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Old Aug 05, 2003, 03:03 PM
Fixed Wing Fanatic
Jim Walker's Avatar
United States, TX, McKinney
Joined Jul 2001
2,344 Posts
How to reverse an HS 81

I'm using a Y cable to connect 2- HS 81's into the gear channel of a reciever and use them as flap servo's in a four surface glider wing. I have to reverse one servo to make it work in unison with the other. How do I do this? Is there some wiring to reverse or do I need some gismo. Is it some circuit I can make from Radio Shack parts?

Thanks for your help.
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Old Aug 05, 2003, 03:11 PM
Profiled Interfractionalist
William A's Avatar
Tacoma,WA USA
Joined Jun 2001
4,039 Posts
I ended up using a gizmo.
I tried doing one of those rewiring tricks found on the net, but it didn't work.
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Old Aug 05, 2003, 03:25 PM
Will work for planes
omega blood's Avatar
Fullerton, California, United States
Joined Jan 2002
1,783 Posts
I think you can buy a servo extension with a reverser built into it. Call your local hobby shops and ask.
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Old Aug 05, 2003, 04:39 PM
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astroboy's Avatar
Carson City, NV
Joined Nov 2000
888 Posts
I needed one of these a while back, and ended up going with the FMA servo reverser. As Omega suggests, it's an extender with a little box on the end of it. Don't quote me on this, but FMA says theire minimum shipping is $7, but since I ordered just this one small item, they charged me only $3.

Jeff
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Old Aug 05, 2003, 09:20 PM
T:W>1= :>)
rc-eflyer's Avatar
St. Louis, Missouri, United States
Joined May 2002
1,446 Posts
Re: How to reverse an HS 81

Quote:
Originally posted by Jim Walker
I'm using a Y cable to connect 2- HS 81's into the gear channel of a reciever and use them as flap servo's in a four surface glider wing. I have to reverse one servo to make it work in unison with the other. How do I do this? Is there some wiring to reverse or do I need some gismo. Is it some circuit I can make from Radio Shack parts?

Thanks for your help.
Jim,
This is copied from the Hitec support site:

Q. How can I reverse the direction of my analog servo?
A. If you're semi-skilled with a pencil tip soldering iron, de-solder the two outside wires of the "pot" and switch them. Then, de-solder the two wires leading to the motor and switch them. Presto.

That should do it
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Old Aug 06, 2003, 12:11 AM
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William A's Avatar
Tacoma,WA USA
Joined Jun 2001
4,039 Posts
Yup, that's where I read it, couldn't remember.
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Old Aug 06, 2003, 09:25 AM
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gregg f's Avatar
shadow hills,ca
Joined Apr 2000
6,594 Posts
it works well. i've done several...............gregg
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Old Aug 06, 2003, 11:43 AM
CMELI
RonAV8R's Avatar
United States, WA, Kitsap County
Joined Apr 2002
74 Posts
Swap the two pot leads AND the two motor leads....that's the only way we had to reverse a servo back in the "olden days". Be sure and mark the servo as "reversed" for future use!
Ron
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Old Aug 06, 2003, 12:40 PM
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Sparky Paul's Avatar
Palmdale, CA
Joined Oct 2000
13,499 Posts
Why not mount the servos the same on both sides?
Output shafts facing left (or right). The arms then move the same directions.
Mounting the servo with the shafts facing oppositely as is done for ailerons.. does require getting inside the servo.
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Old Aug 06, 2003, 01:01 PM
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Thomas B's Avatar
United States, TX, Fort Worth
Joined Jun 2000
14,640 Posts
These days, it is not worth reversing a servo. Our LHS sells the Expert brand of radio accessories and they have a very nice reversing Y harness, where one servo moves normally and the other is reversed. This is perfect for the flap installation you mention, and all your servo mounts are symmetrical. Plus, there is an adjusting pot on the reverser that lets you synchronize your two servos so they move together perfectly.
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Old Aug 06, 2003, 07:56 PM
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William A's Avatar
Tacoma,WA USA
Joined Jun 2001
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Quote:
Originally posted by gregg f
it works well. i've done several
I must of goofed something up then, I tried it on a HS-81 and couldn't get it to work. Swapped them back to original and works as new and in use.
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Old Aug 06, 2003, 08:35 PM
Bob W
Rock Hill, SC
Joined Jul 2003
925 Posts
I just finished a model with split flaps and had the same problem. I ended up using a Miracle Y from Maxx products, worked fine.
Hitec/JR part #3469JRYR
Airtronics # 3369ARYR
Futaba J # 3169 FJYR
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Old Aug 07, 2003, 11:57 AM
Fixed Wing Fanatic
Jim Walker's Avatar
United States, TX, McKinney
Joined Jul 2001
2,344 Posts
Thanks everybody. In fact this sailplane is made where the flap servos have to face opposite each other to fit their wells and well covers. The plane really deserves a 7 channel transmitter but my customer only has a six channel and so here I sit. I ordered one of the $9 servo reversers from hobby lobby and was done with it.

Thanks again
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Old Feb 04, 2014, 08:27 PM
Catch me if you can!
rosemark's Avatar
Woodstock Ga.
Joined Jul 2006
15 Posts
Can't get hs 81 to reverse

I am having the problem William had with hs 81 reversing. I have swapped motor and the pot leads. Servo just keeps chattering. I soldered everything back to original positions and servo works as new. Is there a you tube on an hs 81?
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Old Feb 05, 2014, 03:55 AM
Registered User
Joined Aug 2002
5,811 Posts
Quote:
Originally Posted by rosemark View Post
I am having the problem William had with hs 81 reversing. I have swapped motor and the pot leads. Servo just keeps chattering. I soldered everything back to original positions and servo works as new. Is there a you tube on an hs 81?
Whilst not all relate specifically to an HS-81, the principle is the same. please refer to:
(quick search = Ctrl+F)
. Servo - Reverse operation . DIY pictorial
. Servo - Reverser for Y-cord operation - If site down, email Alan for copy.
. Servo - Modify HS-322HD for continuous rotation
. Servo - Modify HS-311 for continuous rotation
. Servo - Modify for 360 degree rotation.
. Servo - Modify Digital for infinite rotation, 360 degree rotation
. Servo - Modify HS-81 & HS-85 for 180 degree rotation
. Servo - Modify HS-55 & HS-85MG for Continuous rotation/
. Servo - Modify non digital for 180 degree rotation
. Servo - Retract Conversion (S-148)

below
"Radio Systems, Accessories, Alterations and FAQ" at
Alan's Hobby, Model & RC FAQ Web Links

Alan T.
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