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Old Dec 22, 2004, 10:55 PM
Registered User
Santa Rosa, Northern CA, USA
Joined Oct 1999
2,472 Posts
Step by step: Tail motor Mix: For using separates.

Thought this may help someone. I just set-up a micro heli with a DD tail motor, 2 ESC’s, 2 servos, and P3 gyro. I am using a JR 347/388, but any simple computer radio with programmable mix should work.

Here are the steps: “Quotes” are indicated for transmitter menu / adjustments.

1) Plug in the tail rotor speed control. (Disconnect the main motor for this stage.)
2) Depending upon your brand of tail motor ESC, your results will vary. If your ESC has no throttle start-up protection (not likely these days), then the motor will start at ½ throttle. Most ESC’s will not start at all when you plug the battery in, as the rudder stick is not in the off-position. If you then move the rudder full right or left (this arms the ESC), the motor should start and increase speed as you move the stick back towards center stick.
3) Check the direction of the rudder vs. the direction that the tail spins. I had to reverse mine. “Select: rudder – servo reverse.” If needed.
4) SUBTRIM: Now, set the “rudder servo – Sub Trim” to full. This may be + or – sub trim, or R or L sub trim. As you adjust this, the motor should slow down and stop, while the rudder stick has remained centered.
5) Next: Unplug the battery. Now, plug the battery back in. The tail motor should be off. While moving the rudder stick left, the motor should stay off.
6) While moving the rudder stick right, the motor should start and pick up speed (if reversed, go back and do steps 3 to 6 again).
7) Important: We will now mix the throttle channel into the rudder channel. By doing this, as we increase the throttle, the tail rotor will spool up and increase rpm along with the main blades. The mix you want is to “Mix: Throttle - Rudder”, “Mix B - 1 to 4”, etc. (Be sure the mix is set for always on. Do not have a switch control this mix.)
8) Set the “MIX OFFSET “ function of the mix. You need this T to R mix to start when the throttle stick is all the way back / off. To do this, move the T stick all the way back, and use the “mix offset” function. “Mix: 1-4: offset” On my JR radios, pushing the clear button sets it.
9) Next you select the percent of mix. Move the throttle stick up to about 50%, and start adding the percent of mix. What you are looking for is the correct tail rotor speed, for hover flight. (My heli hovers at 50% T, yours may not.)
10) Test it all again. Unplug the battery then plug the battery back in. The tail rotor should be off. Advance the throttle and the tail rotor should spool up. Now double check for rudder direction and make sure it is correct.

If you try this and it works well for you, let us know. If you find errors with my steps, please post and I will correct them. If you have questions just ask.

Dave
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Old Dec 22, 2004, 11:01 PM
Registered User
Santa Rosa, Northern CA, USA
Joined Oct 1999
2,472 Posts
Flight testing and tweaking.

Here are a few tweaks for the mixing:

1) Start at 75% mix. If the tail rotor lags the main rotors, turn up the throttle to rudder mix. And of course, if the tail motor is too strong, turn down the mix.
2) If the tail motor starts to spool up to early, change the “Mix offset” (step 8 above) and set it with the throttle stick up/on a small amount. This will also affect the % of mix required.

Dave
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Old Dec 25, 2004, 10:18 AM
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cupid4600's Avatar
Alberta
Joined Aug 2004
193 Posts
Hi Dave

I have a JR6102, the MIX menu is slightly different than your JR347/388. Here's what mine looks like:
[MX1] THR-> RUD
ON OFFSET 0

75% 0%

SW ALWAYS ON

Here's where I got confused following your setup:

After the "OFFSET" , what should the number be? (instead of 0 ).

Under the "OFFSET", I can change the number "75%" only if I have the throttle stick all the way up. The other "0%" was set with the throttle stick all the way down.

In JR6102, there are only MIX1 and MIX2.

Hope you can advise on my setup.

Thanks and Happy Holidays.
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Old Dec 25, 2004, 12:18 PM
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Santa Rosa, Northern CA, USA
Joined Oct 1999
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Quote:
Originally Posted by cupid4600
Hi Dave

After the "OFFSET" , what should the number be? (instead of 0 ).

Under the "OFFSET", I can change the number "75%" only if I have the throttle stick all the way up. The other "0%" was set with the throttle stick all the way down.


Thanks and Happy Holidays.
If I understand your question correctly, you are asking how to set the OFFSET for the throttle lever. When you push the “set” button for the offset, the offset will be where the throttle stick is positioned. From your numbers, 0 is no throttle stick and 75% is full. Move the throttle stick up about 3 clicks and push the set button. The offset should now read somewhere around 10%.

[QUOTE= After the "OFFSET" , what should the number be? (instead of 0 ). .[/QUOTE]

0 is a good place to start. This setting depends on the response of your main and tail motor speed controls (and the power curve of the motors). The main motor will always follow the T-stick. The offset percentage will set where the tail motor starts to turn. (For example: IF you set the offset to 50%, the tail motor would not begin to spin at all until the throttle stick was past this point. Not much use for a heli, but it explains the offset)

I am using two different brands of speed controls and the tail motor was starting to spool up a little too much before the main motor. I am now using 10% of offset. Now the tail motor still begins to spool up before the main, but the power curves for both track better.

