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Hitec 225 nylon to metal gear conversion

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Old 12-04-2002, 03:19 PM
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jsonin
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Default Hitec 225 nylon to metal gear conversion

I have a half-dozen Hitec 225 nylon-geared servos in my arsenal. After stripping the gears in most of them (after bad landings or an aileron touching the ground during a low-pass, etc), I bought two metal gear packs for the 225s.... but when I replace the nylon to metal gears, I cannot get the servo to return to center once I feed any stick input. The servo moves in the direction of the stick control, but then stops when the stick is released... and it should return to zero/center. I've replaced the metal gears with nylon and it works. I'm only replacing three gears and I can't figure it out...

Help!

Thanks,
Juhan
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Old 12-04-2002, 06:46 PM
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RobertC
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Default Hitec 225 nylon to metal gear conversion

Juhan,

While I don't have an answer to your problem, I am curious to hear exactly what size plane you have been using the 225's in?

I have four (nylon-geared) that I planned to use for a dual-elevator setup in both a CGM Extra and a UCD3D. I chose these servos because of weight, speed, and torque. I am currently using 225's (nylon geared) in a 40-size Cap232 (w/ a 70 four-stroke, one each on the elevator and rudder) and have had no problems, but after hearing people having problems with gears stripping I was considering doing exactly what you have done to your servos (go to metal gears) before I used them in the two previously mentioned planes.
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Old 12-04-2002, 08:02 PM
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jsonin
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Default Hitec 225 nylon to metal gear conversion

Robert,

I've used the 225s in the following planes with success:

* 2x Morris Hobbies Pen Knife (OS 25 and 32 engines)
* Morris Hobbies Sudokhoi (46 FX)
* Ultra Stick 40 (all four wing servos.... for crow, etc)
* 2x Pizza Box Flyer

The Hitec 225 servos are good for 25, 40 and 60-size craft. I typically don't worry about gear stripping during flight (unless there is a bit of flutter.. but any servo could strip with flutter)... I only worry about it on tail-touches, a bad tail touch that ends up skimming the ground and an aileron servo strips, rough landings, etc. So I typically don't put 225 on rudders... a 605 is my mainstay. I have no problem putting 225s on every surface in a 25 or 40 size application... but I'd just put them in ailerons on 60s... just my personal preference.. that's not said with a ton of data (just my own experience).

-Juhan
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Old 12-05-2002, 01:30 AM
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Kevin Greene
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Default Hitec 225 nylon to metal gear conversion

I converted mine after they stripped and almost cost me a plane. I was using them on ailerons and both stripped simultaneously!!! Thankfully, I know how to use a rudder and managed to get the plane down......Anyway---to your question...I don't have them with me at this time but I believe that there are some nylon parts (NOT gears) that you must transfer to the main metal output gear. I think that there is a nylon "lock" that you must remove from the main nylon output gear and transfer it to the metal main output gear. This "lock" engages the pot on the servo so that the pot knows where home is. I believe that there is a round metal clip that provides a friction press fit in the gear. All of this is found if you turn the nylon main output gear upside down after removing it from the servo. Be sure to center the "lock" so that the stop on the main output gear do not hit the case stops under normal servo throws. Let us know if this helps.

Kevin
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Old 12-08-2002, 03:54 AM
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jsonin
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Default The nylon lock...

Kevin,

After closer inspection, apparently the nylon gears have the 'lock' built into the base of the main gear... whereas on the metal, one has to add the plastic lock and fit it correctly. What's even more goofy is that the nylon lock required with the metal gears isn't included in the metal gear set... it's included in the nylon gear set replacement which is the only reason I had them (from the several sets of nylon gears I've bought in the past).

It works.

-Juhan
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