Anti Chatter
When Pobjoy made his engine he relised that he would need revs to get the power but a slow prop speed for thrust and effiency.
Hence the reduction drive.However this drive also incorporated an "anti-chatter" device to help prevent the "chatter" that occured at low revs when the engine was warming up (less than 1100rpm).When power was increased to 1200 and over the engine suddenly will "go quiet" as the railway sleeper of a prop starts to help with the flywheel effect and the natural balance of the engine comes into effect.
There is no question with regard to the effect of a large dia prop on the smooth running of an engine plus the added efficient thrust it provides.
Of course being Pobjoy he also included an "oil slinger" centifugal strainer into the sysytem to help with the filtration.
With a double helical gear driving all this it was about as good as it gets from an engineering aspect, but no doubt expensive to produce.
What reduction gears DO NOT LIKE is the sort of rapid close rapid open operations that engines in training machines get, but then that can be incorporated in the "engine handling" training if required.
Being a radial cooling was never a problem unlike the "close cowled" flat 6 & 8 configuration of Mr Continental and Lycoming.
For years i flew Cessna 175 Skylark (GO 300e i think it was).This went like stink climbed like a homesick angel and was very smooth.However they had a poor reputation mainly due to being used as parachute planes and getting overheated.
If used for what they were designed for and the speed kept up on climbs they were fine.The rated power was at 2800 (with a large vp prop) so the TBO was only 1200 as opposed to 1500hrs but if operated by "thinking pilots" were a great machine out of a strip with a full load.