Ejector Seats: The Rocket Chairs That Save Lives

Once upon a time, escaping an aircraft was a tricky business. You had to unstrap yourself, fling open a heavy glass canopy, and try to wrench yourself out of a small opening without getting smacked by the tail or chopped up by the propeller. Many pilots failed this difficult task, to the tragic loss of their lives.

Eventually, the human cost was heavy enough and militaries grew strained at having to train new pilots to replace the experienced ones lost to accidents and enemy fire. The ejection seat was developed to make escaping a plane as simple as tucking yourself in and pulling a big red handle. Let’s dive in and learn how it came to be.

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A Look Inside A Vintage Aircraft Altimeter

There’s a strange synchronicity in the projects we see here at Hackaday, where different people come up with strikingly similar stuff at nearly the same time. We’re not sure why this is, but it’s easily observable, with this vintage altimeter teardown and repair by our good friend [CuriousMarc] as the latest example.

The altimeter that [Marc] dissects in the video below was made by Kollsman, which is what prompted us to recall this recent project that turned a jet engine tachometer into a CPU utilization gauge. That instrument was also manufactured by Kollsman, but was electrically driven. [Marc]’s project required an all-mechanical altimeter, so he ordered a couple from eBay.

Unfortunately, thanks to rough handling in transit they arrived in less than working condition, necessitating the look inside. For which we’re thankful, of course, because the guts of these aneroid altimeters are quite impressive. The mechanism is all mechanical, with parts that look like something [Click Spring] would make for a fine timepiece. [Marc]’s inspection revealed the problem: a broken pivot screw keeping the expansion and contraction of the aneroid diaphragms from transmitting force to the gear train that moves the needles. The repair was a little improvisational, with 0.5-mm steel balls used to stand in for the borked piece. It may not be flight ready, but it worked well enough to get the instrument back in action.

We suspect that [Marc] won’t be able to leave well enough alone on this one, so we’ll be on the lookout for a proper repair. In the meantime, he’ll be able to use this altimeter in the test setup he’s building to test a Bendix air data computer from a 1950s-era jet fighter. Continue reading “A Look Inside A Vintage Aircraft Altimeter”

Interfacing An Old Engine Cowl Flaps Indicator To USB

[Glen Akins] had a WW2-era aircraft engine cowl flap indicator lying around (as you do) and thought it would make a jolly fine USB-attached indicator. The model in question is a General Electric model 8DJ4PBV DC Selsyn, which was intended for four-engined aircraft. For those not familiar with the purpose [Glen] explains in his detailed writeup, that piston-engine aircraft of that era were air-cooled, and during conditions of maximum engine power — such as during take-off — flaps on the side of the engine cowling could be opened to admit additional cooling airflow. These indicator dials were connected to a sender unit on each of the flap actuators, providing the pilots an indication of the flaps’ positions. Continue reading “Interfacing An Old Engine Cowl Flaps Indicator To USB”

Rubber Band Behemoth Winds Its Way Toward World Record

Egged on by adoring fans who demanded more aircraft videos, [ProjectAir] has decided to break the world record for rubber band powered aircraft… despite having never built a rubber band powered aircraft. Why rubber band power?

Before little two stroke motors became affordable, and long before electric motors and batteries were remotely possible, there weren’t a lot of options for powering your model aircraft. One technology that really took off was that of rubber band power. By winding a rubber band, it could store enough energy to turn a propeller for a short duration. With a 10 foot model taking the current world record, as you can see in the video below the break [ProjectAir] decided to see if he could beat it.

Rubber Band Powered Free Flight c1915 By Unknown author

Starting with a successful free flight aircraft made of foam board, [ProjectAir] simply scaled it up to an eleven foot wing- one foot larger than the ten foot world record holder. Since there were now eight rubber band motors, a mechanism was created to release the propellers in sync, but this was problematic. Eventually a slightly heavy but solid solution was found.

[ProjectAir] did more testing, more problem solving, and through rapid iterations, he eventually was able to have a successful flight under radio control. His personal goal of a 12 second flight was exceeded, and then Guinness called! They’re interested in certifying his attempt as long as his plane can fly for at least 30 seconds- almost double his current ability. What will he do? Check the video, too, for [ProjectAir]’s challenge to the community to join him in trying to beat the world record. Sounds like fun!

Aside from powering world record attempting radio controlled aircraft, did you know that you can build a rubber band powered refrigerator? It’s true!

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Ugliest Airplane Ever Built Predicted The Future

The airplane that many called “the flying barrel” is also widely considered the ugliest plane ever built. However, [Dark Skies] in the video you can see below argues that the Stipa-Caproni was the direct predecessor of the turbofan engine. Either way, it is an interesting and unique part of aviation history.

The plane was built in the days when inventors were experimenting with many different ways to improve aircraft utility and performance. In this case, the inventor built an “intubated propellor” which used a prop to draw air through a venturi tube in an effort to improve engine efficiency. The 570kg vehicle had a wingspan of just over 14 meters and was a bit more than 6 meters long. It could reach about 72 knots and climb to over 3 km.

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Is There A Simpler Aircraft Than This Electric Paramotor?

The dream of taking to the air has probably ensnared more than a few of us, but for most it remains elusive as the safety, regulatory, and training frameworks surrounding powered flight make it not an endeavour for the faint-hearted. [Justine Haupt] has probably delivered the simplest possible powered aircraft with her Blimp Drive, a twin-prop electric add-on for her paragliding rig that allows her to self-launch, and to sustain her flights while soaring.

It takes the form of a carbon-fibre tube with large drone motors and props U-bolted to each end, and a set of brackets in the centre of laid carbon fibre over 3D-printed forms to which the battery and paraglider harness are attached. The whole thing is lightweight and quiet, and because of the two contra-rotating propellers it also doesn’t possess the torque issues that would affect a single propeller craft.

We’re not fliers or paragliders here at Hackaday, so our impression of the craft in use doesn’t come from the perspective of a pilot. But its simplicity and ease of getting into the air looks to be unmatched by anything else, and we have to admit a tinge of envy as in the video below the break she flies over the beach that’s her test site.

If you recognise Justine from past Hackaday articles, you’re on the right track. Probably most memorable is her rotary cellphone.

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New Engines Could Propel The B-52 Beyond Its 100th Birthday

First taking to the skies in April 1952, and introduced into the US Air Force in 1955, the B-52 Stratofortress has since become a mainstay of American air power. Originally developed as a nuclear bomber to carry out the critical deterrence role, changing realities saw it delivering solely conventional munitions in actual operations.

Of 744 B-52s originally built, 76 remain in service with the Air Force and Air Force Reserve. This fleet is set to go on flying beyond the type’s 100th birthday, into 2050 and beyond. To reach that milestone, a new engine package will be key to keeping these birds in the air.

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