Indholdsfortegnelse for May/June 2025 i Popular Mechanics

THE CHILDREN OF CONVICTED SKYJACKER Richard McCoy II believe their dear old dad may have been D.B. Cooper, the notorious central figure in 1971’s unsolved skyjacking. It’s in fact the only one in U.S. history without an answer—until, perhaps, now. Just months after the Cooper incident, McCoy was convicted of an incredibly similar skyjacking that also included a parachute jump. His children, Chanté and Richard III (Rick), have long thought the clues added up. They may now have evidence to back up their suspicions. Chanté and Rick had kept quiet out of consideration for their mother, Karen, who they believed was potentially complicit in both crimes. But as both parents are now deceased, the opportunity arose for the siblings to come forward with their suspicions. And, crucially, they seem to…

CLEAN YOUR FILTER A typical residential central air conditioner moves something like 350 to 400 cubic feet of air per minute per ton of capacity (and residential air tonnage varies between 1.5 and 5 tons, typically). That air filter is the last line of defense to clean air that’s emitted from the appliance. If the filter is dirty, it will cause the appliance to work harder than it should. Any air conditioner in a garage, shop, or industrial work environment will become dirty very quickly. In that case, the appliance or its filter may need weekly attention to keep it clean and working properly. Most filters are washable, but keep in mind that not all last a lifetime. A/C filters should be cleaned monthly at a minimum—and that’s during the…

1750 1758 Benjamin Franklin and professor John Hadley of Cambridge University discover that evaporation of alcohol and other volatile liquids, which evaporate faster than water, can cool down an object enough to freeze water. 1800 1830s At the Florida hospital where he works, Dr. John Gorrie builds an ice-making machine that uses compression to make buckets of ice and then blows air over them. He patents the idea in 1851, but without any financial backing, his dream melts away. 1850 1881 After an assassin shoots President James Garfield on July 2, naval engineers build a boxy makeshift cooling unit to keep him comfortable. The device is filled with water-soaked cloth, and a fan blows hot air overhead and keeps cool air closer to the ground. While this device can lower…

YOU DON’T NEED to be a sommelier or an oenophile to enjoy a bottle of wine. Similarly, you don’t need to be an expert woodworker to build this tabletop wine rack and display your favorite brands or varieties. You don’t need any special tools, and you can easily customize it to suit your style or space. Make it smaller to fit on your counter and under cabinets, choose a lighter or darker species of wood, or select a different type of finish—the choices are yours. Here, we’ll show you the basics of how we built ours. GETTING STARTED 1 CUT PARTS You can use just about any species of wood, as long as you have a board about 8 inches wide by 36 inches long by 1 inch thick. We used…

OVER THE YEARS, WE’VE DUG UP A LOT of stuff buried underneath layers upon layers of ice. Ancient tools, animal corpses, World War II planes—you name it, ice has buried it, and we’ve found it. During a 2024 flight over the Greenland Ice Sheet, NASA scientist Chad Greene added a pretty surprising entrant to that list: a classified military base. Built in secret between June of 1959 and October of 1960 by the U.S. Army Corps of Engineers, Camp Century—also known as the “city under the ice”—comprised 21 underground tunnels spanning 9,800 feet, according to the website Interesting Engineering. In radar images of the site, Greene said, many of the base’s individual structures are clearly discernible. The camp was built from 6,000 tons of material transported via heavy bobsleds that topped…

IT WOULD PROBABLY BE PRETTY ALARMING to learn that, in the early 1980s, scientists decided to drop off a bunch of gophers at the site of a volcanic eruption. But don’t worry, it’s not as bad as it sounds. In fact, according to a new report from the University of California, this particular gopher–volcano encounter proved to be such a net positive that its effects are still being felt 40 years later. It started with the eruption of Mount St. Helens in May 1980. It was the most destructive volcanic event in American history, claiming 57 lives and causing staggering ecological damage. Faced with a devastation that would take the local environment a substantial amount of time to recover from, scientists were open to unorthodox ideas that might speed the process…

All air conditioners pull warm and humid indoor air over a coil of cold tubing. The moisture vapor suspended in the air condenses on the coil. The resulting liquid water, called condensate, drips off the coil into a pan underneath it and drains down a pipe. A backed-up drain can cause significant damage to your heating, ventilation, and air conditioning (HVAC) system, says Pat Porzio, owner of Dayspring Home Inspections in northern New Jersey. The first thing you want to do is find where the drainpipe ends—it differs for various units. If your A/C is located in the attic, for example, your pipe drains into your gutters. But it can also connect to your sink drain or be located outside your house. You should never see any liquid coming out…

