TCDS E-186

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.....