Franklin Engine Company

  (Redirected from Air Cooled Motors)

The Franklin Engine Company was an American manufacturer of aircraft engines. Its designs were used primarily in the civilian market, both in fixed wing and helicopter designs. It was briefly directed towards automobile engines as part of the Tucker Car Corporation, returning to aviation when that company failed. The company was later purchased by the Government of Poland.

Franklin Engine Company
IndustryAerospace engineering
United States


The firm began as the H. H. Franklin Co. in 1902 in Syracuse, New York, USA, to produce Franklin air-cooled automobiles. Barely surviving bankruptcy in 1933, the company was purchased by a group of ex-employees and renamed Aircooled Motors in 1937. While the company kept the name of "Aircooled Motors," its engines continued to be marketed under the Franklin name.[1] Engineers Carl Doman and Ed Marks kept the company alive through the depression by manufacturing air-cooled truck and industrial engines.

During World War II Aircooled Motors was very successful producing helicopter and airplane engines. Several aircraft carried its engines, including the Aero-Flight Streak, Bartlett Zephyr, Bell 47, Bellanca Cruisair, Brantly B-1, Goodyear Duck, H-23 Raven, Hiller 360, Piper J-3F Cub, Seibel S-4, Sikorsky S-52, Stinson Voyager, Taylorcraft 15, Temco TE-1B, and the YT-35 Buckaroo.

Aircooled Motors was purchased by Republic Aviation Company in 1945 to produce engines for its Republic Seabee light amphibious aircraft. After the war, demand for the engines dropped dramatically and Republic was unsure of the company's future.

In 1947 Aircooled Motors was purchased for the price of $1.8 million by the Tucker Car Corporation to produce an engine for the 1948 Tucker Sedan.[2] After purchasing Aircooled Motors, Tucker cancelled all of the company's aircraft contracts so that its resources could be focused on making automotive engines for the Tucker Corporation. This was a significant event, since at the time of Tucker's purchase Aircooled Motors held over 65% of postwar U.S. aviation engine production contracts. For this reason, when the Tucker Car Corporation failed amidst allegations of stock fraud, Aircooled nearly failed with it.

Tucker and the Tucker family continued to own the firm until 1961, when the family sold it to the Aero Industries, which restored the name of the Franklin Engine Company.

In 1975 the government of Poland bought the company and moved it to Rzeszów, first under the name PZL-Franklin and later simply PZL-F.

The company is now called Franklin Aircraft Engines Sp. z o.o. with the address ul. Chełmińska 208 in 86-300 Grudziądz city in Poland. At Aero Friedrichshafen 2016 the company had new engines on display. The innovations include modifications to the type certificate of the 6A-350; the approval for MOGAS, as well as fuel injection is pending at EASA.


Note: The engine displacement designations are fictional unless the engine was given a designation by the US military

Engine displacement Manufacturer's designation by cylinder number and power Manufacturer's designation by cylinder number and displacement
O-110 2A4-45, 2A4-49 2A-110, 2AL-112
O-120 2A-120
O-150 4AC-150
O-170 4AC-171
O-175 4AC-176
O-200 4AC-199
O-225 4A4-75, 4A4-85, 4A4-95, 4A4-100 4A-225, 4AL-225
O-235 4A-235, Sport 4
O-265 6AC-264
O-300 6AC-298
O-335 6A4-125/130/135/140/145/150/165/200, 6V4-165/178/200 6AL-335, 6A-335
O-350 6A-350, 6V-350
O-400 8AC-398
O-405 6AC-403, 6ACV-403
O-425 6ACV-245, 6AG6-245, 6AGS6-245, 6V6-245, 6V6-300
O-500 6A8-215 6AL-500
O-540 8ACG-538, 8ACSA-538
O-595 12AC-596
O-805 12AC-806

See alsoEdit


  1. ^ Flying Magazine: 13. August 1945. Missing or empty |title= (help)
  2. ^ Egan, Philip S.; Design and Destiny: The Making of the Tucker Automobile; On the Mark Publications; 1989
  • Gunston, Bill. (1986). World Encyclopedia of Aero Engines. Patrick Stephens, Wellingborough. p. 57

External linksEdit

  • — WSK "PZL-Rzeszów" S. A., Polish manufacturer of Franklin engines