By Laura Shin
Posting in Science
This remote-controlled tank annihilates land mines as easily as a horse flicks away flies.
Finding and clearing land mines is an extremely dangerous job -- unless you're the Digger D-3.
The Digger D-3 looks like a cross between an Army tank and a combine harvester, and it detonates land mines and turns vegetation into mulch with equal aplomb.
The jumbo tiller at the front has tungsten hammers that pierce the ground 10 inches deep, turning any obstacle into pulp and remaking tree-filled fields into flat plots of fresh soil.
Its hull is protected from land mines by hardened steel plates, which are arranged in a V shape. This configuration means that detonated land mines disturb the Digger D-3 about as much as flies annoy horses.
At full speed, the D-3 can clear 100% of land mines at a rate of 10,000 square feet per hour -- much faster than a human can, and more safely too, since the human manning the D-3 will be tucked away off-site, directing the action remotely.
Human safety is the goal of the Digger D-3's creators, the Swiss non-governmental organization Digger DTR, which is dedicated to improving the efficiency and decreasing the danger of mine-clearing devices.
Even on the occasions that the tank does get a minor boo-boo, the robot is straightforward for others to repair. It's easy to get access to the inner workings and to weld the armor. The Digger even contains plans that you can follow if you need to build your own spare parts. Digger does all these things so that all communities threatened by land mines can use the Digger D-3.
Check out this video of the indestructible tank's predecessor, the Digger D-2:
Photo: screenshot of Digger D-2
Jul 20, 2011
Unless someone has seen the test results, they can't say whether or not the old flail technology is really as effective as the tiller on the Digger. Neither can they compare costs without knowing the rate at which the chains have to be replaced vs the rate at which the wheels have to be replaced on the tiller. It would be more useful to compare the tiller on the Digger against mine plows that are commonly used. A robotic vehicle with a V-shaped bottom rather than ordinary tracked vehicles with crews definitely seems the way to go whatever gadget you put on the front.
This is a tracked robot version of the WW II Flail modification for tanks used to breach fortifications. Flails used heavy chains that allowed the device to be placed further in front of the tank reducing vehicle damage. The chains were just as effective as hammers, easier to replace when damaged and would be far less expensive than tungsten hammers.
Percy Hobart developed several custom tanks to handle various obstacles on D-Day. Everything from Flail, a modified Matilda tank, to Bobbin that carried a spool of canvas or corduroy that was reinforced to be rolled out as a road across soft sand and finally the Sherman DD which made the venerable Sherman tank amphibious in a dangerous manner. Flail was tested with a variety of items for pounding the ground. Hammers, pole and chain combinations that looked like nun chucks and simple heavy chain were among the many items tested. Simple heavy chain proved to be the most effective of the cost effective measures. While the hammers may have been marginally more effective they lost that edge when crews failed to replace destroyed hammers because the process was time consuming. Bent hammers not completely blown off made it difficult to remove them for replacement. All in all when you are dealing with things weighing upwards of 100 lbs each, simple to handle was appreciated. The v shaped bottom was something else that came out of their testing. As the program started in 1943, no such vehicle was built in time for the 1944 D-Day. The smothering shield over the ground pounding mechanism shown in the video was also a design rejected by Hobart. While intended to prevent shrapnel from injuring nearby troops, they found by trapping the explosion they increased the likelihood a mine would blow the entire contraption off the tank. Seeing that these were manned tanks many crews made field modifications to include a vertical blast shield on the front of the tank and periscopes to provide vision over them.
A major problem was the size of the tanks and the device adding several feet to the front made them difficult to maneuver. This machine looks smaller and would likely address some of those concerns. They also did not work well in swampy or rain soaked mud conditions where they were prone to getting stuck and the mines would get splashed out of the way, but not detonated. Many Flail tanks were field modified with the mine plows Swan mentions below. Modified as such they were very effective to clear minefields, but were heavy slow moving targets for German 88s.