Zagi Servos

Panic not. HS-81s are more than good enough unless you have carbonned stiffened the Zagi and put in a power plant of about 6-10 times recommended and expect to crack the 120mph barrier.

D.,

HS-81s are perfect for the Zagi. Mine has been flying on a pair for years. I have the stuff for a brushless upgrade ready to install. The servos will stay.

Good flying, desmobob

Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:

The HS-81 are fine.

As for the oversize holes, measure how much LONGER the opening for the servo is than the HS-81. Get some BASSWOOD of the appropriate size (if you need to it is ok to CA a couple of pieces together to get the correct thickness ) and CA a piece in ONE END of the servo opening. Then mark and drill pilot holes (I use a 1/16" dia drill bit ) for the servo screws.

You are better off with basswood rather than balsa - less chance of the servo screws pulling out.

So who recommended the HS-81s? At least you now know that that party is not a reliable info source. I have a Zagi 60 in which the HS-81s are standard. The servo wells are a tight fit for the servos; nothing holding them in but friction and the mylar tape covering. So you might stuff the dervo wells with pieces of scrap EPP foam and be OK.

However, the gear train in the HS-81 is kind of brittle (ask me how I know). If you're going to do aerobatics close to terra firma you might be better off with larger or MG servos. ;^)

CR

Davey Boy wrote:

I will harmonize with the others here. I have these servos in my Zagi and my Trick Razor. They are a tight press fit. I shimmed with balsa and it is all held in place by compression against the foam...and tape patches over the top. I figured I would watch them and if they loosened, I would respond to that. They've stayed tight and I do some pretty mean outside loops with both models and I fly the Razor upside down more than the Zagi right side up. I also figure that in a really bad prang, the foam would act as "servo savers." Maybe. I am also using the cheapo $20 electronic mixers in both Zagi and Razor with just regular xmitters. I preferred doing this than messing with my one cheapo computer radio. Good luck. (Yes, it is strange to throw a Zagi that way but it works.)

Ken

| I've just bought a Zagi 480 si. I bought Hitec HS 81 micro servos under | recommendation.

The HS-81MG servos are better -- they'll survive a lot more crashes. The MG means `metal gears'.

If you need a slightly bigger/stronger servo, the HS-85MG is a good choice.

The HS-81s you have aren't really micro servos anyways -- they're more mini. But they're probably fine for your plane, as long as you don't crash.

(As for how to mount them, that's already been answered.)

Hitec has had `karbonite' gears for a while now, and I've been very happy with them, and yet to have any of them strip on me. But I don't think they're available on the HS-81MG sized servos yet.

Hi,

I'll go ahead and use the HS 81s cause I already have them. If I crash and strip them I can replace them with something stronger next time. I'll probably use polystyrene and Bass wood to wedge them in and use the covering tape to hold them down. I read an article once about using insulation expanding foam for fixing servos into oversize holes (buy it in a tin, spray it under/around the servo in the hole, it expands, sets and your're done). Trouble is you only get one go at it, if it goes wrong your're buggered. Don't think I'll risk that.

Thanks for the replies; I'll keep checking in case you have any other suggestions.

| I read an article once about using insulation expanding foam for | fixing servos into oversize holes (buy it in a tin, spray it | under/around the servo in the hole, it expands, sets and your're | done).

You wrap the servo in a plastic bag (like from a grocery store) very close to the servo and it creates a very nice little pocket for the servo to sit in, and it's held in with tape. (You remove the bag once it's all dried.)

You can do the same with epoxy too, but epoxy weighs more, which can be signifigant if you need lots of it.

It's a good idea.

| Trouble is you only get one go at it, if it goes wrong your're | buggered.

Not true -- you can cut out the bad foam and try again if something goes wrong.