We take shortcuts all the time with our physical models. We rarely consider that wire has any resistance, for example, or that batteries have a source impedance. That’s fine up until the point that it isn’t. Take the case of the Navy’s Grumman F11F Tiger aircraft. The supersonic aircraft was impressive, although it suffered from some fatal flaws. But it also has the distinction of being the first plane ever to shoot itself down.
So here’s the simple math. A plane traveling Mach 1 is moving about 1,200 km/h — the exact number depends on a few things like your altitude and the humidity. Let’s say about 333 m/s. Bullets from a 20 mm gun, on the other hand, move at more than 1000 m/second. So when the bullet leaves the plane it would take the plane over three seconds to catch up with it, by which time it has moved ever further away, right?
Last year, [Mangy_Dog] was asked by a few friends to consult on a project they were working on. The goal was to build an authentic replica of an F-18 cockpit, apparently for the purposes of creating a film. The project never materialized, but it did inspire him to take a hard look at the 1970s era alphanumeric displays utilized in the real aircraft. One thing lead to another, and he ended up using his own take on the idea to build his own “starburst” digit display.
As [Mangy_Dog] explains, while the faces of these original displays might have been quite small, there was a lot going on behind the scenes. Due to the technical limitations of the time, each alphanumeric character was made up of an array of incandescent light bulbs and fiber optic cables. This worked well enough, but was bulky and complex to manufacture.
Today, we can do better, even on the hobbyist level. As it turns out, 0402 LEDs are just about the right size to recreate the segments of the original starburst displays. So [Mangy_Dog] came up with a simple PCB design to not only align the LEDs properly, but drive them with a 74HC595 shift register and an array of MOSFETs. While assembly wasn’t without its challenges, he made good use of his custom built reflow oven to get all the diminutive components in place.
He went through a few different ideas for the diffuser, but eventually settled on black plastic with tiny holes drilled through courtesy of his laser cutter. Behind each set of three holes is a small pocket that got filled from both sides with transparent UV resin, which was then sanded down after curing. The end result isn’t perfect as you can still tell the center dot is brighter than its peers, but the overall effect is still very nice and definitely has a sort of faux-retro appeal.
The military naturally has access to some incredible technology, though they have a tendency to hold onto it for decades. That an individual with a meager budget and homemade tools can improve upon a piece of hardware installed in a $60+ million airplane is a testament to just how fast things are moving.
The jet engine has a long and storied history. Its development occurred spontaneously amongst several unrelated groups in the early 20th Century. Frank Whittle submitted a UK patent on a design in 1930, while Hans von Ohain begun exploring the field in Germany in 1935. Leading on from Ohain’s work, the first flight of a jet-powered aircraft was in August 27, 1939. By the end of World War II, a smattering of military jet aircraft had entered service, and the propeller was on the way out as far as high performance aviation is concerned.
China’s development of ballpoint pen tips was a national news story in 2017. Source: Xinhua
In the age of the Internet and open source, technology moves swiftly around the world. In the consumer space, companies are eager to sell their product to as many customers as possible, shipping their latest wares worldwide lest their competitors do so first. In the case of products more reliant on infrastructure, we see a slower roll out. Hydrogen-powered cars are only available in select regions, while services like media streaming can take time to solve legal issues around rights to exhibit material in different countries. In these cases, we often see a lag of 5-10 years at most, assuming the technology survives to maturity.
In most cases, if there’s a market for a technology, there’ll be someone standing in line to sell it. However, some can prove more tricky than others. The ballpoint pen is one example of a technology that most of us would consider quaint to the point of mediocrity. However, despite producing over 80% of the world’s ballpoint pens, China was unable to produce the entire pen domestically. Chinese manufactured ballpoint tips performed poorly, with scratchy writing as the result. This attracted the notice of government officials, which resulted in a push to improve the indigenous ballpoint technology. In 2017, they succeeded, producing high-quality ballpoint pens for the first time.
The secrets to creating just the right steel, and manipulating it into a smooth rolling ball just right for writing, were complex and manifold. The Japanese, German, and Swiss companies that supplied China with ballpoint tips made a healthy profit from the trade. Sharing the inside knowledge on how it’s done would only seek to destroy their own business. Thus, China had to go it alone, taking 5 years to solve the problem.
There was little drive for pen manufacturers to improve their product; the Chinese consumer was more focused on price than quality. Once the government made it a point of national pride, things shifted. For jet engines, however, it’s somewhat of a different story.
Aviation instruments are highly interesting pieces of engineering, and it is quite satisfying to watch the often over-engineered mechanisms behind them. If you are into that sort of thing it is worthwhile to check out [Erik Baigar]’s video where he explains the working principle of the attitude indicator from a Tornado jet.
