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Author Topic: Servo Saver  (Read 1051 times)

tizdaz

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Servo Saver
« on: January 08, 2018, 10:12:31 PM »

Hi guys, anyone know where I can get something similar to the pic below, but with DOUBLE arm (not single as in pic!) its a servo saver that clamps straight onto the servo spline but looking for a double, ty!


Brian60

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Re: Servo Saver
« Reply #1 on: January 09, 2018, 07:47:49 AM »

Dunno what you mean by servo saver, a term I've not heard of before. But if its just a double servo arm in aluminium you want then try Hobbyking or any of the r/c car suppliers, they have them by the bucket load.

Brian60

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Re: Servo Saver
« Reply #2 on: January 09, 2018, 07:55:23 AM »

Just got this from a r/c car site......

For servo-savers, usually they aren't adjustable (unless you're talking high-end stuff) - so normally you just install it, and there you go. It's often a spring-loaded type deal where under normal steering conditions, it's all tight, but if you were to move the servo and hold the wheels in place, you'd see the steering linkage have a little "give" in it so that it won't force the issue and snap something.

Usually the servo saver is either installed directly on the servo gear (instead of a straight arm, it's a servo arm with a spring in it, so to speak), or down the line in the servo linkage (by the steering posts it rests on). They help when you slam into things with the steering, so it absorbs the load with some give instead of transferring it all to your servo gears (damaging them).


For the slipper, it's kind of a judgment call. If you're peeling out and wheely-ing hard on takeoff, flipping over, etc, you might want a looser slipper. If you gun it from a standstill and it feels like it's taking too long to get that torque down, it might be too loose.

I think the rule of thumb is you should hear it "slip" for a few feet on takeoff, that's about it. It's something you just have to get used to - if your truck seems to behave fine on takeoff, you're likely ok.


........... So I cannot really see a use for it on a ship, unless of course you are moving the rudder mechanism further than the rudder detents, but then that would be poor set up, its not as though water would cause any shock to the rudder that can be found on rc cars.

Still go to Hobbyking or RCUniverse type in servo saver into the search bar and they have them by the bucketload.

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inertia

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Re: Servo Saver
« Reply #4 on: January 09, 2018, 08:34:51 AM »

$55? Bargain! Cheaper to buy 20 sets of servo gears.
I used to use a Z-bend in the pushrod for steerable nosewheels on model aircraft, then I got really clever with two brass collets and a couple of small compression springs at the servo end. Work it out for yourself - it's called modelling.
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chas

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Re: Servo Saver
« Reply #5 on: January 09, 2018, 08:40:13 AM »

Servo savers have limited use in model ships, shock loads will only happen if you bash the rudder when moving the model. If you want some protection from that possibility, make your own linkage from piano wire or similar and bend a V part way down its length. Simple cheap effective and been used for decades.
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Fastfaz

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Re: Servo Saver
« Reply #6 on: January 09, 2018, 09:06:39 AM »

   Servo savers are used in most Tamiya model trucks as the load on the steering can lock the servo on occasion. I never used them on my trucks I modified the steering linkage to eliminate the huge amount of play. Why don't you make a twin arm of your own by bolting and fixing a piece of brass strip onto a single arm? Good luck with the build.
      Cheers, Pete. :-))
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tizdaz

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Re: Servo Saver
« Reply #7 on: January 09, 2018, 12:17:42 PM »

hi guys


A servo saver is basically a safety mech for your servo to avoid stripped servo gears (My 1/6 petrol FG has one for the steering, slightly different design but same principal!)




i'm building a 1/12 tug & the rudder is fairly large & quite heavy (for a rudder). The servo i'm going to use is a Savox (pic below) has 15kg torque

If for some reason or by accident I quickly shift from left to right this can put a lot of strain on the servo gears so a servo saver acts like a sponge so to speak whereas it wont instantly "bite" thus avoiding stripped gears. Even during transport, if i should accidently knock the rudder fairly hard this again can cause the gears to strip in the servo, hopefully this will never happen, but prevention is always better than a cure! But it seems the design i'm after only do single arm type, I was thinking of using the "Z" bend method in the linkage arms which is basically a simplified servo saver, but will this work with double linkages that use the push-pull method ?


cheers

tizdaz

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Re: Servo Saver
« Reply #8 on: January 09, 2018, 12:26:07 PM »

$55? Bargain! Cheaper to buy 20 sets of servo gears.
I used to use a Z-bend in the pushrod for steerable nosewheels on model aircraft, then I got really clever with two brass collets and a couple of small compression springs at the servo end. Work it out for yourself - it's called modelling.
DM


I am trying to work it out, its why i've asked on here for advice, 2 brass collets & a couple of springs will not work as a servo saver, if for whatever reason the rudder takes a huge knock, 2 small springs with collets wont protect the gears! ..i know because I have a similar setup on the throttle arm of my FG as a throttle return.. unless you mean a different type of setup? Have you a pic of what you mean so I can see, cheers!

tizdaz

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Re: Servo Saver
« Reply #9 on: January 09, 2018, 12:31:37 PM »

heres a pic of what i mean, this is no use a servo saver..


