ORIGINAL: Villa
Hi OkadaKeisuke
Ok, so it is an ARF. But you installed all of the components. Longer engine mount to move engine forward. Flat battery instead of conventional battery so it fits in a tight place. I once added a second battery and second switch for CG control, and gained more reliability. It is true that sometimes there is no choice but to add weight. I look at it as a personal failure if I have to add dead weight.
Yes, I had considered doing these things. I did move the battery and reciever as far forward as possible, and had added a muffler extesion (as needed), which added a little weight. However, I believe that if I installed the engine any further out on the mount or with a longer mount that I would not be able to install my cowl without making some more modifications.
I figure adding a little more weight to the plane will be a minor trade off. I believe the SIG Kadet Senior can withstand quite a bit of extra weight anyhow, because of its light wing loading. Isn't it used to tow sailplanes?