De HAVILLAND HYDROMATIC AIRSCREW

De HAVILLAND HYDROMATIC AIRSCREW PROPELLER AIRCRAFT BRITISH EDUCATIONAL FILM 75764
PeriscopeFilm
The video combines two short films. The first one is assembly and installation and runs about 16 minutes. I found it totally engrossing. The second one is about testing. Not so interesting, though a few bits were a little confusing. Evidently when the engine is running it provides the oil to operate the hub, but when it is not there is an electric pump that supplies the oil to turn the blades into their feathered position.

Pitch Control Cam

At the end of the first film (at the 15 minute mark) there is a brief shot of the some of the parts that go into this device and you can see the cylindrical cam that is used to control the pitch of the propeller blades.