I was wondering how to get airflow over an outrunner if you have a spinner in place - I see Bob Hunt and Mike Palko have full spinners on their planes - but it appears they are running in-runner motors. 

Can you use a full spinner on an outrunner ?

Yes you can. As long as there is some airflow around the motor (and you have a physically large enough motor for the application) you will probably have enough cooling. Outtunners get their major cooling through the magnet bell. Not really that much air can get through the very tightly wound stator (IMHO  ) .

If you are concerned, or if you are getting some serious actual motor heating, you can do some tricks, like use a prop nut (like the Dubro one I shown in the photo of my Vector in the "list your setup" thread. I get a lot of air entering the nose ring.

It all depends on what you may be willing to put up with.

I think Dennis A. included some air scoops on the nose of one of his stunters, and the latest has a cowl which resembles one you would see on a tightly cowled radial.

added: just went back and looked at some of the photos in the "List Your Setup" thread. Especially look at the planes that Will Moore has for some ideas. I think the radial cowl is the way to go for us.