Franklin O-300 Explained

The Franklin O-300 (company designation 6AC-298) was an American air-cooled aircraft engine of the early 1940s. The engine was of six-cylinder, horizontally-opposed layout and displaced 300abbr=onNaNabbr=on. The power output ranged between 130abbr=onNaNabbr=on and 175abbr=onNaNabbr=on depending on variant. The 6ACG-298 featured a geared propeller drive.

An enlarged displacement version was known as the O-315, 6A3 or 6AL-315.

Variants

O-300

6AC-298:

6AC-298-F3 (O-300-1):130abbr=onNaNabbr=on at 2,600 rpm

6ACT-298:150abbr=onNaNabbr=on at 3,000 rpm

6ACT-298-J4 (O-300-3):150abbr=onNaNabbr=on at 2,930 rpm

6ACT-298-35 (O-300-11):150abbr=onNaNabbr=on at 2,930 rpm

6ACG-298-P5 (O-300-9):Geared propeller drive 0.63:1, 160abbr=onNaNabbr=on at 3,200 rpm

6ACTS-298:Supercharged, 160abbr=onNaNabbr=on at 3,200 rpm

6ACTS-298-K4 (O-300-7):Supercharged, 175abbr=onNaNabbr=on at 3,000 rpm

6ACV-298:Vertical installation for helicopters,160abbr=onNaNabbr=on at 3,250 rpm

O-315 (6A3)

6AL-315:175abbr=onNaNabbr=on

6ALG-315:175abbr=onNaNabbr=on

Applications

Direct drive

• Aeronautical Products A-1
• Aeronautical Products A-3
• CNNA HL-6
• Culver XPQ-9
• Culver XPQ-14, YPQ-14A, XPQ-15
• Bell 30
• Bellanca T-14
• Erco XPQ-13
• Fleetwings 33
• Hockaday Comet
• Piper PT-1
• Troy A
• Zodiac Libra-Det

Geared drive

• Culver PQ-14 Cadet
• Republic RC-1 Thunderbolt (O-315)

Supercharged

• Northwestern XPG-1 (Waco CG-4 twin-engine conversion)

References

Notes

Bibliography

• Gunston, Bill. (1986) World Encyclopedia of Aero Engines. Patrick Stephens: Wellingborough. p. 57