CP Reversal

[scallybert]

Does this ring any bells ? I'm sure I'm doing something silly.

I'm playing around setting up the CCPM, etc for a collective pitch heli on a DX6i.

The cyclic pitch works fine, but the collective pitch is reversed (more throttle gives less pitch). I can fix it by putting in a negative slope pitch curve, but somehow that doesn't seem the right solution.

I did all this ok with my GAUI 3-blade and a DX7, so I'm guessing I'm just doing something silly or not thinking straight.

It will probably be obvious when I compare it with the 3-blade/DX7 set-up, but meanwhile does this sound familiar ?

[richieclarkie]

Try going into your swash mix and reverse the pitch. If its +60 then change it to -60

[Ade_Law]

be aware that the swash goes the "wrong" way... swash at the top is negative pitch swash at the bottom is positive.

check the pitch change on the blade to be sure you have it right.

Ade

[Mikee]

be aware that the swash goes the "wrong" way... swash at the top is negative pitch swash at the bottom is positive.

check the pitch change on the blade to be sure you have it right.

Ade

My mates mini titan was like that.. Grrr spent 20 mins working it out

Damm had to get the manual out and do some reading

[scallybert]

be aware that the swash goes the "wrong" way... swash at the top is negative pitch swash at the bottom is positive.

check the pitch change on the blade to be sure you have it right.

I did that - at least looking at the blade grips - and swash at the top is +ve; the same as on the 3-blade.

This is useful, though, as it suggests that not all swash set-ups work the same way. Explaining why some might need thinsg reversed.

I guess -ve at the top would mean that the swash-plate tilted the 'wrong' way too ?

[scallybert]

Try going into your swash mix and reverse the pitch. If its +60 then change it to -60

They are all +60.

I've never figured out what these do, so I should have a play.

[JeromeF]

The swash mix percentages define the ammount of throw as such, the higher the number the more the certain mix will move. If the head is set right, the pitch ammount will alter the max and min range - ie 60% gives +/-9, 65% gives +/-11 and so on.

Someone may have the correct terminology for this, just an example of what it means though.

[JeromeF]

Oh and just to add: When you change the mix from a + to - it acts like the servo reversing does... but due to CCPM using multiple servos it changes the overal direction of all the servos.

[scallybert]

Try going into your swash mix and reverse the pitch. If its +60 then change it to -60

Thanks, this did it.

Do you know what this 'mix' set-up actually does ?

[JeromeF]

Do you know what this 'mix' set-up actually does ?

Check the two posts I made

[scallybert]

Check the two posts I made

Ah yes - the posts passed in the ether.

CCPM is doing electronically, what would otherwise be done by mechanical linkages. So I guess these mix percentages are like changing the lengths of the links.