Thats the ideal, but the only way to accomplish this is to severely restrict the number and types of lubricants purchased by Natos 28 member forces, according to Peter Bartl of Germanys Federal Armed Forces (Bundeswehr). Unfortunately, this logistical necessity cannot help but lead to compromises in some lube applications. It also means Nato forces tend to be slow in making upgrades, and to lag the civilian sector when it comes to taking advantage of improvements in lubricant technology, he went on to show.

Despite these challenges, each Nato member tries to provide the best possible service to the system, Bartl told the 18th International Colloquium on Tribology at the Technische Akademie Esslingen in Ostfildern, Germany, in January. In joining Nato, each country agreed to meet the organizations need for high mobility, streamlined logistics and vehicle protection. That includes having the fewest possible number of product types in the field.

If Nato were a civilian fleet, it could select a limited number of vehicles of the same type and run them on a small list of manufacturer-approved products, observed Bartl, who is with the Bundeswehr Research Institute for Materials, Fuels and Lubricants in Erding, Germany.

Instead, in the armed forces, our system is totally different, he pointed out. We have to service different OEM equipment, using multiple vendors products, and yet we have to be able to service them all with the same lubricants. The aim is inter-operability, where every nation can expect to get service from another. This is only possible if everything fits together.

Another challenge arising at the local level is each Nato countrys procurement practices, typically by tender, which mean that lubricant vendors change regularly, even yearly, Bartl said. So brands need to be compatible and miscible. And reliability is certainly a part and aspect of great importance to any military.

For Germany, Bartls department supports these efforts by setting quality standards, writing approval procedures, and doing equipment tests for the military. Germanys army now uses one standard motor oil for every ground vehicle, an SAE 15W-40 diesel engine oil meeting ACEA E3/B3. It buys just two gear oils; one an SAE 80W-90 grade meeting API GL-5, the other a Dexron III-type automatic transmission fluid.

Notably, Dexron III ATF has not been recommended in any civilian vehicles since General Motors upgraded to Dexron VI in 2005. But Bartl said that the German military is seeing more medium-weight trucks equipped with automatic transmissions, a significant and welcome relief for drivers in the field. So an upgraded ATF seems likely to join the Bundeswehrs list of lubricants. One option could be to adopt the current commercial specification and choose from brands approved to it – provided mixing of brands is permitted, he suggested.

Germany also maintains one hydraulic fluid standard for army applications, and adds a fire-resistant phosphate ester fluid for the air forces use.

We also have one multipurpose grease, an NLGI 02 grade lithium complex grease which we make do as much as possible, Bartl said.

The inventory of lubricants can be kept this simple in part because the Bundeswehr decided years ago to have just one type of fuel for all vehicles: We got rid of gasoline and just diesel is used, Bartl said. Then we decided to see if aviation and [ground]vehicles could also share the same fuel, AV jet fuel, if need be. The care of course is to have adequate lubricity for ground vehicles, and this is addressed by additizing the fuel.

Germanys military buys all its lubricants according to the Nato standard for interchangeability (STANAG 1135), and takes care to buy only equipment that is capable of running on these lubes. Its also mindful that the same limited arsenal of lubricants must be able to serve a wide range of vehicles, whether its a Dingo infantry vehicle built by Germanys KMW, a Grizzly armored vehicle from the United States, a Land Rover utility truck from the U.K., or another allys vehicle.

We have facilities to do full motor testing on lubricant products, which must prove their compatibility with high-sulfur diesel fuel, prove they can operate with jet fuel, and prove their compatibility with other motor oils meeting the standard, Bartl said. We also do failure analysis.

The Bundeswehr buys lubricants now in smaller volumes than it used to, he added, and it also faces political pressure to avoid military-only purchases and to use products that are available in the field. So we expect to see more off-the-shelf products in the system.

To prepare for that, and to comply with Euro IV emissions mandates, were thinking of going up to ACEA E4 or E5 engine oils. Other research efforts under way involving lubricants include elastomer compatibility tests, attempts to extend oil drain intervals, and oil condition monitoring.

Nato and the Bundeswehrs biggest priorities, Bartl emphasized, are to meet the strategic demands of the military mission, followed by budget constraints, and deadline pressures. Concerns about maintenance cost tend to take a back seat, he conceded, until the problems become too large to ignore or might put the military mission at risk.

All told, he concluded, Natos concept of limiting lubricants to a chosen few is valid, but it takes a lot ofmeasures to make it work.