Thought these may be of interest to the "tracked" crowd:
http://www.treehugger.com/files/2008/12/military-vehicles-apc-tanks-rubber-tracks-mpg.php
Some info above from this article:
http://www.economist.com/science/tq/displaystory.cfm?story_id=12673347
http://www.treehugger.com/files/2008/12/military-vehicles-apc-tanks-rubber-tracks-mpg.php
Rubber Tracks Make Military Vehicles More Efficient, Durable, and Quieter
by Michael Graham Richard, Gatineau, Canada on 12.15.08
Cars & Transportation
Looks More Like a Toy, but Performs Better
Recently, we wrote about the fuel consumption of some common US military vehicles (f.ex., the M2A3 and M3A3 Bradley Fighting Vehicles get about 1.7 MPG and the M1A1 Abrams Battle Tank gets about 0.6 MPG). This matters because we're not talking about small amounts of fuel: according to NPR, all the tanks, planes and ships of the U.S. military burn about 340,000 barrels of oil per day, making it the "single-largest purchaser and consumer of oil in the world."
One way to make tracked vehicles both more eco-friendly and safer and more comfortable for the people inside them is to use new high-tech rubber tracks. Read on for more details.
Photo: Soucy International, who also makes rubber tracks for construction and agricultural equipment.
The Economist has an interesting piece about this in their technology quarterly edition. But let's start from the beginning...
The Washing-Machine, and Not a Delicate Cycle
Most tracked military vehicles use tracks with metal plates. This has several inconvenients, including severe vibrations (some soldiers call Armored Personnel Carriers (APC) washing-machines) that are bad both for the health of the people inside and for the mechanical health of vehicles, leading to more frequent breakdowns.
These metal tracks are also bad for roads, causing a lot of damage that must be repaired, and they wear out fast. "On average, the segments of a steel track must be repaired or replaced after just 400 km (250 miles) of use." The new rubber tracks last more than 3,000 km (1865 miles) before they need to be replaced.
Fuel economy is also affected: Metal tracks are heavy, and you also need to carry replacement tracks, which means you need a beefier suspension. All things considered, rubber tracks could improve fuel economy by about 1/3, according to TACOM, the American army’s Tank-Automotive and Armaments Command. That's significant when you think about what kind of MPG Tanks and APCs get.
Rubber tracks also provide more traction, in part because, being lighter, they can be made wider than steel tracks. That means vehicles fitted with them do not get stuck in the mud. The vehicles accelerate faster, too, and drivers say they handle almost as well on paved roads as wheeled vehicles do. On top of this, they are quieter.The only problem is that so far these rubber tracks (many of which are made in Quebec, Canada, by Soucy International) are not yet strong enough for 50-tonne battle tanks. But they are getting there, and already some 30-tonne vehicles are being tested with them.
Some info above from this article:
http://www.economist.com/science/tq/displaystory.cfm?story_id=12673347
Quiet, please
Dec 4th 2008
From The Economist print edition
Military technology: Using rubber rather than steel tracks on military vehicles could reduce wear and tear on both soldiers and equipment
RATTLING along in the “washing-machine environment” of an armoured personnel-carrier (APC) on steel tracks can shake the soldiers inside to the point of exhaustion, according to Dan Goure, a military analyst at the Lexington Institute, a think-tank in Arlington, Virginia. And J.G. Brunbech, an APC expert at the Danish Army Material Command in Oksboel, observes that the crew’s limbs are prone to becoming prickly and numb, and their hands get tired, because they must grip the vehicle’s safety handles tightly. The vehicle itself suffers, too. The vibrations cause rapid wear and tear—not to mention outright damage, especially to electronics.
In the past, engineers have tried to reduce these vibrations by fixing rubber pads to the treads. The pads wear out quickly, however, and often get torn or even melted. But now tough, new rubbers have come to the rescue. Moreover, these rubbers are not being used just as pads. Instead, they are crafted into enormous rubber bands that replace the steel tracks completely. The Danes are converting their entire APC fleet to rubber tracks. This will increase the amount of time a soldier can safely spend on board from just one and a half hours to ten hours.
Details of how the new super-rubbers are made are still classified, but the results are not, and they are impressive. Rubber tracks weigh less than half as much as their steel counterparts. That, in turn, allows the weight of the suspension system to be reduced by 25%. All this can cut fuel consumption by as much as 30%, says TACOM, the American army’s Tank-Automotive and Armaments Command.
Rubber tracks also provide more traction, in part because, being lighter, they can be made wider than steel tracks. That means vehicles fitted with them do not get stuck in the mud. The vehicles accelerate faster, too, and drivers say they handle almost as well on paved roads as wheeled vehicles do. On top of this, they are quieter. That has two benefits. One is that crews are often able to talk to each other without resorting to intercoms. The other is that it is harder for the enemy to hear them coming. According to Curt Aspelund, the head of tracks and suspension development at BAE Systems, a British defence firm that is collaborating with TACOM to design a new APC called the Manned Ground Vehicle (MGV), rubber tracks will reduce the distance from which the vehicle can be heard by 40%.
Rubber tracks are more reliable, too. Tracked military vehicles are notorious for breaking down. On average, the segments of a steel track must be repaired or replaced after just 400km (250 miles) of use. Carrying spare segments adds to a vehicle’s weight. Rubber tracks, by contrast, usually last more than 3,000km.
They are also kinder to roads. Traditionally, of course, that did not matter much. The whole point of a tank or an APC is that it is the ultimate off-road vehicle. But the growth of peacekeeping operations, in which showing the flag to the locals is an important tactic, means that road-friendly vehicles are becoming more desirable. The locals will certainly not love you if you chew up their tarmac and make their streets impassable.
As a result of all this, Soucy International of Drummondville, Quebec, one of the firms that makes the tracks, reports booming business. The armed forces of both Canada and Norway have converted almost all their APCs to tracks made by Soucy. Those of several other countries, including Britain, Germany, Italy, the Netherlands, Singapore and Sweden, are following suit or are in the advanced stages of testing the tracks. France plans to start tests next year. And although America has not sent APCs with rubber tracks into action, they form part of Future Combat Systems, the Department of Defence’s main modernisation programme.
At the moment, rubber tracks can support only vehicles weighing less than 20 tonnes. They are not strong enough for 50-tonne battle tanks. But this is changing. The MGV, for example, will weigh 30 tonnes, and Canada recently began a trial of rubber tracks on the Mobile Tactical Vehicle Light (MTVL), a 22-tonne APC. If the MTVL passes muster it will join Canada’s rubber-tracked 20-tonne M113 APCs in Afghanistan. Soucy, meanwhile, is developing rubber tracks for full-sized tanks. Warfare, it seems, is about to get quieter.
