# TCDS TC 121: Air Repair Inc. - Type: Type certificate data sheet - Status: Current - Holder: Air Repair Inc. - Revision: 1 - Revised: January 2, 2002 - Product: Engine - Data sheet PDF: https://openairdocs.org/files/sha256/8d/56/8d56d30f793c89d39354ee93a6fb151733d2d1ac299c75913b0877e9e14d115a - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/51566F96F16478D586256BCE0070CF61.0001 - Page: https://openairdocs.org/tcds/TC%20121 ## Models (2) As the data sheet lists them. - L-4 (Military R-755-9) - L-4 Series (Military R-755-9) ## What the data sheet says From the PDF's text layer, line by line; tables lose their columns. The PDF is the record. ```text P a g e N o . 123 R e v . N o . 111 DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION 121 Revision 1 Jacobs L-4 Military R-755-9 January 2, 2002 TYPE CERTIFICATE DATA SHEET NO. 121 Engine models described herein conforming with this data sheet (which is part of Type Certificate No. 121), and other approved data on file with the Federal Aviation Administration, meet the minimum standards for use in certificated aircraft in accordanc e with pertinent aircraft data sheets provided they are installed, operated, and maintained as prescribed by the approved manufacturer's manuals and other approved instructions. Type Certificate Holder Air Repair, Inc. 920 Airport Service Road Cleveland, Mississippi 38732 Type Certificate Holder Record: Air Repair, Inc. assumed ownership of this type certificate from Jacobs Service Company, 4305 Saturn Way, Chandler, Arizona 85334 on January 2, 2002. Model L-4 L-4M, -4MA, -4MA7 L-4MB Type 7RA Direct Drive - - - - - - - - Rating: Maximum Continuous, hp, rpm, at S.L. pressure altitude 225-2000-S.L. - - - - - - - - Take-off (5 minutes), hp, rpm at full throttle 245-2200 - - - - - - - - Fuel (minimum octane aviation gasoline) 73 - - - - - - - - Bore and stroke, in. 5.25 x 5.00 - - - - - - - - Displacement, cu. in. 757 - - - - - - - - Compression ratio 5.35:1 - - - - - - - - Weight (dry), lbs. 505 507 520 Propeller shaft, SAE No. 20 - - - - - - - - Carburetion Stromberg NA-R7A carburetor with 2-1/16 in. venturi - - - - - - - - Ignition, dual Bosch AFV or Scintilla WL7A battery ignition units Scintilla MN7-DF, VNM7-DF, MN7-DF5, or VMN7-DF5 magnetos Combination Scintilla MN7-DF5, or VMN7-DF5 magnetos and Scintilla WL7A or Bosch AFV battery ignition unit Ignition timing, degrees BTC 30 - - - - - - - - Spark Plugs BG-4B2(s), 174(S), SS54, SS485, Bendix 9ES2, 437J Champion M3-1S, C-27S - - - - - - - - NOTES 1,4,6,7 1,2,3,4,6,7 1,4,5,6,7 Certification basis Type Certificate No. 121 Production basis None. The manufacturer no longer holds a production certificate for engines under this type certificate; therefore, each engine produced subsequent to February 20, 1957, is subject to a detailed inspection for workmanship and conformity with the approved data by a FAA representative. In addition, the engines must have a satisfactory run-in including at least 5 hours at rated power and speed. Upon satisfactory completion of the above, the representative shall tag the engine with Tag Form ACA-186. 121 2 NOTE 1. Maximum permissible cylinder head, barrel, and oil inlet temperature, 550 o F., 325oF., and 200oF., respectively NOTE 2 The approval of model L-4MA expired December 9, 1942. No engine of this model manufactured after that date or with serial numbers above 661 are eligible for use in certificated aircraft. This model is similar to model L-4M except that it incorporates autogyro rotor drive gears which entails a weight increase of 3 lbs. NOTE 3. Model L-MA7, similar to the L-4M engine, is eligible at eight (dry) 506 lbs. This model engine incorporates autogyro rotor drive gears, a 2-piece main crankcase and other minor modifications. NOTE 4. Eligible with aluminum rear and front crankcases and main bearing plate replacing the magnesium parts with a possible weight increase of 11 lbs. Engine dry weights listed above include starter drive, generator drive, one pump drive, and the following: Accessory drive unit - pump drive (L-4MB only) 3 lbs. Radio shield ignition (standard equipment on later engines) 10 lbs. Automatic valve gear lubrication (standard equipment for engines above No. 4571, included