I was thinkin of converting my trainer to dual aileron servos. Will Hitec Hs-311's work?

Yes it will work. They will deliver 42.00 oz/in of Torque at 4.8 volts ( a 4 cell battery) When you do it, make sure you do a good pre-flight to ensure your servo travel is good and not reversed! mostly NOT REVERSED. Good luck.

DOing it is not a problem but for what purpose. Just get another plane and do it on it.

My question too. Why?

Are you thinking flaperons? (Need a computer radio and usually don't do much on a trainer.) Thinking better performance because of direct servos on a "Y" connector? (Won't make enough difference to be worth it.)

Just for the experience of trying it? (Go for it! )

Hitec HS-81's would be powerful enough, and fit in the wing better, by the way.
Dennis-

While you could use HS-81's (based on their torque rating), I wouldn't. The HS-81's have a fairly weak gear train, and will easily strip if you get a touch of flutter or even bump the aileron just wong (hanger rash). I use a lot of HS-81's, but generally on throttles. There is a metal gear version that fixes that problem, but it's more expensive. If it was me, I'd go with the servos you mentioned, or maybe spring for something in the HS-4xx line. Not that you'd notice a difference in performace on a trainer's ailerons.

I use the Hs-81's all the time on my 40-60 sized warbirds and they work fine for ailerons. I use them with a rotary drive system for ailerons too.

I know it sounds kina weird but I'm doing it One for the experience Two for flaperons<got acomp radio and three got a St 51 in my hobbico superstar and the ailerons can flutter pretty bad at times.