Uncontrollable spinning

[kiwi1080]

Well it seems if it isn't one thing it's another!! I have my T-rex set up with the pitch so that it wants to start taking off at just over 50%, perfect! Got it to take off today for a short hover until the hext issue began Now the issue seems to be that it wants to spin to the left uncontrollably. No amount of right stick and trim will stop it from doing it. It almost seems like the tail doesn't have enough power, which is not right as it is belt driven. I have the blades on the right way on the tail going counter-clockwise before you ask ;D. Anyway, I would assume that this would be something with the gyro, but even without a gyro it shouldn't spin like that should it? Everything else seems fine except for this new, but very large problem. Any suggestions would be great as I am itching to finally get this thing flying!!!!!

[fergie]

i just had this problem w/my blue ray. it turned out to be how i mounted my gyro, it liked to be mounted on it's edge( not stock BTW). i know you know what your doing kiwi but i thought i would throw this in just in case. ya know what i mean? ya it could be something totally different to, so.......
take care

[McKrackin]

Have you tried sliding the servo forward on the boom to shorten the throw?Sounds like the servo is positioned where it can't get enough right stick to work.

[McKrackin]

Turn on your throttle hold and give it full right rudder and see if the slide goes all the way left against the boom.

It should.

[Doozer]

Mar 12, 2009 16:47:21 GMT -6 fergie said:

i just had this problem w/my blue ray. it turned out to be how i mounted my gyro, it liked to be mounted on it's edge( not stock BTW). i know you know what your doing kiwi but i thought i would throw this in just in case. ya know what i mean? ya it could be something totally different to, so.......
take care

Had the same problem as fergie and you kiwi. Had to change gyro positioning like fergie. Also try the reversing on the gyro.

[kiwi1080]

Yeah I thought it may be something with the gyro and thats what it sounds like. I will have a play round tonight and tomorrow and see what I can do. I'm so close to flying it now I can taste it...I am getting plenty of travel in the tail as you mentioned Ern so will just have to play round until I get it. Fergie, the gyro is mounted upright as the manual says so hopefully positioning is good. It is also as close to center of the heli as I can get it by my reakoning. Will let you know how I get on, thanks guys.

[jerry]

Have you checked to be sure that none of the gears are slipping on the shafts?

[akent]

Hi Kiwi:
I have been reading your posts about the Trex and some of them are really pretty scary.
Did you really watch the Finless Bob videos for setup?

Have you done some research into why you are having the problems that you have had?

A spinning tail can be caused by a few things.
1. Loose belt or pulleys.
2. Radio rudder direction backwards.
3. Gyro direction backwards.
4. Tail spinning backwards.

I hope it's easy to find for you!

Best,
Kent

[Doozer]

the other thing you can try is to reduce the gain. I reduced my gain until it had just a touch of with torque spin, but still had some gain to speak of. Then i hit the rudder sub trim a little... Nice and straight.

[kiwi1080]

I think I found the problem and I kinda don't want to say... Will test it out and then let you know if that was the problem. It is something pretty simple that I completely overlooked I think.

[Doozer]

haha.... man... no worries. I don't think anyone here has been without making the "No Sh!t" error. I left the screw out of a servo horn and burnt up a servo and ESC... just recently.

[kiwi1080]

Well after running through some simple stuff to remove the idiot factor, I have come to the conclusion that I have no freakin idea what is wrong!! The gyro responds to movement by hand, the tail rotor is spinning in the right direction and has enough pitch and travel, and no amount of trim will stop it spinning. The interesting thing is that it changes its direction of spinning from left to right depending on how it feels I think. Been trying some ideas with the guy at my LHS but to no avail. Going to see him again on Wednesday and really get this thing sorted. Spring is here and I can't fly, hate it!!

As a side note, I managed to shear the main shaft of my HB off yesterday and can't work out how either. I flew it for 2 batteries, charged them and went outside for a 3rd. There was a massive wobble, I landed it, took off again, and then BAM, off flew the whole head . It was the extreme metal upgrade and for some reason the head sheared off the main shaft, must be really soft or something. Anyway, not a good couple days of flying overall but I'm hoping for the best on Wednesday. If not there will be a broken man before you on Thursday!!

[akent]

Hi Kiwi:
With a little more info, we can figure this out!

I just finished building my 3rd 450 today, an Exi T450 Carbon Fiber version.
I am running a G401B gyro from XMhobbies (cnchelicopter.com). These are very similar to the Futaba 401.

I robbed this one from my Exi 450 SE, until another one shows up from DealExtreme (if it ever does).

It mounted upside down on the T450 and had to be mounted right side up on the SE.
Because of this, the gyro itself was backwards working. I just assumed it would work and spooled it up.
The heli spun like crazy in one direction, but when I used transmitter rudder to compensate, it would go crazy in the other.

This was easy. Just needed to reverse directions on the gyro. I already had to reverse the rudder channel on the transmitter, but that one is obvious when you are setting up the bird. When bypassing the gyro with initial setup, you know what direction it should go in.

Otherwise, what are the symptoms in detail?
Kent

[kiwi1080]

Kent, thanks for the advise on the servo, mine is doing exactly what you described. I tried putting up the % on the gyro setting in the DX6i and that gave better servo movement but still the spinning issue. I also tried reversing the gyro to no avail. The belt tension is good and the belt twist in the boom is the right direction as per the manual. The gyro is definitely registering movement and moving the servo the right way so not sure why it continues to spin like crazy. Will do some more playing round today and see what I come up with. If all else fails I am going to see the same guy again at the LHS to get it worked out. Thanks again for all the help guys.

[kiwi1080]

BOOYAH!! Got it sorted finally!! It was a combination of reversal switches and the idiot factor on my part, lets just leave it at that . It was one of those instances where you look at something 20 times thinking everything is good then suddenly a light goes on and you realise what you effed up. It hovers smooooooth now. Just need to adjust a couple linkage trims and then she will be rock steady. I'm charging the battery and then I will get my wife to take a vid of it and hopefully post it up soon, finally!! Next issue is whether or not the laptop will work online to post the vid but thats another story....