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SwePilot · 10-10-2009, 03:20 PM

Quote:

Originally Posted by ollie2893

Well, let's think: you have a clock-wise rotor whose thrust force is opposed by a counter-clockwise torque vector. If you increase collective thrust you increase counter-clockwise torque ... and your tail should be expected to kick out to the right. That's what you would expect to happen if the tail is "loose", ie the gyro gain is too low.

So opposite recommendation: increase your gyro gain until your tail begins to oscillate around center (swinging left to right). Then back off a notch or two...

I can try it, please check out post above about gyro placement also.

ollie2893 · 10-10-2009, 05:56 PM

Gyro placement is not really an issue, with two exceptions:
(1) on an EP helicopter the gyro, like the Rx, is exposed to EMI from the motor, BEC, ESC... Everything on these birds pulses like mad. So you should try to keep the gyro as far away from this as you can. (Easier said than done. Also, I have seen plenty of pictures on HF of birds with all sorts of high freq componentry right under the Rx. I would not do it. But these things seem to fly somehow.)
(2) different gyros bed differently; every manufacturer has their own preferred foamy pad. In my experience, mainly gathered in the NP domain, pay up for the original part. On EP people seem a little more relaxed (fewer vibes)...

SwePilot · 10-10-2009, 11:58 PM

I use the original foam pad and its isolated.

But hey, the torque tube shaft aint 100% straight, I can feel a some wobbel by just spinning the tail rotor by hand and holding the torque tube.

This gotta be it right?

ollie2893 · 10-11-2009, 03:18 AM

Chances are that you fitted the end bearings too tightly whereby squashing the tube itself, which responds by buckling (slightly) which leads to a wobble. At high rotational speeds, this wobble will "snap" from side to side every so often, and that will prompt a disruption. Which is indeed quite likely the source of your travails...

SwePilot · 10-11-2009, 04:07 AM

Quote:

Originally Posted by ollie2893

Chances are that you fitted the end bearings too tightly whereby squashing the tube itself, which responds by buckling (slightly) which leads to a wobble. At high rotational speeds, this wobble will "snap" from side to side every so often, and that will prompt a disruption. Which is indeed quite likely the source of your travails...

Might be so, I have also wrecked 3 pair of tail blades

ollie2893 · 10-11-2009, 04:59 AM

Hm ... not sure how a wobbling TT would have contributed to that though...

SwePilot · 10-11-2009, 07:15 AM

Quote:

Originally Posted by ollie2893

Hm ... not sure how a wobbling TT would have contributed to that though...

Can you advice how to fit the bearings and exacty which bearings when i reassemble, Iam ordering a new TT shaft.

Thanks!

ollie2893 · 10-11-2009, 08:10 AM

Sorry, my friend, I fly a belt. I only read about this problem on some other thread. Just make sure that the assembly is not too tight; that the tube does not end up being pushed together by the tail and front pinions. I guess you have some slop in the tail drive assembly, no? That thing, rather bizarrely, has no fixation points. So just make the mesh on both ends sit a little looser...

SwePilot · 10-11-2009, 04:35 PM

Possible remedy: bought 2x torque tubes, new bearings, castle creations ICE 75A ESC.......

SwePilot · 10-12-2009, 03:43 AM

The poor plastic tail servo mounts moves back and forth when the servo works.
I ordered aluminum units. Could be a reason two.

ollie2893 · 10-12-2009, 04:35 AM

Yes, that's awful BUT ... in my experience, this is indicative of the tail pitch assembly being stiff! Forget about the servo and try to push the control rod by hand. Does it move willingly? If you are flying the standard push rod, there's a good chance that it rubs against the guides. I have never been a fan of these assemblies. I prefer to fly the guide-less carbon pushrod (a la Quick UK for Raptor 50). TT and servo wobbles will all be contributors to the twitch...

