I have had it with this problem. I cannot figure out why my t-rex is spinning everytime i spool her up?

I bought this Trex 450XL complete package off a friend of mine who is in Iraq. I have an Eclipse 7 radio and the trex was flying great!

One day I went to fly and all it did was spin around in circles. I never crashed or anything. I own a blade CP and since i didnt put the Rex together I dont know all the basic functions or how to fix issues that arent in plain sight.

At first I thought i had the Gyro reversed, but i tried adjusting the gain and the reverse switch and it has very little effect on how fast it spins.

It is using a Telebee head lock Gyro

I made 2 videos of the problem and also with some close ups of my t-rex.

Maybe someone can suggest something. I am almost ready to replace the Gyro, but i want to make sure other people agree that's my problem.

I check the rear tail servo, and it seems to work when it initilizes on start up, its an HS56.

Video #1 is here http://media.putfile.com/Trex-Spin-1

Video # 2 is here http://media.putfile.com/Trex-Spin-2

Thanks so much for anyone who can take a minute or two to help!

-Jeff

I would check to make sure that the tail drive belt isn't slipping on the front gear.....that would make it spin. Also, if you have it set up to where you can remotely alter the gain settings on the controller, you might want to make sure that it didn't accidentally get switched out of heading hold mode.

It definitely looks just like a reversed gyro though.

When you move your rudder stick to the right, the tail pitch servo should pull the push rod towards the front of the heli, and if you hold the heli (throttle hold on) with the nose pointing at you, and rotate the heli to your left, the tail slider should go towards the boom, and the servo should pull towards the front of the heli.

If your gyro is pushing the tail slider in the wrong direction, then you need to reverse the gyro. If the rudder stick is pushing the slider in the wrong direction, then you need to reverse your rudder channel on your receiver.

Can't tell from the video, but in view of the fact that hitting the reverse switch doesn't do anything, your initial tail set up may be wrong. Be sure the Tail rotor blades are essentially in "Neutral" position ie:Flat with the rudder control in Neutral and the Tail servo in neutral. Of course check for proper servo travel, proper direction of servo & blade travel, both with rudder control & rotating the Heli. The tail rotor seems to be rotating in the correct direction, but are the blades pitch changing properly? I would guess they are not.

Lloyd.

Hi Jeff,
It looks to me like your tail blades are spinning backwards.
It is hard to tell from the video, but the front half of the tail rotor, the half closest to the main blades, should be traveling up.
The second vid does not show it, but the first does at 45 seconds, and a little more clearly at 1:03.
Again, I am not positive that it is backwards, it could just be a trick of the frame rate of your video camera.
Try turning the main blades by hand, in the proper direction of rotation. The tail blades should rotate up through the downwash of the main blades.
If they do not, then it means that your twist in the belt went the wrong way.

Let us know if this in indeed the fix.
Vince

I see it now!!!! you have the belt twisted the WRONG way. its a easy mistake. You can see it if you spin the main rotor clockwise, the tail should be counter-clockwise. in other words, the tail should cut from bottom up.

Flytoolow is right......it sure looks like your tail blades are rotating in the wrong direction.

I wasn't even looking for things like that, because Jeff had originally said that he just went to fly it one day, and it was like this. Someone would have had to physically turned the tail belt, to get the blades to turn in the wrong direction........he made it sound as if it hadn't been touched.....strange.

Yep--Jeff- the tail rotor is spinning backwards even though the blade are correctly oriented. Twist the belt 180 degrees and "ALL BETTER".

Lloyd

Hey guys I have a problem with my T-Rex also, maybe someone can help..... I baught a combo deal off ebay (HDE kit, Align 25A ESC, 3500KV align motor, align headlock gyro, and acouple of batteries.. I use a Futaba 6EX TX with the RX that came with it..) and just finished putting everything together. Everything seems to work fine except the motor will cut out for maybe 1/4 second randomly whenever it feels like it.. Sometimes as soon as I lift off, other times 3 minutes later, and its not just once, it will keep doing it randomly maybe every 5-30 seconds. I still have complete control of everything when it cuts out, and it comes right back on and still flyes fine.

First I thought it was the ESC or battery, but I tied the heli down to a table and unplugged everything from the receiver except for the ESC and ran it for 5 minutes and the motor worked fine.. Then I plugged pitch, alieron, elevator one by one and everything still worked fine.. Now I get to the gyro.. Once I plug it in, the motor starts doing its cut out thing again. I thought the gyro might have been too close to the receiver, so I moved the receiver a lot closer to the front of the heli, and on the bottom so it is very far away. The motor still did its cut out thing... Now I unplug the tail servo from the gyro, while keeping the gyro plugged into the receiver and the motor works fine.. The tail servo is an HS-65..
So basically I think now there is some type of conflict with the tail servo. I'm not really sure what it is conflicting with or how to fix it..

Anyways, this is where I am stuck right now.. If anyone has had this problem or has any suggestions, please let me know. Thanks!!

You may have a bad gyro, or more likely radio interference. It's been dealt with a great deal in these forums. Check them out. Doubt if the gyro will interfere with the receiver, but keep the ANT away from it & the servos esp the tail servo & servo wires..
However- A few basics. Keep your Radio in back & ESC in front. Make sure Batt is good. Batt cut off as low as possible on ESC.
Route ANT away from the motor & ESC . Be sure No BARE wire on the ANT touches the frame, boom, etc.(I use the Dean ANT)
Check the Main shaft--There shound be NO vertical movement at all--If there is, tighten the collets. Same for the "Top" of the rotor head. With all due respects, I Mean ZERO motion. Even .1mm can cause radio problems. You might very lightly spray the belt with a static suppressing spray, like one for TV or computer screens. The belt can develop a huge static charge.Then again if all else fails (I doubt you'll have to go this far) use the small Ferrite suppressors on the ESC to Motor leads.

Lloyd

Yeah, I had the very same glitch on my TRex HDE. I installed a Revolution whip antenna, and went away.

If the above suggestions do not help, you should look into a ubec. The stock Align controller has a wimpy bec.

YUP...get a seperate BEC.
Most ESC's have a BEC built into them...but its only setup to run a few servos. So when you plug 4 servos into it its ok, but add a power hungry gyro, and it cant handle it.

The broblem isn't BEC related........did you guys look at the video? his bloody tail blades are obviously rotating in the wrong direction. I don't think an external BEC will help that, do you? ;-)

If you read the previous posts, you would see the following.


This was the problem the BEC issue was addressing. Thanks

Oh......hehe, sorry......you were answering the thread-hijacker's question, I get it now. Apologies.

I'm interested to know if the original problem was ever fixed, personally.

I havent been able to figure it out. I now know my tail is spinning the wrong way. I tried un-screwing the 4 screws that hold the tail boom to the chasis, then flipping the belt around so it rotates the other way, but everytime i twist the belt it locks up and it wont move.
I bought this thing fully assembled and am now regretting it. I am thinking about just selling the whole thing all together and sticking with My Honeybee Cp2 for now. This thing is waay too complicated for me.

The only thing I replaced was the little gear that the belt sits on, didnt think it was possible to reverse the belt. Now I just cant figure out how to twist the belt so it goes it the right direction without it binding up. Seems simple enough but let me tell you, Its not!

Take the taill boom all the way off the main frame so you can look down it and get the belt so it doesn't have any twists in it. Then with the tail boom in the same orientation as when it will be when attached to the frame, rotate the belt 90 Degrees to the left (when viewed from behind), put it on the gear and tension the belt...all should be well (check that the tail rotor rotates up into the main rotor)