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Best way to mount a servo?

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mooffle

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I'm trying to build a small field RC boosted glider, I'm running into a snag trying to mount the servos to the curved surface of a BT-55. Does anyone have any tips? ideally I want to keep it user servicable and not just glue them.
 

OverTheTop

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Make a 3D printed mount that you can glue in place, but mount the servos with screws. That's how I would do it. You could whittle some balsa to achieve the same outcome.
 

watheyak

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You can also wrap them in large heat shrink tubing and glue that it. You can remove the servo by slicing the tubing. From there it's pretty easy to peel out the remains of the tube.
 

burkefj

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Do you have a picture of how it needs to be installed?
 

mooffle

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I'll post some pictures of the build later tonight when I leave work.
I don't have a 3d printer unfortunately but a balsa bulkhead sounds like a decent option. Should I be concerned about screws stripping the balsa? I have some thin plywood (1/8 inch i think) that I could try to sand a curve into.
 

dvdsnyd

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I'll post some pictures of the build later tonight when I leave work.
I don't have a 3d printer unfortunately but a balsa bulkhead sounds like a decent option. Should I be concerned about screws stripping the balsa? I have some thin plywood (1/8 inch i think) that I could try to sand a curve into.
You can strengthen the balsa a couple ways. Making it thicker by laminating a couple 1/8" sheets together to make 1/4". Also, for the mount holes. Make your threads in the balsa with whatever way you choose. Unscrew the screws, and soak some thin CA glue in and around the threads. This will greatly strengthen the area around the thread.
 

burkefj

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For lightweight models with small servos, I just screw into the tubing and harden the hole with CA and not even use balsa...
 

mooffle

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First image is the overall planform with the tail and elevator on the right, I haven't made the tail and rudder yet.
After reading the responses I'm kind of leaning toward a bulkhead with the servos mounted on the inside and sandwiched next to each other, the tube is *just* big enough to fit them comfortably.
Second image shows the fit in the tube.
I'm thinking the arms would have to be on top of the model with the exhaust pods the way they are.
Oh and the elevator will be mounted sort of high on the tail so it won't be blasted by exhaust of course.
The end result will be sort of b1-b or mig-15 looking.
IMG_20200520_223906978.jpg
IMG_20200520_224157866.jpg
 

mooffle

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After distancing myself from this project by building an entirely different rocket, this weekend I'll tackle these servo mounts. I'll post an update once its all set.
Most likely going for a rectangular hole that the servo arms will come up through with the servos mounted inside a bulkhead/tray that gets pushed down the tube.
I will definitely do CA as well. Hopefully this many tube holes wont weaken the frame.
IMG_20200528_183237084[1].jpg
 

mooffle

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I decided on the above backed by a balsa block, the block is a bit longer than the servo housings and provides strong enough friction fit that I don't see a need for screws.
I do have to mount one more servo all by itself and for that I will just cut the hole and CA the cardboard.
Thanks for all the ideas!
IMG_20200530_140532820.jpg
 

Crawf56

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For these type of situations, I have used Hot Glue, like you get at Walmart (Arts & Crafts).

I have also used medium CA. Either way, try to keep glue off the wires.
 

mooffle

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This has been a very slow build, no rushing the construction until I felt totally ready to work on it and now it's almost done. Three servos mounted thanks to the suggestions here. So thanks everyone!

However, I purchased a 3/16 inch launch rod a couple months ago only to get close to finishing and realized: I have no 3/16 lugs in my parts bin...
Of all the reasons to delay a build this one makes me pretty salty.
IMG_20200915_003136508[1].jpg

Not shown is the third servo just behind and under the nose that will have a swing out canard, CA threading for some leftover laptop screws secure that one.
 
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