More good advice from Jim Thomerson. I find that APC props will sometimes turn more revs & give more thrust than a MAS prop, for example -- but not always -- so experimentation really is the word.

The 11-4 works pretty well at full throttle with the TT in the vertical (probably unlimited vertical with the Kadet), but it will indeed turn pretty fast in level flight -- not engine blowing stuff, but faster than necessary.