In these stories, a Boy Scout patrol finds an abandoned Time Machine in the wilderness; the Smart Kid figures out the controls and they roar off to adventure, acquiring new patrol members from ancient Sparta and from 4000 A.D. along the way.
They were published, starting in 1959, under the byline "Donald Keith," a pseudonym for the father-and-son team of Donald Monroe and Keith Monroe. Eventually Keith Monroe published some of the stories under his own name.
I greatly enjoyed these when I was a Scout. I now recall that I read some even before that. My dad was a Scout leader and I remember reading a Time Machine story, maybe the origin story, in one of his issues of Boys' Life before we moved out of The Little Red House, so it must have been 1962 or earlier.
The Time Machine itself-- a luxurious saucer-shaped model-- was quite powerful, if not quite user-friendly. You could set the controls for any point in space and time, it was built to survive even in outer space, and it featured a time-viewer so you could study history or the future.
Boy, I wanted one of these so badly I could taste it.
(Using the time-viewer could be dangerous, though. On some occasions Brains Baynes would be watching some horrible scene from history, then somebody would trip and fall on the gearshift knob and the Polaris Patrol would find themselves in the middle of trouble...)
In the past, I have tried to track down some of the Time Machine stories I haven't read. I've pursued this quest for a long time.
Recently Google has been bringing more magazines down from the attic. In the past week, they have been adding freshly scanned issues of Boys' Life almost daily. One benefit is that we can all enjoy some of the Time Machine stories.
Here are the Time Machine stories I know of. (Tip o' the hat to Jerry Boyajian, who helped me get this list started years ago.)
Some of the stories were combined into two fix-up books, Mutiny in the Time Machine (1963) and Time Machine to the Rescue (1967).
Using another pen name, Rice E. Cochran, Keith Monroe also published Be Prepared, a comic memoir about his experiences as a Scout leader, in 1952. It was the basis for a 1953 movie, Mister Scoutmaster.
(Part 2 of this series is Arthur C. Clarke's "The Sunjammer." Part 3 is Robert A. Heinlein's Scouts into Space. Part 4 is Dale Colombo's Starship MAGELLAN, more stories for which Keith Monroe was a co-author.)