RCU Forums - kangaroo II

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Hello i have a kanagaroo II with each wing having 2 control surfaces, totaling 4 servos for the wings.
I understand this is a redundancy setup.
I would like to know how do they work ? Are they both evlons or the outer ones are ailerns and the inner are elevators ?
Because of the reduncany what servos should i use ?

They are linked together to be elevons.I use Hitec 645MG.Make sure they are syncronized.You might have to open up control rods slots on wing.

JR 8411s used to be very widely used for the elevons. JR have since released new servos. JR 8321 are going in mine.

To synchronise them properly you will have to either, plug them all into different channels and mix them on your TX or buy a synchroniser such as JR Multibox or Futaba MSA-10 (one for each side). Either that or have amazing mechanical skills.

A lot of people use Y-leads and this seems to work OK. Some manufacturers kits (it has been made by several people) came with only one surface per side. I believe some people have permanently fixed the two together and used a single servo per side (if you're not bothered about the redundancy).

Quote:

ORIGINAL: siclick33

JR 8411s used to be very widely used for the elevons. JR have since released new servos. JR 8321 are going in mine.

To synchronise them properly you will have to either, plug them all into different channels and mix them on your TX or buy a synchroniser such as JR Multibox or Futaba MSA-10 (one for each side). Either that or have amazing mechanical skills.

A lot of people use Y-leads and this seems to work OK. Some manufacturers kits (it has been made by several people) came with only one surface per side. I believe some people have permanently fixed the two together and used a single servo per side (if you're not bothered about the redundancy).

I was simply careful how I glued the horns into the elevons on mine and made sure that the linkages were the same, and I got the movement to be within less than 1/8" for the two halves of the elevon and the difference between the inside and outside one is the same on both sides. With this result I can not notice any roll-to-pitch, or pitch-to-roll coupling. With a little care, a Matchbox or MSA-10 is not necessary in a Kangaroo, and none of the guys I know with Kangaroos have used one.

I have (4) JR 8411's on my elevons...

Bob

Fair point. As an aside I am not using any synchronisers either. I will be using separate channels for each servo, and if I need any adjustment I will do it on the TX.

I accept that small errors will probably be difficult to detect in flight, especially if the errors are 'mirrored' as in your case.

Quote:

ORIGINAL: bahamadude
Hello i have a kanagaroo II with each wing having 2 control surfaces, totaling 4 servos for the wings.
I understand this is a redundancy setup.
I would like to know how do they work? Are they both elevons or the outer ones are ailerns and the inner are elevators ?
Because of the redundancy what servos should i use ?

I also have a Roo II, and per the advise of a few of the Roo pro's on here (thanks Todd), I bonded each set of elevons together. I've installed the new JR 8611's in the outer servo bay. The new 8611 produces 260 oz/in of torque, and can definitely handle any stress you can throw at them.

The reason there were 4 servos designed into the wing was due to the load placed on the elevons during flight maneuvers; older technology servos could not handle the high stress. If you go with four servos, you'll need a matchbox or other devise, with just two there's no need.

My 2 cents.......

Good luck with yours!

Quote:

ORIGINAL: warbird_racer

I also have a Roo II, and per the advise of a few of the Roo pro's on here (thanks Todd), I bonded each set of elevons together. I've installed the new JR 8611's in the outer servo bay. The new 8611 produces 260 oz/in of torque, and can definitely handle any stress you can throw at them.

The reason there were 4 servos designed into the wing was due to the load placed on the elevons during flight maneuvers; older technology servos could not handle the high stress. If you go with four servos, you'll need a matchbox or other devise, with just two there's no need.

My 2 cents.......

Good luck with yours!

You can certainly glue the two together and an 8611 (or really an 8411) will handle that load. I left mine separated and I actually have each set (outer and inner) on a different receiver/battery/switch for redundancy. However, if you stay with 4 servos and do a decent job of installing the linkages and horns, a Matchbox is NOT needed on the elevons. You can get close enough with the mechanical setup that the slight differences in surface deflection will not be noticed in flight.

Bob