i made one few years ago to prove it could be done. i used a simple plastic prop and a sheet alulimmim deck. and put it on a arm. this was for a unimog i made heres the vid
http://www.youtube.com/watch?v=J4f4_...vcvtQ&index=11
i also made a drag behind type to for a older uninmog
http://www.youtube.com/watch?v=cnSsC...vcvtQ&index=13