Hi... I saw the video of your last plane and it is to light... you could see it is unstabil even on the ground... You need something that have a little weight...
go for a old school trainer i balsa and ply.
http://www.hangar-9.com/Products/Trainers.aspx
look at world models and greatplanes too.
I also had a Hobbico Nextar which where great.I super frontier senior from world models and a sky raider... al very good trainers.

go for a small 2 stroke engine and these planes will fly them self slow and study.
and buy from some of the big companys... theire instruction books are very good.
And whit a balsa, ply model repering them would be easier.