It would be nice to know if this helps.

Merry Christmas,
Dave
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Old Dec 25, 2004, 03:09 PM
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cupid4600's Avatar
Alberta
Joined Aug 2004
193 Posts
Quote:
When you push the “set” button for the offset, the offset will be where the throttle stick is positioned.
I don't have the "set" button. I manually use the "increase" to +10 (adjacent to the "OFFSET".


Quote:
Move the throttle stick up about 3 clicks and push the set button. The offset should now read somewhere around 10%.
For this, I have to move the stick all the way down, then manually key in +10%.

I think I have other problems rather than the MIX problem. Right now, the heli keeps on spinning left, with almost full right rudder. I have changed the gyro position, up, down, facing in, facing out and etc.. I have also replaced the tail motor, brand new GWS EDP50 with 3030 (orange) blade. Rotation is correct but still can't hold the tail.

Tried using the MIX1, still rotate CCW.

Any suggestions?

Cheers and Merry Christmas.
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Old Dec 26, 2004, 03:52 PM
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Santa Rosa, Northern CA, USA
Joined Oct 1999
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More tail rotor is needed.

I did a search and could not find what heli your flying. Would you mind listing what you have for a set up? Heli, motors, esc’s, batts, gyro, weight.

“Right now, the heli keeps on spinning left, with almost full right rudder.” Looking at “almost” it sounds like you need more tail rotor, but may be getting close. It is possible that you just don’t have enough tail authority no matter what we do, but here is how we find out.

(I do suggest that we bypass the Gyro to start with, just to make sure that it is not the problem).

1) Move the Throttle offset back to 0 percent. This should start the TR sooner.
2) Try increasing the rudder channel travel adjustments, for both right and left rudder. Keep increasing this until the TR (tail rotor) reaches full speed before you reach full right rudder stick (now we know that we can get max power from the TR.)
3) Increase the Throttle to rudder mix. Go as far as you can. Some radios go to 100%, some to 125% or 150%.
4) If the above are not still not enough, reduce the travel adjust for full throttle. This will cause the main motor to spool up slower, hopefully letting the tail motor keep up with the main. This adjustment would be the Full throttle endpoint / travel adjustment.

Let me know how it goes.

Dave
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Old Dec 26, 2004, 04:29 PM
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Joined Oct 2004
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Do you have to have a computer t/r. Iam very new at this
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Old Dec 26, 2004, 05:44 PM
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Kelowna BC Canada
Joined Jul 2004
42 Posts
equipment:had a pha-01 worked great till it stopped working one day, so had to get a pgo3 gyro and an ics 50 esc for the tail motor and a 20p for the main motor with the stock gws radio.

dilemma: everytime i arm the tail motor and return the stick to the centre, the helicopter spins in circles. pull the stick back to the left and it stops spinning. i've followed the instructions on the gyro to get a red and green light to find neutral. when i move the tail by hand to the left or right the lights go red or green so i know it's working. but once i arm the speed control it spins in circles.

question: how do i get it to stop spinning in circles when the stick is in neutral? need all the help i can get
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Old Dec 27, 2004, 10:46 PM
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Santa Rosa, Northern CA, USA
Joined Oct 1999
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Quote:
Originally Posted by scott1
Do you have to have a computer t/r. Iam very new at this
Hello Scott,

Yes, this thread is about setting up the mix, on a Simple Computer Tx. It may also be a good starting point, or help with, setting up more complex functions on other Tx's.

Dave
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Old Dec 27, 2004, 11:01 PM
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Santa Rosa, Northern CA, USA
Joined Oct 1999
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Quote:
Originally Posted by pitbull
equipment:had a pha-01 worked great till it stopped working one day, so had to get a pgo3 gyro and an ics 50 esc for the tail motor and a 20p for the main motor with the stock gws radio.

dilemma: everytime i arm the tail motor and return the stick to the centre, the helicopter spins in circles. pull the stick back to the left and it stops spinning. i've followed the instructions on the gyro to get a red and green light to find neutral. when i move the tail by hand to the left or right the lights go red or green so i know it's working. but once i arm the speed control it spins in circles.

question: how do i get it to stop spinning in circles when the stick is in neutral? need all the help i can get
Hi,

Sorry, I can't help to much with this. You need to dial in the offset for the rudder on the Tx. This is step 4) of the first post.

Here's your problem. Once your rudder stick moves back to center, the T-rotor is at 50% power. IF you do not have a computer radio with mix and subtrim on the Tx, then you need another solution. I think they are 3-1 boards, better Tx, or heading hold HH Gyro.

