that horn shaped valve is the exact same valve the use on a Mc 202 & 205's with the DB605 engine. its a boost blow-off valve.
its designed to bleed off pressure if the manifold builds to much pressure.
Experten109/40 - Thanks for the input...but which item are you refering to as the "horn shaped valve"?...I'm not sure which is which.
dionysusbacchus - Wow, the tailwheel turned out fantastic...I'm a little too far along on mine to steal your design...but wish I had!