I'm having a hard time finding information about dynamo construction.

I know how to build a simple generator. Thanks 8'th grade science.

What I am having difficulty with is finding out how to build a dynamo with a specific output voltage.

I can buy one on the internet. Hand Crank 110v ac generators are all over the place.

But I want to build one with my kids in the garage.

If someone could just help guide my questions, so that I know how to ask the question in the proper format to get me to the information I am looking for, that would be awesome.

Is it primarily based on the RPM's? The number of magnets? The number of windings?

Any help would be appreciated.

Thanks!