Between trapshooting and earning a merit badge in ham radio operation, Bobby Minehart, 16, managed to find time last week to amaze NASA scientists and take home the grand prize in the Arts and Science Expo at the National Scout Jamboree.

For this, Minehart, of Sterling, won an iPod. It is not the first or best thing he's won. Over three years of working on the same project, Minehart has trounced competition in regional and international science fairs. In May, he won three awards -- including an $8,000 scholarship -- at the Intel International Science and Engineering Fair in Phoenix.

His topic, he acknowledges, is complicated for lay people. This year, he strove to determine how to stabilize rocket torpedoes. His conclusion: micro-foils -- two bent, wing-like attachments on the torpedo.

In announcing Minehart's victory, Scout officials said he "wowed the NASA judges."

"I think they said they were impressed," said Minehart, who attends Dominion High School. This month, he will start his senior year in the first class at Loudoun County's Academy of Science, which will be housed at Dominion and draw students from high schools countywide.

Minehart took the project -- which involves plastic tubing, a .30-caliber bullet fashioned to simulate a torpedo and a wooden test chamber that took him and his father, Robert, six months to build -- to the jamboree in a shiny wooden case. As at other science fairs, he set up the device on a table and tried his best to describe it to the judges and simplify it for other Scouts.

During the rest of the 10-day campout, he delved into the jamboree's outdoor activities with nearly 32,000 other Scouts from around the nation. Minehart, who has been in the Boy Scout movement for 10 years, said he especially took to the Army adventure area, which included jumps off high platforms into nets. "Almost every guy likes doing that," Minehart said.

Minehart said he has long had a passion for science and math, partly because he is dyslexic and reading can be a challenge. Inspiring teachers help, he said, as do the books his father, a mechanical and electrical engineer for the federal government, has at home. His father's books offer better explanations than textbooks, Minehart said.

The torpedo project began with an idea Minehart got from the magazine Scientific American. He turned that into a science fair entry in 2003 and has expanded on it since, never growing weary of it, he said.

Even when doing other things -- such as rock climbing or wrestling for the Dominion varsity team, which he captains -- he is thinking about the torpedo research, he said. Well, usually.

"Right now, I should be thinking about it," he said. "But it's summertime."

His torpedo research is not necessarily a conversation starter with friends, in large part because it is so complex, he said. When pals ask about it, he slows down his naturally quick rate of speech and uses drawings to explain. Usually they are more interested in what he has won, he said.

A year from now, Minehart said, he hopes to be starting mechanical or aerospace engineering studies at the Massachusetts Institute of Technology or the U.S. Naval Academy. That is the plan for now, at least.

"I'm getting a lot of 'What are you going to do after high school?' " he said. The NASA judges asked, too.

For now, he is finishing up his Eagle Scout project, which has nothing to do with torpedoes. He is designing a picnic area -- and building five tables for it -- next to the football field at Dominion. And he is thinking about improving the torpedo project. When asked why he did not try to patent previous ideas connected with the project, he said it was because those ideas were "pretty basic."

"But this new idea . . . I think it will be a better idea," he said.

Bobby Minehart, winner of the grand prize in the Arts and Science Expo at the National Scout Jamboree.