Popular Mechanics South Africa April 2020

The South African edition of Popular Mechanics was launched in 2002 and has fast become the acknowledged voice of science and technology in South Africa. Underpinning its rich sci-tech content is an ever-changing mix of articles covering everything from automotive news and outdoor adventures to DIY projects. In essence, it explains how our world works

South Africa
RamsayMedia (PTY) Ltd
12 Issues

in this issue

2 min
unknown quantities

IF YOU’RE anything like me, you will know that buying a good-quality used car is no simple feat. I have an enquiring mind, but that can be a burden – the more I discover, the more I want to know. The rabbit-hole effect is real! For example, I learn that I need to consider one thing – perhaps about the frequency of changing a cam belt – and then I’m factoring in the potential future costs associated with every minor- and major service during my likely ownership period of the car. Similarly, tyres are a bigger subject than I could write about on this page alone. Wheel size naturally correlates to tyre size, which in turn has substantial cost implications, unless you’re happy to opt for a no-name (or unknown-name) tyre…

3 min
affordable off-grid solution

WRITE TO US popularmechanics@ramsaymedia.co.za I thoroughly enjoy the magazine and always turn to the letters section first to see comments from the other readers. I read Ian Gilmour’s letter in the recent March issue regarding going off-grid and, although I mostly agree with him, I also have some things I disagree with. I’ve made a few points to elaborate on my thinking: 1. The initial cost of the equipment: Yes, currently this is still high, however, by shopping around, we have been able to install 2 × 5 kVA/4 000 W grid-tied hybrid inverters with 14 × 400 W panels and 12 × 250 Ah batteries. The current from this allows us full autonomy from Eskom for up to 23 hours a day. There are also new companies emerging that do free installation,…

4 min
wildfire rethink

I’ve been studying the recent fires that have swept through Australia, killing so much wildlife and wiping out entire ecosystems in the process. It concerned me so much, I couldn’t help but apply my mind to think of various ways to help firefighters combat such a devastating force. I’m no firefighter, but I made a few observations that raised questions I feel need answering. I thought about it, and after analysing the fires, I came up with some discussion points that could really help matters: First, the sheer size of the flames was too large – some reached almost 20 m! It was discouraging to see a brave firefighter stand with a two-inch pressure hose trying to extinguish or pre-wet the trees enough to stop a wave of blazing fire heading to…

1 min
time machine

1 APRIL 1971 The Incredible Skyshark – First Amphibious Jet The Skyshark was due to become the world’s first amphibious jet, able to land on terra firma and water, and reach cruising speeds of up to 885 km/h at 30 000 feet. Key to its performance would’ve been its telescoping wing, but sadly the project never came to fruition. The full story was featured in this issue, including a schematic of the jet. 2 APRIL 1973 What It Takes to Build and Fly a Radio-Controlled Model Copter Here we dived into the sport of R/C whirlybirding with our kit-built Whirlybird 505. At first, fixed-wing model enthusiasts weren’t impressed with mini helicopters. But popularity grew fast, and ready-to-assemble kits became hot favourites with aviation hobbyists. 3 APRIL 1955 He Irrigates With Clocks Here we met John Gentry, a Texas…

1 min
the bigger picture

US MARINES assigned to the Amphibious Vehicle Test Branch (AVTB) manoeuvre a new amphibious combat vehicle (ACV) on to the well deck of the USS Somerset during late January. This was the first time they had operated the new vehicle while boarding and departing a ship. The Marines of this division have been testing the US Marine Corps’ latest amphibious vehicle, which will soon replace the existing hardware. This test was designed to verify how well the new ACV would integrate with naval shipping operations. DISCLAIMER: THE APPEARANCE OF US DEPARTMENT OF DEFENSE (DOD) VISUAL INFORMATION DOES NOT IMPLY OR CONSTITUTE DOD ENDORSEMENT.…

2 min
how one mathematician solved a 2 000-year -old lens problem

IT’S AN ISSUE that has plagued photography since its creation: blurring, even when everything is in focus. No matter how high-quality the camera is, maths has dictated that the curve of spherical lenses means that rays of light coming through won’t converge on the exact same spot. At least, that was the problem until Rafael G González-Acuña, a doctoral student at Mexico’s Tecnológico de Monterrey, up and solved it. The problem goes back thousands of years to the Greek mathematician Diocles. A contemporary of Archimedes, Diocles wrote a book that was titled On Burning Mirrors, in which he describes what would become known as a ‘spherical aberration’. As light rays fall on a lens, different rays don’t meet in a single focal point. Even the most high-end lenses can’t totally remove…