RE: Considering buying Tower Trainer 40 ARF
The 4*40 is really a low wing trainer, with plenty of dihedral, light wing loading . . . etc. Sometimes they don't want to land, if they are moving, they are flying. They excel at slow flight. I built 3 - 4*60's as well. The last one I kit bashed, taking out one degree dihedral and extending and couter-balancing the tail feathers. I also used a 120 4 Stroke on it and it 3-D quite well. Don't be afraid of flying the 4*40. It's a tail dragger and is different than your trainer was, but with smooth take-off and landing characteristics. Just make sure you don't get any warp in your wing during the covering process. It warps (and straightens) much better than D-tube wings, but can warp again later if you "tighten" the covering later. I needed to set up "spoilers" (up flaperons) on mine at about one degree down, using airbrake switch on computer radio, and it came down well and 3-point landings were easy with spoilers set. Otherwise it floated and bounced allot. Also reinforce your landing gear platform much more than the plans call for if you fly off a rough grass field very much.
When you get better at flying it, you will need to program some rudder and aileron coupling for smooth rolls and aileron, rudder and elevator coupling for knife edge flight. They fly well inverted, but are a little tipsy upside down due to the dihedral.
Our club is looking at building chopped wing versions for club pylon racing. They are very stable, fairly neutral, and easy to fly basic aerobatics.
Hope you have fun, it is a great second airplane, and a steady, stable everyday sport flyer for many.
Happy Landings
Mike B.