Hacking when it Counts: GI Ingenuity

For most of us, hacking is a hobby, a pleasant diversion from reality. Yes, a lot of us work on projects which have the potential to change the world – witness the 2015 Hackaday Prize semifinalist list. But in general, almost any of us could walk away from the shop at any time without dire consequences. Indeed, that’s the reason a lot of our work benches are littered with projects started with the best of intentions but left unfinished for lack of funds, lack of interest, or lack of time. We’re free to more or less willingly shelve a project and come back to it whenever we please, or not at all.

But not everyone has that luxury. For some people, hacking is much more than a hobby – it’s a means of survival. Sometimes people are thrown into situations where they have to cobble together a solution to an immediate problem with whatever is at hand, when the penalty for failure is much higher than a cluttered bench and a bruised ego. I’ve already covered one such case, where biohacked insulin saved hundreds of lives in occupied Shanghai in WWII.

In this occasional series I’ll explore historical cases where hacking really counted; cases where lives were saved or improved by a hack performed under desperate conditions.

A Bustle in the Hedgerow

Unsurprisingly, war offers a lot of opportunities for field expedient solutions under dire circumstances, and battlefield conditions might be the most extreme example of hacking when it counts.

In the early days of the Invasion of Normandy during WWII, Allied forces were having a difficult time dealing with the bocage terrain of northern France. A mixture of pasture and woodland, the Normandy bocage was a natural killing field for Allied tanks because the woodlands took the form of hedgerows – earthen dikes topped with thick tangles of brush. Hedgerows separated pastures and kept livestock controlled, but also made things tough on infantry and mechanized cavalry alike. Climbing the steep hedgerows exposed the vulnerable bottom hull of the tanks to enemy fire, and waiting for engineers to demolish the hedgerows with explosive made them sitting ducks for German artillery. The Allied advance was seriously hampered by the hedgerows, and both men and materiel were being winnowed down from fixed German positions chosen specifically to take advantage of the bocage terrain.

curtis cullin
Sgt. Curtis G. Culin (source: Cranford (NJ) Patch)

Enter Sgt. Curtis Grubb Culin III. Sgt. Culin, a tanker himself, was acutely aware of how vulnerable he was in his Sherman M4. The hedgerows were the problem, one apparently known to Allied command prior to the invasion for which no provision had been made. In the tradition of soldiers at the front of every battle throughout history, Sgt. Culin and his fellow tankers had to improvise a solution.

While kicking around ideas, one of the men suggested setting saw teeth on the front of a tank to cut through the hedgerows. He later attributed the comment to “A Tennessee hillbilly named Roberts”, and it was met with general laughter from the group as a crackpot scheme. But Sgt. Culin saw the potential in the idea, and began to develop it into a prototype.

Rhino-equipped tank (source: Wikipedia)

Raw materials for his prototype were not hard to come by. Czech hedgehogs, giant anti-tank barriers made of crossed steel beams, still littered the Normandy beaches. The failed German defenses were harvested with a cutting torch and welded to the underside of a tank to form a series of “tusks” across the hull between the tracks. Equipped with these tusks, the tank could now blast through the tangled roots of the brush-covered earth of the hedgerow dykes.

When demonstrated for General Omar Bradley, he was impressed enough to order them built in quantity for the tanks. Eventually the prototype became an engineered product (dubbed the “Culin Rhino Device”) that was fitted to many tanks before being shipped over from England. Rhino-equipped tanks ripped across Normandy and shredded the German battle plan, which assumed the hedgerows would funnel Allied forces through heavily defended chokepoints.

Without Sgt. Culin’s battlefield hack, and his inspiration by a hillbilly named Roberts whom history otherwise forgets, the invasion of Europe might have taken a very different course. The fact that he did the hack while under fire makes it all the more impressive, and is a perfect example of hacking when it counts.

Know of any more examples of hacking when it counts? Send us a tip for use in a future Hacking When it Counts article.

[Main image of Czech Hedgehog by Jesse CC-BY-SA 3.0]

Hackaday Prize Entry: Molded Tracks For Vehicles

There are a lot of robotics platforms out there, and whether for educational use or for robot fightin’ time, two things remain constant: tracks are often the best solution, and there aren’t very many modular track systems that can be used with a variety of designs. There are even fewer that can be built at home. [jupdyke]’s project fixes that. It’s a modular and easy to replicate system for tracked vehicles.

The design for this system of track uses roller chain, chosen because the components of roller chain are mass-produced in incredible quantities, sprockets are available in every imaginable size, and all the parts are available in different materials.

Rolling two chains around a few sprockets isn’t a problem; the hard part of this build is figuring out how to make the actual treads, and then making a lot of them. [jupdyke] is making them by 3D printing a few mold masters and doing a few test prints with silicone and polyurethane rubber. For a one-off project, it’s a lot of work, but if you’re making thousands of tracks, molds are the way to do it.

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DIY Tank Tracks Give Tons of Traction

If you’re building a robot for off-road or rough terrain, chances are you’ve thought about using a tank-tread style drive. There are a ton of kits available with plastic tread and wheels, but they are typically really expensive or pretty flimsy. Instead of going with an off-the-shelf solution, [Paul B] designed a heavy-duty tank tread made with common bike chain and conduit.

