# STC SA4974NM - Type: Supplemental type certificate - Status: Current, Amended - Holder: Radial Engines Ltd, United States - Description: Installation of Jacobs Model R-755-9, -A2 or B2 engine with Hamilton Std 2B20/6135-15 propellers. - Applied: March 14, 1989 - Status date: May 1, 2008 - Product: Aircraft, Single-Engine - Certification basis: Part 21 - Data sheets: [TCDS A-743](https://openairdocs.org/tcds/A-743) - Certificate PDF: https://openairdocs.org/files/sha256/70/00/70007a5b934a448a79bc0f33101ebbe3374a7a0ee5c549531852789d13838832 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BD3F9EA4379F0E4C86257471007F71AA.0001 - DRS record last changed: December 5, 2025 - Page: https://openairdocs.org/stc/SA4974NM ## ADs that name it (0) None. ## Approved models (9) - Boeing Airplane Company Wichita Division 75 (Army PT-13) ([TCDS A-743](https://openairdocs.org/tcds/A-743)) - Boeing Airplane Company Wichita Division A75 (Army PT-13A; -13B; -13C) ([TCDS A-743](https://openairdocs.org/tcds/A-743)) - Boeing Airplane Company Wichita Division A75J1 (Army PT-18) ([TCDS A-743](https://openairdocs.org/tcds/A-743)) - Boeing Airplane Company Wichita Division A75L3 ([TCDS A-743](https://openairdocs.org/tcds/A-743)) - Boeing Airplane Company Wichita Division A75N1 (Army PT-17; -17A; Navy N2S-1; -4) ([TCDS A-743](https://openairdocs.org/tcds/A-743)) - Boeing Airplane Company Wichita Division B75 (Navy N2S-5) ([TCDS A-743](https://openairdocs.org/tcds/A-743)) - Boeing Airplane Company Wichita Division B75N1 (Navy N2S-3) ([TCDS A-743](https://openairdocs.org/tcds/A-743)) - Boeing Airplane Company Wichita Division D75N1 (Army PT-27) ([TCDS A-743](https://openairdocs.org/tcds/A-743)) - Boeing Airplane Company Wichita Division E75 (Army PT-13D; Navy N2S-5; PT-13D/N2S-5) ([TCDS A-743](https://openairdocs.org/tcds/A-743)) ## What the certificate says Read from the PDF's text layer, without the form's printed wording; the layout is lost and the order can differ. The PDF is the record. Part 4a of the Civil Air Regulations. Description of Type Design Change: Installation of Jacobs R-755-9, A2, A2M, B2, B2M engine or Jacobs R-755A2, A2M, B2, B2M engine modified for fuel injection per STC SE01288WI with Hamilton Standard 2B20/6135-15 or -16 propeller in accordance with Ray’s Aircraft Service, Inc. Drawing List Report No . 1, dated July 27, 1989 or later FAA approved drawing list. Limitations and Conditions: Approval of this change in type design applies to the above model aircraft only. Compatibility of this design change with previously approved modifications must be determined by the installer. A copy of this Certificate , Continuation Sheet and FAA Approved Operation Manual Supplement dated October 12, 1990 or later FAA Approved revision required for non-fuel injected intstallation, FAA Approved Airplane Flight Manual (See continuation sheet 3 of 4) Radial Engines, Ltd. 602 E. Renner Field Road Goodland, KS 67735 A-743 Make : Boeing Model : A75L3, 75, A75, B75, E75, A75J1, A75N1, B75N1, and D75N1 Date of application : March 14, 1989 Date of issuance : October 12, 1990 Date reissued : January 19, 2007 Date amended : January 19, 2007; May 1, 2008 Original signed by TLM ( Signature) Tina L. Miller Program Manager Wichita Aircraft Certification Office ( Title) Transfer the ownership of the Supplemental Type Certificate Number to (Name of transferee) (Address of transfer) (Number and street) (City, State, and Zip code) from (Name of grantor) (Print or type) (Address of grantor) (Number and street) (City, State, and Zip code) Extent of Authority (if licensing agreement): Signature of grantor ( In ink): Number SA4974NM Date of Issuance: March 14, 1989 Date Amended: May 1, 2008 Supplement dated May 1, 2008 and FAA Approved Radial Engines, Ltd. Instructions for Continued Airworthiness Report REL1007, Revision (IR), dated September 18, 2007 or later FAA Approved revision required for fuel injected installations If the holder agrees to permit another person to use this certificate to alter the product, the holder shall give the other person written evidence of that permission. The conditions and limitations of Type Certificate Data Sheet No. A-743 apply except where superseded by the following: This Supplemental Type Certificate Addendum, which is part of STC SA4974NM, prescribes the conditions and limitations under which the product for which the STC was issued meets the airworthiness requirements of the Civil Air Regulations. A copy of this STC Addendum is required to be maintained as part of the permanent records for the modified aircraft. SUPPLEMENTAL TYPE CERTIFICATE HOLDER: Radial Engines, Ltd. I. Boeing Model 75 Series, 2 PO-CLB (Acrobatic Category – See Note 7 of TCDS A-743) as modified by STC SA4974NM Engine: Jacobs R-755-9, R-755A2, A2M, R-755B2, B2M carbureted or fuel injected Fuel: Aviation Gasoline Grade 80 or higher fuel conforming to ASTM Specification D910 or equivalent required. Automotive gasoline is not approved for airplanes modified to this design Engine Limits: Maximum Manifold Pressure R-755-9 (225 hp) 24.5 in. Hg R-755-9 (245 hp) 26.3 in. Hg R-755B2 or B2M (275 hp) 26.5 in. Hg R-755A2 or A2M (300 hp) 28.0 in. Hg Maximum RPM 2200 RPM NOTE: For R-755-9 do not operate at 2200 RPM for over 5 minutes Maximum Oil Pressure 90 psi Maximum Oil temperature 200°F (93°C) Maximum Cylinder Head Temperature A2,A2M,B2,B2M 500°F (260°C) -9 550°F (287°C) (Page 3 of 4) Number SA4974NM Date of Issuance: March 14, 1989 Date Amended: May 1, 2008 Propeller and Propeller Limits: Hamilton Standard 2B20/6135-15 or -16 Maximum propeller diameter 93” Minimum propeller diameter 91 1/8” Placards: The following placards must be insta lled in plain view in the front cockpit: Solo From Rear Seat Only Intentional Spins Prohibited Above 2950 lbs. - END - ## Every issue (2) - May 1, 2008: Amended, Current. [certificate](https://openairdocs.org/files/sha256/70/00/70007a5b934a448a79bc0f33101ebbe3374a7a0ee5c549531852789d13838832) - January 19, 2007: Reissued, Historical. [certificate](https://openairdocs.org/files/sha256/05/ba/05bace882ad85c723b5ea505f6fc8462771edc9b0425da19f2fb7761205135c7) --- 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.