Contrary to popular belief, A/C systems don’t make cold air. “You’re not adding cooling, you’re removing heat,” says Craig Bradshaw, executive director of the Air Conditioning and Refrigeration Center at the University of Illinois Urbana-Champaign. All air conditioners pump a refrigerant fluid (which absorbs heat) through a series of coils to move heat from one location to another. One end of the system compresses the refrigerant into a liquid while the other end allows it to expand into a vapor. The aim is to create two zones: the hot zone (where the condenser moves heat outside) and the cold zone (where the evaporator moves cool air inside).…

WINDOW LOGIC → This may seem obvious, but the very best way to cool down a room is to block the sun’s solar heat before it enters your home. Here’s how: In the morning, shut all the windows that face east and south; be sure to draw the curtains and lower the blinds, too. Then, open all the windows on the west and north sides of the house. That will help block out the sun, yet still allow fresh, cooler morning air to enter rooms. In the late afternoon—when the outside temperature drops below the temperature inside your home—reverse the morning routine. Open the windows on the east and south sides of the house, and close the windows on the north and west sides. This is important because once the…

ALTHOUGH ONLY ONE SPECIES OF hominin exists on the planet today—good ol’ Homo sapiens—the human family once comprised a complex tableau of members. And over the years, scientists have tried to get a clearer picture of that prehistoric story by excavating ancient human sites around the world. Now, anthropologists from the Chinese Academy of Sciences and the University of Hawai’i are illustrating a previously unknown—or, rather, uncategorized—chapter of that story with the introduction of a new human species, H. juluensis. H. juluensis—also known as “large head people”—thrived in eastern Asia from 300,000 years ago to around 50,000 years ago, when the species died out. According to the researchers, this group likely hunted wild horses, fashioned stoned tools, and even processed animal hides to survive frigid winters. Christopher Bae from the University…

For the exterior unit (sometimes also called the condenser) to work properly, it needs an unobstructed flow of air around it. Make sure there is at least two feet of clear space around the unit, free of shrubs, wood piles, and low-hanging branches. The condenser’s fan spent all of last summer sucking air, leaves, debris, and pollen into it. To prep it for the upcoming season, use a wet/dry vacuum and then spray it down with a garden hose. Manufacturers recommend using nothing more powerful than water from a garden hose.…

Cooling your house sucks up a lot of energy, and the Department of Energy (DOE) says you can slash about 3 percent off your energy bill for every degree you raise your central air’s temperature. Here’s how to not go overboard with your A/C in the summer. SET THE TEMPERATURE RIGHT → Consumer Reports via Energy Star, a joint program from DOE and the Environmental Protection Agency (EPA), recommends the following settings: ▶ 78°F when you’re home ▶ 85°F when you’re at work or away ▶ 82°F when you’re sleeping Economically and environmentally, an 82-degree bedroom checks out. From a comfort standpoint? Not so much. For the best A/C temperature for sleeping, the National Sleep Foundation says your bedroom should be somewhere between 60 and 67 degrees for optimal snoozing,…

Sixty-six-year-old Brian Benadom’s heart stopped on a Sunday evening, and it took paramedics 25 minutes to get it beating again. He is unconscious, eyes closed, with a breathing tube taped to his mouth by the time his older brother, David, reaches the emergency department at Mercy San Juan Medical Center in Carmichael, California. After speaking with the doctor, David understands that Brian, who had lived with Parkinson’s disease for years, is gone. But doctors can be wrong, he thinks. By morning, however, an electroencephalogram reveals minimal electrical activity in Brian’s brain, and further tests show his kidneys are shot. He isn’t coming back. Brian had never wanted to talk about the end of his life and had no living will. But David, 74, wants for his brother what he wants…

PENNY CHLEBOWY WAS living in the Washington, D.C., area in 1987 when she received the first phone call. A traveling saleswoman for AT&T, Penny loved her work. “It was blast,” she recalls. “I mean, I was young and thin and beautiful. [I] had a really good job, drove a really nice car… Life was good.” She had made it out of Bradford, Pennsylvania, a once-booming oil town that had become a blue-collar factory town where everyone knew everyone else’s business. Her older sister, Cindy, had stayed in Bradford, though. So had their younger teenage brother, Al, along with their father, Dale. But now, it seemed, Dale had vanished. Dale Kerstetter, 50, had reported for his shift as a security guard at Corning Glass Works on Saturday, September 12, at 10:30…