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Retract servos

Old 05-19-2008, 09:02 PM
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Ernie P.
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Default Retract servos

Guys; what are you using for retract servos in a full electric (rather than air/servo systems) system, in the 9 gram and standard size servos? Thanks; Ernie P.
Old 05-19-2008, 09:10 PM
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RCKen
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Default RE: Retract servos

You need to use a retract servo similar to this: [link]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXPB42&P=ML[/link]

Retracts are different from normal servos in that they only have two positions. Normal servos are fully proportional meaning that they can move to any point within their travel range. Retract servos are designed to move from one position and turn 180° to the other position. While normal servos can do this, they will absolutely drain your battery. Retract servos move to a position and then draw no more current while they rest in that position. A normal servo will move to that position and then have to draw power to remain there. It's entirely possible that you can drain a flight pack in just one flight by using normal servo for a retract servo.

Hope this helps

Ken
Old 05-19-2008, 11:25 PM
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ChuckW
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Default RE: Retract servos

What he said...

Also, retract servos are usually low profile (thinner). This allows them to fit better in the wing and allows space for the linkage.
Old 05-20-2008, 07:03 AM
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da Rock
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Default RE: Retract servos

If you happen to be assembling one of the H9 warbirds that have rotating gear (P40, F4U, or F6F), you might look at these.

No screwing around with a servo linkage or building in all the stuff that air retracts require. Put 'em in where the mechanicals go, plug 'em into the RX, and fly.

https://smartweb.ipower.com/lado/pro...0&productID=19
Old 05-21-2008, 06:36 PM
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Ernie P.
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Default RE: Retract servos

Thanks for the info, guys. I'm looking for a good source for the 9 gram size retract servos. BTW; why is the servo 180 degrees, when the gear only rotates through 90 degrees? Seems strange. Thanks; Ernie P.
Old 05-21-2008, 07:23 PM
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Allfat
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Default RE: Retract servos

Well, the servo is hooked up to the gear through some sort of linkage I assume. The servo is not directly hooked up to the gear.

Same thing with all your control surfaces. Your servo may be maxed out at 180*, but your control surfaces may have only moved a fraction of that. Your servos are not directly hooked up to your control surfaces similar to how it is not directly hooked up to the retract gear.
Old 05-21-2008, 08:16 PM
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2HI2C
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Default RE: Retract servos

da Rock
Those are what I have been looking for.
Thanks
Old 05-22-2008, 07:32 AM
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2slow2matter
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Default RE: Retract servos

90 degrees from center each direction equals 180 degrees of travel. 90 degrees extend and 90 degrees retract equals 180 degrees. Trust us, you need 180 degrees. And, if you don't hook the linkage up just right, you'll have too much or not enough travel, and there is no electronic end point adjustment on these. So you might need some help if this is your first time to set up mechanical retracts.

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