Float the valves is when you have more rpm's than the valve springs can respond to, so the valves will float instead of closing all the way. This can lead to broken valves, pushrods or rockers. This mostly happens when you do not have enough load on the engine and it is allowed to over-rev.
...does it have a camshaft and the usual spring loaded valves?
Yes. (click the pics for more info)
Whats the difference between the real deal and R/C 4 strokers?
Not much, but they are more like a diesel engine than a gas engine. (the glowplug thing)