Originally Posted by
Samuel
someone to turn the props through a full cycle [nine blades?], before start up. It was a peculiarity of the nine -cylinder Alvis Leonides engines I suspect, something to do with oily stuff. In the Twin Pioneers they carried a pole with a loop on it to do the same job!
Standard procedure on all old large radial engined aircraft at startup to turn it slowly a "number of blades" (in this case a three-bladed prop so three complete revolutions) to check for lubricating oil accumulated in the lower cylinders which can jam the engine, as described above.
Nine blades and a 9-cylinder engine is a coincidence.