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How do top mount aileron servos ?

  • Thread starter Thread starter Pelagicide
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Pelagicide

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I got my first quality dlg kit about 2 years ago, but because of health issues and a reluctance to do a bad job on a nice dlg I've only recently gotten serious about starting the build. Originally I was going to pay someone to build it, then I had a very generous and talented builder and pilot who was going to do it for just the cost of shipping it both ways and the cost of any hardware used in the build. Unfortunately an upcoming surgery made me (well, that's my excuse anyway lol) wait to long to ship it to him and he got a paid building commission and 2 others waiting for him to get to them so he doesn't have the time to do any pro-bono builds for me.

The kit I have didn't come with any of the necessary hardware (it's a Maat, not top of the line, but for someone who to this point has only "built" and flown foam ARF's, it's a huge jump in quality and needed skills), and I've just finished getting all of the needed hardware with the exception of aileron servos. The guy who was going to do the build has offered the opinion that I should use KST-08's in the wing and I will most likely use them even though the price put me off when I first saw them. Remember - only done foamies till now. I'd like to mount them on top of the wing with the push rods routed mostly through the wing rather than hang them on the bottom with totally exposed push rods both for aesthetic reasons as well as being more aerodynamic.

I've never done this before and am very leery of attempting it for fear of messing up a really nice wing. My question is can anyone point me to a good build thread that shows how it's done this way and that shows all of the steps? I know the Maat isn't competition DLG but it's light years ahead of the ARF's and scratch builds I've done till now. Thanks and sorry for such a long lead in to the actual question!
 
Is this what you are working with?
https://flightcomp.com/products/maat-1-f3k

I'm sorry I know nothing about it.

But here are some of my initial thoughts. As the core is polystyrene I'd use mostly 30 min epoxy. Do not use CA or 5 min epoxy. (If using any CA make sure it is "Foam safe", and this model deserves better than 5 minute epoxy)
Do not put any holes in the spar assembly. I don't know if the wing is thick enough to allow the servos to be mounted aft of the spar. I don't know if aft mounted servos would cause an aft Center of Gravity issue. As this a novice plane I'd line the servo pocket with a layer of 2 oz glass and epoxy for durability.

Make sure the control horn hole for the clevis is placed above the hinge line so that a line drawn from this hole through the hinge line is 90° to the wing chord.

Use sharp knifes and a rotary tool with sharp burrs. After cutting the slot in the aileron top skin only (top skin for top drive ailerons) place a piece of masking tape about 3mm ether side of this slot. Fill the slot with epoxy, push the horn all the way down to the other skin of the aileron (bottom) and align the hole with the hinge line. With the epoxy still wet lift off the masking tape. This should remove the excess epoxy and leave a nice epoxy fillet between the horn and the aileron skin.

Making the tunnel for the push rod is tricky. I don't have a process for this other than to say I use a hot piece of music wire to melt this tunnel.

In all likelihood you will need an aileron servo cover with a tear drop hump.

Here are some links that may shed some light.
https://forum.alofthobbies.com/inde...ds-servo-mounts-etc-step-by-step-install.198/
https://forum.alofthobbies.com/inde...glass-and-rohacell-racer.367/page-2#post-4136

All the best,
Konrad

P.S.
It pains me to send you to this site! But this thread might be a good start, as it has a lot of links.
https://www.rcgroups.com/forums/showthread.php?1686059-Top-Drive-Servo-install

Head down in shame for sending you to RCGoofs.-Konrad
 
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