Some DIY tread designs we’ve featured just use a single bike chain on either side of the tread pieces. This gets the job done, but each section of tread is usually bolted through the chain. This means that you can’t use a sprocket to drive the chain since all the bolt heads block where the teeth engage. Instead, these designs typically use drive wheels inside the tread, which are prone to slip under a heavy load. [Paul B]’s design is a bit different: it uses a DIY double-wide chain so he can bolt tread segments to the chain and still use a drive sprocket.

Constructing the double-wide chain took quite a bit of work. [Paul B] completely disassembled a couple of bike chains with a delinker tool and then reassembled the chain in a double-wide configuration with M3 bolts instead of the original chain pins. Each section of tread (made out of cut pieces of plastic conduit) bolts on the outside section of chain, and a sprocket runs on the inside. His DIY chain approach saves him money too, since double-wide chains are pretty expensive. Since his sprockets directly engage the drive train, his design should be able to handle as much torque as his drivetrain can put out.

Tank Track Motorcycle Goes Anywhere, Slowly

There are just somethings you don’t see often when it comes to motorcycles, 2 wheel drive and tank tracks. Well, [jeep2003] has combined both those oddities into one project he calls the Track-Powered 2×2 MiniBike.

As his descriptive project name suggests, this minibike has tracks instead of wheels. The track assemblies originally came off a snow blower. As if just having tracks wasn’t difficult enough, both sets are powered. The back has a straight forward chain and sprocket setup while the front ads in a clever jack-shaft and universal joint contraption which is shown in the video after the break around the 3:08 mark.

Tank Track Mini Bike

[jeep2003] doesn’t say where the tubing for his custom made frame came from, but from the photos available it appears they were once old bicycle frames. The powerplant is a 6.75hp vertical shaft Briggs & Stratton engine. The output shaft connects to a Peerless 5 speed transmission that also has reverse. This transmission usually outputs to two rear drive wheels of a riding lawnmower. [jeep2003] dedicates each axle output from the transmission to power one of the two track systems.

Although this minibike won’t be breaking any land speed records anytime soon, we here at HaD still think it’s a pretty rad build.

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Reverse Engineering An RC Spy Tank

[Michael] sells a remote control spy tank through his company, and although it’s a toy, there’s an impressive amount of electronics in this R/C tank. It’s controlled from an Android or iDevice over a WiFi connection, something that simply won’t do if you’re trying to sell this to the hacker and maker crowd. The solution to this problem is Wireshark, and with a little bit of work this spy tank can be controlled from just about anything, from a microcontroller via WiFi to a Python app.

Wireshark, everyone’s favorite network packet analysis and capture tool, was used to listen in on the communications between an iPad and the tank. This immediately showed the video stream coming from the camera in the tank, and pointing VLC to the correct port displayed the video.

The motors in the tank were a little trickier, but looking at the data stream, a few packets stood out as being responsible for controlling the motors. After a little experimentation the simple command set was decoded and a Python app whipped up.

These spy tanks are cheap – about $70 from [Michael]’s company and the other usual vendors. It’s not a particularly useful piece of hardware, but someone out there is sure to do something cool with this bit of reverse engineering.

14 Wheel Drive Vehicle Climbs Over Most Things

What do you get when you cross 7 hobby gearboxes with 14 wheels and a LiPo battery? Instead of speculating an answer, we can just check out one of [rctestflight’s] projects.

He came across those hobby gearboxes and thought it would be fun to build a 14 wheel drive contraption. Each gearbox has its own motor and is wrapped up in a nice tidy package also including the axle and wheels. All of the wheels mounted on a straight board wouldn’t be much fun so [rctestflight] used heavy duty zip ties that act as a flexible frame to connect one gearbox to the next. This allows the vehicle to bend and climb over obstacles while keeping as many wheels in contact with the ground as possible.

14 Wheel Drive

All 7 motors are powered by a single cell LiPo battery. In the video after the break it appears the vehicle can steer or that it is remotely controlled, but that is not the case. Once the battery is plugged in it just goes forward. This isn’t the first time one of [rctestflight’s] projects has been featured on Hackaday, check out his Free Falling Quadcopter Experiment.

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Retrotechtacular: The (Long, Arduous) Birth of a Tank

Throughout the 1950s and early 1960s, the United States Army provided regular status reports to both its interior members and the American public through a half-hour documentary television show called The Big Picture. Since the program was produced by the government, every episode immediately entered the public domain. This particular report tells the story of the T-48 project that culminated in the 90mm M48 Patton tank.

The film opens by providing a brief history of tanks and the lessons learned about them between WWI and the Korean War. The Army sought a more robust vehicle that could handle a wide variety of climates and terrain, and so the process of information gathering began. After a series of meetings at the Pentagon in which all parties involved explored every facet, the project was approved, and a manila folder was officially designated to the project and labeled accordingly.

vesselsWe then tour the R&D facility where new tank materials and components are developed and tested. It is here that the drive gears are put through their paces on a torsion machine. Air cleaners are pitted against each other to decide which can filter out the finest dust and sand. After careful analysis, different tank shell materials are test welded together with various, well-documented electrodes, and these panels are taken outside so their welds can be directly fired upon.

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