We bought a catapult in 2012, but after the novelty wore off and the hassel of transporting it to site, setting up into wind, we just found it easier to hand launch our Maja! If you fly solo, then a catapult is very handy, but if the wind is blowing from the edge of the field, it is difficult to launch of the catapult if you need to be in the standing crop!
Here is a video of the launch you can expect;
Maja catapult launch or try a hand launch Hand Launch and another Hand Launch 2