The most challenging plane I had was the Bearcats. I built 3 but after losing the first to a radio I built two to copy the Reno racer Rare Bear. I made my own canopy. Every rib and former hand cut. I had a nice one and a practice one. The nice one had a lot more detail including hand made folding retracts. The nice one weighed 34lbs with a Brison 100cc. The wings are clipped with very short ailerons like the real airplane. The airplanes REQUIRE good rudder control with such small ailerons. Many adventurous flights with them including dead sticks from lost spinners and loose spark plug wires. Still got both but will not fly them again. Just looking for more relaxing fun with the Balsa USA Phaeton 90 for now.