# TCDS E-186: Pratt & Whitney Division

- Type: Type certificate data sheet
- Status: Current
- Holder: Pratt & Whitney Division
- Revision: 4
- Revised: March 4, 1960
- Product: Engine
- Data sheet PDF: https://openairdocs.org/files/sha256/16/34/163421b051aa4011ab7f539e015376a7b97a0123971054abc048a42bf1d76355
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2EB8F57FA084CABE8525670D0060147A.0001
- Page: https://openairdocs.org/tcds/E-186

## Models (6)

As the data sheet lists them.

- Twin Wasp S1C-G
- Twin Wasp S3C4-G
- Twin Wasp SC-G
- Twin Wasp S1C3-G
- Twin Wasp SC3-G
- Twin Wasp S4C4-G

## What the data sheet says

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

```text
Page No. 1 2 3
Rev. No. 4 4 4
FEDERAL AVIATION AGENCY
E-186
Revision 4
PRATT & WHITNEY
Twin Wasp
SC-G
SC3-G
S1C-G
S1C3-G
S3C4-G
S4C4-G
March 4, 1960
AIRCRAFT ENGINE SPECIFICATION
Engines of models described herein conforming with this specification and approved data on file with the Federal Avation
Agency meet the minimum standards for use in certificated aircraft in accordance with pertinent aircraft specifications and
applicable portions of the Civil Air Regulations provided they are installed, operated, and maintained as prescribed by the
approved manufacturer's manuals and other approved instructions.
Manufacturer Pratt & Whitney Aircraft
Division of United Aircraft Corporation
East Hartford, Conn
Model                         Twin Wasp SC-G & SC3-G S1C-G & S1C3-G S3C4-G S4C4-G
Type                                    14RA 3:2 and 16:9
reduction gears
-  - -  - -  -
Rating:
  (with low imp. gear ratio)
7.15:1 -  - -  - -  -
  Max continuous, hp, rpm, in.Hg.at:
    Critical alt. (ft.) 900-2550-34-12000 1050-2550-39.5-7500
1000-2700-37.5-10000
1100-2550-41.0-6200 1050-2550-39.0-7500
    Sea level press. alt. 900-2550-36-S.L. 1050-2550-41.5-S.L.
See Note 3.
1100-2550-43.5-S.L. 1050-2550-41.5-S.L.
  Takeoff (5 min.), hp, rpm, in.Hg. at:
    Sea level press. a.t 1050-2700-42-S.L. 1200-2700-48-S.L. -  - -  -
1200-2750-47-S.L. -  - -  -
  (With high imp. gear ratio) — — 8.47:1 -  -
  Max. continuous, hp, rpm, in.Hg.,at:
    Critical altitude (ft.) — — 1000-2700-39.0-14500 900-2550-35.5-15400
    Low critical press. alt. (ft.) — — 1000-2700-40.0-9000 —
Fuel (min. grade aviation fuel) 87 91/98 100/130 91/98
(Lubricating oil See P&WA Service
Bulletin 118)
-  - -  - -  -
Bore and stroke, in. 5.5  X  5.5 -  - -  - -  -
Displacement, cu. in. 1830 -  - -  - -  -
Compression ratio 6.7:1 -  - -  - -  -
Weight (dry), lb. 3:2-1438 -  - 3:2-1460 -  -
16:9-1450 -  - 16:9-1490 -  -
Propeller shaft, SAE No. 50 -  - -  - -  -
Carburetion Stromberg NA-C12B,
NA-C12D1 or 2, NA-
C12DX, NA-C12E1,
or PD-12B4, 6 or 8,
carburetor, with
3-3/16 in. venturis, or
PD12H1, H4 or H7
with 3-1/4 in. venturis,
or Chandler Evans
1375 DB-1 or 3
carburetor
-  - Stromberg PD-12F2 or
F5 carburetor with
3-1/4 in. venturis
-  -

E-186 2
Model                         Twin Wasp SC-G & SC3-G S1C-G & S1C3-G S3C4-G S4C4-G
Ignition, dual Scintilla SF14LN4,
SF14L6, SF14L3,
SF14LN3 or
SF14RN-8 magnetos,
or Bosch SF-14LU-6,
07, or -8 magnetos
-  - Scintilla SF14L3 or
SF14LN3 magnetos
-  -
Ignition timing, °BTC 20 25 (37-cruising) 25 20
Spark plugs See Note 8. -  - -  - -  -
NOTES 1,2,3,4,5,8 1,2,3,4,5,6,8 1,2,3,5,8 1,2,3,5,8
