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Flybarless Rotor Head Systems > Tail drift with v-bar
 
 
abrajim
Senior Heliman
Location: bogota colombia

i was having drift in the tail so i add some trimm to the tail and it was fixed but it seems that it's not the rigth thing to do, so i will doing this calibration procedure

sorry for my english
09-09-2008 07:19 PM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

Every time you turn on the vbar any trim in the radio (on any channel feeding the vbar) is seen as the new center point for that control versus if you change the trim after the rx/vbar is on it's seen as a pilot input. Just like any other heading hold tail gyro.

With the 611 gyro one can switch from heading hold to rate mode with a switch and if you switch it quickly a few times you can reset the gyro if the trim is off. If I bump the heli when I turn it on and notice the tail drifting in a hover, rather than shutting the power down in the heli I'll just reset the gyro with this method.

Is there a way to reset the tail center after the vbar is on, without turning off the vbar?

I noticed with mine the tail servo would drift with the heli on the table. I'm not sure why but maybe because the nose was pointed slightly down caused the problem. However the tail drifts in a hover so I think two things need resolving. For hovering I'm going to try two pieces of gyro tape. For the bench drifting sometimes it does it sometimes it doesn't. I can't see a pattern as to why.

Charles

Please stand by for faster service!
09-09-2008 08:26 PM
 
 
abrajim
Senior Heliman
Location: bogota colombia

i add trim but in the vabar setup software, i still don't understand very well all the vbar goodies, but i am doing my homework and reading all i can, i like the performance so far, but i can get the conected feel that i have with my old flybared synergy, i get the impresion that i am about to lose control of the heli some times, and i can't get as fast response as i want from the cyclics but i am pretty sure that i am getting closer to what i want. so i will be doing this reclibration procedure and keep playing with the values.

sorry for my english
09-10-2008 05:53 AM
 
 
ArtK
Veteran
Location: San Marcos, Ca

VBAR set up.

You really want to try to get the gain up as high as you can. That is probably why it feels loose for you. Also, you need to make sure that the cyclic throw is far enouph (without binding) for good cyclic rates. You can then increase the speed setting on the VBAR. Cyclic rates can be stupid fast with the VBAR so it sounds like there is a setup issue.

I love these things!!!
09-13-2008 05:39 AM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

I just discovered the reason for why the tail servo drifts in my setup.

I'm using the 14mz and it seems that there is some calibration error with the rudder /throttle gimbal in the tx. That is the center position of the rudder stick is changing when I move the throttle from low to high. I see this in the vbar software when I try to calibrate the tx and in movement of the rudder servo as I move the throttle without giving any rudder. When I move the throttle from low stick to high stick the rudder servo moves a little from one side of center to the other. The center in this case depends on where the throttle stick is when I power up the vbar. when I power up the vbar with the throttle at low stick I see the rudder servo centered at one point and the servo center moves if I power up the vbar with the throttle at high stick. After power up if I change the throttle position I'll start hearing the servo buzz and watch it drift to one side after 30 seconds or so.

I'll try a few other 14mzs and even other tx to see if I can repeat this observation. The tx will be going back to Futaba for service this winter anyway so I'll have them take a look.

With the 611 gyro I never noticed this.

Edit: When I power up the vbar with the throttle at mid stick I still see the rudder servo move a little from low to high stick but the tail servo doesn't drift. I'll flight test it to day to see if it drifts in the air and if this works I can live with this until I get the tx calibrated by futaba.

Charles

Please stand by for faster service!
09-13-2008 01:37 PM
 
 
inkspot1967
rrProfessor
Location: cranston ri.

hmmmm interesting discovery

Trex700e Ray N e- kit & "Fueled By Hate" Head
Next-D Rave Flybarless
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09-13-2008 02:00 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

vbar often drift when you have computer connected regardless because of dirty power via the usb.

always check without that to make sure.. just a fyi


Team Autopartner - Team pilot
09-13-2008 03:40 PM
 
 
inkspot1967
rrProfessor
Location: cranston ri.

oh my heli is a dirty heli yeah baby your a bad helicopter arent you........lol



Trex700e Ray N e- kit & "Fueled By Hate" Head
Next-D Rave Flybarless
Outrage Battery
09-13-2008 03:43 PM
 
 
abrajim
Senior Heliman
Location: bogota colombia

i got two logos and both makes this when i move the pitch, but in one in fligth the tail drift and in the other not(both with futaba 14mz) so i think this is something in the vbar program not a radio issue, also if your radio was having interaction with the ruder you will see it in the servo monitor. that why you didn't see it in the 611 gyro

sorry for my english
09-14-2008 03:35 AM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

tail moves due to tail torque compensation.

check wiki and make sure it goes right direction otherwise the heli fly like ....


