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View Full Version : Still a wag :( New gyro, New Tail Servo, or both?


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Ah Clem
10-15-2010, 02:40 PM
PitchOrDie,

"optimal ball distance on the tailservo is ~4.5mm worked best for some friends and me"

I am curious as to whether you are using the metal tail bellcrank-which is longer than the stock bellcrank on the input side. This might explain why mine is working with the ball further out that yours.

"I would advise before you gonna buy a new gyro, get a beastx it's about the same price as a good gyro (at least in europe), and trust me the 250 likes being FBL so do you!"

I could not agree more. The MicroBeast is even better than the Spartan on tail control (IMHO) and the 250 is excellent as an FBL machine.

Excellent to compare notes on this!

altascape
10-15-2010, 04:59 PM
To stop the wag I used a carbon push rod and v1 tail :confused: on my 250 SE. Tried everything else and nothing seemed to work . Using an Align gp750 and a jr 386 servo

PitchOrDie
10-15-2010, 05:20 PM
PitchOrDie,

"optimal ball distance on the tailservo is ~4.5mm worked best for some friends and me"

I am curious as to whether you are using the metal tail bellcrank-which is longer than the stock bellcrank on the input side. This might explain why mine is working with the ball further out that yours.


Ah Clem

Yes we 2 friends and I are using the metal tail bellcrank, we have tried different distances for the ball link, our findings on the 3500G and beastX was a sweetspot at arround 4.3 to 4.6 mm with the 40mm KBDD tailblades, we have tried between 4 and 6mm. At least for us this seems to work pretty well.


I could not agree more. The MicroBeast is even better than the Spartan on tail control (IMHO) and the 250 is excellent as an FBL machine.

I have the same impression as you, the tail control on the MicroBeast is really outstanding, I mean I was really amazed how good the spartan quark did, but beastX topped it.

I can't wait until MicroBeast is releasing the adaptor cable for sats, then my wiring dreams on the 250 comes true :)

Trex600JC
10-18-2010, 07:15 PM
Not sure if anyone answered this but i was having the same problem and it ended up being a setting in my control. Make sure your gyro gain is set very close, or equal. I think mine is at 0: 65 and 1: 65...the gain.
I swapped out everything like u, did that and works fine.
goodluck

Steve Joblin
10-18-2010, 07:27 PM
I tried the metal control arm... still wagging.
I tried 0 delay and 100 delay... still wagging.
Tail is not binding... still wagging.
CF Tail Pushrod... still wagging.
Servo ball is at 4.5mm from center.
Tried the small batwings, the larger batwings, and the 42mm straight cut tail blades... still wagging.
My gain settings are 0: 62 and 1: 62... still wagging.

dbennettya
10-18-2010, 07:44 PM
Steve,

If you back off on the gain more does the wag stop? Try 51 or 55 is there still wag? If not is the tail loose when flying or is it locked. Are you sure you have the gain plugged into the right RX channel? Is the plug in the RX reversed (doesn't damage anything due to + in the center)? My WK-2801pro is set for AUX2 and under the input screen it shows AUX2/GYRO. Under the gyrhld mine shows gyrosens then GYRO/AUX2 0:64% and 1:35%. So position 0 is set for HH and position 1 is set for rate mode for adjusting center rudder position for minimum drift.

Hope this helps, Don

I tried the metal control arm... still wagging.
I tried 0 delay and 100 delay... still wagging.
Tail is not binding... still wagging.
CF Tail Pushrod... still wagging.
Servo ball is at 4.5mm from center.
Tried the small batwings, the larger batwings, and the 42mm straight cut tail blades... still wagging.
My gain settings are 0: 62 and 1: 62... still wagging.

Steve Joblin
10-18-2010, 08:35 PM
I'm pretty sure my gain is plugged into the receiver correctly... if I set the gain at 70, I get a real bad fast wag... if I set it at 55, I get a smaller , but slow wag. If I go much lower, the tail doesn't hold. So I start at 65, go to a hover, notice the wag, land, lower the gain by and and repeat the process... There is no number at which the tail will remain still. I can set the gain so it isn't as bad as if I set it at 70, but shouldn't the tail hold perfectly still when simply hovering in a closed room?

g9w7bje0140

Cadjocky
10-18-2010, 09:02 PM
Hello steve,

Been following your plight. Although I have the quark + ds290 your issue sounds familiar regarding dropping your gain down to rate mode and still have the wag. Awhile ago I experimented from 0 deg to 8 deg tail pitch setup and reset the tail end points. After that I had wag that would not go away even with dropping gain down into the rate mode threshold. So, I moved my servo ball in from 5mm to 4.5mm and the wag was gone and gain set at 63%.

