@flybyjohnI'd like to make a few corrections to my statement above.
Regardless of the power plant you use, the aircraft will technically fly the same. However, when you have a power to weight ratio higher then 1:1, you will be able to do things more quickly (e.g., rapid take offs and flips) and also perform maneuvers the aircraft may not have been intended to do (e.g., hovering a piper cub). When you're closer or below the 1:1 ratio the most dangerous element in r/c is stalling. Not because you can't stall at high speeds (see below) but because the pilot is attempting to maneuver the aircraft without sufficient lift. I've seen many-a-rc-pilot throttle down the runway and pull up too quickly on take off, stall, roll a wing over, and crash. All because they are use to flying with extra power(Note: The aircraft in the video did not "tip stall". It stalled asymmetrically (one wing dropped before the other) and the corrective actions by the pilot aggravated the stall which is why it violently flipped the other direction).
Me? I appreciate flying an aircraft the way it was meant to be flown. That's probably why you'll never see me hovering a Piper Cub.
High Speed Stalls
A wing can stall at any speed above the ‘slow stall speed’ for the same reason. For example, an aircraft may go into a steep dive. At the bottom of the dive the pilot may pull back on the stick to make the aircraft flatten out and then climb. If done too quickly, or because of poor aircraft design, the wings can be pointing up but momentum i.e. gravity, continues to make the aircraft go down. If the wings are pointing up but the direction of travel is down the critical angle is exceeded and a high speed stall occurs.