Pratt & Whitney R-4360
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The Pratt & Whitney R-4360 "Wasp Major" was the largest aircraft piston engine to be mass produced in the United States. Although it found extensive military application, its 28 cylinders, 56 manually-adjustable valves, and 56 spark plugs prevented it from finding favor with the airlines. |
R-4360 Firing Order
Cylinder rows are designated A through D from anti-propeller end to propeller end. Cylinder banks are designated 1 through 7, with numbers increasing clockwise, cylinder 1 being the topmost cylinder. Master rods are located in cylinders A7, B4, C4 and D1.
R-4360 Cutaway at the
Museum of Flight, Seattle, Washington
Submitted by Robert Wahlgren
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| QEC on Boeing maintenance stand, propeller is on right | Carburetor and induction piping | Cylinder and intake manifold with oil drain hose | Left upper engine mount to airframe attach point | Exhaust manifold | Left rear showing generator and cowl flap motor | Engine mount to case | Right side showing generator with cooling hose, starter under it and fire detection sensors |
C-97 QEC, R-4360-59B Specifications
Courtesy of Robert S. Wahlgren
| Weight with propeller | 7,988 lb | |
| Weight without propeller | 6,500 lb | |
| Bore | 5.75" | |
| Stroke | 6.00" | |
| Displacement | 4,360 in³ | |
| Compression Ratio | 6.7:1 | |
| Propeller Shaft Rotation | Clockwise, 0.375:1 ratio | |
| Spline size | 60-A | |
| Maximum dry weight | 3,691 lb | |
| Diameter | 55.0" | |
| Length | 96.5" | |
| CG from main crankcase rear face | 18.4" | |
| CG at crankshaft | @ Centerline | |
| Impeller diameter | 14" | |
| Impeller Ratio | 6.375:1 | |
| Carburetor | Bendix PR100B3-4 | |
| Magneto | Scintilla S14RN-15 | |
| Magneto Ratio | 0.875:1 | |
| Spark plug gap | 0.011" - 0.014" | |
| Spark Advance Normal | 20° BTC | |
| Spark Advance Cruise | 30° BTC | |
| Cam Timing | ||
| Intake Opens | 64° BTC | |
| Intake Closes | 76° ABC | |
| Exhaust Opens | 135° BBC | |
| Exhaust Closes | 79° ATC | |
| Intake Duration | 320° | |
| Exhaust Duration | 394° | |
| Overlap | 143° | |
| Cold valve clearance, not incorporating overhaul change 273 | ||
| Intake | 0.040" | |
| Exhaust | 0.025" | |
| Cold valve clearance incorporating overhaul change 273 | ||
| Intake | 0.035" | |
| Exhaust | 0.035" | |
Index of Wasp Major and R-4360 Designated Engines (568K Acrobat File)
History of the R-4360 (764K Acrobat File)
R-4360 Service History for C-97 and KC-97 Aircraft in Air National Guard Units
R-4360 Gallery (Warning! Large Files)
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| Crankcase and Crankshaft | Part Finishing Processes | Cross Section | VDT Schematic The Variable Discharge Turbocharger (VDT) concept was meant to produce over 4,000 HP and allow piston-powered airliners to fly non-stop from Chicago to London. |
VDT 3/4 Rear View Exhaust ducts, intake ducts, turbochargers and aftercooler dwarf the already large R-4360 engine |
R-4360 with Remote Gearbox This fan-cooled engine with a remotely-mounted propeller reduction gear was used in the Northrop XB-35 "Flying Wing." |
Right Side | Right Front | B6 Oil Flow |
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