Propeller
Propellers: Hamilton Standard. Three blade hydromatic
contract # WEE50-473/505
HUB - 23E50-473
BLADE: 6477A-6
DIAM: 11ft 7in
Standard hydraulic feathering, controlled by the prop-feathering governor. An expansion on explanation below, under prop feathering.
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Three of the four blades had been recovered; two of them, exhibit an aggressive state of corrosion, and the third is relatively in good condition except for one blade missing a tip. In two blades, bent-prop is present, which proves that the engines were still turning or running as they hit the ground. It is suspected that one engine is not present as it is thought this engine took a direct hit and may have been blown off. In addition to mention the three serial numbers found are of three engines, and in all engine covers, only 1,3, and 4 are represented. There is some flak damage on one or two blades. It is not possible to tell what blade was on any particular engine.
Operation
The propeller governor maintains a constant engine speed by controlling propeller pitch. Engine speed is selected by a cockpit control connected to the governor speed control shaft.
The governor consists of a gear-type oil pressure boost pump and a spring-loaded governor, which are driven through gearing from the engine crankshaft. This pump is a Pesco Oil Pump, mounted on the engine firewall of the nacelle behind the engine. This pump is widely used in street cars known as low-riders, that can rise up and down as well as bounce high.
A feathering valve in the base of the governor, admits (engine) oil from the feathering pump to the propeller. The feathering valve is spring-loaded and normally supplies oil to the propeller from the governor boost pump.
