Tom Swift Young Inventor #4 Rocket Racers by Victor Appleton*

My third grader read this book to himself.
Tom and his friends, Yo and Bud, are competing in a rocket racer competition with Tom's new rocket-powered plane-Swift-Racer.
As the competitors practice, planes begin crashing.  Tom thinks someone is behind the disaster, not just random crashes.
A few times I heard my son chuckling while reading this book.
*Highly recommend.
*Borrowed from the library.