RE: 4.8V versus 6V for receiver battery?
About the different times from 4.8V packs versus 6V packs.
The theory says the 6V won't last as long.
In theory, theory and practice are the same. In practice, they are not.
There was an excellent article in a magazine last year or year before. The guy did a reasonably sensible test that compared the two. His findings showed that in our models, 4cell packs and 5cell packs gave almost identical flight times. Why? I think he surmised it was because the added power for the servo caused it to draw less amps.
And if I remember correctly, he said something very smart at the end of the article. Something about not needing to know why to know it worked.