Vasek ... I may be wrong but I doubt that the 3S 1,800 packs will be enough for the Discus. The plane is 2.6M and should be no less than 5 lbs. If you wanna cruise around you will want a system that pulls 100W/lb. That means you want to push the packs to 50A for the lift off. Your packs will die fast. I would go with 3,000 mAh packs or run on 3s2p, giving you 3,600 mAh. for me I will want to turn a nice big folding prop of about say 14" for that plane.

Are we talking about the same CMPro Discus?