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Setting Control throws

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Old 11-10-2005, 02:21 PM
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Default Setting Control throws

What is the advantage of using control arm position to adjust throw, as opposed to using servo throw in the radio to adjust it?

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Old 11-10-2005, 03:07 PM
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Default RE: Setting Control throws

by using mechanical advantage instead of electronic you benefit by haveing more power out of the servo since it uses more of it and better percision since your using more points of referance on both the Tx and servo. This seem to be a lost art since with computer radios make it seem pointless to do it. I'm a big fan of computer radios. Now servo position in the model is a none issue. and with atvs i found are indespensible when you need just a 1/16 more for full throttle arm movement

But nothing takes the place of spending a little time thinking about what the control surface is doing and set the linkage position and offsets to get smooth strong control
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Old 11-10-2005, 03:20 PM
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Default RE: Setting Control throws

If we are talking full throw, the advantage is torque. If we are talking setting the neutral point, the advantage is better tracking when set properly. The disadvantage of both is it takes more time to set throws mechanically compared to dialing it in with the radio.

With full throw, the more the servo must move to get “X” surface movement, the better the mechanical advantage, i.e. the servo needs less torque. My recommendation is to never run with ATVs (endpoints) below 80%, but this will depend somewhat on what servo is used on which surface on a particular plane, your flying style, etc. If possible, always try to mechanically set your max throws with servos being driven to 100%. Depending upon your linkage type, you may be forced to tweak this some with the radio ATVs to get exactly what you want, which is fine.

The tracking issue isn’t quite as intuitive. Most servos use a radial arm (servo arm) that drives another radial arm (control horn) that drives a surface thru radial movement. Everything follows trig rules. If geometry of any of these links is off, movement won’t be symmetrical. For example, you can have your end points set to +/- 10 degrees of surface movement and neutral set in the middle. Half stick one way may translate into 5 degrees of surface movement, but half stick the other way may be 7 degrees of movement, all do to servo link geometry. This causes a “funny” stick feel as left/right or up/down is not the same. In addition, on coupled surfaces, such as ailerons or elevator halves where two servos are used, this will cause the two surfaces not to track the same, which will affect flight performance. Imagine at half stick one aileron move 5 degrees but he other moves 7 degree, you will impart a yaw moment from aileron… which normally isn’t desired. The kicker is that endpoints and neutral match so most think all is well, when it isn’t. Tracking is important, but the precision required will depend upon the pilot and plane. However, every plane, be it a wiz-bang patter ship or a trainer will fly better with properly tracking surfaces. Even with perfect geometry, there is no guarantee the servos will match, so getting good tracking is always seems to be a struggle. You can fix tracking errors with point mixes and maybe to a lesser extent with a non-symmetrical expo mix, but in general, you are best to start out with good geometry first.

Hope that answered your question.

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Old 11-10-2005, 03:31 PM
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Default RE: Setting Control throws

Hi!
Fully agree !

Jan K
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Old 11-10-2005, 06:16 PM
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Default RE: Setting Control throws

one other advantage for those using non computer radios with many recievers is once set up the trims are all the same.don't think i ever used the atvs feature on my futaba gold tx's nor on my 9vap's plus no need to use model memmory for each one.
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Old 11-13-2005, 06:15 PM
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Default RE: Setting Control throws

I don't get it? the main point of a computer radio is to save trim settings for each model, so centered trims for each model doesn't matter. This way were not spending another 2 hours screwing and unscrewing clevises which wear them out and weakens them so every model works on the same trim settings. if we put the equipment in a new plane you just hit reset on that model setting and it's back to center

in most cases you won't ever use atv's or epa. but when you do run across a situation were you do. you'll wonder how you eve got along without it.

" one other advantage for those using non computer radios with many recievers is once set up the trims are all the same"
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