With .46 FX's you'll need quite a bit of throttle management, and I'm not sure that even the 9 X 6 prop will be enough. Probably will need something more in the line of a 10 X 6 or 10 X 5 three blade. The FX is capable (and even likes) to swing an 11 X 6 or 11 X 7 prop very efficiently. 11 inche props will cut the nose off of the twinstar, so 10 inch is all that is really possible. Therefore, the 10 X 6, or 10 X 5 (if available) would be the best choice.

Now, to the good stuff. I have twin 40 LA's on my twinstar, and run 9 X 6 three bladers on it, and it will cruise at around 75 mph (as clocked by a handheld radar gun). So, a 46 FX turning 10 X 6 three bladers should get you up in the upper 80's. That might be enough to rip the surfaces off. Flutter would definitely begin to be a problem

I wouldn't recommend the .46 FX's for the twinstar, and I wouldn't really recommend the twinstar (or any twin, for that matter) as a second or third plane. Why? A few reasons

First, and foremost, there's the engine out situation--can be devestating if you are green. I know there is a lot of outthrust built into the twinstar nacelles, but it's still something to contend with.

Second, there's the tuning. You need to get the engines running at close to the same RPM's, and you have two engines to tune, and syncing them can sometimes be a challenge.

Third, the twinstar (as well as most other twins) has the glide ratio similar to that of a set of keys. In other words, pull the power back, and she's coming to earth! It lands fairly hot because of this, and has a fairly significant wing loading.

There are other reasons, but I'm out of time. Twins are luring, I know. I love the sound of my twin, but I had flown 5 or 6 other planes before I got into it. I still don't know how well I can handle an engine out--i've not had one go out yet. I've had both go out--fortunate--but not just one. WIthout any power, the thing just came on down like a brick. Really had to work to get it down in one piece.

I've not been flying long, but I've flown a lot in my short time. Experience is your friend--especially with twins. In any case, I woulnd't put BB .46's on a twinstar.

Happy flying!