Servo recommendations for spoilers

[TheNightowl]

Already looking ahead to wings I'll be building next season, and looking to build an RES, I was wondering about spoilers. With the advances in servos, I was wondering if something like an HS-55 in each wing will handle the load on a spoiler, as opposed to a single servo mounted in the fuse driving both. Even an HS-81 mounted on its side will fit in the Oly II wing if it really needs that much torque to drive it. So, what are other people doing? Are you putting servos inside the wings to lift spoilers or dealing with long linkages? How much torque are you asking it to handle? Any ideas on this?

Thanks.
Nightowl

[Al M]

Wing mounted servos arethe cleanest way to do it. You don't need strong ones.

[mlee8249]

Hi Nightowl,

I have two Oly II's and one has a single servo driving the spoilers through a torque rod, similar to the set-up used in strip ailerons. The servo is a mini, like the HS-85. More than enough power. The other bird has independent micro servos in the spoiler bay, and they are HS-50's. Also, plenty of power. The real key is to have the spoiler hinge free-moving and not bound up. The spoiler isn't really that big, and the Oly simply doesn't go that fast. Hope that helps.

Thanks!

[Andy W]

I can get 90 degree of spoiler on my AVA with a measly HS-81 - and in case you're not aware, the spoiler on the AVA is HUGE!
..a

[TheNightowl]

Many thanks, Gentleman. The information is greatly appreciated.
Nightowl

[lincoln]

I'm not entirely sure that it's harder to do the pull strings than the servo wiring. You have to think about it a little, but it's got to be lighter than the wire unless you use really heavy guide tubing. And then, at least with something like the Oly where there's probably room, you can use a dirt cheap servo. The Oly doesn't really need weight savings, though it's better if the weight is in the middle. I find that I don't really need spoilers in my Oly. Comes down pretty fast if you just put the nose down about 15 or 20 degrees, but gets really draggy so it's not going forward all that fast.

I've had my Oly 2 maybe 10 or 15 years and haven't been tempted to put in the spoilers. The framing is there.

Unless you really do a clean job with spoilers, they make you come down if they're open, and they make you come down when they're "closed".

[Mark Miller]

I have been using HS-65MG's lately with good success. Small in size and good torque. I use them in my Soprano where the single spoiler like the AVA is huge.

Mark Miller

[TheNightowl]

I looked at a couple of the HS-65mgs when they came up on eBay. I was thinking that they looked like a nice mid-range servo as far as torque. I was even thinking they might be okay for R/E for a 65-inch motor glider I've got working. But since I already have some HS-81s and some Hobbico C-12s on the way, I don't think I'll get them for that. I might look at them again when it gets closer to time to need a spoiler servo. Actually, that was kind of why I asked the question in the first place. I wasn't sure how much torque the spoilers would be exerting. So, while the plans for a plane may call for 35-45 in/oz of torque for R/E surfaces, I wasn't sure the spoilers would need that much, but getting down into the 15-20 in/oz range with something like an HS-55 seemed kind of questionable. But I didn't think I really needed something quite as powerful as the HS-81 for it. However, mlee above said he's getting by with HS-50s, with only 8-10 in/oz of torque. Given availability and price, the '55s (or an equivalent) sound like maybe they would be adequate for an Oly II and cost less than the 50s. (Unless I build a faster SD7037 or SD3021 wing, I guess. Then I'll consider the 65s!).

Again, thanks for all the input, folks. It is greatly appreciated!
Nightowl

[Andy W]

I have been using HS-65MG's lately with good success. Small in size and good torque. I use them in my Soprano where the single spoiler like the AVA is huge.

Mark Miller

Good to know, I'm thinking of using them in my High-Aspect for flaps. I do have a couple of previously-used 81MG's sitting around that need a home, however..
..a

[atjurhs]

Futaba has just come out with a 3156 servo.

It is a 9gram, metal gear, digital servo with 30oz.in of torque and is the same size as a DS285. That's almost twice the torque!

They're at the top of my list!