Hey all,

I recently acquired a JBB and got to fly it this weekend. I have it powered with a 26cc engine and do realize this plane wasnt meant for speed, pure fly fun type stuff. With that said, I am having hard time keeping the ailerons from fluttering. I redid the linkages that were on it to 4-40 rod and metal geared digital servos, still doing it. I am not doing any straight line full throttle speed runs or anything like that.

I was hoping some of you that either have had this plane or have some engineering ideas can tell what I can do to help reduce the potential to flutter.

Thanks

Z

If you have not, tape up the aileron gaps from the underside of the wing for a start...

Z, most likely the ailerons are lightly built stick and covering and perhaps not able to handle much speed. If you have already experienced a lot of flutter most likely they are are damaged internally with small fractures here and there. I would recommend building new rons and making them much stiffer than stock. That coupled with decent servos and linkages should solve your problems. Also make sure your servo mounts are very solid. All the aboe is useless if your servo mount structure is flimsy.

Thanks for suggestions:

I was also wondering if I angled the tips of ailerons (like a 45 degree cutback angle),if that would help any?

Thanks
Z

Angled tips are helpfull when you cartwheel a plane (You'll only do that once with your JBB anyhow) so don't bother.
Building new alirons is kind of a big step (and may not help).
How old are your servos? MG servos get slop kind of quickly sometimes- replace gears.
The control arms on the alierons can also get sloppy after time. easy to replace if the hole is woollered out.
And already mentioned seal the hinge gaps.

Okay, thanks. The servos are brand new. I changed out all the hardware, new rods, clevis' etc. Other than just being a big ole aileron, I can't find any obvious slop. I will seal what gap is there (ailerons are pretty much butted right up to wing) and see what happens.

Thanks

dumb question since you orginally didn't build this JBB - it does have DUAL aileron servos (2 per wing) correct? I'm running a G23 on EI with 17x6 APC (spins it 9100 rpm). I've got (4) HS5475's in the wing with stock 2-56 short rods, sealed gaps, and there are no fluttering problems. In addition to the items mentioned above, make sure that the control horns on the wing are solidly mounted, no slop, and no slop between the clevis and those control horns.

By the way, what makes you suspect that you have aileron flutter?

With the receiver and servos powered up, if you apply pressure to the ailerons, do they move up or down easily? If they do, and you can easily overpower the servos without the plane trying to lift up when you do it, you possibly have a problem with the servos, linkage, link geometry, and/or battery voltage.

Yes, it is 2 ail servos and 2 flap servos. It was a classic flutter when it did, almost looked like whole wing was going to go before I cut throttle and speed but it still got both ail servos.