Constant Speed Props

[uwochris]

Hey guys,

I have a question regarding the governor system on constant speed props.

I understand the basic principles of how these things work to maintain a constant RPM by varying the blade angle. It's also my understanding that the governors are geared to the engine, and that the flyweights rotate at the same speed as the props.

I am, however, confused as to what really goes on when one adjusts the RPM control (the blue lever). When you move the control, is the pilot adjusting the tension on the speeder spring, or is somthing else going on? I know that there has to be an equilibrium between the speeder spring force and the oil pressure, so I assume one or the other has to be affected by the prop lever.

Thanks in advance for any comments,

Chris.

 

[rfeathe1]

Yes, the prop control adjusts the pressure on the speeder spring. The more pressure (tension) on the spring the faster the flyweights must turn to spread apart. There is a pilot valve attached to the bottom of the flyweights. As the flyweights spread, they pull the pilot valve up which directs engine oil pressure to the appropiate side of the prop dome, changing the prop pitch. Hope this helps.

 

[ventus]

http://www.mccauley.textron.com/prop/prop-tech/pg03govern.html

 

[minitour]

awesome link...thanks!

-mini

 

[Vik]

Who woulda thunk'd! Learnings about CSP at a propeller compnay! Great diagrams!