Boeing unveiled its hydrogen-powered Phantom Eye unmanned airborne system during a ceremony in St. Louis on July 12. The demonstrator, which will stay aloft at 65,000 feet for up to four days, is powered by two 2-liter, four-cylinder engines that provide 150 horsepower each. It has a 150-foot wingspan, will cruise at approximately 150 knots and can carry up to a 450-pound payload.
Pay attention to the comments about the two Ford 4-cylinder truck engines
A contribution from Jerry NC USA