ORIGINAL: Andy P.

Hi Guy's,
Firstly, Derek I didn't use wing adjusters on my Impact. David Gibbs fortunately was ahead of me with his build when I reached this stage, I decided that the set-up he was running with regards initial incidences showed the kind of flying qualities I was looking for. Measure several times, then glue!
My tail servo's are placed inside the stabs. I achieved this by cutting a small access panel on the underside but only big enough to place the servo bearers in position. I then slid the servo's in through the root former and secured them with the screws. Took me around 6 hours to complete, with the hatches re-fitted using self adhesive trim.
With regard to the fuselage strengthening at the rear of the fus, I installed the new formers before any flights were made, not easy!
I made up the formers and carried out a dry fit, this was achieved by drilling a 1.5mm hole along the horizontal axis of the horizontal former and tapped a thread for 2mm rod. I then made up an extension pole with a 2mm threaded end and attached the former to it. You can then slide the former all the way to the back of the fuselage and un-screw the rod, which leaves the former in place. Three hour epoxy and micro balloons were used as the bonding agent.
However, I still experienced a problem on the second trimming flight whereby after landing and retreiving the model from the flight line, I noticed a fracture/crease from the top of the fuselage to the bottom (vertical axis) around 4" in front of the new former.
Rudder flutter has been given as the reason for this, yet I have no slop in the closed loop and bottom hinge and in fact, all are still very much in tact! I'm also running an 11kg pull Digital servo on the rudder, JR DS8401, tremendous holding power.
So where do these flutter forces go? It has been explained to me that they travel along the fuselage with a rippleing/wave like effect around each side of the fuselage, couple this with the effects of using a closed loop system for the control and you have a compression element/force between the servo output shaft centre and the output horn on the rudder, over the length of the fuselage rear. Don't get me wrong, I'm not a self appraised expert in this field but merely a modeller who seeks guidance and listens with consideration to all coments made.
MY experience with MY particular model, tells me that extra strength is going to be essential around this area, you must make your own descision whilst completing yours.
A real shame with such a fantastic product! comp-arf and all the contributers to this products existance should be proud......................................

I'm off to think about were I go from here!