I believe I read that you moved yours to 4.5mm.....try 4mm, who knows might work. :dontknow

Steve Joblin
10-18-2010, 09:16 PM
Funny you should mention moving the servo ball... I have always had mine at 4.5, which is the closest mounting hole... so I wondered if I could get it really close and see if that helped.

I couldn't get the ball real close as the screw is in the way, so I made a piece that attaches over the horn and enabled me to get the ball closer to the center... well guess what? my big wag went to a smaller wag (which makes sense)... the servo is still oscillating, so it still moves the horn which moves the rod, etc., etc., etc.

So, short answer is that moving the ball closer to the center does reduce the distance traveled by the ball, but it doesn't stop the servo from oscillating :(

http://www.helifreak.com/attachment.php?attachmentid=185610&stc=1&d=1287450976

http://www.helifreak.com/attachment.php?attachmentid=185611&stc=1&d=1287451072

Tomy.
10-18-2010, 09:49 PM
I'd think that (might) make things worse. Moving the ball in reduces the forces required by the servo, but increases how far (and fast) it needs to travel to compensate for accidental tail moves. Think of it this way: the further "in" the ball is, the larger the turn required from the servo to provide the same tail pitch (this also limits the max pitch by the way). The larger the turn required, the slower the response. The slower the response, more likely by the time the pitch is inroduced, it's too late, the tail is over the required position and the gyro needs to adjust back. Hence the wagging.

From the other hand moving the ball out will increase the forces required, but improve response time. If you have the chinese weights that reduce the forces required by the servo, you might want to consider experimenting with moving the ball out. I just installed my chinese weights over the weekend but did not have the time to move the ball out and see if it reduces my occassional 1/2" wags. Hopefully tomorrow.

Cadjocky
10-18-2010, 09:49 PM
That's pretty close to center :shock:, nice work :thumbup:


Looks like you have been thorough with the mechanics, time for electronics.
The jr ds290 is relatively cheep around $34 might be time.

Corrari
10-19-2010, 04:59 AM
I had a prob with my 600 and after trying everything inc new servo, bec, gyro, it turned out to be the cnc tail grips. Swaped them out for the stock plastic ones and wag gone. It may be something to do with the bearings in the grips.

Just a thought.

pitchp
10-19-2010, 06:31 AM
oh man steve, you still haven't found the problem? Did you end up ordering a new gyro or was it the servo? Anyways I just watched your heli video. I just don't understand it. When you spooled it up, it's super smooth compared to my piece of crap. I think I have a bent main shaft. hmm Let me rephrase that, I have a bent main shaft, but I don't have the wag. I even had the flybars facing the wrong way around and she was flying smoothly(the hex screws were loose, i forgot to threadlock it), until someone pointed it out to me. I just don't understand. That gyro must be super sensitive or is a baad gyro servo combo. I got to get a video of my beater heli, to show you the main shaft osciallting, but the tail is good. I've crashed it a couple of times(pilot error, I crash all the time), but these things happen. :) I hope you get your new gyro/servo soon!

Starcruiser
10-19-2010, 10:21 AM
it has gotta be vibes in the tail causing this, I would tear the tail apart and go over it.

ATM I am experiencing a slow wag on one of my 450's, this is after I replaced the tail case, I will be putting the old one back on today to see if this resolves it.

I noticed when spooling up the tail case is vibrating (up and down) but the head is smooth. When it is up to speed I do not see the vibe. There is no tail shaft oscillation (bent shaft). So it must be the belt, pulley or bearings in the tail.

Just a thought for you to consider

Steve Joblin
10-19-2010, 10:46 AM
Funny... that is what got me started down this road in the first place...

I started with a CopterX 250SE, and "cheap" electronics... It all worked "o.k.", but the tail wasn't holding like I thought it should and there was a bad wag... I figured that it was due to the poor quality gyro and tail servo, so I figured I would get a GP780 and DS420 combo. The cost of the Align 250SE Super Combo was just a few dollars more, so I decided to get the entire Super Combo. I just used the GSP780 and DS420 on my CopterX but the tail was still wagging... then I replaced the motor and ESC... then I replaced the entire head assembly... then I replaced the entire tail assembly. I am right back where I started... I have the same wag that I did with my CopterX! Very annoying.

