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.
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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 the Boeing maintenance stand, propeller is on right
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Carburetor and induction piping
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Cylinder and intake manifold with oil drain hose
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Left upper engine mount to airframe attach point
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Exhaust manifold
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Left rear showing generator and cowl flap motor
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Engine mount to case
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Right side showing generator with cooling hose, starter under it and fire detection sensors
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C-97 QEC, R-4360-59B Specifications
Courtesy of Robert S. Wahlgren
| Weight |
7,988 lb with propeller,
6,500 lb without propeller. |
| 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" |
| Position of CG from rear face of
main crankcase |
18.4" |
| CG at crankshaft |
@ Centerline |
| Impeller diameter |
14" |
| Impeller Ratio |
6.375:1 |
| Carburetor |
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 |
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| Cam Timing |
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| Intake Opens |
64° BTC |
| Intake Closes |
76° ABC |
| Exhaust Opens |
135° BBC |
| Exhaust Closes |
79° ATC |
| Intake Duration |
320° |
| Exhaust Duration |
394° |
| Overlap |
143° |
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| Cold valve clearance, not
incorporating overhaul change 273 |
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| Intake |
0.040" |
| Exhaust |
0.025" |
| Cold valve clearance with
overhaul change 273 |
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| Intake |
0.035" |
| Exhaust |
0.035" |
R-4360 Cutaway Preparation
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
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Part Finishing Processes
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Cross Section
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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.
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VDT 3/4 Rear View
Exhaust ducts, intake ducts, turbochargers and aftercooler dwarf the already large R-4360 engine |
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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."
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Right Side
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Right Front
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B6 Oil Flow
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