I notice all the radials referred to are of US origin
Its like Mr P & W had a patent on them
Having worked many hours ( and nights ) on Mr Pratts fine products I'm afraid they could not hold a candle to the Bristol Beauties.
When we were getting between 800 and 1,000 hours on the wing from Pratt we were getting 2000 hours + on Centaurus.
We never changed a cylinder in anger on a Centaurus. Bit different from Pratts ! On the 1830 we got plenty of practice and you just hoped it wasn't a bottom cylinder on your shift.
Incidentally for the uninitiated the Bristols were sleeved valved