severe yawing back and forth with spartan on 250

[akular1]

Hey everyone,

I have been setting up my spartan gyro to the 250 I just purchased. Unfortunately, I am experiencing some severe yawing left and right...the heli wags strongly when I try and lift it off the ground. Can someone shed some light for me on this? I have also experienced some light wagging on my 500 where I have the spartan installed as well. Any help would be appreciated

Thanks,
Andy

[ndoren]

How are you setting your gain?

[blade strike]

Yeah we need to know more.. Like do you have the new hub / 2mm bearings ? How high is your gain settings? The 250 req. a gain setting that is almost in half of a 500. Have you checked for any type of binding in the tail?

The more info you give when posting will get you a better answer to your problem

[akular1]

Thanks for your reply. I brought the gain down from 35 percent to around 15 percent. I dont know what people are currently using for gain settings.

At 15 percent, there is still wagging...although less so. I was told that I may have to change my deceleration to almost 0. Unfortuantely, I have the black USB connector...I think it was one of the original ones. Is there a way to set this up to almost 0 without using the USB? I was never able to get this USB to work.

Thanks so much
Andy K

PS I do have the new tail hub assembly, and there is no binding whatsoever on the tail assembly

[ndoren]

I have my gain at 64 on a scale of 50 to 100. If you're going 0 to 100, that'd be around 28 on your scale. What happens if you turn the gain all the way off? You should be in rate mode and there should be no wagging whatsoever. Just slop.

The black connector should be just fine for USB... if you are running XP you need to install the driver manually. Your deceleration profile is set to MAX by default, but that should really only affect stops after hard piros. I played with my acceleration and deceleration profiles and neither really has much effect when you hover, so it shouldn't be causing your wag.

Which tail servo are you using? Did you have this issue when using the Align GP750 gyro, or did you not ever install that one?

[akular1]

Thanks for your reply. I actually am using the jr 290 servo. Never got the align version. Not sure what the problem might be. I am going to try and get the USB working again. The version that readyheli currently sells is not the one I have. It is a black usb connector that links to a blue endpiece that goes into the spartan servo. I am not certain what version I have, and when I go to detect it, it doesnt work. anyways, I will try and get this resolved. Any other advice would help

Thanks again!
andy k

[ndoren]

There is a driver for the older blue-plug on spartan-rc.com:

http://www.spartan-rc.com/products/f.../flashlink.php

There should be no problem getting your gyro to work with this driver, your blue-plug USB adapter and your PC.

I'm running the DS290G servo, too, with no problems. All you can do is adjust the end points and servo reversing without the PC, but all the other settings you can't get to yet should be ok. There's a gyro profile for the 250 and the DS290G on Bert's website, once you get to that point. Yet, as I said, the gyro defaults shouldn't be causing such a severe wag.

[akular1]

Thanks so much for your help.

Andy K

[akular1]

hey everyone,

so, I checked everything and downloaded the file for the gyro off of bert's website. There is absolutely no binding, and I am at 20% gain. I still cannot get rid of the motion! Also, when I go into idle up, it swings back and forth violently ...less so and more controllable when I am in normal mode. Does anyone have any ideas as to what the issue might be? I even went as far as moving my electronics thinking that it could have been some sort of glitching. it doesnt appear to be the case. any help would be greatly appreciated!

thanks,
Andy

[ndoren]

Well I didn't think Bert's profile would help, because it's basically the defaults already in your gyro, except for the deceleration profile, which wouldn't have caused your wagging.

How far out on the tail servo arm is your ball link? When you read out the servo endpoints on the PC, what are the values? It's a mysterious problem... the 290 and Spartan should be a rock-solid combination.

You have the single, 2mm bearing installed in each hub?

My idle-up pitch and throttle curves are identical to my normal curves above 50%, which is below the hover point. Thus, when I switch to idle up during hover, there is no change in behavior. What are your curves set at?

[akular1]

Thanks for your response. The ball link is on the closest link on the tail servo. There is moderate yawing in normal mode...my throttle curves are linear in normal mode, and flat in idle up. I know that there is a large rpm shift...but this is also occuring moderately in normal mode. In idle up, it is almost uncontrollable. I am running single bearings in the tail blades. Not sure what can be wrong here ...

Andy

[jimheliboy]

Are your tail blades turning in the correct direction, I am not that up on the 250 just a thought, twist in belt, if not a torque tube?

[akular1]

main blades are going clockwise and tailblades are counterclockwise. My endpoints are both at 100 on the gyro menu

[akular1]

do you think that perhaps there may be a twist in the belt? even though the tail blades are going in the right direction...could the friction of a twist cause the waggin? I will check this out

[ndoren]

It's probably not a twisted belt. Since your tail rotor is going the right direction, you'd need the proper 1/4 turn in the belt, as well as an extra twist. You'd have a mess, and I don't think the tail hub would rotate well, if at all. It's worth checking, though.

As much as I've messed with the tail hub, I've got a bit of experience there (as do many others). It seems to me that you're perhaps experiencing some binding in the tail blade holders at high speeds, even though things seem smooth with the heli off. This would prevent you from finding any "peace" between the tail wagging and a loose sloppy tail, depending on the gain. You may want to disconnect the tail servo control rod at the servo, and double check to make sure things are super smooth. Grab the tail blade holders and "kink" them sideways and check for smooth rotation as you turn them. You can remove the main blades, power up the heli, and move the tail control rod to check for smooth operation under power. Not sure what else you can try.

[Cromer]

I might be way off here but on my Futaba 8U I can use the gyro menu or the gyro channel endpoints to control gain. If for some reason you are using the gyro channel endpoints for gain and not the gyro menu then 100 for the endpoints would be too much gain.

Phil

[akular1]

Thanks for your input everyone. Do you think that I may have a faulty spartan gyro perhaps? Has anyone not had any issues with this setup at all regarding this type of wagging? Ive really exhausted everything. I will check again to ensure that there is no binding, but I was very careful during this setup since I know that this was a critical concern

Thanks
Andy

[micky]

I had a similar problem on my 250 using a Spartan Gyro, are all your Gyro wires clear of the servo wires (not cable tied together),? if not they need to be because this will give you a problem, improved my set up.

[akular1]

wow..really? i did not know that this would pose an issue. Everything is bunched up together because of the limited space within the frame. How bad was your issue?

Thanks,
Andy

[ndoren]

It really sounds to me like the infamous "tail problem," and not your gyro. It just sounds all too familiar in terms of your heli's bad behavior, based on what so many others have gone through, including myself Are you using the squishy foam tape to mount your gyro? The pad that came with the gyro, that is? Have you tried cutting down the tail blades, as has been done successfully by many others? I noticed with my tail that while trying to fix it, I never had any binding or rubbing, yet depending on the bearings I used, the tightness, etc, the tail issue would get better then worse. I also noticed that stacking bearings and further reducing tail blade holder slop made things worse for me, not better. Someone else mentioned this, too. As a last resort, you can try backing out the tail hub screws a turn or two, and actually add a bit of slop to the blade holders. Try a test hover (and be careful so as not to have things come loose in the tail). It's worth a try and only takes a few minutes. The tail blades are cheap, and if you cut down a set and it doesn't work, you're only out a few bucks.

My gyro wires are squished down behind the gyro. Not much choice, given the long length of the leads. I don't have them near the servo wires, though. Well, you can only get them so far apart, obviously. As a test, you could pull out the gyro wires and tie them to the outside of the frame, far from anything else. Ugly as can be, but only very temporary for testing the setup.