I acquired on of these little models last October (from somebody's loft of course) and fitted some radio gear over the Christmas holiday. Having read the posts here I was expecting trouble and I was not disappointed. The Dutch roll was hilarious. For safety I hand launched it and all was well until I touched the rudder. It's essentially set up as a freeflight model with a tiny fin to give it strong spiral stability at the expense of Dutch roll damping. I had a few flights with it in that state, with the CG at about 69mm for the LE (34%). It was quite aerobatic in it's own sweet way: loops, rolls, spins, outside loops, but all a bit hairy. I have just enlarged the fin and flown it again - what a difference. The Dutch roll is all but gone and it flies like a standard aileron trainer, although I still have to be gentle with the rudder. I've moved the CG back to 75mm (37%) and that's about as far as I think it should go. Down thrust and right thrust are both about 2 deg but I've fine tuned with throttle to down elevator at 5%. It has a nice glide on deadstick and doesn't require too much trim change with speed. Engine is a sweet little Enya 25 that is still running-in. All up weight is 1.33kg which gives a hefty wing loading of 61 g/dm2. Our strip is a bit long this time of year so I've not attempted a ground takeoff, but hand lunches need to be energetic at full power with a 10x5 prop. I definitely recommend enlarging the fin - mine has a height of 190mm with and average chord of 110mm, TE the same but much reduced LE sweepback. I extended the rudder height but not its chord. Oh, and I'm using 35MHz of course
