Yep...the Invisible line into a stall with some control line models comes with very little warning.
Money well spent is to get a Wakkerman ARF .15 or .35 sized plane if you would like to experience one of the best combat designs ever.
They are "Eyes Off The Plane" stable, but ready to jump when you crack the whip.
With a 8 x 6 or 9 x 6 on your TT.40 you would be doing 2 second laps on 60 foot lines.
For sport flying with this much power you can move up to 70 foot lines and that really opens up the hemisphere. It gives you much more time to enjoy watching the plane.