Basic CCPM Setup On a New Machine

[jamiem]

thanks for the comments guys, hopefully it will help a few people out as it took about 2 hours to sit here and think about as i wrote it all down

[Boggy]

its a great post Jamie. hope you dont mind me asking for a sticky. it will be far easier to find when referring newbies to it

[jamiem]

not at all, glad to be of help

[motorblock]

Jamie, what a great write up.

I enjoy building my heli's!! so the more i can do my self and less i have to rely on others at the field is a bonus for everyone. many thanks again. keep up the good work.

[Brian Gifford]

Jamie, just wanted to say that after my first big smash, this guide was invaluable in helping me understand what to do, and telling me how to do it. A very big thank you.

[Supercaptaincrash]

Thanks jamie this has help me understand it a little easier and seem to be getting somewhere close setting it up now ! cheers bud

[bolders]

Great write up jamie nice and clear

However (and im probably gonna get flamed for this) I have to disagree with your comment on end points in section 11.

I dont want to start a flame war or anything, I just wanted to post an alternative view on things so people can make up their own mind.

The way I see it is like this

Sub trim adjusts where the centre point of the servo is. When you adjust subtrim the end points of the servo also move up or down the same amount so the total travel of the servo remains the same.

End points adjust how far the servo will move in each direction from the centre point for a full stick input. So adjusting end points will alter the total amount of travel a servo will provide. Adjusting endpoints should not effect the servo centre point (although admitedly in scallyberts case this does not seem the case but this is definately true of my DX6i)

Servos are never identical some will have slightly more total travel than others and may move at slightly different speeds (hence the need to use the same make and model servo for all 3 cylic servos to reduce this effect). Therefore the only way to get all servos to move through the same distance (thus reduce interactions) is to adjust the end points. Sub trim will not achieve this as the total travel range is not effected - only the position of the centre of the servo will change.

As an example assume you are level at mid stick have no interaction at -ve pitch but do have an interaction at full +ve pitch
If you adjust sub trim to remove the interaction at +ve pitch then recentre at midstick by adjusting the link it will once again throw out the swash at full pitch. BY going back an forth between mid stick and full positive and making fine adjustments eventually a balance will be found where the swash is level at mid and full +ve.
However the problem is that this adjustment has been done at the expense of the full -ve pitch setting which will now have an interaction. The reason for this is because the interaction is due to 1 servo not having as much travel as the other 2 across its full range. Adjusting the subtrim does not alter this fact it just offsets the problem.

This is true for pitch control and cyclic also - if the servos are set to move through the same amount of travel by adjusting endpoints and the swash is level at full -ve, mid and full +ve there should be no adverse effects to the cyclic controls

[supamansuper]

Ha ha ha.I've been looking all over the net for an instruction manaul like this.This is probably one of the best threads i've ever found thanks.there should be a copy of this advice in the troubleshooting part of every manual. that way when begginers like me crash and have to rebuild a helicopter we actualy know how to set it up properly.

[sacko]

You dont use subtrim to adjust interaction?

It says you use subtrim to get all your servos to 90degrees whilst having 0 pitch, so your swash is level.

From there you use the end points to remove interaction..

[squeaky pete]

Basic CCPM Setup On a New Machine

Subtrim effects the centre point of the servo, thats where u need to get ur servo horns bang on 90degree, then u use the atv to get rid of the ineractions at the top and bottom stick
If u have to correct the centre point again after this then u more than likely got servos with poor centring

[Sqwidge]

I have got my centres bang on to 90 according to my dreary old eyes, how do I set up the end points to ensure I dont get interaction? Is this done in the (DX6i) servo travel menu?

As the full amount of travel stays the same when you adjust the centre point its no biggie but my Subtrim is 35 on pitch, 35 on aileron and 10 on elevator, I tried to dismantle my servo to see if I could rotate the final cog a little so that it would centre without subtrim but this isn't an option, any ideas?