In converting my radio control airplanes from 72 Mhz to 2.4 Ghz I recently installed a new Spektrum receiver, 2200 mah nimh battery pack, and a switch jack in my Gentle Lady sailplane. It required me to solder on new plugs to the old Futaba servos but that was the only major change needed. I knew the tiny receiver would be lighter but I didn't think it would change the balance as much as it did.
It was a beautiful spring day today with relatively low wind and cloudless sky, I was excited to test the Gentle Lady with the new equipment but I did have the sense to try a couple of hand glides before doing a hi-start launch. It was a good thing because the Gentle Lady climbed at a steep angle and I couldn't push in down elevator fast enough to avoid a stall. As I fly some free flight I had modeling clay along so I taped a big wad of clay under the nose. Another hand toss proved it was back in trim.
The field I was flying from is rather small so I was using a short hi-start designed for hand launch type gliders. I also find it more challenging to grab thermals at 150 feet high instead of 350 feet or so. On the first launch I thought I found lift but it wasn't enough to keep going up. It took several more launches until the Gentle Lady connected with a thermal that kept it rising to a good altitude at which point it was getting far downwind. I had one more good thermal flight but it seemed like a struggle to get over a certain altitude. After landing I watched a turkey vulture struggle to go up in lift, it made me feel like I did pretty good.
Next I got out my Hyper DL for some discus launching. This is a rather heavy DLG and it took a fair number of throws before it was climbing in a thermal. More throws and it was climbing in another thermal, as much as I tried to find the strongest part of the thermal the glider only went so high. That was fine, it is more fun when it is challenging.