I am having a serious case of deja vu here. Did you ask this question before somewhere else? I believe I've answered this exact same question recently.

Sure you can fly something, but it won't be terribly impressive. As you've observed, the battery is awfully heavy. Because it's only 6 cells, you need to draw lots of Amps to get enough power, which means a short flight times. That motor won't be very efficient drawing lots of Amps, either.

I've seen the Great Planes PT-Electric and ElectriCub fly on such a power system. Also, look at the JKAerotech T-52.