Savox 1290 Tail Servo

[FourT6and2]

Anybody using this servo on the tail? I'm having a hard time figuring out how to mount this thing to my Atom 500.

The servo mounting brackets have a flange molded into them. This flange prevents the servo from sitting flush against the frame when mounted from the outside.

And the servo, itself, is too large to fit it inside the frame and out the cutout to mount from the inside.

The only way I can see mounting this thing is from the inside IF I take the servo apart and mount the top plastic case (by itself) from the inside of the frame. Then screw the servo back together from the outside.

Is this normal?

[sly the dogman]

This is how I did it ;

http://video.helifreak.com/?subpath=...g_mounting.wmv

[FourT6and2]

Originally Posted by sly the dogman

This is how I did it ;

http://video.helifreak.com/?subpath=...g_mounting.wmv

Perfect. That's what I thought I'd have to do. Thanks!

[FourT6and2]

Well, that was incredibly difficult. Took me 3 hours. Wound up having to use one of the stainless screws that came with the servo instead of the Compass part because the phillips groove in the head was just too small and wouldn't provide enough torque to tap into the plastic servo nut.

But, finally managed. All four servos are in. I'm praying that the geometry will be good and I won't have to reinstall them from the outside...

[Chargersforlife]

My savox 1290mg went in w/o a hitch...

[fulcrum2]

@chargersforlife

Without a hitch? How?
Can't put it from the outside (like shown in the manual) because of the little ribs on the plastic servo mounting brackets....
And if you want to put it from the inside of the frame you have to take the carbon frame off or tear the servo down. So please explain to us how you did it

[FourT6and2]

Originally Posted by fulcrum2

@chargersforlife

Without a hitch? How?
Can't put it from the outside (like shown in the manual) because of the little platic ribs on the plastic servo mounting brackets....
And if you want to put it from the inside of the frame you wave to take the carbon frame off or tear the servo down. So please explain to us how you did it

Exactly.

And if you take the servo apart and install it from the inside, then you have to cut one of the plastic servo nuts in half and find a way to keep them from rotating when you tighten the self-tapping screws down. Which was the hardest part for me since it required a LOT of torque to tap those things.

And on top of that, no screw driver will adequately line up with the screws from the inside. There are no holes in the frame for one to fit through.

So all in all, it's a huge pain in the ass.

[PieroCapredoni]

Please, I am in the 1290MG installation right now..... Can you share some pictures of the installation and/or finished work????

[FourT6and2]

Originally Posted by PieroCapredoni

Please, I am in the 1290MG installation right now..... Can you share some pictures of the installation and/or finished work????

I don't have any detail/closups. But I can walk you through it.

There's also a video from Finless Bob: http://video.helifreak.com/?subpath=...g_mounting.wmv

1. Remove the four bolts holding the servo together.

2. While holding the bottom servo case and metal mid-section, push down on the spline of the servo. The top plastic case will pop off.

3. Set the servo aside.

4. Take one of the plastic servo nuts and cut it in half so you now have to separate plastic nuts.

5. Install the top plastic servo case from the inside of the heli. The opening for the spline should face toward the tail.

6. Place the servo screws through the front mounting holes in the frame from the outside. Then through the servo case.

7. Place a washer on each screw. Then place the cut servo nuts on. It may help to tap the servo nuts before installing them as they are quite tight.

8. Get a long needle nose pliers to keep the nuts from rotating as you screw them down. It's difficult. Start with the nut that's higher up, toward the top of the frame first.

9. Install the rear-most screws from the inside.

10. Place the washer on the screws first then through the servo case (from the inside).

11. Then screw on he servo nut from the outside.

12. It's difficult to reach the screws on the inside. But it's possible. Just have to work at it without stripping the heads.

13. Screw the servo back together from the outside of the heli.

Done.

[sly the dogman]

When I did mine I followed the vid carefully, the holes closest to the main gear I screwed the bottom bolt first (it helps a lot) from the "outside" of the frame, holding the plastic servo nut with a pair of long-nose plyer and then doing the top one after also from the "outside". I was able to screw the other bolts from the inside of the frame. But if you find it difficult to do just screw them from the outside.
Fonctionnal is better than pretty.

[fulcrum2]

To me, the Finless Bob video made not so much sense. Still a major hassle - stripping the servo, cutting the plastic nuts, still difficult to reach the screws...
I just took the complete side-frame off and installed the servo without any issues. Total time maybe 45 mins without the risk of screwing up the internals of the servo.

Hope this helps. Cheers, Stefan

[FourT6and2]

Originally Posted by fulcrum2

To me, the Finless Bob video made not so much sense. Still a major hassle - stripping the servo, cutting the plastic nuts, still difficult to reach the screws...
I just took the complete side-frame off and installed the servo without any issues. Total time maybe 45 mins without the risk of screwing up the internals of the servo.

Hope this helps. Cheers, Stefan

I already had the rest of the heli built. I did the servos last. So breaking down the frames would have been a major pain in the ass.

[skinart76]

Why can't you guys just take a dremel to the ridge and shave that off? I've done that to plenty of servos, and it takes maybe 20 seconds on each ridge. It'll make life a lot easier down the road, when you strip a gear and need to change those out.

[FourT6and2]

Originally Posted by skinart76

Why can't you guys just take a dremel to the ridge and shave that off? I've done that to plenty of servos, and it takes maybe 20 seconds on each ridge. It'll make life a lot easier down the road, when you strip a gear and need to change those out.

Still have to install the servo from the inside. Otherwise it looks like the spline/arm/ball won't line up with the center of the tail, causing the tail push rod to bend. It's not a huge difference, though.

[Chargersforlife]

I just put it on from the outside. Not a problem.

You can see pics in the pics thread, although not too close up. (Nothing really to see anyways...)

[FourT6and2]

Originally Posted by Chargersforlife

I just put it on from the outside. Not a problem.

You can see pics in the pics thread, although not too close up. (Nothing really to see anyways...)

You put the ball on the inside or outside of the servo arm?

[Chargersforlife]

Outside.

[skinart76]

I run a Futaba BLS251, mounted from the outside. Using the stock star servo arm with the ball mounted on the outside. The pushrod is perfectly inline.

[PieroCapredoni]

Hi all, im using the manual stated distance from center to ball link of 13mm and i hav a little tail wag. what are you using from center to ball link?? im thinking that maybe tail wag will dissapear moving ball link to center, what do you think??

[chopstick]

I run a DS650 servo, and 11mm.