Odd. Looking at the gif posted by wacki, the timing seems a bit odd.
The intake stroke doesn't seem to allow for compression, as the intake port passes the vane, the chamber continues to grow. As the chamber reduces in volume before the power stroke, it *looks* like you would have only atmospheric pressure.
Also, those vanes would really create stacks of friction, I mean, in the animation I can see five. Thats 10 seal points and I can only guess that there are double that many vanes, so 20 seal points... Thats a lot of friction and I would expect to lube it you would end up burning a lot of oil.