SwePilot · 10-12-2009, 04:42 AM

Quote:

Originally Posted by ollie2893

Yes, that's awful BUT ... in my experience, this is indicative of the tail pitch assembly being stiff! Forget about the servo and try to push the control rod by hand. Does it move willingly? If you are flying the standard push rod, there's a good chance that it rubs against the guides. I have never been a fan of these assemblies. I prefer to fly the guide-less carbon pushrod (a la Quick UK for Raptor 50). TT and servo wobbles will all be contributors to the twitch...

Its very smooth actually!

Can you link me to those items?

ollie2893 · 10-12-2009, 05:22 AM

This doesn't compute. Where does the torque come from that bends the plastic tail servo holder?

Do a Find for "RT24" on here: http://www.modelhelicopters.co.uk/ac...aptor3050.html. It's pretty much the bottom of the page. The complete kit even comes with a flash new alu servo holder, like you wanted.

ollie2893 · 10-12-2009, 05:24 AM

PS: Being the cheap-skate that I am, I obviously ordered only RT241+RT242

SwePilot · 10-12-2009, 05:29 AM

Quote:

Originally Posted by ollie2893

This doesn't compute. Where does the torque come from that bends the plastic tail servo holder?

Do a Find for "RT24" on here: http://www.modelhelicopters.co.uk/ac...aptor3050.html. It's pretty much the bottom of the page. The complete kit even comes with a flash new alu servo holder, like you wanted.

Thanks for the link.

No its more that the servo isnt attached good to the plastic, not the plastic itself, but anyways alu = good.

jonp · 10-12-2009, 05:54 AM

I have had a similar problem on my new 600ESP - adjusting the gyro gain made no difference. I found a bad lower main bearing - the inner race of the bearing had been spinning on the main shaft causing bad scoring of the shaft, the bearing and also causing inteference that I believe the gyro must have been pickin up (I don't know this for sure beccause I am waiting for the new parts).

When I built the heli I was satisfied that I had tightened up eberything nice and straight but maybe I was a bit off causing this to happen?

Looking at the scorong on the inside of the bearing and the main shaft it must have got pretty hot and made a lot of noise.

Fingers crossed this was my problem!..........and maybe yours...?

SwePilot · 10-12-2009, 06:04 AM

jonp: was it the lower main axle bearing?

jonp · 10-12-2009, 08:15 AM

Quote:

Originally Posted by SwePilot

jonp: was it the lower main axle bearing?

Yes, the lower bearing.

Looking closely at the bearing - I removed the dust seals - the bearings 'look' OK, but something is wrong to cause the inner to turn on the shaft.

jonp · 10-12-2009, 08:52 AM

Here is a picture for you!

SwePilot · 10-12-2009, 08:57 AM

Quote:

Originally Posted by jonp

Here is a picture for you!

Very interesting, I will disassemble mine today!

Thanks alot.

10-12-2009, 05:54 AM	#36 (permalink)
jonp Registered Users Join Date: Jan 2009	I have had a similar problem on my new 600ESP - adjusting the gyro gain made no difference. I found a bad lower main bearing - the inner race of the bearing had been spinning on the main shaft causing bad scoring of the shaft, the bearing and also causing inteference that I believe the gyro must have been pickin up (I don't know this for sure beccause I am waiting for the new parts). When I built the heli I was satisfied that I had tightened up eberything nice and straight but maybe I was a bit off causing this to happen? Looking at the scorong on the inside of the bearing and the main shaft it must have got pretty hot and made a lot of noise. Fingers crossed this was my problem!..........and maybe yours...? __________________ T-Rex 550E V2 / DS-610 / GY401 / 620 / CC ICE 100 T-Rex 600 ESP / DS-610 / GY401 / 9254 / CC ICE 100 T-Rex 700E F3C / DS-610 / GY520 / 650 /CC ICE 2 HV 120

10-12-2009, 08:52 AM	#39 (permalink)
jonp Registered Users Join Date: Jan 2009	Here is a picture for you! Attached Thumbnails __________________ T-Rex 550E V2 / DS-610 / GY401 / 620 / CC ICE 100 T-Rex 600 ESP / DS-610 / GY401 / 9254 / CC ICE 100 T-Rex 700E F3C / DS-610 / GY520 / 650 /CC ICE 2 HV 120

