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Keith B

Wing Servo's

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Keith B

Ok to start with I'm not a terribly experienced builder, I'm putting together a sunbird, and I've decided to use Hi Tec HS125 MG's in the wings, now these come with a double sided sticky pad for installation, now every bone in my body says throw the pads out and use epoxy and micro balloons, am I over engineering a 1.5m model or am I right?

 

TIA

 

Keith

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swarrans

I think you're right for what it's worth Keith - I'd never use double sided tape whatever the model.  Well, perhaps if it was a boat!....

 

Si

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Rooster-X

Bare servo and Epoxy or frames epoxied in, anything else like insulation or masking tape wrapped around the servo eventually comes loose, ask me how I know. I have superglued them into a D60 as Joe Manor reccommends but doesn't give you much room for error and I havn't tried getting one out yet. Tony Fu's site gives some good advice on the best way to install servo's, last time I don't think I even bothered with micro balloons on a Vector 3, just a small amount of 30min epoxy.

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Janek

I'm a naked 30 min epoxy man as well, never had an issue, and they are easy to get out should the need arise. A little, careful, blast with a covering blower (or a hair dryer would do, if you have any hair) to heat up the area, a large pair of pliers, and a sharp twist, and out they pop.

 

Don't forget to de-grease/de-wax the area, and roughen it up, before you initially glue.

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Keith B

Yeah this is pretty much as I figured, I think I was being a tad lazy thinking about the tape!

 

I just needed to know I wasn't over engineering it

 

Thanks guys

 

Keith

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f3fman

Neat 5 minute epoxy for me too, pops out no trouble with a good tug.

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isoaritfirst

Cyano and ply frames is very quick and very easy, then just cover with a few gobs of hot glue to retain the servo.

Although I use many different ways, because experimenting or just doing something differently is more interesring , I would advise on masking tape, folded very neatly as a full wrap around the servo and epoxy and micro balloons. The balloons add thickness which is needed when trying to stick a flat sided servo to a curved wing skin. Using just epoxy may increase the chances of the top skin sinking and highlighting the servo position beneath, as will Cyrano and frames'although you can and should sand the frame to match the profile a little.

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Woodstock

I rely almost totally on a brace expoxied on top of the servo (tying it into the "top" skins") to retain the servos.  Given that approach, what you use to glue it to the "bottom" skins isn't critical:  even the double-sided tape is fine...

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JG

Hello Everyone - A few people in my club have used "the glue way" to hold there servo's in with some maskin tape around them,but myself i use servo frames which i find easyer,the only thing is you have to stick with the same servo if you have to replace.

 

Use 30 minute Epoxy in my opinion ;)

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Bobbyr

Chris has it how i do mine ,

              I do use some of the double sided pad (1/4) , thats placed into the middle of the servo , then 5 min and micro balloons around the edges , fit the servo and press so that the pad touches down , it springs up a small amount and draws the epoxy/balloons back underneath the servo,

              Then using a lolly stick or slither of ply , bridge the top skin , and glue in place , makes a strong fit , but take the top off and twist the servo , it pops off , and leaves a socket ready made for a replacement servo of the same size .

 

        Million ways to skin a cat , but get a method you are happy to trust .

     And every suggestion here so far is a servicable solution , and i would be happy doing any of them

 

                                               Bob

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EssexBOF

Wing servos using frames are the best bet although I personally would not use Hs 125,s

Having tried various methods over time, if the servo does not have lugs on the side to screw down into a frame but is a standard type of servo, I use the following. Remove the output arm, then slide a suitable sized piece of heat shrink tubing over the servo, leaving a bit of ecess each side,from the mounting lug side, so as the lead can pass through the side.

Shrink over the servo without applying excessive heat. Rough up the side to be glued down into the wing. I usually apply another layer of carbon cloth onto the surface to be glued to, the top in most cases. When satisfied as to the correct position, glue in with Rapid Araldite, as I find this is slightly flexible but holds well and can be held in place whilst setting takes place.

To remove simply cut through the heat shrink on the top of servo and pop servo out. Clean out the old glue and heat shrink, then reglue in when satisfied

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Yoyo

The thing that gets me about all these answers is the assumption of enough space for frames, braces etc. - almost everything I've installed stuff in for a long time has been a real squeeze.

 

Is that the price I pay for liking sporty gliders, even in the big ones the servos are crammed in? I guess powered and scale planes have acres of room inside the wings for the servos.

 

 

 

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Rob Thomson

Agreed!

