Franklin 4AC
| Franklin 4AC | |
|---|---|
 Franklin O-200 |
|
| Type: | Boxer engine |
| Design country: | |
| Manufacturer: | |
| Commissioning: |
1938 |
The Franklin 4AC series is a series of four-cylinder boxer engines made by the American manufacturer Franklin Engine Company , which were used to power numerous light aircraft in the 1940s and 50s.
history
In 1938, Aircooled Motors introduced a range of light four- and six-cylinder aircraft engines. Aircooled Motors was the successor to the automobile manufacturer HH Franklin Manufacturing Company , which had become insolvent in 1935 , but which continued to market its products under the old name.
The first aircraft engine developed was the Franklin 4AC-150 , where 4AC stood for four-cylinder air-cooled (aircooled) and 150 for the displacement of 150 in 3 . The power was 50 hp. As a result, Franklin concentrated on engines in the power range from 65 to 175 hp, with the cylinders mostly having a bore of 4.25 inches and a stroke of 3.5 inches. The proportion of interchangeable parts should be as large as possible in order to keep the costs for spare parts low. For this reason, the use of reduction gears between the motor and propeller was also dispensed with.
Military designations
according to enginehistory.org:
- O-150 : 4AC-150
- O-170 : 4AC-171
- O-175 : 4AC-176
- O-200 : 4AC-199
Technical specifications
| Parameter | 4AC-176 (O-175) | 4AC-199 (O-200) |
|---|---|---|
| Hub | 87.5 mm | |
| drilling | 100 mm | 106.2 mm |
| Displacement | 2.8 l (176 in 3 ) | 3.0 l (199 in 3 ) |
| compression | 6.3: 1 (Model B, C, D) 7: 1 Model F |
6.3: 1 (Model D) 7: 1 Model E. |
| Continuous output | 65 hp at 2300 min −1 (model B) 75 hp at 2500 min −1 (model C) 80 hp at 2650 min −1 (model D) 80 hp at 2500 min −1 (model F) |
85 hp at 2500 min −1 (model D) 90 hp at 2500 min −1 (model E) |
| Mass (dry) | from 79.4 kg (models B1 and C1) to 98 kg (models B3, C3 and D3) | from 86.3 kg (model D2 and E2) to 101.7 kg (model D3 and E3) |
| Octane number | 73 (Model B, C and D) 80 (Model F) |
73 (Model D) 80 (Model E) |
literature
- Bill Gunston: World Encyclopaedia of Aero Engines , Patrick Stephens Ltd., 3rd updated edition, 1995, ISBN 1-85260-509-X , p. 57
- Leonard Bridgman (Ed.): Jane's All The World's Aircraft 1945-1946. Samson Low, Marston & Company, Ltd., London 1946, pp. 76d, 77d
Individual evidence
- ↑ Overview of the military designations ( memento of the original dated December 30, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b Jane’s 1945–46, p. 72d
