Lewie 7 Posted June 14, 2011 Theory is an inline engine equipped aircraft will always have a higher ceiling than a rotory, because of the higher compression possible in the engine. Compression can be boosted with changes to the pistons. Changes were impossible with a rotary. This is only partly true, as the Gnome Mono 160 and the Bentley made Clergets had cylinders with threaded bases and a lockring that could be twisted in and out to adjust the compression slightly. It was the rather intricate and inefficient air intakes of the rotary's crankcase, which all of them used, that reduced the normal atmospheric pressure ahead of the intake valve, or cylinder fluting, in the Gnome. The main problem was with the early rotaries, that used complex and inertially heavy in-piston intake valves operated entirely by atmospheric pressure. If you add the slight amount of centrifugal 'supercharging" done in the fuel-air intake ducting it still comes out a wash. Also, the BR2 Bentley in the Sop Snipe was making over 200 HP in an engine not much bigger and heavier than the 130 Clerget the first Camels used. There were some 11 cylinder prototype Clergets that were slated for the late war that were approaching 300 HP. but they had weight and gyro precession issues, much like the twin row 14 cylinder Gnomes. The Seimens-Halske Sh.III contra rotary, if the Germans had developed a suitable lubricant and had access to 1930 metallurgy would have been a huge success, as it relied upon internal gearing and running the engine at twice the RPM (internally,) that normal rotaries ran at. Seimens-Halske Sh.III contra rotary Share this post Link to post Share on other sites
