Re: Limit and throw

Hello Rainer
Can i add some more questions to this thread?

When setting throws on my 67' plane (using EVO transmitter, servos SAVOX 1261 MG) maximum throw is 120 which was just about for recommended throws for 3D. I know that i could play with lengths of links but it's ART pilot rc kit with linkages supplied and already not very deeply screwed in ball links. Most other radios offer much brother setting up to 140 i think.
2) Also when centering servo setting max throws when setting inputs in banks - and + are not equal (although they are in throw setting) and the larger throw the bigger difference. On small 20 degree throw about 2-3 degrees on 45 degrees elevator almost 9 degrees. I noticed that it was on servos where i had to center them for more than 17 . It almost looks like that centering didn't take effect. Is that possible?

Thank you very much for any ideas. Radek

Hi,

I'm trying to shed some light on this:

Servo throws, usually it makes not much sense to overdo them very much, otherwise the linkages often angle out to a degree where there's only little leverage left (push direction). If more than 120 is necessary, well, how shall I put it nicely the design is worthy of rework

2) I don't quite comprehend:
. does centering work? How much offset are you using? Is that the 17 (+) you mention?
. does setting limits work, individually (example elevator, up/down)?
. did you notice that changing center rotates the whole thing, so the limits move accordingly?
. are there any mixes set up (something to elevator, for example)?
. then, outside the setup and if not in bank 1, the control loop is active. Even though you won't notice as much, on the ground, as on helis, this might also affect things
. lastly (or firstly), the geometry of the linkages and levers also plays a big part, around center, +/– (without adjustments) is pretty similar, but with increasing deflection, the ratio between the angle of the servo arm and the angle of the control surface changes substantially, so you'd have to linearize (or at least set the maxima)—I didn't try, but you _could_ use curve macrocells directly on the output (CH1 for Elevator, for example), to adjust the servo throw (and linearize), and use FC Ele(vator) as the input, then with –100/0/+100.
This can also help if you need to equalize two separate elevator servos.

If I'm on the wrong track, help me on the right track

—Eddi

Born to fly ...
forced to work.

Hello Eddi
Thank you very much for your reply and recommendation. Totally agree with everything you say. It was ART plane and i thing few things were not right. Yes never ever had any issue on my helis and yes needing more then 120 is bit 'unhealthy' Although it's 3d plane and can take big deflection. I'm now away but will check all centering, length of linkages etc and will report back.
Thank you again and really appreciate your help.
Radek