Dave
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Old Jan 05, 2005, 02:44 PM
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Joined Dec 2004
920 Posts
hh help

dave,

wondered if you could help me out...

i know you're talking about mix and revo here for the tail... and i've got that dialed in pretty ok now... (although it took a bit of doing.. trial and error and more trial and error)....

but i'm still having trouble getting a good HH operation on my Trex450X...

using a standard and dual rate HH gyro.. telebee i think, with futaba T6XHs computer Tx...

when i switch off the REVO mix and flip on the HH switch... i bring the heli into a hover and get a bigtime left-right oscillation of the tail, and can observe the rudder servo (this is belt driven rudder of the main), going back/forth, obviously causing this tail action...

i've tried all points on the gyros 'gain' control dial that is actually located on the gyro, and i've tried increasing/decreasing the ATV of the both rudder and the gyro channels separately and together... always just get this left/right osciallation, about 40 degrees of left/right in each movement happening about 2-4times each second... sure makes for a hard to hover heli... adjustments have only had this effect... heli tail hunts to one direction or the other, depending on the adjustments of gain... or holds its heading, albeit wagging back and forth the whole time...

any ideas about what i'm doing wrong here? i know it must be something i'm missing with setup... cuz i'm noobie all the way.

thanks in advance for any help and suggestions.

Ron

oh yeah... if i hold the heli in hand, spool up to a hovering head speed, and then use other hand to give push heli tail to left or right direction, she evens out, the servo stops oscillating left/right, and the headinghold is smooth... the minute i stop providing a force to one direction or the other of the tail, the servo goes back to a quick back/forth movement...

is HH only for use in a windy situation and the heli needs a force in one direction or other for HH to work correctly?
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Old Jan 05, 2005, 09:26 PM
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Santa Rosa, Northern CA, USA
Joined Oct 1999
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Hi Ron,

Quick disclaimer here: I am not a heli expert (actually very little heli time), but do have 30+years of RC, Electronics, and programming experience. I may be way off course here...

“using a standard and dual rate HH gyro.. telebee i think” I am a little confused. Is this one gyro that you are having this problem with, or have you tried two different HH gyros? Let’s assume one HH gyro for now. I have read that a HH gyro measures rotation and time. Then applies a signal for the opposite rotation for the same amount of time. (If anyone can correct me on this, please do )

Here’s my best shot:

If your HH gyro has an airborne hi and low rate switch, I would not be turning off the Revo Mix when changing rates. The dual rate should only lower the effects of HH. Have you tried this?

And reaching for other ideas:

If you bypass the gyro, does the rudder / tail rotor, move the right way?

Maybe the tail servo has problems. Too slow, bad centering, to long of a servo arm? This was derived from other post…

Is the gyro mounted correctly? That is, not vibrating?

Please let us know what you try and if any of this helps. And of course, what fixed the problem

Dave
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Old Jan 05, 2005, 09:54 PM
Jgels
Lyndhurst Ohio
Joined Dec 2004
24 Posts
Hello Dave,
Great post on setting up tail motor mix. I just got on the site to ask those very questions.
I'm in the process of setting the tail & ESC up on my machine. I am new to this hobby so this may sound like a dumb question but how do you determine the correct rotation of the tail rotor?
Thanks JOhn
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Old Jan 05, 2005, 11:22 PM
Registered User
Northen CA, Bay Area
Joined Jun 2003
131 Posts
I agree I am at the same point and have a JR6102 so I'm facing the same issues as cupid4600. So to be clear, I have to setup mixing before Revo?

Thanks a ton!!!
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Old Jan 06, 2005, 12:42 AM
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College Park, MD
Joined Sep 2002
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Ron, The tail on the TRex is belt driven and not the same type of setup as is mentioned in this post. The other guys posting in this thread have a separate motor for the tail and it requires revolution mixing to spin the tail rotor. The TRex tail rotor is slaved to the main rotor and revo mixing should NOT be used.

I don't have a Futaba Tx but the basic things you need to do to set your Telebee gyro up are to turn off revo/tail rotor mixing by setting their values to 0% or inhibit. Make sure the gyro gain channel connector is plugged into the proper gyro gain channel on the Rx (usually ch 5) While you are in hover/normal mode set the gyro gain to 50% or greater (mine is set to 72%) That will select HH mode on the gyro. You can verify this by looking to see if the tail rotor servo creeps to one side.

Mine is set up to move the tail rotor pitch slider all the way forward so the tail rotor pitch will move the tail clockwise (nose to the right) This setting basically counteracts the torque of the blades which also turn clockwise. If your gyro creeps in the wrong way, reverse the rudder servo in your Tx.

Once you have gotten the servo creeping the correct way, move the rudder stick all the way to the left. The rudder servo should move the tail rotor pitch slider all the way to the opposite side so that the pitch is reversed. Then release the rudder stick and it should slowly creep back to the extreme opposite position. I adjusted my gyro gain so that the creep would stop with the servo right at the extreme position. If you adjust the gyro gain you will see the servo move. I slowly increased the gain from 50% to 72% and that's where the servo didn't move any more.

Once you get that far make sure the gyro is mounted with the label facing the side (mine is facing the left side) using the mounting tape provided. If you have it mounted with the label facing up it won't work properly.

The tail holds very solid on mine. I was flying in 5-10 MPH winds yesterday and it performed very well.
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