Franklin O-805 - Misplaced Pages

American air-cooled aircraft piston engine designed in the mid-1940s

O-805/12AC

Franklin O-805 on display at the National Museum of the United States Air Force
Type	12-cylinder horizontally opposed piston engine
Manufacturer	Franklin Engine Company
First run	c.1945

The Franklin O-805 (company designation 12AC) was an American air-cooled aircraft piston engine, designed in the mid-1940s and was to be used in radio-controlled pilotless drones that were to be guided from an accompanying control plane. Due to project requirement changes and cancellations the engine was not produced.

A smaller displacement 12-cylinder Franklin engine of 1941 was known as the O-595 or 12AC-596.

Variants

O-805

12AC-806: 450 hp (336 kW)0
12ACG-806 (XO-805-1): 456 hp (340 kW) at 3,200 rpm, geared to 0.632:1.
12ACGSA-806 (XO-805-3 and O-805-5): 500 hp (373 kW) at 3,200 rpm, supercharged and geared to 0.632:1 (XO-805-3), or to 0.587:1 (O-805-5).

O-595

12AC-596: 300 hp (224 kW) at 2,600 rpm

12ACG-596: 350 hp (261 kW) at 3,500 rpm

Applications (intended)

Survivors

There is an O-805-2 on display at the New England Air Museum, Bradley International Airport, Windsor Locks, CT
One surfaced and was sold privately in August, 2016, on eBay for US$8500.

Specifications (12ACGSA-806/XO-805-3)

General characteristics

Type: 12-cylinder air-cooled horizontally opposed aircraft piston engine
Bore: 4.625 in (117.5 mm)
Stroke: 4.0 in (101.6 mm)
Displacement: 806.4 cu in (13.2 L)

Components

Valvetrain: OHV
Cooling system: Air-cooled
Reduction gear: 0.632

Performance

Power output: 500 hp (373 kW) at 3,200 rpm

References

Notes

NMUSAF (June 8, 2015), Franklin O-805-2, National Museum of the United States Air Force
"New England Air Museum".
"13 Liter WW2 Drone Engine: Super Rare Franklin 0-805". 29 August 2016.

External links

A table showing the relationship of the military models

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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