12FG Mixing to not bind on full collective and cyclic

[derelict]

Hi all

I'm binding my swashplate on my t-rex 600 (rotohead pins.... or the bottom main shaft collar) if i go full collective and either full ele or full ail.

I know... i could fly like that IF i'm careful with collective management..... but i like to keep things "failsave" and idiot proof :-)

So i thought...hmm.... maybe there is a way to somehow "squeeze" the cyclic throw down if i'm either at full positive or full negative on collective.... in order to now bind on anything.

i'm NOT talking about the virtual swashring.... what i would like to achieve is something that has the same effect as making the swashring smaller at full collective.

Does anyone know if this could be done using some kind of mixing ? and if so... how ?

Thanks for any help guys.... i really appreciate it!

Greets

Marcel

[derelict]

bump.... is this to special....or just not possible ? :confused::confused:

[heliplane]

I am having the same problem on my 600. I know that you could just take some pitch and cyclic out and that would cure it but I like my +14 and -14. There has to be some good solution.

[derelict]

well... I've played around with a lot of settings... like enabling dual rate if the stick is at a certain position.... but using that method would just cause the swashplate to "jump" very quickly once it gets near the pins or the bottom...... but you would have to adapt that setup each time you change your pitch range.

Nobody out there having a solution for that ? i'm looking for something that flattens the cyclic pitch throw on top and bottom pitch.

I've just trimmed the top pins about 1.5mm which gives me +/- 14 and +/- 9 on cyclic without binding on the top... but i still bind at the bottom collar on the mainshaft.... an although many run that setup just fine... i would like to have the peace of mind... that in NO circumstance I'll be binding !

Greets

Marcel

[andrewt1971]

Deleted post, thought I'd figured it out but took 4 programmable mixes and still had a nasty kick to the cyclic if zero'd at or close to full collective..

[derelict]

that's the same i had achieved :arggg::arggg: no solutions or nasty tricks to solve this?

marcel

[chopperben1]

not sure if you solved it yet, but just adjust you AFR setting. This limits the "throw" on the collective pitch for all three servos at once. See the Finless "CCPM" set-up videos in the how to section of this site for a video on this.

[derelict]

i haven't solved it yet..... but i'm fine with the virtual swashring and not being maxed out on collective pitch for the moment !

i know about the AFR... but this would reduce collective pitch at the top and bottom.... but i'd like to maintain a straight pitch curve and reduce CYCLIC throw ONLY at the top and bottom collective points.

Greets

Marcel

[tgo]

Have you try use LIMIT to limit servo's maximum throw?


i haven't solved it yet..... but i'm fine with the virtual swashring and not being maxed out on collective pitch for the moment !

i know about the AFR... but this would reduce collective pitch at the top and bottom.... but i'd like to maintain a straight pitch curve and reduce CYCLIC throw ONLY at the top and bottom collective points.

Greets

Marcel

[derelict]

i don't think that this will work for cyclic (because one servo moves in the other direction than the other)... not ?

marcel

[tgo]

If you set both the upper & lower limit of 3 CCPM servos, it will works to stop binding at extreme cyclic imput. For example, your swash can have +/- 14deg pitch without cyclic input, at 0 deg, you can have 9 deg cyclic pitch, at full neg and you have full cyclic input, because of the limit setting, the downside servo will stop at the limit position and the other side with continue to move up, the total cyclic pitch is reduced and binding is eliminated.

I use the same technique on my T450V2 to stop the servo horn touching the main gear. It works great !


i don't think that this will work for cyclic (because one servo moves in the other direction than the other)... not ?

marcel

[derelict]

i see.. BUT.... lets say i'm at -14 in pitch.... now i give half elevator.... which mean two servos will move down... and the other servo will move up..... so lets continue adding elevator input.... now the two servos which were moving down reach their limit setting and stop..... but the other servo which moves up (and therefore DOES NOT reach it's limit) will continue to move..... it's true that NO BINDING will occur.... but that servo which keeps on moving will:

- add even more elevator cyclic because it still moves
- and add a little bit of positive COLLECTIVE because the other servos aren't moving anymore!

am i wrong ?

Greets

Marcel

[tgo]

You are right, but...
1. no binding (this is what you want at exteme condition)
2. as servos travels towards to down side will down, elevator pitch is limited
3. as you said, some positive pitch will applied because servos servos travels towards down side aren't moving, 14 deg neg collective + 9 deg elevator will definitely overload your motor, so this limited cyclic + auto decrease collective is an advantage !


i see.. BUT.... lets say i'm at -14 in pitch.... now i give half elevator.... which mean two servos will move down... and the other servo will move up..... so lets continue adding elevator input.... now the two servos which were moving down reach their limit setting and stop..... but the other servo which moves up (and therefore DOES NOT reach it's limit) will continue to move..... it's true that NO BINDING will occur.... but that servo which keeps on moving will:

- add even more elevator cyclic because it still moves
- and add a little bit of positive COLLECTIVE because the other servos aren't moving anymore!

am i wrong ?

Greets

Marcel