ORIGINAL: flywilly

Tom - geared engines are very noisy. The high pitched prop whine was eliminated, but the gear noise was impressive at a slightly lower pitch. Too much noise for FAI requirments and no way to eliminate it. The engine noise was also a problem as the engines were still turning high rpms. OS and Webra are the only manufacturers that produced geared engines that I'm aware of. Dean Koger used an external belt drive reduction system on his Vortex design which he campaigned quite successsfully, but that never caught on either except for the TOC airplanes.
-Will B.