It was a book about three or four kids who build a rocket with themselves as the payload. I think they did it at a camp in the woods but I'm not sure. I don't even remember if it got off the ground. I thought is was called something like "Tree-Two-One Liftoff!", but the only thing I can find close to that is a Regent reader book that I know is not the correct one. Can anyone here help me to find the actual title so I can try to buy one for my grand kids?
I was looking for a similar book and it ended up being "Blast-Off" by Bruce Cassiday. Maybe it's your book as well?
The inside flap text:
"T minus 10 seconds...9...8..." came the voice. "This is it," Gene Long thought. In 8 more seconds, the Starbound would take off. The other members of the Hillstown High School Science Club were grouped around him, intent on the rocket they had designed and built themselves. "7...6...5..." So much effort had cone into this firing! There had been a team to get together, designs to draw up, fuel to decide upon. When hatred flared up between two members of the team, Gene had gotten them working together again. And now, their reward.... "4..3...2..1.." Gene reached for the red firing button. "Blast Off!" Gene pushed the button....
Rocket Ship Galileo was a 1947 young-adult book by Heinlein about three kids building a rocket, but they do it with their uncle's help, and in the desert. They make it to the moon and discover a Nazi camp up there. It seems a very tenuous match, but I figure I'll mention it on the off chance that you misremember the details.