Team Autopartner - Team pilot
09-14-2008 05:45 AM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

Bad heli... whack!!!!

Thanks for the suggestions guys.

Yes I see that the tail servo will move with throttle due to the vbar settings. The tail servo moves when I give cyclic as well. The thing is I still think I have something out with my tx as I see the trim change when I'm looking at the tx calibration screen.

The heli pros perfectly on the main shaft but the tail does move to one side when I punch it or hit full negative. I'll check the other setting for direction as suggested.

I'm going to try to use two pieces of gyro tape and see it that eliminates the drifting tail due to vibrations.

Charles

Please stand by for faster service!
09-14-2008 04:51 PM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

I tried two pieces of futaba gyro tape and the tail still drifts though not as much.

Any suggestions?

Charles

Please stand by for faster service!
09-14-2008 10:13 PM
 
 
ArtK
Veteran
Location: San Marcos, Ca

Does the tail at least lock into position after initialization?



I love these things!!!
09-15-2008 12:08 AM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

Yes and the tail holds for all maneuvers, tail slides, etc.. In a hover the very slow tail drifting can be seen. While flying I need to adjust for the drifting. The drifting is probably due to the motor vibrations. The motor was set on the lean side to see if that would help but it didn't. I have the gyro on the plastic tray above the front two cyclic servos. I could try another position or even mount the gyro on the servos directly.

Charles

Please stand by for faster service!
09-15-2008 01:10 AM
 
 
ArtK
Veteran
Location: San Marcos, Ca

Have you tried increasing the gain?



I love these things!!!
09-15-2008 02:15 AM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

I started with Inky's 600n settings. Tail gain is at 60 now. I haven't tried upping the value. I did try increasing gyro deadband and it didn't help.

Charles

Please stand by for faster service!
09-15-2008 02:45 AM
 
 
inkspot1967
rrProfessor
Location: cranston ri.

hey chuckie i got your files and you have 3 different settings on each flight mode you only need to setup one for all the modes. on idle2 change your gain on commom gain to 85 on i gain to 35 and set your zero collective to 0 gyro deadband to 5 or 6

Trex700e Ray N e- kit & "Fueled By Hate" Head
Next-D Rave Flybarless
Outrage Battery
09-15-2008 02:48 AM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

Hey inky.

I was test flying different settings to see the affect in the air. I had two or three setting differences between idle up 1 and 2.

For Zero collective I moved the throttle stick to mid position, where the pitch curve was showing zero, and I set zero collective. The value changed to 7. I assume that is the value needed due to my tx.

I did change the deadband to 2 or 3 after I sent you the files.

For the gain I did try 80 and the tail was more locked in when moving collective quickly. I don't remember where I left it at the end of the day but I'll bump it up.

None if these changes affected the tail drifting but the heli is flying much better.

Charles

Please stand by for faster service!
09-15-2008 03:35 AM
 
 
inkspot1967
rrProfessor
Location: cranston ri.

ok try the setting i said above and definately set the zero collective to 0

this is what the wiki says and i have always used that setting.

Zero Collective

Zero collective is a value to tell the system the point of minimum main rotor torque in the system. This will be 0° collective when using symmetrical blades and about -1.5° collective when using airfoil S blades. This will be the point of minimum torque compensation in the system.

The sense of the torque compensation at the tail can be confirmed as follows. Temporarily set the tail torque compensation mixing collective=>tail to 100 in the rudder menu. Watch the tail while giving collective now. The tail pitch will change to give more thrust in the direction counter to the main rotor torque (i.e. to rotate the heli in the direction of rotor rotation) as the collective is moved to maximum and minimum. If the thrust is less in both directions change the sign of the compensation value. The pitch of the main blades shall be at the point described above when the tail gives the lowest thrust. You can set this point with a click at the Button here.

Don't forget to set the changed value for the torque compensation back from 100 to the appropriate value.

For 3D use with symmetrical collective range the hover collective correction can stay at 0° which is the default preset.

Trex700e Ray N e- kit & "Fueled By Hate" Head
Next-D Rave Flybarless
Outrage Battery
09-15-2008 03:45 AM
 
 
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Flybarless Rotor Head Systems > Tail drift with v-bar
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