Chris,

as far as we know only the Hippo Tippo (Hippo because of the 825 squares) has a molded recess in the side of the fuse for the pipe. All other earlier versions carried the pipe under the wing - mostly with side mounted SE engines. Later versions were designed for 4 stroke engines and I believe that they were conceived for inverted mount engines.

The most graceful to me are the designs with pipes tucked into the wing belly, or, better yet, those with enclosed pipes.

David.