Prop & windmill quiz

[cdavenport]

Lots of great ideas.

The difference between a propeller and a windmill has nothing whatever to do with airfoil shape or angle of attack relative to the wind. The only difference is that a windmill uses wind passing over the blades to create rotational torque and, thus, transmits power. In contrast, a propeller uses a dedicated power source to convert torque into thrust.

A brief history of propellers and windmills reminds us that the Wright's first propeller had little if any airfoil. In contrast, todays wind-driven turbines, windmills, use highly sophisticated airfoil shapes.

Therefore, this is a windmill because the device has no provision for producing its own power. If it did, there would have to be some sort of intake/exhaust manifold and cooling mechanism.

The angle of blade is nearly feathered which means it was intended to turn slower than the propellor.

For the final question, one really needs to see the other side of the mill. If it is a hydraulic pump, there must be a return line to the mill because that's how hydraulic systems work. If it's a fuel pump, it needs another line also. That drop of oil on the plug may come from the oil reservoir located directly above the shaft housing. The shaft of the mill is likely a simple journal bearing which would have required constant lubrication.

One respondant suggested this may power the Vickers gun sychronizer. There was a hydraulic synchronizer developed by a Romanian that worked independantly from the propeller shaft. Since the F2B was introduced in 1917, this very well could be such a device. But, it may be the airspeed indicator, too. The latter gets my vote.

So, do you know the answers?