The Elbow,flange to Tube, cataloged under National Stock Number 4730-00-491-3759, is classified within Federal Supply Class 4730 (Hose, Pipe, Tube, Lubrication, and Railing Fittings) of the Pipe, Tubing, Hose, and Fittings group. The manufacturer of record is Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney. Government technical data includes 20 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 6 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4730-00-491-3759 |
| Primary Part Number | 657996 |
| Item Name | Elbow,flange to Tube |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Manufacturer | Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney |
| Status | ACTIVE |
| Flange Shape | OVAL WITH HOLES SECOND END |
| Flow Angle | 63.0 DEGREES |
| Flange Face Design | RAISED STRAIGHT SECOND END |
| Connection Style | SOCKET (TUBE) FIRST END |
| Nominal Length | 2.113 INCHES SECOND END IN |
| Bolt Circle Nominal Diameter | 1.545 INCHES SECOND END IN |
| Tubing Wall Nominal Thickness for Which Designed | 0.058 INCHES FIRST END IN |
| Connection Type | FLANGE SECOND END |
| Connection Type | UNTHREADED INTERNAL TUBE FIRST END |
| Material Document and Classification | AMS 5646 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Bolt Hole Nominal Diameter | 0.263 INCHES SECOND END IN |
| Nominal Outside Diameter Tube Accommodated | 0.625 INCHES FIRST END IN |
| Leg Length | 0.500 INCHES NOMINAL SECOND END IN |
| Leg Length | 0.625 INCHES NOMINAL FIRST END IN |
| Bolt Hole Quantity | 2 SECOND END |
| Nominal Width | 1.030 INCHES SECOND END IN |
| Material | STEEL COMP 347 OVERALL |
| Raised Face Nominal Diameter | 0.090 INCHES SECOND END IN |
| Raised Face Nominal Height | 0.750 INCHES SECOND END IN |
| Nominal Thickness | 0.100 INCHES SECOND END IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 657996 | Rtx Corporation Div Pratt & Whitney (USA) |
| 657996 PRIMARY | Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney (USA) |
| Reference | Meaning |
|---|---|
| 657996 | 5/9 Secondary reference Lucid Mfg Co Div of Birken Mfg Co |
| 657996 | 5/9 Secondary reference Dell Manufacturing Co., Llc Dba Pursuit Aerospace |
| 657996 | 5/9 Secondary reference Cecilware Corporation |
| 657996 | 5/9 Secondary reference General Electric Co Apparatus Sales Division of Apparatus Group |
| 657996 | 5/1 Secondary reference Enjet Aero Bloomfield, Llc |
| 657996 | 5/9 Secondary reference Turbo Power & Marine System Inc Sub of United Technologies Corp |
NSN 4730-00-491-3759 is a Elbow,flange to Tube, manufactured by Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
NSN 4730-00-491-3759 has 2 manufacturer part numbers on file: 657996 (Rtx Corporation Div Pratt & Whitney), 657996 (Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney).
1 possible match (shared part number, not a government interchangeability claim): 4720-01-275-1602. Verify interchangeability with system specifications before substitution.
Key specifications for 657996: Flange Shape: OVAL WITH HOLES SECOND END; Flow Angle: 63.0 DEGREES; Flange Face Design: RAISED STRAIGHT SECOND END; Connection Style: SOCKET (TUBE) FIRST END. 20 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.