If we're going to talk about floatplanes, here's an idea to add to the mix.

Floatplanes need "Beta" props, that is, props that reverse pitch.  Not
only is this really useful when you need to back away from short or
pier, but it is really the only braking you've got.

Now, if you look at the rotary engine, how hard would it be to set it up
to rotate the "wrong" way?  Looks like you just need a second starter
and another couple of plug holes in the right place to support opposite
rotation.

It's probably not practical (Beta props aren't all that expensive or
complex), but an interesting idea anyhow . . .

Keith

Unlike a two cycle a rotary will not run in reverse.