Herkimer OK Four Cylinder 2.40 Experimental Military Drone Engine by Herkimer Tool & Metal Works, NY, circa 1940
According to the limited information Herkimer scheduled production for single propeller commercial version of this engine in the early 1940's. Other than a few repro’s, fabricated by welding two twins together, it appears no commercial engines were actually produced or sold.
The military version sports a coaxial drive for contra rotating propellers with a dual point distributor in the back. It measures 11.5 inches long, 8 inches wide plug to plug, 5 inches high, and weighs 4 pounds- 12 ounces; it burns gas with oil mixed in for lubrication. As the war approached a few were produced for military testing but one or two either failed or were destroyed by the Army, which ended the program. This engine is believed to be the only engine, or possibly one of two original engines that survived.
Like the OK twin it has a single updraft carburetor with manifold tubes extending to each cylinder. Interesting is the tubes that make up the manifold appear to be rolled from brass sheet stock with the seams soldered.
See Tim Dannels article in his Engine Collectors Journal, Volume 32 number 3, Issue 183, July 2007.
Courtesy of Dave and Gloria Evans
Paul and Paula Knapp
Miniature Engineering Museum
Herkimer OK Four Cylinder 2.40 Experimental Military Drone Engine by Herkimer Tool & Metal Works, NY, circa 1940
According to the limited information Herkimer scheduled production for single propeller commercial version of this engine in the early 1940's. Other than a few repro’s, fabricated by welding two twins together, it appears no commercial engines were actually produced or sold.
The military version sports a coaxial drive for contra rotating propellers with a dual point distributor in the back. It measures 11.5 inches long, 8 inches wide plug to plug, 5 inches high, and weighs 4 pounds- 12 ounces; it burns gas with oil mixed in for lubrication. As the war approached a few were produced for military testing but one or two either failed or were destroyed by the Army, which ended the program. This engine is believed to be the only engine, or possibly one of two original engines that survived.
Like the OK twin it has a single updraft carburetor with manifold tubes extending to each cylinder. Interesting is the tubes that make up the manifold appear to be rolled from brass sheet stock with the seams soldered.
See Tim Dannels article in his Engine Collectors Journal, Volume 32 number 3, Issue 183, July 2007.
Courtesy of Dave and Gloria Evans
Paul and Paula Knapp
Miniature Engineering Museum