# TCDS TC 221: Franklin Engine Company

- Type: Type certificate data sheet
- Status: Current
- Holder: Franklin Engine Company
- Revision: 0
- Product: Engine
- Data sheet PDF: https://openairdocs.org/files/sha256/a6/b0/a6b034483d5cadccfd8c3a85915ab964e1d7cd336733bce4ca1ac74f81ac4185
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F53083F2E12063B58525670C005652F3.0001
- Page: https://openairdocs.org/tcds/TC%20221

## Models (1)

As the data sheet lists them.

- 4AC-176 Series

## What the data sheet says

From the PDF's text layer, line by line; tables lose their columns. The PDF is the record.

```text
FRANKLIN ENGINE COMPANY
MODELS:  Aircooled Motors Franklin 4AC-176 Series
T.C. NUMBER:  T.C. 221
Model-
   Franklin 4AC-176
B2, B3 BA2 (O-175-
   1), BA3
C2, C3 D2, D3 F2, F3
Type 4HOA - - - - - - - - - - - - - - - -
Rating:
   Maximum
   continuous, hp, rpm,
   at S.L. press. alt. 65-2200-S.L. 65-2300-S.L. 75-2500-S.L. 80-2650-S.L. 80-2500-S.L.
   Take-off, hp, rpm,
   full throttle 65-2200 65-2300 75-2500 80-2650 80-2500-S.L.
Fuel (minimum octane
   aviation gasoline) 73 - - - - 80 - - - - - - - -
Bore and stroke, in. 4.0 x 3.5 - - - - - - - - - - - - - - - -
Displacement, cu. in. 176 - - - - - - - - - - - - - - - -
Compression ratio 6.3: 1 6: 1 6.3: 1 - - - - 7: 1
Weight (dry), lbs. 182; 189 - - - - - - - - - - - - 183; 190
C.G. location (with
   all accessories)
   Forward of rear
   mount C.L., in. 5.7; 3.7 - - - - - - - - - - - - - - - -
Propeller shaft Special with
   integral
   flanged hub,
   6-3/8 in.
   bolts - 4 in.
   circle
- - - - - - - - - - - - - - - -
Carburetion Marvel MA-3
   or MA-3A
   carburetor
   with 1-9/64
   in. venturi
Marvel MA-3P
   or MA-3SPA
   carburetor
   with 1-5/16
   in. venturi
Marvel MA-3
   or MA-3A
   carburetor
   with 1-5/16
   in. venturi
- - - - - - - -
Ignition, dual Eisemann AM-
  4
(unshielded)
   or LA-4
   (shielded)
   magnetos
   with impulse
   coupling
   (retard 25
   degrees)
- - - - - - - - - - - - - - - -
Ignition timing,
   deg. BTC 26 or 28 - - - - - - - - - - - - - - - -
Spark plugs    Champion C-
   10S, AJ-66,
   78S;
   Simmonds-
   Benton 4D3-
   S; AC SA-
- - - - - - - - - - - - - - - -

47; Auto-Lite
   A5-B or A4-
   S
Oil sump capacity,
   quarts 4 or 5 - - - - - - - - - - - - - - - -
Certification basis Type Certificate No. 221 (See NOTE 2)
NOTE 1.    Maximum permissible cylinder head, cylinder barrel and oil inlet temperatures, 500 degrees F.,
   335 degrees F., and 240 degrees F., respectively.
NOTE 2.      Approval expired 11/5/50.  No engines of these models manufactured after the date shown
   below or with serial numbers above those noted are eligible for use in certificated aircraft.
Date Model Serial No. Date Model Serial No.
4/1/42 4AC-176B2 101706 7/10/45 4AC-176BA3,
   C2, C3
102172
4/1/42 4AC-176B3 100306 7/10/45 4AC-176D2 125356
9/29/50 4AC-176BA2 102234 9/4/41 4AC-176D3 125356
5/15/41 4AC-176F2 125128
5/18/41 4AC-176F3 125351
NOTE 3.    The following accessories are eligible for use on the specified engine models at the indicated
   additional weights:
Accessory Weight (lbs.)
Optional Accessories Housing for F2 only
With drives for two generators, starter, hydraulic and vacuum pump 12
Generator
Auto-Lite GDY or GAS (6 or 12 volts, Models B3, C3, D3, F3, BA3 only) 12
Auto-Lite No. 10621 and 10622 (both used, F2 only) 26
Starter
Auto-Lite MBG or MZ (6 or 12 volts, Models F2, B3, BA3, C3, D3, F3 only) 16
Fuel Pump
AC No. 10551  3
Hydraulic Pump
Pesco 194-C (F2 only)  3
Vacuum Pump
Pesco 194-C (F2 only)  4
Miscellaneous
Fram P-1/2 or PB-1/2 oil filter  2
8 quart finned oil sump --
AC air cleaner, No. 1529265 (65 hp models only)
The following drives are provided:

Accessory
Nearest AN
Pad
Designation
Direction of
Rotation, C =
Clockwise
CC = Counter-
clockwise
Drive Speed I
Crankshaft
RPM
Maximum Torque (in. - lbs.)
Continuous                  Static
Maximum
Overhang
Moment (in. -
lbs.)
Starter None CC 11.444: 1 - - 240 30
Generator None CC 1.000: 1 8 15 45
Tachometer AND 10005 CC 0.500: 1 20 60  2
NOTE 4.    Military model C-175-1 is identical to Model 4AC-176BA2.  The corresponding model designation
and T.C. No. 221 should be incorporated on the engine nameplate when used in certificated aircraft.
```

## ADs (1, in force first)

- [AD 69-09-01](https://openairdocs.org/ad/69-09-01): Eisemann Magnetos · Eisemann Magnetos, 2A4-45-B2, 2A4-49-B2 and 158 more

## STCs approved under this data sheet (1)

- [STC SE04651CH](https://openairdocs.org/stc/SE04651CH): To allow use of l00R grade aviation fuel meeting Swift Fuel, LLC specification SPEC-l00R-22. Swift Fuels LLC

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