who had the exact issue you describe. Turned out to be a small shim missing from the tail blade grip bearing assembly, and it only started to bind when the heli was spooled up and running.

Worth checking all is assembled correctly in the tail grips.

Dean

Dean, just stripped it all down and used some 1000 paper to clean it while running the motor, really clean, there is a little stiffness to the plastic balls, but still quite free. Just tried it at 40%gain up to 70% and TC from 70-95% and still the same osserlaterion, makes no difference at all. I ran the motor up with out tail hub on and noticed a sligh and I mean very slight movement on shaft, I'm wondering if tail shaft is out enough to make it do it?
Nick, it's all brand new mate and I've put an extra washer over bolt to give it more space so it's not fowling anything. Got me puzzled

[philipjdall]

Have you got another tail servo you can try?

[Pj1969]

Have you got another tail servo you can try?

Only on my trex 550, if I take all blade off and spool up, surely I'd see it pulse???

[Raving Jim]

If it's wagging it's mechanical an 99% it's the plastic link balls , there too tight from new , pop the links an sand them allover with a nail file , when the rod isn't connected it should be really free , also make sure at centre in software , your a couple of degrees against the torque , makes a massive difference to the logo tail in flight .

[kenny d]

I'm with raving Jim , when I've had that problem it's always been some form of binding on the tail mechanism

[Pj1969]

The rear end is all brand new so I'll give it a rub down with some 1000 grit and see if that helps?? Shaft is now all shinny and run really freely. So if not a head speed problem?? Was going to buy new gears lol. I've even checked mesh and seems perfect.

[Raving Jim]

High an low headspeed won't give you an issue, even if it's brand new Sand the plastic balls allover so the links are really free , make sure the main bearings in the frame are OK also .