Saturday, February 03, 2007

Single Military Fuel - How Long?

The Single Fuel for the Battlefield concept,[1] driven by the need to simplify battlefield fuel logistics (associated with transporting and distributing multiple fuels to domestic and overseas bases), requires the Air Force and Army to use a single fuel for all aircraft,[2] ground vehicles and support equipment, such as generators.

This single fuel is JP-8[3] (Jet Propellant or Jet Propulsion Fuel-8), which is essentially commercial kerosene based Jet A/Jet A-l fuel[4],[5] with three military specified additives; a corrosion inhibitor/lubricity improver, an anti-static additive, and a fuel system icing inhibitor.[6] But JP-8 has less energy per gallon and a bit more expensive than JP-4.

Further adding a dispersant, an anti-oxidant, and a metal deactivator to JP-8 yields JP-8 +100, which adds an additional 100°F to the operational range of JP-8.

JP-8 has started to replace JP-4 as the single military fuel in the 1990's, primarily to reduce the risk of fire encountered with the low-flash-point than JP-4. JP-8 is less flammable and less likely to ignite accidentally[7] than JP-4. It has also a lower vapor pressure, which means that less fuel is lost to evaporation. The Navy uses JP-5[8] for ships and ship-based aircraft. Land based Navy aircraft typically fly on JP-8.

Source: P. Dimotakis, R. Grober, N. Lewis, Reducing DoD Fossil-Fuel Dependence, JASON, The MITRE Corporation, September 12, 2006.

The single military fuel concept was first implemented in December 1989 during Operation Just Cause in Panama. There JP5 was used as the single fuel. In August 1990, during Operations Desert Shield and Desert Storm, the single fuel used was Jet A1. Except for some minor problems related to hot-engine restarting difficulty and gradual loss of power in engines of some tactical wheeled vehicles, such as HMMWVs, the concept worked.

But starting with operations in Afghanistan major problems have been encountered. In Afghanistan, much of the aviation kerosene that initially was procured was Russian TS1 aviation kerosene[9] which is widely available in the neighboring refineries. The fuel being used in onshore Iraq by the US military is JP8.

Not because of the compatibility of available fuels with JP-8 but because of the JP-8 itself problems are arising. For example, minor problems encountered in the first Gulf War due to the use of JP-8 in ground vehicles, especially in Humvees, became more acute. Keep in mind that in both Afghanistan and Iraq the ground vehicles and equipment are being used much more extensively than they would be used in normal service.[10]

Considering this added use, the hot temperatures and the increasing engine-power demands imposed by the increased weights of up-armor kits, it is no wonder that the ground vehicles and equipment that have rotary-distribution, fuel-lubricated fuel-injection pumps have had many fuel-related engine problems. Since almost half of the Army’s diesel vehicles and equipment have rotary-distribution, fuel-injection pumps, a solution is urgently needed to overcome the shortcomings JP-8 has. Failure to recognize and act on the problems inherent in the use of kerosene-based fuel with rotary-distribution, fuel-injection pumps will only serve to decrease operational readiness and increase maintenance costs over time.[11]

The real problem with the single fuel concept will became more acute in the future. The Air Force is testing blended synthetic JP-8 (derived from natural gas) as a viable fuel. A gallon of that synthetic fuel is $20, whereas JP-8 derived from natural gas is below 3$. Even if we leave the cost part aside, it is a crime to use JP-8 in compression ignition engines. Combat vehicles operating in high temperature environments (in Iraq for example) therefore must be either allowed to use diesel or they should be remodified. Similar holds for generators.

US Department of Defense must understand that reality does not match theory and wishful thinking most of the time. Surely some factors such as cost (besides availability, applicability, practicability etc) must be taken into account on deciding what type of fuel should be used in war but environment should not be push into front. Thinking about environment in battle ground is a nonsense luxury.

[1] DOD Directive 4140.3 of 1988.
[2] The U-2 runs on JP-TS and SR-71 runs on JP-7.
[3] MIL-DTL-83133E, NATO code F-34.
[4] In the first Gulf War large numbers of Army ground vehicles and equipment were routinely fueled with JET A1 with no major reported problems. See, USA Quartermaster Center and School website on JET A-1 vs JP-8 -- Differences and Effects on Long Term Use.
[5] Jet A-1 is similar to Jet A except for a lower freezing point, -53 F vs. -40 F. Jet A-1 is an operational fuel for all turboprop and turbojet aircraft requiring a low freezing point product.
[6] Fuel system icing inhibitor (MIL-DTL-85470), corrosion inhibitor and lubricity enhancer (MIL-PRF-25017), and static dissipator additive. JP-8 has <>[7] This means JP-8 is less likely to explode if the aircraft suffered combat damage.
[8] JP-5 has a higher flashpoint temperature ( 60C, or 140F) than JP-8 (38C or 100F). It is used for safety reasons and costs slightly more than JP-8.
[9] It is similar to Jet A1, but it is more volatile due to its lower flash point and a lower viscosity.
[10] An article in the July 2004 issue of National Defense magazine, “Army Ponders New Diesel Engine for Humvee Trucks,” notes that maintenance nightmares have been experienced in Iraq because engines regularly break down and often must be replaced after only 1,000 to 2,000 miles of operation.
[11] Maurice E. Le Pera, The Reality of the Single-Fuel Concept, Army Logistician, March-April 2005.


At 8:15 PM, Anonymous Gary Neal said...

Hi Sohbet. I have a question about injection pumps and I was wondering if you could help me? What are the differences between a centrifugal pump and an injection pump?

At 3:43 PM, Blogger sohbet karbuz said...

Unfortunately this question is beyond my expertise. Sorry.


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