Franklin O-175 - Misplaced Pages

(Redirected from Franklin 4AC-176) American piston aircraft engine

O-175/4AC-176
Type	Piston aircraft engine
National origin	United States
Manufacturer	Franklin Engine Company
First run	1940

The Franklin O-175 (company designation 4AC-176) was an American air-cooled aircraft engine of the 1940s. The engine was of horizontally-opposed four-cylinder and displaced 175 cu in (2.9 L). The power output was nominally 80 hp (60 kW). A later variant was designated O-180, despite sharing the same displacement.

A related four-cylinder engine of slightly smaller capacity was known as the O-170 or 4AC-171. It produced 60 hp (45 kW).

Variants

O-170

4AC-171: 60 hp (45 kW)

O-175

4AC-176

4AC-176-B - 65 hp (48 kW) at 2,200 rpm

4AC-176-BA/(O-175-1) - 65 hp (48 kW) at 2,300 rpm

4AC-176-C - 75 hp (56 kW) at 2,500 rpm

4AC-176-D - 80 hp (60 kW) at 2,650 rpm

4AC-176-F - 80 hp (60 kW) at 2,500 rpm

4ACG-176

O-180

4AC-176-F3 (O-180-1)

Applications

Specifications (4AC-176-BA2, O-175-1)

Data from Wilkinson

General characteristics

Type: 4-cylinder air-cooled horizontally opposed aircraft piston engine
Bore: 4 in (102 mm)
Stroke: 3.5 in (89 mm)
Displacement: 176 cu in (2.88 L)
Length: 28.6 in (726 mm)
Width: 30.2 in (767 mm)
Height: 20 in (508 mm)
Dry weight: 182 lb (82.6 kg)

Components

Valvetrain: OHV, 1x inlet valve, 1x exhaust valve operated by pushrods
Fuel system: 1x Marvel-Schebler MA-3P updraught carburetor
Fuel type: 73 octane gasoline
Oil system: Pressure system at 40 psi (3 bar), wet sump
Cooling system: Air-cooled

Performance

Power output: 65 hp (48.5 kW) at 2,300 rpm for take-off
Specific power: 0.37 hp/(cu in) (16.837 kW/L)
Compression ratio: 6:1
Specific fuel consumption: 0.49 lb/(hp h) (0.298 kg/(kW h), 220 US gal/(hp h)) cruising
Oil consumption: 0.003 lb/(hp h) (0.0018 kg/(kW h), 1.4 US gal/(hp h)) cruising
Power-to-weight ratio: 0.357 hp/lb (0.587 kW/kg)

References

Notes

Wilkinson, Paul H. (1945). Aircraft Engines of the world 1945. New York: Paul H. Wilkinson. pp. 88–89.

Bibliography

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

Franklin aircraft engines

By displacement

Two-cylinder engines

By displacement	O-110 O-120
By company designation	2A-110 2A-120 2A4-45 2A4-49 2AL-112

Four-cylinder engines

By displacement	O-150 O-170 O-175 O-180 O-200 O-225 O-235
By company designation	4A-225 4A-235 4A4-100 4A4-75 4A4-85 4A4-95 4AC-150 4AC-171 4AC-176 4AC-199 4ACG-176 4AL-225 Sport 4

Six-cylinder engines

By displacement	O-265 O-300 O-315 O-335 O-350 O-405 O-425 O-500
By company designation	6A-335 6A-350 6A3 6A4 6A8-215 6AC-264 6AC-298 6AC-403 6ACV-245 6AG-335 6AG4-185 6AG6-245 6AGS-335 6AGS6-245 6AL-315 6AL-335 6AL-500 6ALV-335 6AS-335 6V-335 6V4 6V6-245-B16F 6V6-245 6V6-300-D16FT 6V6-300 6VS-335

Eight-cylinder engines

By displacement	O-400 O-540
By company designation	8AC-398 8ACG-398 8ACG-538 8ACGSA-538 8ACSA-538

12-cylinder engines

By displacement	O-595 O-805
By company designation	12AC-596 12AC-806

v t e United States military piston aircraft engine designation system
H (four-bank H-configuration inline)	H-1640 XH-2240 XH-2470 XH-2600 XH-3130 XH-3730 H-4070
IV (inverted-V inline)	IV-1430 IV-2040 IV-2220
L (single-bank inline)	L-330 L-365 L-375 L-390 L-410 L-440 L-510 L-825
O (opposed)	O-15 O-40 O-45 O-90 O-100 O-145 O-150 O-170 O-175 O-180 O-190 O-200 (C) O-200 (F) O-205 O-235 O-290 O-300 O-335 O-360 (C) O-360 (L) O-405 O-425 O-435 O-470 O-480 O-520 O-540 (F) O-540 (L) O-550 O-580 O-805 O-1230
R (radial)	R-250 R-265 R-270 R-370 (LB) R-370 (K) R-420 R-440 R-500 R-540 (W) R-540 (K) R-545 R-550 R-600 R-670 R-680 R-720 R-755 R-760 R-790 R-830 R-915 R-975 DR-980 R-985 R-1044 R-1300 R-1340 R-1454 R-1510 R-1535 R-1640 R-1670 R-1690 R-1750 R-1820 R-1830 R-1860 R-2000 R-2060 R-2160 R-2180 R-2600 R-2800 R-3350 R-4090 R-4360 XR-7755
V (upright-V inline)	V-720 V-1150 V-1237 V-1400 V-1440 V-1460 V-1510 V-1560 V-1570 V-1650 (P) V-1710 V-1950 V-3420
V (inverted-V inline)	V-770 V-1650 (L)
VG (inverted-V inline)	VG-1410
W (three-bank W-configuration inline)	W-2779
See also: X-1800 US military gas turbine aeroengines Piston engine configurations

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