all R-755-9 models) 7 lbs. Propeller oil transfer sleeve (standard equipment for engines above No. 4571, including No. 4571, including all R-755-9 models) 3 lbs. Generator and control (15 amp.) (L-4MB only) 17 lbs. NOTE 5. Military engines, model R-755-9, otherwise identical to the L-4MB engine, incorporate AN type spark plug elbows and special carburetor control level arms. The designations L-4MB and T.C. No. 121 should be included at the first opportunity on the designation plate of these military engines when installed in certificated aircraft. NOTE 6. The following accessories are eligible for use on the specified engine models at the indicated additional or substitute weights: Engine Models Optional Accessories Weight (lbs.) L-4 L-4M L-4MA7 L-4MB Governor – Hamilton Standard hydraulic propeller governor model 1A4 (including drives) 5 Yes - - - - - - - - Hydraulic pump – Pesco model 320F 2 Yes - - - - Fuel pump -Pesco model M-400A 2 Yes - - - - -Pesco model B-400BLY (4 stud pad) or Romec model RD-4140 2 Yes - - - - - - - - -Pesco type R-400-BLH or Romec type C-16 (3 stud pad) 2 Yes - - - - - - - - - - - - Vacuum pump – Pesco B-2A (Model 194-C or 194- B) or Romec Type B-2A (Model RD2112) 4 Yes - - - - - - - - - - - - Generator - Eclipse type D (25 amp, 12 volt) and control 26 Yes - - - - - - - - - - - - - Eclipse type LV-180 (15 amp) and control 17 Yes - - - - - - - - - - - - - Bosch type GEG (6 amp) and control 12 Yes - - - - - - - - - - - - - Leece-Neville (25 amp, 24 volt) and control 27 Yes - - - - - - - - - - - - Starter – Eclipse Series E-80, Type 397 19 Yes - - - - - - - - - - - - Accessory drive unit including -3 pump drives 6 Yes - - - - -2 pump drives 5 Yes - - - - -1 pump drive 3 Yes Std. Propeller hub (fixed pitch) 15 Yes - - - - - - - - - - - - *The L-4, L-4M, and L-4MB models are eligible for optional use of 2-position hydraulically controllable propeller when the control valve is used in lieu of the constant speed governor. 3 121 NOTE 7. The following accessory drive provisions are available: Maximum T orque Inch- Pounds Drive Drive of Rotation Drive Ratio Continuous Static Maximum Overhang Moment Inch-Pounds Starter CCL 1.5: 1 - - - - 5500 100 Generator CCL 1.4: 1 50 300 110 Fuel pump (rear crankshaft) CL 1: 1 20 150 - - - - Tachometer CCL .5: 1 - - - - - - - - - - - - *Vacuum pump CCL 1: 1 or .875: 1 30 200 - - - - *Propeller governor CCL 1: 1 30 200 - - - - *Hydraulic pump CCL 1: 1 or .875: 1 30 200 - - - - *Fuel pump CCL 1. 1 30 200 - - - - All directions of rotation are given facing engine drive flange. *Accessories marked with an asterisk are mounted on accessory drive unit. The total continuous torque taken off all the drives on the accessory drive unit should not exceed 70 inch-pounds. Overhang moment for drive pads not listed is not critical provided accessory weights listed in NOTE 6 are not exceeded. ....END..... ``` ## ADs None name its models. ## Registered aircraft by registry model (OpenAirDocs) - [Jacobs L-4](https://openairdocs.org/engine/jacobs-l-4): 0 aircraft (registry code 35026) ## STCs approved under this data sheet (5) - [STC SE04136AT](https://openairdocs.org/stc/SE04136AT): Installation of Bendix Scintilla WL-7A Battery Ignition Timer (distributor) modified from a breaker points and condenser design to a Hall Effect electronic sensor design. Air Repair Inc - [STC SE00809WI](https://openairdocs.org/stc/SE00809WI): Installation of a modified alternate source of supply, engine ignition coil assembly and condenser. Air Repair Inc - [STC SE01652WI](https://openairdocs.org/stc/SE01652WI): Modification of engine to replace contact points and condenser controlled Bendix Scintilla WL-7A battery timer (distributor) with an electronically controlled WL-7A-M battery timer.. Radial Engines Ltd - [STC SA4005NM](https://openairdocs.org/stc/SA4005NM): Precise Flight Inc. Pulselite Control System. Precise Flight Inc - [STC SE01243WI](https://openairdocs.org/stc/SE01243WI): Installation of Barron Aviation intake tube drain kits on the engines listed on the attached FAA Approved Model List (AML) No. SE01243WI, dated April 26, 2004, or later FAA Approved revision.. Barron Aviation --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.