Mark T

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Re: Servo Saver
« Reply #10 on: January 09, 2018, 12:53:41 PM »

Hi mate this is what I do. Use what ever diameter rod you want to use and run it through a servo connector that allows it to slide. Then fit a spring and collet either side and your sorted. RS components sell loads of different types of springs so just get ones that suit your needs. Obviously for your problem just fit the same thing both sides of the servo horn  :-))





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tizdaz

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Re: Servo Saver
« Reply #11 on: January 09, 2018, 01:40:09 PM »

Great stuff cheers Mark ;-)

Stavros

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Re: Servo Saver
« Reply #12 on: January 09, 2018, 02:59:46 PM »

Daz the rudder on my happy hunter is bigger than the tid one and i have never had a problem using a hitech sail arm servo and am using the same servo on the Tid so why on earth are you are worrying at all...I'm not at all worried about stripping gears on it as it isn't an issue.......Just to give you an idea.....the Hunter is powered by a 3/4 hp brushless and 2 x900 motors so the propwash is far more over the rudder than a single motor and i can go flat out port to stbd with no issues at all.....try and stop trying to reinvent the wheel and over complicating stuff when it is not needed....as long as the servo is properly mounted and your rudder rods are strong it wont budge or break


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McGherkin

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Re: Servo Saver
« Reply #13 on: January 09, 2018, 03:34:14 PM »

I canít say Iíve ever felt a need to have a servo saver since theyíre more built for crashing into walls at 20+mph, but then I do have a lifeboat so the rudders are well protected anyway.
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Big Ada

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Re: Servo Saver
« Reply #14 on: January 09, 2018, 06:12:16 PM »

On my 20 foot long Bulk Carrier I have a 3" x 2" fish tail rudder operated by a bog standard Acorns Servo, its never been a problem.

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tizdaz

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Re: Servo Saver
« Reply #15 on: January 09, 2018, 08:14:49 PM »

 
hi guys, ty for info, its more for peace of mind knowing that should anything happen, the gears wont be stripped, i'm going to just use the Z bend in the rods as this seems to be a well used method & simple to do :)

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dougal99

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Re: Servo Saver
« Reply #16 on: January 09, 2018, 08:19:13 PM »


Last posting at readable size.


hi guys, ty for info, its more for peace of mind knowing that should anything happen, the gears wont be stripped, iím going to just use the Z bend in the rods as this seems to be a well used method & simple to do :)
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tizdaz

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Re: Servo Saver
« Reply #17 on: January 09, 2018, 08:21:39 PM »

Last posting at readable size.


hi guys, ty for info, its more for peace of mind knowing that should anything happen, the gears wont be stripped, iím going to just use the Z bend in the rods as this seems to be a well used method & simple to do :)


thanks :)


it keeps doing that often & i usually notice & edit it, the code gets messed up & it randomly places font code in the post! :(

RAAArtyGunner

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Re: Servo Saver
« Reply #18 on: January 10, 2018, 12:58:31 AM »

After reading all the commentary, My conclusion, totally unnecessary bit of kit.

 As pointed out 55 quid which is $83 AU dollars, to save ruining/damaging a servo that if it happens can be replaced for less than $30 AU dollars.

The 'bend' in link works for me.

Obvious what I would be doing.
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tizdaz

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Re: Servo Saver
« Reply #19 on: January 10, 2018, 01:18:56 AM »

After reading all the commentary, My conclusion, totally unnecessary bit of kit.

 As pointed out 55 quid which is $83 AU dollars, to save ruining/damaging a servo that if it happens can be replaced for less than $30 AU dollars.

The 'bend' in link works for me.

Obvious what I would be doing.


hey :)


Aye, I wouldn't spend $85 on any servo saver (a brand new servo costs much less!) the servo savers i was looking at was around £10 which double up as a servo horn to (which is just a little more than an alloy horn) so I wouldn't of mind paying that as I will be using an alloy horn anyway. But like I say though, decided to just go with the Z bend trick :)

Fastfaz

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Re: Servo Saver
« Reply #20 on: January 10, 2018, 07:34:26 AM »

   Stav's spot on you are making things too complex for yourself I don't see a problem if you are using a metal geared servo. When tug towing the strain on the steering can be very heavy but I've never seen or heard of anyone stripping the servo gears. Make it simple you'll enjoy it more. Nice work though.
      Regards, Pete.
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