RE: 3W 75i Question
The Zenoah 80 twin is not the ideal motor for this plane. It is very heavy, and down on power when compared to the 80cc singles. (It does make a great scale aircraft power plant, but not ideal for aerobatic aircraft where power to weight is a big consideration) Apart from the DA 85, the ZDZ 80 and MVVS / Evolution 80's are ideal choices for this plane. The early DA 85's had big vibration problems, but I understand that they have rectified this now. The ZDZ runs fairly smooth. The MVVS / Evolution, however, has 4 crank bearings. 1 rear, and 3 in the front. This is done to reduce crankshaft flex and deliver smooth operation (As smooth as possible for a big single)