How long does it take to learn to play the flute?

I know it is easy to pick up other instruments once you already play one. I have been playing the clarinet since was in middle school. I have also played the violin, french horn, and a little piano. That said, i read music well, but am learning a whole new instrument. How long did it take you to pick up a second or third instrument and play it well?

When I say play well, I mean, enough to play a solo or confidently say that I play (not play at) the instrument.