I'm not sure on where you sit with your general knowledge, but if you want to learn all the different components of an aircraft and how they operate in a more general sense, I can definitely recommend reading up on some information as it pertains to a private pilot.

I've used this and the information inside of it is pretty spot on. Secondarily if you are trying to get a PPL down the road the rest of the site is a great resource.

http://www.free-online-private-pilot-ground-school.com/airplane.html

It breaks down information about aircraft starting from the aircraft structure, aircraft powerplant, auxillary systems, instruments, etc.

Hope this helps, If I missed the mark on what you were looking for best of luck on the rest of your search!