From the Vault: British Report on the US M46 Medium Tank

Today we have something sent to us by British researcher and author P.K. Knight.  Knowing of our interest in anything having to do with US tanks powered by Continental Motors engines, he forwarded us a copy of a British F.V.R.D.E. (Fight Vehicles Research and Development Establishment) report examining a US M46 medium tank.  This is a fairly short report and mainly focuses on automotive performance.  The most interesting thing revealed by this report is just how much difference there is between the stated gross horsepower of the engine, the actual power output taking into account power lost to engine cooling and accessories and then the actual power at the sprocket.  The M46 was the first US tank equipped with a Continental 12 cylinder 1790 cubic inch aircooled engine and the Allison CD-850 transmission.  The report states that while the listed gross HP of the engine is 810, their bench tests show an actual power output of 646 HP, which they attribute to losses from air cleaners, cooling fans and the exhaust system.  The power at the sprocket is measured at 433 HP.  So what does this all mean?  Not much, other than always take those gross horsepower numbers listed in books with a grain of salt, they don’t always tell you all that much about how much power is actually being transmitted to the drive sprocket.

Report below.

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