"-  -" indicates "same as preceding model."
"—"  indicates "does not apply."
Certification basis Type Certificate No. 186
Production basis Production Certificate No. 2
NOTE 1. Maximum permissible temperatures are as follows:
Cylinder Head Cylinder Base Oil Inlet
500°F spark plug gasket 335°F 220°F single speed
supercharger
475°F cylinder head well 212°F two-speed
supercharger
NOTE 2. Fuel and oil pressure limits: Max. Min.
Fuel pressure (psi)   16 14 with 5 lb. discharge nozzle spring
  23 21 with 10 lb. discharge nozzle spring
Oil pressure (psi) 100 50
NOTE 3. The following accessory provisions are available:
Direction of
Rotation
(Clockwise or
Counter-
Speed Ratio
(Times
Crankshaft
Maximum Torque
(in. lb.)
Maximum
Overhang
Clockwise)  Speed) Cont. Static (in.-lb.)
Starter C 1.0 2500 16500 200
Generator C 1.4 600 6000 260
Vacuum or hydraulic pump C 1.4 250 1200 40
Vacuum or hydraulic pump C 1.0 125 500 20
Fuel pump CC   .875 150 450 10
Goverrnor C   .958 100 600 —
NOTE 4. Model S1C3-G eligible with applicable setting to give Automatic Rich mixture performance as follows:
Maximum continuous hp, rpm, in.Hg., at:
Rated pressure altitude (ft.) 1000-2700-38-10000
1050-2550-41-7000
Sea level pressure altitude (ft.) 1050-2550-42-S.L.
NOTE 5. Models SC-G, SC3-G, and S3C4-G become models S1C-G, S1C3-G and S4C4-G or vice versa respectively,
depending only open the octane rating of the fuel used and the ignition timing where applicable in which
case the pertinent model designation and rating applies without changing the engine nameplate.
NOTE 6. S1C3-G engines with nose mounted magnetos and PD 12H7 carburetors incorporate a built-in automatic
spark advance mechanism.
NOTE 7. Models 2SC9-G and SSC7-6 formerly listed hereon have been deleted since no engines of these models
are used in civil aircraft.

3 E-186
NOTE 8. The following spark plugs are approved for use on these engines:
AC LS-87*, LS-88, 161, 171, 181, 261, 271, 281.
BG 240, 245, 340, 341, 345, 346, RB19R-2, RB21R-1, RB27R-1, RB39R.
Champion C34S, C35S, RC35S, R37S-1, REA37N, REB37N, R115, RHA37N, RHA37E, RHB37N,
RHB37E
Lodge RS19-2R.
*Limited to use with engines of 1200 hp and under 170 hours service with no reconditioning permitted.
.....END.....
```

## ADs (1, in force first)

- [AD 56-06-02](https://openairdocs.org/ad/56-06-02): Cylinder Flange Attaching Stud · Pratt & Whitney Division Double Wasp CA15, Double Wasp CA17, Double Wasp CA18 and 115 more

## STCs approved under this data sheet (6)

- [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
- [STC SE01966WI](https://openairdocs.org/stc/SE01966WI): Use of GAMI G100UL High Octane Unleaded Avgas in spark ignition piston aircraft engines. General Aviation Modifications Inc.
- [STC SE5189NM](https://openairdocs.org/stc/SE5189NM): Installation of chip detector light system.. A & L Aircraft Parts Inc
- [STC SE1046GL](https://openairdocs.org/stc/SE1046GL): Incorporation of fuel flow transducer.. Shadin Company Inc
- [STC SE157EA](https://openairdocs.org/stc/SE157EA): Modification of AS-5999 to incorporate the use of flat sides.. Aircraft Supplies
- [STC SEW-5](https://openairdocs.org/stc/SEW-5): Ni-resist valve guide LGL 4700.. National Aircraft Sales, Inc

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