Popular Mechanics May 2018

I’M SITTING ON a train right now. (Probably not anymore, but when I wrote this I was.) I’m reading in the paper about the recent crash of a sightseeing helicopter. Five people died. The passengers were in harnesses so that they could dangle out the doors to take photographs. The victims apparently weren’t told in detail where the safety knife was in the event that they needed to cut themselves loose from those harnesses, and they were dragged to their deaths, unable to escape. Deep breath. Exhale. You just never know, do you. There is no bright side to this kind of story. Later today, however, after I get off this train I’m no longer riding, the Popular Mechanics staff will be finishing up the issue you’re now holding. It includes 14 pages of…

SINCE 1902 IT'S FOCUSED ON SCIENCE & TECHNOLOGY & NEW INNOVATIONS LIKE CARS & TV PM ONLINE Do you know the answer to this Jeopardy question? (Or is it the question to this Jeopardy answer?) You’re reading it. We loved the Popular Mechanics shout-out on our favorite game show, but it got us thinking: Who writes these questions, anyway? So we talked to head writer Billy Wisse, who’s been working on the show more than 25 years. Check out the interview exclusively at popularmechanics.com/jeopardy. THE PODCAST The hosts of the Most Useful Podcast Ever are trying to put you to sleep—but not while listening. At night, when you’re supposed to. Hosts Jacqueline Detwiler and Kevin Dupzyk are testing smart white-noise machines, spiky sleep mats, and other weird gadgets that promise to help you sleep…

WHEN THE HUBBLE Space Telescope launched in 1990, becoming the first truly powerful telescope not handicapped by interference from Earth’s atmosphere, there were nine known planets. In the entire universe. One of which would turn out not to be a planet. (Sorry, Pluto.) Today we know of about 3,700, and, while most weren’t found by Hubble, in retrospect it was the beginning of a sequence of missions, which NASA formalized as the Exoplanet Exploration Program in 2009 (planets outside our solar system are called extrasolar planets, or exoplanets for short), that are exploding our conception of how crowded space may be. Pending final preparation of its Falcon 9 launch vehicle, the Transiting Exoplanet Survey Satellite will have departed Cape Canaveral by June. Smaller than a Smart car, it’s a modest satellite…

BLUE ORIGIN STARTED work on its next-generation BE-4 engine in 2011. It wasn’t revealed to the public for three years. News of the BE-4 is always sparse. Last October, after the first test, at 50 percent thrust, Blue Origin tweeted a six-second-long video. In January, it was 13 seconds after another crucial test. In the private space industry, where companies tend to present themselves with style and panache, Blue Origin has always been the quiet one. So the BE-4 project is worth a close look, because it offers clues to where Blue Origin is at as a company — and because it’s helping solve a national security issue. Blue Origin announced the BE-4 in 2014 when the company won a contract with United Launch Alliance to supply the engines for its…

WET MANGROVES LINE the rivers that meet the ocean along Colombia’s Pacific coast. The dense tropical canopy beneath them makes for stifling heat—and the per fect cover from prying U.S. satellites. For the past 25 years, drug smugglers have hidden entire manufacturing operations beneath these trees. Not drug-manufacturing operations—they’re making submarines. In the middle of the jungle. And, for the first time ever, they’ve gone electric. Last summer, the Colombian military captured a drug sub powered by smaller, quieter electric engines and more than 100 batteries. At the building sites, smugglers ferry in thousands of pounds of materia ls, a labor force, and, sometimes, Russian submarine designers. They construct subs up to 100 feet long, typically made of wood, fiberglass, and Kevlar to avoid radar detection, and capable of carrying as…

askroy@popularmechanics.com @askroypm If I switch from bagging my grass clippings to mulching them, do I need a new blade? James C., Belmont, Massachusetts There are three basic blade types, and many hybrids: standard for side-discharging clippings, mulching for recirculating clippings back into the lawn, and high-lift for bagging. Blade shape, profile, and curvature on the blade’s back edge determine performance. At this point, manufacturers have engineered blades that handle two or three operations very well, if not perfectly. That way, if the homeowner does change his mind—as you have—in most cases he doesn’t need to also change his blade. Assuming your blade is sharp and balanced, many times all you need to do is adjust two variables on your mower: 1. Raise the deck to an appropriate level relative to grass type and height, while…