Vanquish Your Foes With Lego Playing Card Machine Gun

March 7, 2020 by Jenny List 14 Comments

There was something exceptionally satisfying about those playground games of cops and robbers when we were young, but they were missing something in that a pretend gun made with your fingers lacks a certain Je ne sais quoi. Our youthful blood-lust demanded something a bit more real, and though the likes of NERF and other toys could supply it their lost projectiles came at a price not all parents could sustain. We’d have given anything for [Brick Experiment Channel]’s rapid-firing Lego playing card gun! (Video, embedded below.)

The principle is simple enough, one of the larger Lego road wheels is spun up to a respectable speed through a gear train from a pair of motors, it’s positioned over a channel through which playing cards are fed, and it picks each one up and accelerates it to a claimed 20 miles per hour. The card is fired off into the distance, ready to take down your Lego figure or plastic drinking cup enemies with maximum prejudice.

It’s clear some significant thought has gone into the firing platform design, with the cards sliding along smooth rails and the wheel sitting in a gap between the rails so that the natural springiness of the card can engage with it. The cards also emerge with a spin, due to the wheel being offset. The mechanism is completed with a third motor which acts as a feeder pushing individual cards from the deck into the main firing platform. This achieves an astonishing six cards per second, as can be seen in the video below the break.

We can see that this is a huge amount of fun, and we hope should any youngsters get their hands on it that there are not lurid tales of kids with playing card injuries. It’s not the first novelty projectile gun we’ve brought you, there have been numerous rubber band guns but our favourite is the automatic paper plane folder and launcher.

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US Navy Looking To Retire Futuristic Prototype Ships

March 5, 2020 by Tom Nardi 91 Comments

From the Age of Sail through to the Second World War, naval combat was done primarily in close quarters and with cannons. Naturally the technology improved quite a bit in those intervening centuries, but the idea was more or less the same: the ship with the most guns and most armor was usually the one that emerged victorious. Over the years warships became larger and heavier, a trend that culminated in the 1940s with the massive Bismarck, Iowa, and Yamato class battleships.

But by the close of WWII, the nature of naval combat had begun to change. Airplanes and submarines, vastly improved over their WWI counterparts, presented threats from above and below. A few years later, the advent of practical long-range guided missiles meant that adversaries no longer had to be within visual range to launch their attack. Going into the Cold War it became clear that to remain relevant, warships of the future would need to be smaller, faster, and smarter.

It was this line of thinking that lead the US Navy to embark on the Littoral Combat Ship (LCS) program in the early 2000s. These ships would be more nimble than older warships, able to quickly dash through shallow coastal waters where adversaries couldn’t follow. Their primary armament would consist of guided missiles, with fast firing small-caliber guns being relegated to defensive duty. But most importantly, the core goal of the LCS program was to produce a modular warship.

Rather than being built for a single task, the LCS would be able to perform multiple roles thanks to so-called “mission modules” which could be quickly swapped out as needed. Instead of having to return to home port for a lengthy refit, an LCS could be reconfigured for various tasks at a commercial port closer to the combat area in a matter of hours.

A fleet of ships that could be switched between combat roles based on demand promised to make for a more dynamic Navy. If the changing geopolitical climate meant they needed more electronic reconnaissance vessels and fewer minesweepers, the Navy wouldn’t have to wait the better part of a decade to reshuffle their assets; the changeover could happen in a matter of weeks.

Unfortunately, the Littoral Combat Ships have been plagued with technical problems. Citing the expensive refits that would be required to keep them operational, the Navy is now looking at retiring the first four ships in the fleet, the newest of which is just six years old.

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Stinger: The Hacked Machine Gun Of Iwo Jima

February 3, 2020 by Tom Nardi 55 Comments

During the Second World War, the United States was pumping out weapons, aircraft, and tanks at an absolutely astonishing rate. The production of military vehicles and equipment was industrialized like never before, and with luck, never will be again. But even still, soldiers overseas would occasionally find themselves in unique situations that required hardware that the factories back at home couldn’t provide them with.

Which is precisely how a few United States Marines designed and built the “Stinger” light machine gun (LMG) during the lead-up to the invasion of Iwo Jima in 1945. The Stinger was a Browning .30 caliber AN/M2, salvaged from a crashed or otherwise inoperable aircraft, that was modified for use by infantry. It was somewhat ungainly, and as it was designed to be cooled by the air flowing past it while in flight, had a tendency to overheat quickly. But even with those shortcomings it was an absolutely devastating weapon; with a rate of fire at least twice that of the standard Browning machine guns the Marines had access to at the time.

Six Stingers were produced, and at least on a Battalion level, were officially approved for use in combat. After seeing how successful the weapon was during the invasion of Iwo Jima, there was even some talk of putting the Stinger into larger scale production and distributing them. But the war ended before such a plan could be put into place.

As such, the Stinger is an exceedingly rare example of a field modified weapon that was not only produced in significant numbers, but officially recognized and even considered for adoption by the military. But the story of this hacked machine gun actually started years earlier and thousands of kilometers away, as Allied forces battled for control of the Solomon Islands.

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This Crossbow Fires Cannonballs!

January 31, 2020 by Jenny List 9 Comments

The would-be invader of a mediaeval kingdom could expect to face some stern opposition from a variety of formidable weaponry. Making modern versions of these deadly curiosities seems to be a popular pursuit, and the bug has bitten [Turbo Conquering Mega Eagle], who’s created what he calls a “Stonebow”, a crossbow on steroids that fires stones or large ball bearings with considerable force.

