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What size servo should I use?

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What size servo should I use?

Old 01-20-2007, 11:34 PM
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sebo
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Default What size servo should I use?

I needed to know what size servos to use in my plane. I needed to know the torque.
I found this address [link]http://www.morgantech.com/Servo%20Torque%20Caculator.htm[/link] .
You post the numbers in the proper slots and it calculates the amount of torque you need.
Old 01-21-2007, 12:07 AM
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alan0899
 
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Default RE: What size servo should I use?

G'day Mate,
We may need to know a bit more than that to answer, what was the question again?
Like plane type, size, engine, type of flying, etc. all that mundane stuff.
Old 01-21-2007, 08:07 AM
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OldScaleGuy
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Default RE: What size servo should I use?

The old rule of thumb to get you started is one ounce of servo torque per one square inch of control surface. In other words if you have an aileron that is 3 X 30, that equals 90 square inches. You would need a servo with a minimum of 90 ounces of torque.
Old 01-21-2007, 09:56 PM
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sebo
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Default RE: What size servo should I use?

That sounds reasonable. I used 3x33 and a half inch of deflection and got roughly 114 ounce/inch.
The good part of the formula is that it includes amount of deflection that you expect to use. Had I gone for a 35 degree deflection, a stronger servo would be needed.
I really think this thing is cool and I going to continue using it.
This can be exceptionally helpful when it is used for calculating the strength of the flap servo.
A 35 degree drop would need a stronger servo than one that is only going to drop 15 degrees (I think!!)
I also think your method has great merit.
Take care,
Ron
Old 01-21-2007, 10:03 PM
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sebo
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Default RE: What size servo should I use?

I was just offering a calculating system that I came across.
As a general rule, it gives you minimum starting figures. I never hurts to utilize larger servos.
If you've got something better, please let us all in on it.
I'm open to knowledge. I sure ain't the guru here.
Thanks,
Ron
Old 01-22-2007, 03:58 AM
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venom290
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Default RE: What size servo should I use?

My clubs web www.yankee-flyers.com site has a chart that lists major mfg. servos and there tourqe ratining. might help. Check out the site while your there. Look under links at top of home page, then bottom of page, says servo chart.
venom
Old 01-22-2007, 01:20 PM
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carrellh
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Default RE: What size servo should I use?

Sebo, if RCU allows it, you should edit the title of your thread to say something like "I found a calculator for servo torque requirements" because the current title appears to be asking for a recommendation.
Old 01-22-2007, 01:25 PM
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Sport_Pilot
 
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Default RE: What size servo should I use?


ORIGINAL: OldScaleGuy

The old rule of thumb to get you started is one ounce of servo torque per one square inch of control surface. In other words if you have an aileron that is 3 X 30, that equals 90 square inches. You would need a servo with a minimum of 90 ounces of torque.

Lots of sixty sized pattern planes have been built with one standard servo and two 1 1/2" ailrons about 60" long, so looks like your estimate requires about double of what is actually used here.
Old 01-22-2007, 07:50 PM
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sebo
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Default RE: What size servo should I use?

Sorry. The first 4 words are "I NEEDED to know". Needed is past tense. It means that "I was in need of". It doesn't mean that I am seeking information now.
I wish that I hadn't tried to offer a means of calculating what servo torque would be needed for a specific application.
How about you contacting the administrator and telling him how incorrect I am.
I made an offer of a method that works for me. If you don't like it, don't use it.
Would you please publish the correct method for calculating needed servo torque.
Please allow for eliptical and all other possible configurations.
I think that a person with your talents should make it available to all R/C enthusiasts.
The method I offered was developed by someone else.
I also said I wasn't a guru at this stuff.
I won't respond to any more nit picking.
Yetch,
Ron



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