Suggestion regarding neutral test.

[R-4-L]

the servo neutral lock (or test) in the servo monitor menu is really nice. all servos are locked into their neutral state.

but sometimes you find your self forced to input some subtrim to straighten servo arms especially when setting up ccpm swash systems.

the servo neutral test, when activated, ignores the subtrim settings you'v made, making it kinda useless when you have subtrims.

my suggestion is: wouldn't it be nice to have an option in the neutral screen to simply take subtrim settings into account or ignore them during neutral test?

Thanks.

[DavidH]

No the idea of the neutral test is get the servos centered exactly. I use the neutral test to install the servo horns exactly as they should be installed. No need for subtrims.

My opinion is subtrims are for people that just don't want to do the job correct.

David

[R-4-L]

I am not the kind of people who don't want to do the job correct, I have HAD to use subtrim once because the servo arms either don't want to be straight no matter how I try, sometimes I have to drill into the servo wheels but there is always like 0.5-1.0mm out of alignment.
another case is the ball-links, you want to do pairs of the exact same length of ball-links but i find that sometimes you need half a turn to achieve the exact same length, but if I do turn half, the balllink is not at the correct side for ball installation.. and end up with 1mm or more difference in ball link sizes.. forcing me to subtrim the servo to compensate for the difference in that servo.

[RCfan]

Sub-trims exist for a reason and there's nothing wrong with using them but only WHEN ABSOLUTELY necessary. Sometimes you simply cannot get exact linkage setup on an aircraft, no matter how hard you try or how experienced you may be. However, there are many who depend too much on subtrims instead of taking the time to do the job right. I'll leave it at that! :arggg:

Back on topic ... what I do is create a special condition (called "Center") where all inputs are centered, e.g. throttle/pitch/rudder/aileron/elevator curves are all a horizontal line around mid-stick (using proper curve screen or AFR(D/R) menu). In that same fashion I also use another condition ("Setup") that gives me max throws on all inputs. I set both of these up with highest priority and a hard-to reach switch/slider (usually latter). You can also create a separate model on the radio and use that exclusively for the setup portion, just remember to copy the changes back to the "flight" model when you make any changes. The 14MZ/12Z are so flexible ... I love my radios! :smokin:

[R-4-L]

creating conditions for setups, thats actually a good idea. thanks.

[DavidH]

Maybe I am just lucky. Never had to use subtrim. Wheels always line up where I need them. If they don't I drill the hole where it needs to be.

Only time I have ever used subtrims is on someone else's radio to stop gyro from drifting. Used subtrim on the rudder channel to stop the drift due to the fact the pot on the rudder channel was not centering well.

I do basically the same as RCFan. I have a setup model in the radio. Then when I set up the model. All I have to do is switch to the program for that model and everything is like it needs to be.

David

[flyinfool]

I set both of these up with highest priority and a hard-to reach switch/slider (usually latter).

Would you not want to make theses setup conditions with the lowest possible priority so that if you did accidentally hit the least accessible switch, any other flight mode would over ride it and allow a controlled landing?

[RCfan]

You want it to override all other conditions (Normal, Idle-up, Hold, etc.). Don't know how you'd do that without playing games with Normal condition, etc. I setup a slider switch with a specific point in it's travel where it engages each of the special conditions and never had any trouble (accidents), knock-on-wood. But if that's a concern, just use a separate model for setup and another for flying or use the new logic switch assignment (e.g. only from Normal can you switch to the special conditions).

[Finless]

Hmm on CCPM if you dont drill your own wheels I have yet to get a servo where a ARM would be exactly center no mater whayt you do. Thus subtrim is the olny recourse!

For instance on the little Trex450 most people use HS65 or 56 servos. YOU CANT GET wheels for those so your stuck.

I myself have set up many little Trex's and used subtrim to get the arms 90 and have seen no issues with doing so. I have also helped many people out at the field that used arms and thus again to get them all set up properly I had to use subtrims.. Again never had an issue.

I have also made several tests on a few radios (14mz, 9C, JR9202) and have found that the subtrims do not effect total throw in any way. Years ago on older radios it did but not with recent radios.

So I am curious why you folks say not to use subtrim? Explain to me why?

Bob

[rkeith2]

Yep -

I agree with Bob on trying to get good angles - I do however level all I can via lengthening and shortening arms thereby getting to the point where the only trim I need is std flt trims

[RCfan]

I use subtrims all the time, but again, only when necessary. I always try hard to get the linkages just right, with everything square. Few times, as David said, when you're lucky, you can get it done correctly and not need it. But most of the times, no matter how much you try, you have to use some.

[steph280]

Late to the party but here is my 2 cents.

The Futaba servo horns are marked with degree of offset from 0 degrees on each arms. So if the arm seems a bit off, take it off and rotate it to next arm. Repeat until you find the one with the perfect offset.

This was started back when Futaba 132SH servos were the norm for RC helis. It is explained on the instruction manual.

[Finless]

Late to the party but here is my 2 cents.

The Futaba servo horns are marked with degree of offset from 0 degrees on each arms. So if the arm seems a bit off, take it off and rotate it to next arm. Repeat until you find the one with the perfect offset.

This was started back when Futaba 132SH servos were the norm for RC helis. It is explained on the instruction manual.

I can tell you there are times when you wont find a position that is perfectly centered! What I do then is used the wheels and drill my own holes.

Bob

[DavidH]

The Futaba servo horns are marked with degree of offset from 0 degrees on each arms. So if the arm seems a bit off, take it off and rotate it to next arm. Repeat until you find the one with the perfect offset.


I have been using Futaba servo arms and wheels since 1990. All I have ever seen on them is numbers. 1, 2, 3, 4, etc. I believe these numbers are just for reference and have nothing to do with amount of degrees.
I do agree that you can take the 4 point and 6 point type arms and rotate them, If your lucky sometimes they will line up where needed. I really don't use servo arms on helis. So I do like Finless suggested. If the servo wheel will not line up correctly I just drill the hole where needed.

David

[steph280]

Each number on the arm designates certain degrees of offset, and is represented on a table in the servo's instruction manual. Wish I can still find mine, but who RTFM anyway. I didn't know it could be useful back then, until CCPM came out.