This classic poster from the 1930s celebrates the four engines on the Handley Page H.P.42 ‘Heracles’ airliner of Imperial Airways. Back then, engine reliability (from your family car to an aero engine: pre-space travel, the latter was one of the most advanced forms of technology) was nothing like the ‘turn key’ and never open the bonnet / hood of today’s internal combustion engines.

But we’re here for the illustration. Note the way the artist’s ‘shimmer’ of the propellers isn’t the ‘normal’ we’re used to, our ‘normal’ actually being a function of images taken by cameras. It’s cool enough a painting, though, for several online retailers to offer it for your modern wall. Poster by V.L. Danvers, 1938. Other versions on French, German and Italian.

Imperial managed an enviable record with the HP-42s, without any passenger deaths in the type, but forced landings, even between the proximate, London (Croydon airport) and Paris (le Bourget airport) weren’t that rare – the four engines were all needed to be working on most flights, and if one played up, a landing was going to be needed soon.

Interestingly, we don’t have advertising for the modern equivalent. A few decades ago, ‘big’ international airliners had four engines, but today, the majority have two high-bipass jet turbines, thanks to the operational and statistical success of ETOPS, or, its original name, ‘Extended Range Operation with Twin-Engine Aeroplanes’. It’s complicated, but in short, that’s the process that means airlines are happy it’s OK to fly a long way (over water and big rocks) because two engines are reliable enough and there’s a safety margin good enough to bring their customers back to earth safely.

That said, in notable contrast to ‘four engines for safety’, airlines haven’t been that keen in advertising ‘two engines better’ because it doesn’t ‘fly’ as an improvement in human risk perception.

Imperial emphasised the four engines in 1936 in their monoplane landplane. Perhaps because they were also using the biplanes and didn’t want to highlight the contrast.

James Kightly, Vintage Aero Writer.

But wait, there’s more, see here! Reference: ‘Riding the Skies – Classic Posters from the Golden Age of Flying’ Intro by Jan Morris, Bloomsbury, 0747503370.