Most of my models don't even have space for double sided, tape.

Just a servo, masking tape, bead of epoxy, done!

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isoaritfirst

On the of occasion that i decide to frame my servos i make my own frames from ply. Usually by making them as two halves, as it is a few seconds work on the band saw to nibble out two U shaped pieces, and once they are glued in place they make the full frame just the same.

I have never bought any frames as I have so few occasions when I need to remove servos, having servos which screw in and out is of little importance to me. I prefer to put the cost of the frames into buying better servos.

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EssexBOF

The thing that gets me about all these answers is the assumption of enough space for frames, braces etc. - almost everything I've installed stuff in for a long time has been a real squeeze.

Is that the price I pay for liking sporty gliders, even in the big ones the servos are crammed in? I guess powered and scale planes have acres of room inside the wings for the servos.

Sorry can't agree on that at all. Using heat shrink as I described, have fitted DS 09,s into fins to operate rudders or elevators no problem. Masking tape is a no no as far as I am concerned as is it becomes prone to letting go in warm conditions. What models can't you fit a frame into. Most of the Nan range are not a problem also Stork 4.

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satinet

The thing that gets me about all these answers is the assumption of enough space for frames, braces etc. - almost everything I've installed stuff in for a long time has been a real squeeze.

 

Is that the price I pay for liking sporty gliders, even in the big ones the servos are crammed in? I guess powered and scale planes have acres of room inside the wings for the servos.

 

Whether you use them or not, frames ususally fit in okay in f3x style models. They don't add anything to the width of the servo and only a small amount to the footprint, especially the plastic ones.

 

Most servos fit under the wing skin even on tight models, so you can usually put a brace across the top of the servo, if you want. 

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Janek

Yoyo has hit the nail on the head regarding lack of room, I've been in the position on a number of occasions of having to remove the lugs from brand new servos to get anything to fit into the wings.

The price we pay for super slim wing sections.

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isoaritfirst

Still not built that ProdiJ HM then Tom  :D

 

Just built the servos into my Aroso wing - Into depron - cut in tight dab of UHU and a layer of tape across the wing. Perfect for the job. No frames or braces or tape.

 

Incidental I have models which have masking tape on servos which are 10 years old and flown for hundreds of hours without problem. But I do parcel the tape with neat cuts around lugs etc, rub it very well down and make the join under the servo in the 30 minute epoxy /balloons mix. Greasy servos and a rough wrap is likely to fail.

I haven't tried Heat shrink, I am sure it works well is probably easier and quicker to do than tape, but I tend to use what I have around me at the time. Never had any heat shrink of a suitable size, so for me masking tape is more convenient and works perfectly well.

 

 

 

Bracing servos to both skins or bracing both skins to each other by pocketing out the servo hole is something that is always worth doing, but of course some models just do not warrant it, do it if you have time and the inclination but for some models its just not necessary.

 

For example It would be possible with the ProdiJ HM's 10mm wing to brace the skins together and use a 10mm servo but if you wished to brace across the servo (which is no better just usually easier) you would have to use  <8mm servos.

So its all down to choices. The ProdiJ is a light but fast flier with full carbon wing skins, and doesn't go through the rigours of winch launches, so boxing out the wing is a lot of work for little gain, and using <8mm servos is not a choice I would make. I chose to mount a single former between the top and bottom skin running parallel with the pushrod, I also allowed the former to protrude out of the bottom wing skin to act as a fairing for the servo arm, as there is no room for servo covers/fairings.

 

Lots of ways, none are definitive, but all the advice offered in the thread is relevant and useful, but each model needs to be assessed individually for your model and your needs. Sometimes the servo can be glued more to the wing spar than the skins, or both, so tied skins are less important.

 

Another example I could give is my first Vector which I used ply frames, because I had fitted over the top servos which i removed when the model was upgraded and the airframe sold on. Servos were held in with large gloops of hot glue which was also used to fill between the servo and the bottom skin/servo cover as a skin tie. 

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satinet

I did say models, not carbon based crypton factor puzzles.

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Woodstock

Whether you use them or not, frames ususally fit in okay in f3x style models. They don't add anything to the width of the servo and only a small amount to the footprint, especially the plastic ones.

 

Most servos fit under the wing skin even on tight models, so you can usually put a brace across the top of the servo, if you want. 

Exactly.  If it's a tight squeeze, I use an aluminium sheet brace, bent with double "S" bends on each side of the servo to get under the skin.  If it's REALLY tight, I use thin steel. It can always be done.

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