[NSRCA-discussion] Aileron servo arm size and resolution?

[Fred Huber]

Taking it to extremes:::  Someone hooking up the controls with the pushrod 
at the furthest hole out on the servo arm and furthest hole in on the 
control horn and ATV set at 20% to get the throw down to the ARF's 
recommended.  He essentially was getting less than 10 in oz of effective 
power from his 42 in oz servo in a 60 size plane.  Thats a case of flutter 
waiting to happen.  Sure seems like fast response... but the ailerons "blow 
back" in every pull.

*********

Servos have ratings for a reason... so you can select the servo with the 
power and speed you require.  If you need speed and not torque.. select a 
servo rated for speed.

I have a servo that is rated 90 in oz at .13sec.60 deg.  There is a differnt 
servo in the same case, using the same motor and same circuit board rated 
126 in oz at .22 sec/60 deg.  All thats different is the gear ratio.  More 
torque due to lower gearing and less speed.

There are servos rated for just about any combination of speed and torque 
you could need....

*********

Pattern is about PRECISION flying... why sactifice half the precision 
(resolution) of your servo by setting up the linkage to where you need 50% 
ATV for the desired maximum throw? (High rate)

When you flip to low rate, at half the throw of high rate... guess where you 
are:::  25% power... 25% precision.  And wondering why you can't get 1/4 
click of trim to work.

FHH

----- Original Message ----- 
From: "Kelly Regan" <kelly.regan2 at verizon.net>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Wednesday, January 03, 2007 9:26 PM
Subject: Re: [NSRCA-discussion] Aileron servo arm size and resolution?


>I forgot to add that I am running 6.0 volts with a
> 7.2 volt li-ion pack and Fromco regulator.
>
> Fred, can you explain or give me an example of what you
> mean by bad control system?
>
> I have been trying to understand the affects of high atv's and resolution
> for a long time and the information I find is conflicting.
>
> At what point do you realize full resolution?  100% ATV and 100%
> on the duel rate screen?   Is there an advantage in going to 130% ATV
> as far as resolution is concerned?
>
>
>
>> You should get your full surface travel (high rate) as close to 100% ATV
>> setting as possible.  ATV is a trap and if abused can lead to some really
>> bad control system installations.
>>
>> FHH
>> ----- Original Message ----- 
>> From: "Kelly Regan" <kelly.regan2 at verizon.net>
>> To: <NSRCA-discussion at lists.nsrca.org>
>> Sent: Wednesday, January 03, 2007 8:14 PM
>> Subject: [NSRCA-discussion] Aileron servo arm size and resolution?
>>
>>
>>
>>> What length servo arms do you run on the ailerons?
>>>
>>> Why do I ask....
>>>
>>> When I first set up my Brio with the 9411 sa's on the ailerons
>>> I wanted to make sure I had full servo/radio resolution.
>>>
>>> I fly with a Futaba 9C and have CHP control arms on the ailerons.
>>>
>>> I set my ATV or End Point in the 9C to 130.  I used a standard JR
>>> servo wheel with the linkage set to the inner most hole.  In order to
>>> get the 1/2" aileron travel per the Brio manual I ended up with 120%
>>> duel rate.  It was my understanding that this is exactly what I wanted.
>>> High ATV and high duel rate for full resolution?
>>>
>>> When Don flew my plane he said the aileron servo's seemed slow
>>> to him?  He was surprised to hear I had 9411sa's.    He suggested
>>> that I use longer servo arms and reduce the ATV to 100% to make
>>> the to keep the throw at 1/2" while increasing the surface speed.
>>>
>>> Tonight I installed the shortest Dubro arms with the linkage on the 
>>> inner
>>> most hole.   That put the numbers at 100% ATV but I had to reduce
>>> the duel rate way down to 50% to get the same 1/2" throw.
>>>
>>> Am I wrong in assuming that cuts my resolution in half?
>>>
>>> I wanted to get you opinions on since I am now totally confused.
>>>
>>> What does a faster aileron speed do for me versus the loss of 
>>> resolution?
>>> What is an acceptable loss in resolution to gain the speed?
>>>
>>> Thanks for you help
>>>
>>> -- 
>>> ______________________________________________
>>>
>>> Kelly Regan
>>> www.reganbrothers.com
>>> Home Page: http://mysite.verizon.net/vze6uror/
>>> ______________________________________________
>>>
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>>> NSRCA-discussion at lists.nsrca.org
>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>>>
>>>
>>>
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>>
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>>
>
> -- 
> ______________________________________________
>
> Kelly Regan
> www.reganbrothers.com
> Home Page: http://mysite.verizon.net/vze6uror/
> ______________________________________________
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
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>
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