why don't you take a look over at the Zealot forum,ages ago I built 3 versions of the E.III ;
New Fokker E-III (okay, several) - Zealot Hobby Forum.
in the downloads section there's an dditional part for the front of the engine cowling and on my homepage,
The Brainstorm Inn proudly presents previously unpublished work by Richard Schulten there's a better version for the engine.
I remember this model having some issues but for a freebee it's a pretty decent one.