It uses a couple of leaves from automotive springs, mounted in a welded steel riser with two strings and a pouch for the projectile. The barrel is an oak fencing post, and at its other end is a cocking lever which also forms a stock, and a cleverly designed trigger mechanism. The projectile is loaded, the bow is cocked, and it is fired at a scrap Land Rover radiator in which it places a satisfying impact mark.

Despite two successful firings it’s evident that so much force isn’t easy to contain. The crimps that secure the strings aren’t up to the job, and neither is the oak fence post, which has cracked at the end. We trust that our Essex hacker friend will return having fixed these flaws, and more defenceless scrap car parts will be sacrificed for our entertainment.

We’ve featured [Turbo Conquering Mega Eagle] before, most recently building a mini-bike for his youngsters. Meanwhile, enjoy the Stonebow in the video below the break.

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Bullet-proofing Your Car With An Affordable Composite Armor

January 18, 2020 by Sharon Lin 35 Comments

Remember those actions movies like The Fast and the Furious where cars are constantly getting smashed by fast flying bullets? What would it have taken to protect the vehicles from AK-47s? In [PrepTech]’s three-part DIY composite vehicle armor tutorial, he shows how he was able to make his own bulletproof armor from scratch. Even if you think the whole complete-collapse-of-civilization thing is a little far-fetched, you’ve got to admit that’s pretty cool.

The first part deals with actually building the composite. He uses layers of stainless steel, ceramic mosaic tiles, and fiberglass, as well as epoxy resin in order to build the composite. The resin was chosen for its high three-dimensional cross-linked density, while the fiberglass happened to be the most affordable composite fabric. Given the nature of the tiny shards produced from cutting fiberglass, extreme care must be taken so that the shards don’t end up in your clothes or face afterwards. Wearing a respirator and gloves, as well as a protective outer layer, can help.

After laminating the fabric, it hardens to the point where individual strands become stiff. The next layer – the hard ceramic – works to deform and slow down projectiles, causing it to lose around 40% of its kinetic energy upon impact. He pipes silicone between the tiles to increase the flexibility. Rather than using one large tile, which can only stand one impact, [PrepTech] uses a mosaic of tiles, allowing multiple tiles to be hit without affecting the integrity of surrounding tiles. While industrial armor uses boron or silicon carbide, ceramic is significantly lower cost.

The stainless steel is sourced from a scrap junkyard and cut to fit the dimensions of the other tiles before being epoxied to the rest of the composite. The final result is allowed to sit for a week to allow the epoxy to fully harden before being subject to ballistics tests. The plate was penetrated by a survived shots from a Glock, Škorpion vz. 61, and AK-47, but was penetrated by the Dragunov sniper rifle. Increasing the depth of the stainless steel to at least a centimeter of ballistic grade steel may have helped protect the plate from higher calibers, but [PrepTech] explained that he wasn’t able to obtain the material in his country.

Nevertheless, the lower calibers were still unable to puncture even the steel, so unless you plan on testing out the plate on high caliber weapons, it’s certainly a success for low-cost defense tools.

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Catapult Your Best Wishes With This 3D-Printable Card

January 1, 2020 by Jenny List 12 Comments

It’s the season to be surrounded by greeting cards of all shapes and sizes from friends old and new. News of their families and achievements, reminders that they exist, and a pile of cards to deal with sometime in January. Wouldn’t it be great if you could send something with a little more substance, something your friends would remember, maybe even hang on to?

[Brian Brocken]’s 3D-printed Da Vinci catapult kit may not fill that niche for everyone, but we can guarantee it will be a talking point. The Da Vinci catapult design uses a pair of springs similar to an archer’s bow, to unwind a pair of ropes and thus turn the shaft upon which the catapult shaft itself is fitted. All these components are mounted in a single piece with sprues similar to an injection moulded model kit, allowing the whole to easily be posted in an envelope.

The parts are all available to print separately among the files on the Thingiverse page for those with no need to mail them. For the casual spectator he’s made a YouTube video that we’ve placed below the break, detailing the design and build process as well as showing the device in use.

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How Ammo Temperature Will Affect Shooting Accuracy

November 5, 2019 by Pat Whetman 32 Comments

The last time we visited the Hackaday shooting range we were all psyched up to get the right posture, breathe correctly, lower our heart rates and squeeze the trigger at exactly the right moment that the wandering cross hairs align with the target ……. and lastly accommodate the inevitable recoil. But never did we think to check the temperature of our ammo! Ok, temperatures aren’t likely to vary that much there unless the range cat chooses to lay down on top of the ammo box, but out in the wilderness the temperatures can easily vary by up to 30 degrees, which would certainly be a problem.

If we take a quick look at what’s happening on Johnny’s Reloading Bench we get an in depth comparison of different powders at different temperatures, with data being collected via a bullet velocity radar. If nothing else, it’s interesting just to get a peep into the mysterious world of ‘Reloading’ where every one of the tiny kernels or ‘balls’ of powder make a difference and different powders require particular primers to make them burn properly.

Just to make it clear, bullet speed makes a big difference to the trajectory, especially at long distances. For example, if the bullet were to travel at close to the speed of light, there would be almost no trajectory at all and the shooter would not have to adjust the vertical aim for distance. Normally, we have to aim upwards to hit the target:

It may be that we ‘zero in’ our sights at room temperature, but then end up actually shooting the firearm on a cold, frosty morning with cold ammo, and given what we have now learnt from the video, we could now make a small adjustment for that eventuality, depending on the particular ammo we are using. Johnny’s video is after the break:

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