Roberto Alonso

BEB,   thanks for your reply. By "+2 degrees up" I meant that, if we take the wing as datum line (zero), the stab is turned 2 degrees in the direction required to command "up", that is, lower leading edge, higher trailing edge. This is a working ballpark for most models, I find.   Sorry if I didn't make myself clear - I am based in Spain and English is not my mother tongue. 

Hi Timbo,   thanks for your reply. I am thoroughly familiar with the need to start nose heavy and scoot back to taste, and conservative CG locations on plans, but what I'm seeing here is a different animal - a CG so far forward that the model had a difficult time staying airborne without massive "up" input, or at least these were the apparent symptoms. Somehow I don't think this is Tony's choice for flight behaviour, something must be amiss.   Maybe someone who's built and flown one of these will take a minute to measure their actual CG. Decalage info would be brilliant, too.   Thank you so much. I am aware I am starting life in this forum with a request for someone to trouble himself for my benefit, but I am confident I will be able to give back the favour some time.   Cheers! 

Hello all,   I have maidened my plan-built MIG 25 today with not-so-great results. I had CG as indicated on the plan, and as with every all-moving-tail model I have, I had both 0/0 decalage and "+2 degrees up" marked on the fuse. We launched  with the stab on the +2 mark, and even then I had to reeeeally pull on the stick, the model felt very nose-heavy during the whole flight, so much that I couldn't really release the stick to operate the trim. Aileron response was ok, speed was good, but it felt very nose-heavy.   I would be exceedingly grateful if any builders of this model would care to share their CG point and resulting decalage with the plane already trimmed. I am a bit confused right now.   Can't remember exact weight now, but I'm within spec, maybe in the upper third of the range.   Any ideas?   Thanks!