COOLING CHARACTERISTICS of STEEL- and ALUMINUM-FINNED CYLINDER BARRELS for In-Line Aircooled Engines 450226
COMPARATIVE cooling tests were conducted with two Ranger V-770 cylinders, one provided with a conventional, steel-finned barrel, the other with an aluminum-finned barrel in which fins were milled from an aluminum muff integrally bonded to the steel liner. Both cylinders were provided with the same cast aluminum head.
At rated horsepower and equal cooling conditions the average temperature of the aluminum-finned barrel was 58 F lower than that of the steel-finned barrel.
In order to maintain the same average barrel temperature of 295 F, the aluminum-finned barrel required only 60% of the cooling air mass flow, 40% of the baffle pressure drop, and 25% of the cooling horsepower required by the steel-finned barrel.