The attitude indicator or artificial horizon of an airplane is one of the most important instruments, especially during poor sight. The ADI42-124 used in the Tornado jet is completely standalone and only needs a DC power supply which is why [Erik Baigar] can show it off while standing on his balcony. At the heart of this instrument is a gyroscope which consists of a spinning disc attached to a gimbal mount. Due to the conservation of angular momentum, the spin axis will always keep its orientation when the instrument is rotated. However, mechanical gyroscopes tend to drift over time and therefore include a mechanism to keep the spin axis upright with respect to the direction of gravity. The ADI42-124 uses an entirely mechanical mechanism for this based on free swiveling weights. Forget everything we said earlier about overengineering as [Erik Baigar] also uncovers a fatal design flaw which leads to the instrument’s self-destruction as shown in the picture here. Unfortunately, this will render most of the units you can buy on eBay useless.
Be sure to check out [Erik Baigar]’s webpage which is nerd paradise for vintage computer and avionics fans or watch another gyroscope teardown.
Air-to-air combat or “dogfighting” was once a very personal affair. Pilots of the First and Second World War had to get so close to land a hit with their guns that it wasn’t uncommon for altercations to end in a mid-air collision. But by the 1960s, guided missile technology had advanced to the point that a fighter could lock onto an enemy aircraft and fire before the target even came into visual range. The skill and experience of a pilot was no longer enough to guarantee the outcome of an engagement, and a new arms race was born.
An F-15 launching flare countermeasures.
Naturally, the move to guided weapons triggered the development of defensive countermeasures that could confuse them. If the missile is guided by radar, the target aircraft can eject a cloud of metallic strips known as chaff to overwhelm its targeting system. Heat-seeking missiles can be thrown off with a flare that burns hotter than the aircraft’s engine exhaust. Both techniques are simple, reliable, and have remained effective after more than a half-century of guided missile development.
But they aren’t perfect. The biggest problem is that both chaff and flares are a finite resource: once the aircraft has expended its stock, it’s left defenseless. They also only work for a limited amount of time, which makes timing their deployment absolutely critical. Automated dispensers can help ensure that the countermeasures are used as efficiently as possible, but sustained enemy fire could still deplete the aircraft’s defensive systems if given enough time.
In an effort to develop the ultimate in defensive countermeasures, the United States Navy has been working on a system that can project decoy aircraft in mid-air. Referred to as “Ghosts” in the recently published patent, several of these phantom aircraft could be generated for as long as the system has electrical power. History tells us that the proliferation of this technology will inevitably lead to the development of an even more sensitive guided missile, but in the meantime, it could give American aircraft a considerable advantage in any potential air-to-air engagements.
On October 24th, 2003 the last Concorde touched down at Filton Airport in England, and since then commercial air travel has been stuck moving slower than the speed of sound. There were a number of reasons for retiring the Concorde, from the rising cost of fuel to bad publicity following a crash in 2000 which claimed the lives of all passengers and crew aboard. Flying on Concorde was also exceptionally expensive and only practical on certain routes, as concerns about sonic booms over land meant it had to remain subsonic unless it was flying over the ocean.
The failure of the Concorde has kept manufacturers and the civil aviation industry from investing in a new supersonic aircraft for fifteen years now. It’s a rare example of commercial technology going “backwards”; the latest and greatest airliners built today can’t achieve even half the Concorde’s top speed of 1,354 MPH (2,179 km/h). In an era where speed and performance is an obsession, commercial air travel simply hasn’t kept up with the pace of the world around it. There’s a fortune to be made for anyone who can figure out a way to offer supersonic flight for passengers and cargo without falling into the same traps that ended the Concorde program.
With the announcement that they’ve completed the initial design of their new Affinity engine, General Electric is looking to answer that call. Combining GE’s experience developing high performance fighter jet engines with the latest efficiency improvements from their civilian engines, Affinity is the first new supersonic engine designed for the civil aviation market in fifty five years. It’s not slated to fly before 2023, and likely won’t see commercial use for a few years after that, but this is an important first step in getting air travel to catch up with the rest of our modern lives.
While most of us will never set foot in a fighter jet, some of us can still try to get as close as possible. One of the most eye-catching features of a fighter jet (at least from the pilot’s point-of-view) is the heads-up display, so that’s exactly what [Frank] decided to build into his car to give it that touch of fighter jet style.
Heads-up displays use the small reflectivity of a transparent surface to work. In this case, [Frank] uses an LED strip placed on the dashboard to shine up into the windshield. A small amount of light is reflected back to the driver which is able to communicate vehicle statues without obscuring view of the road. [Frank]’s system is able to display information reported over the CAN bus, including voltage, engine RPM, and speed.
This display seems to account for all the issues we could think up. It automatically cycles through modes depending on driving style (revving the engine at a stoplight switches it to engine RPM mode, for example), the LEDs automatically dim at night to avoid blinding the driver, and it interfaces with the CAN bus which means the ability to display any other information in the future should be relatively straightforward. [Frank] does note some rough edges, though, namely with the power supply and the fact that there’s a large amount of data on the CAN bus that the Teensy microcontroller has a hard time sorting out.
That being said, the build is well polished and definitely adds a fighter jet quality to the car. And if [Frank] ever wants even more aviation cred for his ground transportation, he should be able to make use of a 747 controller for something on the dashboard, too.