I only had one crash which I used the opportunity to replace the main shaft, feathering shaft, and Metal Tail Rotor Shaft Assembly.

Starcruiser
10-19-2010, 11:24 AM
Steve,
Some of the OP have replaced the tail case/assembly with the MH unit and had good results. I am stock on my 250SE tail except for the CNC pitch arm, I did grind the hub down a bit to reduce the slop and the tail holds well, not as good as the 450 but well.

The other 450 I mentioned is the one that developed the slow wag and it is using a JR 370 and a 3500G servo. I can see the horn oscillate when I spin it up on the bench, it is worse at certain speeds so I know this is a vibe issue. I have been trying to track it down and have rebuilt the head (needed it anyways), replaced the OWB and gears (had a spare) and the front tail pulley assembly (again have spares). SO the last item is either the gyro is the culprit or the tail case I put on is a problem.

I am betting on the tail case ATM, I have a spare one of these too so I will change it out and see what it does.

I would suggest that you pull the main blades and tail blades and watch the head and then tail for vibrations while spinning her up, notice at what speeds the vibrations occur. Watch the pulley for any oscillations (out of true) as well as the shaft being bent. You will need to spin her up and down a few times to catch slow speed oscillations.

bullet3030
10-20-2010, 05:46 AM
JO steve,

Did you fixed the tail wag problem??
I have an 450 sport with the same electronics and have the same wag.
I also tried many things and it's driving me :bomb:

dizzymarkus
10-20-2010, 06:57 AM
Hey Steve -- a might bigger than a 4g6 ah? lol

I see you are fighting the dreeded wag with the 250 's tail. I cannot say this willwork for you --however this works everytime I rebuild (;)) and get the wag, hopefully it will for others.

Some of the OP have replaced the tail case/assembly with the MH unit and had good results

I have a gyro in which I can dial out left/right prio speed and stops so I can dial some of it out, but I only changed the grips and case witht he ALIGN bellcrank .I bought the wholes case and could not get it to flow smoothly without the slider binding -- as others but some had more patience but the ALIGN slider works great. The problem IMHO is in the grips and the bearing stack of the stock grips. MH tolerances are much closer as they are after market and are suppose to be :smokin: I still end up with a remote gain of 22 on gear channel but shes locked in tight upside down or right side up, JR290 tail servo (did the heated pin trick to get a spot so close im about on the spline) scorp motor, inertia 860 gyro, smallest batman blades in kit -------spot on :thumbup:

Markus

Steve Joblin
10-20-2010, 09:31 AM
Yep... still have CWS (Cronic Wag Syndrome). :(

Dizzy: Looks like you have made the leap I was trying to avoid which was getting a new gyro and tail servo... I have the latest version tail grips with the built-in weights, one bearning and a single step washer. I've tried some pretty small blades, and still have a wag... mind you, I am not trying to do anything "fancy"... just hover. Thanks much for the thoughts though... I might try the JR290 as I don't like the size (or cost) of the 3500G!

Starcruiser
10-20-2010, 10:12 AM
Steve,

Check the tray you have the gyro mounted on, is it loose? Some have had issues with it wiggling thus causing gyro issues.

Steve Joblin
10-20-2010, 10:23 AM
Tight as a drum... I even put a drop of CA on each of the mounting tabs to ensure that it wasn't loose.

Steve Joblin
10-20-2010, 11:51 AM
Breaking News! Breaking News! Breaking News!

Just for fun, I decided to play with the settings...

I changed the BEC Output Voltage on the ESC to 6.0V

I changed the GP780 Digital/Analog Setting from "DS" to "AS"

My wag is... dare I say? GONE!

It is almost as though my servo is too sensitive and was reacting too fast for the gyro?

The tail is kind of "mushy" and doesn't hold super tight, but at least I can hover without a wag!

Very Very Very strange!

Tomy.
10-20-2010, 01:06 PM
Can you increase the gain to the point where the mushiness is gone before the wag comes back?

Steve Joblin
10-20-2010, 01:08 PM
Sort of... still working on it, but I think I may be on the right track!

Tomy.
10-20-2010, 01:22 PM
What happened when you went up to 6V and kept the gyro setting on digital servo?