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10-10-2009, 05:56 PM	#22 (permalink)
ollie2893 Registered Users Join Date: May 2009	Gyro placement is not really an issue, with two exceptions: (1) on an EP helicopter the gyro, like the Rx, is exposed to EMI from the motor, BEC, ESC... Everything on these birds pulses like mad. So you should try to keep the gyro as far away from this as you can. (Easier said than done. Also, I have seen plenty of pictures on HF of birds with all sorts of high freq componentry right under the Rx. I would not do it. But these things seem to fly somehow.) (2) different gyros bed differently; every manufacturer has their own preferred foamy pad. In my experience, mainly gathered in the NP domain, pay up for the original part. On EP people seem a little more relaxed (fewer vibes)...

10-10-2009, 11:58 PM	#23 (permalink)
SwePilot Thread Starter Join Date: Dec 2008	I use the original foam pad and its isolated. But hey, the torque tube shaft aint 100% straight, I can feel a some wobbel by just spinning the tail rotor by hand and holding the torque tube. This gotta be it right?

10-11-2009, 03:18 AM	#24 (permalink)
ollie2893 Registered Users Join Date: May 2009	Chances are that you fitted the end bearings too tightly whereby squashing the tube itself, which responds by buckling (slightly) which leads to a wobble. At high rotational speeds, this wobble will "snap" from side to side every so often, and that will prompt a disruption. Which is indeed quite likely the source of your travails...

10-11-2009, 04:59 AM	#26 (permalink)
ollie2893 Registered Users Join Date: May 2009	Hm ... not sure how a wobbling TT would have contributed to that though...

10-11-2009, 08:10 AM	#28 (permalink)
ollie2893 Registered Users Join Date: May 2009	Sorry, my friend, I fly a belt. I only read about this problem on some other thread. Just make sure that the assembly is not too tight; that the tube does not end up being pushed together by the tail and front pinions. I guess you have some slop in the tail drive assembly, no? That thing, rather bizarrely, has no fixation points. So just make the mesh on both ends sit a little looser...

10-11-2009, 04:35 PM	#29 (permalink)
SwePilot Thread Starter Join Date: Dec 2008	Possible remedy: bought 2x torque tubes, new bearings, castle creations ICE 75A ESC.......

10-12-2009, 03:43 AM	#30 (permalink)
SwePilot Thread Starter Join Date: Dec 2008	The poor plastic tail servo mounts moves back and forth when the servo works. I ordered aluminum units. Could be a reason two.

10-12-2009, 04:35 AM	#31 (permalink)
ollie2893 Registered Users Join Date: May 2009	Yes, that's awful BUT ... in my experience, this is indicative of the tail pitch assembly being stiff! Forget about the servo and try to push the control rod by hand. Does it move willingly? If you are flying the standard push rod, there's a good chance that it rubs against the guides. I have never been a fan of these assemblies. I prefer to fly the guide-less carbon pushrod (a la Quick UK for Raptor 50). TT and servo wobbles will all be contributors to the twitch...

10-12-2009, 05:22 AM	#33 (permalink)
ollie2893 Registered Users Join Date: May 2009	This doesn't compute. Where does the torque come from that bends the plastic tail servo holder? Do a Find for "RT24" on here: http://www.modelhelicopters.co.uk/ac...aptor3050.html. It's pretty much the bottom of the page. The complete kit even comes with a flash new alu servo holder, like you wanted.

10-12-2009, 05:24 AM	#34 (permalink)
ollie2893 Registered Users Join Date: May 2009	PS: Being the cheap-skate that I am, I obviously ordered only RT241+RT242

10-12-2009, 06:04 AM	#37 (permalink)
SwePilot Thread Starter Join Date: Dec 2008	jonp: was it the lower main axle bearing?

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