Although a lot of tools have been digitized and consolidated into our smartphones, from cameras, music players, calendars, alarm clocks, flashlights, and of course phones, perhaps none are as useful as the GPS and navigational capabilities. The major weakness here, though, is that this is a single point of failure. If there’s no cell service, if the battery dies, or you find yourself flying a bomber during World War II then you’re going to need another way to navigate, possibly using something like this Astro Compass.

The compass, as its name implies, also doesn’t rely on using the Earth’s magnetic field since that would have been difficult or impossible inside of an airplane. Instead, it can use various celestial bodies to get a heading. But it’s not quite as simple as pointing it at a star and heading off into the wild blue yonder. First you’ll need to know the current time and date and look those up in a companion chart. The chart lists the global hour angle and the declination for a number of celestial bodies which can be put into the compass. From there the latitude is set and the local hour angle is calculated and set, and then the compass is rotated until the object is sighted. After all of that effort, a compass heading will be shown.

For all its complexity, a tool like this can be indispensable in situations where modern technology fails. While it does rely on precise tabulated astrometric data to be on hand, as long as that’s available it’s almost failsafe, especially compared to a modern smartphone. Of course, you’ll also need a fairly accurate way of timekeeping which can be difficult in some situations.

When it comes to aviation curiosities, few machines captivate the imagination like the Fairey Rotodyne. This British hybrid aircraft was a daring attempt to combine helicopter and fixed-wing efficiency into a single vehicle. A bold experiment in aeronautical design, the Rotodyne promised vertical takeoffs and landings in cramped urban spaces while offering the speed and range of a regional airliner. First flown in 1957, it captured the world’s attention but ultimately failed to realize its potential. Despite featured before, new footage keeps fascinating us. If you have never heard about this jet, keep reading.

The Rotodyne’s innovative design centered around a massive, powered rotor that utilized a unique tip-jet system. Compressed air, mixed with fuel and ignited at the rotor tips, created lift without the need for a tail rotor. The result: a smoother transition between vertical and forward flight modes. Inside, it offered spacious seating for 50 passengers and even had clamshell doors for cargo. Yet its futuristic approach wasn’t without drawbacks—most notably, the thunderous noise produced by its rotor jets, earning complaints from both city planners and residents.

Despite these hurdles, the helicopter-plane crossover demonstrated its versatility, setting a world speed record and performing groundbreaking intercity flights. Airlines and militaries expressed interest, but escalating development costs and noise concerns grounded this ambitious project.

To this day, the Rotodyne remains a symbol of what could have been—a marvel of engineering ahead of its time. Interested in more retro-futuristic aircraft tales? Read our previous story on it, or watch the original footage below and share your thoughts.