Hi Fellers,

I had the same problem with similar size plane and OS.91 on it, about 4kg weight.
And servos were same Futaba 3004. The Problem is for SURE that you use ONLY one
servo for both ailerons. I have found the SOLUTION in this slow and painful(!) way:

1. I changed to 6V but not just by adding one more cell because the overvoltage then in fully
charged battery pack is 5x1.35=6.75 and that might cause problems on you radio or if in the
radio there is voltage protection that will drain your battery till gets to the 5x1.2=6V. I have
used for each servo a separate voltage regulator 7806 and 8(8x1.25=10V !) cells to make sure
that after the voltage drop over the 7806 of about 2V I will still have the dreamed 6V even when
the batteries are almost exhausted. The Improvement was very little ... the time spent - huge !

2. Then I placed for each Airleron a Separate servo 3004. The rolling improved enourmously
much. Got it like about 4-6 rolls/sec !!! Very Good enough - the Ariplane is not Rock-and-Roll
and is like "PROPELLER" itself - everybody is wandeing what kind of Digital Servo I am using...
and gets very dissapointed when see only the good old 3004 for 12$ there.

3. Then I took away the 6V system and got back to the 4 cells and number of rolls per second is
is only a bit lower, like 3-4 rolls/sec. That is maybe what you call Rock-and-Roll.

It is true that the ailerons are bending, but that is avoided to great extend if your control point
of the Aileron is about 30-40% from the outer end of the Aileron. Gap is also important, but I
did not seal it - it is even too big now, about 3 mm at least but that is something to fix on
the next airplane.

Of course the simplest solution would be to put powerful servo, but then the bending of the
Ailerons will be there to ruin the effect and then you have to firm the Ailerons which is not
very quick and easy job. While making two servos on the wing and connecting them in
parallel takes just couple hours work in total.

Cheers,
Nick