Time machine: The PM archives are a treasure trove of interesting articles.

1 JANUARY 1941 Army’s ‘Big Bertha’ Cameras Map Huge Areas

Kicking off the new year sky high, we brought you the story of ‘Big Bertha’, a one-metre focal camera used by the US military to photograph and map terrain from an aeroplane. Flying at a height of 6.5 km, the plane was equipped with electrical heating so that pilots and photographers could operate Big Bertha in comfort while peering out of an open window.

2 JANUARY 1929

How Fast Can A Man Fall?

In the late ’20s many questions were being asked about what the maximum velocity of a person falling from a high altitude would be and whether they’d remain conscious. We presented testimonials from airmen who’d parachuted and the military’s response to their experiences. In addition, we conducted experiments and answered those questions.

3 FEBRUARY 1960

Surfacing Rough Lumber

Generally, planing wood isn’t a job that requires its own dedicated piece of machinery (well, that’s what we said back in 1960). Instead, there were a number of accessories for your drill or circular saw to help you get the job done. We explained how these accessories work, while also revealing how best to get a surfacing job done.

4 JANUARY 1968

Rescue from the Deep!

Rescuing the crew of a sinking submarine can be very dangerous, especially as the pressure at a certain depth can start to crush the hull. As a solution, in the late ’60s the US Navy was working on a fleet of Deep Submergence Rescue Vehicles. This edition showed you what these vessels were capable of, and how they went about saving lives.

5 FEBRUARY 1972

Plastic teeth that ‘take root’

False teeth are really costly, uncomfortable and prone to slipping out when chewing or talking. That is why scientists were experimenting with a special permanent implant: A tooth that fools the body into accepting it by way of new bone and tissue growth. We explained how the procedure is conducted.