Trimming the tail

[toetapper]

When setting up the tail on a heli with heading hold gyro( in this case a 401`), am i right in saying you set all neutrals in heading hold OFF mode, and set the tail blades with enough pitch to hold center?..all this with the servo arm a 90 degrees to servo..is there anything im missing?

Regards
Simon

[beerdeor]

Simon you are bang on all you need to do from then on is hover the heli in normal mode and see which way the tail goes then move the tail servo up or down the boom accordingly only millimeters at a time its a bit of trail and error and can take time but it is the propper way to do it and will benifit you and your heli
Hope this helps Jim

[toetapper]

Trouble is its on a trex 600nsp sothe servo sits in the frames, looks like im going to run out of push rod?

Regards
Simon

[beerdeor]

Not familiar with the 600 is the pushrod not adjustable im sure one of the members with 600 knowledge will jump in soon and sort it for you

sorry i cant help any further

happy new year jim

[Mike W]

Tail should be roughly 5 degrees pitch and then trim it for hovering in rate mode ... then adjust the control rod so ya servo is back in the centre and measure the distance from trimmed to servo centre then adjust ball link accordingly ..Not known n e one with a 600 that has run out of control rod thread tho ....

[moyesboy]

If you are close to running out of control rod thread then make sure that the tail boom is actually pushed fully home. It can be difficult to get it all the way in! (get a bishop and an actress to help?)

With he 401, you can follow the above advise and it will work fine.
However it is not strictly necessary to do that. The 401 you cannot adjust left and right limit only the total throw, so adjust he linkage so you get the travel all the way to the stop on both left and right in rate mode. The servo arm should be a length that achieves this with the limit pot close to 100%.
With that setup the gyro will work great in HH mode (slightly better than if you adjust the linkage for trim in rate mode - but you wont notice unless you fly fast backwards or sideways loops and stuff.).
If you want to fly in rate mode with this style of setup then you use sub trim to correct the turn in rate mode and then just switch the power off and back on again. The gyro will pick up the trimmed neutral and consider that mid stick for HH. Everything else will be the same. Alternatively switch rapidly in to HH and out again a few times and then the new stick centre will be "learned" for heading hold. This trimming then allows the gyro to use an offset neutral (set in the tx) even though left and right limits are not independantly adjustable like most other gyros.
If you read the 401 instructions with the help of someone with a perfect command of chinglish and ability to read the missing lines then this is what the instuctions actually say
How the 401 now managed to get to the end of the product life with instructions that hardly anyone can interpret correctly is quite beyond me - they should have been inproved years ago. Fortunately whoever's advice you follow the gyro will work very well anyway!

[toetapper]

Yes i must admit not having the travel limit for each direction is a pain in ass!
if i set about 5 degs of pitch ,i have to limit the travel on the pot that much so it doesnt bind that you get very little travel in the opp direction, but if i dont do the true mechanical trim in rate mode will i be suffering tail drift in hh mode?

Happy new year

Simon

[Mike W]

Easy way to set it up .... get the limit on the gyro to close as 100 as possible .. if ya have to move the ball in or out on the servo arm to make a diff then do it ... The gyro will perform better if you set it up in rate mode first as its not working against itself all the time in HH ....Ask someone here with a 600 to post a pic of there tail setup and then you can see if yours is nearly the same .. this way it will eliminate if theres something wrong with it ... Just a thought .....Hope you get it sorted ...

[toetapper]

Thanks mike, can anyone help with a pic of there tail set up on a 600 pro, it would help me out alot.

Happy new year
Simon

[pieter]

When setting up the tail on a heli with heading hold gyro( in this case a 401`), am i right in saying you set all neutrals in heading hold OFF mode, and set the tail blades with enough pitch to hold center?..all this with the servo arm a 90 degrees to servo..is there anything im missing?

Regards
Simon

i used this ^ to setup my tail servo/gyro and it worked fine, you wont need trim to stop the drift and even if you do it wont be much