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Engine Competition Fuels Diesel-vs.-Turbine Debate 

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by Sandra I. Erwin 

Several engine manufacturers will be battling for more than $3 billion in future Army contracts, resulting from the service's plan to purchase a common engine for two of its flagship vehicles: the Abrams main battle tank and the Crusader next-generation artillery system.

The Abrams-Crusader common engine program replaces a now-defunct project called "Abrams Re-Power," which was announced last November. The change, said Army officials, reflects recent shifts in service priorities. The goal is to align the Abrams and Crusader programs on "parallel development paths for new propulsion system solutions," said an announcement in the Commerce Business Daily (CBD).

The Army has asked industry to submit proposals by May 31. Interested vendors will be expected to demonstrate that their proposed engines not only offer the best available technology, but also will help the Army slash maintenance costs. And because Crusader is being redesigned to lower its weight from 55 tons to 40 tons, this engine also will have to contribute to the program's weight-reduction effort.

"In the engine program, we are looking to lower the weight of Crusader and the life-cycle costs of the Abrams," Army Maj. Gen. John Michitsch told National Defense. He is the program executive officer for ground combat and supply systems.

According to the CBD announcement, the Army "established a long-term funding stream for the development, integration, production and application of an Abrams tank propulsion system targeted specifically at reducing the [operations and support] O&S burden of the existing engine, without sacrificing current system performance."

It will be a traditional cost-type contract, split into two phases.

The request for proposals for phase I was released last month. Under this phase, the Army will award a contract for the development, production and testing of a prototype engine. For Abrams, the second phase of the program will be a five-year production contract for at least 2,845 engines to be built over eight years, beginning in fiscal 2003. Contractors are asked to propose the most economical yearly production rates.

For Crusader, the second phase will involve the purchase of 18 power packs through the Crusader prime contractor, United Defense LP, based in Arlington, Va. The power packs will be used in Crusader's engineering manufacturing development (EMD), scheduled to begin in 2003. The Army anticipates that United Defense will procure 828 power packs over six years beginning in fiscal 2006. A power-pack refers to an engine that is integrated with a transmission.

This program could have enormous implications for the Army in the long term, officials said, because it could help save billions of dollars in O&S costs. Michitsch noted that the tank engine is responsible for about two-thirds of the vehicle O&S costs.

The current engine in the Abrams is the AGT 1500 turbine. That technology was perfected in the late 1960s and has not been upgraded to keep up with advances in the commercial sector. More than 12,000 AGT engines were delivered by Allied Signal, headquartered in Morris Township, N.J. The company is now part of Honeywell Inc. The last new AGT 1500 was delivered in 1992. The newer versions of the Abrams, the M1A2 AIM and M1A2 XXI, use overhauled engines.

The AGT was the only successful application of a turbine engine in a military ground vehicle. In all other systems, the Army has converted to diesel engines.
Savings expected from a new engine would stem from improvements in various categories, such as fuel consumption, number of parts and mean time between repairs.

A common Abrams-Crusader engine, also would result in efficiencies ranging from lower development costs, economies of scale on the production line, fewer spares to stock and manage, shared costs for tools and diagnostics, and common training skills, said Col. James R. Moran, Abrams program manager. Both programs would share technical data and there would be one depot repair line. In Army parlance, the "overall logistics footprint would be reduced for both systems," said a briefing chart presented by Michitsch to an industry conference.

Kevin M. Fahey, the Army's deputy project manager for Crusader, said a common engine would provide "operational and logistics benefits," such as fewer and interchangeable components, and common test and measurement devices. Efficiency also would result, he said, from dealing with only one chain of supporting subcontractors.

One of the main sources of speculation within industry circles is whether the Army will stay with a turbine engine for the tank or switch over to a diesel engine. Crusader already had an engine selected-a 1,500 horsepower CV-12 Caterpillar Perkins diesel, paired with an HMPT transmission made by General Dynamics Land Systems, in Sterling Heights. Mich. But now that the program is going back to the drawing board to be trimmed down, it is clear that the engine will have to change. "The CV-12 engine is too large for a 40-ton Crusader," said E. Jeffrey Van Keuren, United Defense spokesman.
The lightening of Crusader involves shrinking the howitzer and the resupply vehicle from 55 tons to 40 tons each. The Army eventually plans to buy 488 systems.

Not all the weight reductions, however, will come from the engine. Other potential targets include switching from built-in armor to appliqué armor, shortening the vehicle and making it narrower. That means it will need a smaller engine and possibly narrower tracks. Another consideration is the use of titanium, rather than steel, in certain components.

Once the Army picks an engine, United Defense will be responsible for integrating that engine with a transmission.

Crusader Redesign
The Crusader redesign will continue throughout 2000, and a proposal will be submitted to the Army for approval. Prototypes would be built during the EMD phase that begins in 2003. Systems could be deployed in the field as early as 2008. "That explains why the engines have to be produced beginning in 2006," said Van Keuren.

On the diesel-vs.-turbine debate, he said, "We are not going to make that decision." That choice will be made by the Army Tank-Automotive and Armaments Command, which manages all vehicle programs.

The current Abrams engine, the AGT 1500, gets about three-fifths of a mile per gallon. It is hardly fuel efficient. "It is less fuel efficient than diesel because it spins at a high rate to get the power regardless of whether the vehicle is sitting or moving," explained Peter Keating, spokesman for General Dynamics Land Systems. The company builds the Abrams tank and also is considering entering the engine competition with its own diesel system.

"The Army did not invest in turbine technology and instead rebuilt the engines, replacing worn out parts, rather than the entire engine," said Keating. Diesel technology, meanwhile, has improved and now provides better weight-to-power ratio, he added. That is important for the Abrams because it weighs 70 tons.

The work potentially involved in retrofitting a tank for a diesel engine would not be significant, said Keating. "No major work would be required in the hull. The engine compartment is very adaptable to different propulsion systems."

The new engines likely would be installed at Anniston Army Depot, in Alabama. "The refurbishing would be done as part of a broader effort to update tanks with digital equipment," he said. "They would not bring the tanks in, just to replace the engine."

One industry source who asked not to be named said that, even though turbine engines are less fuel efficient than diesel systems, the Army also is concerned about the cost of retrofitting the Abrams in order to install a diesel engine. The Army could lean toward a turbine because it is more compact, taking up less space than a diesel engine, said the source.

Which factors will weigh more in the decision-fuel efficiency, life-cycle costs or compactness-is something Army officials are loathe to discuss in these early stages of the program. "I can't tell you that right now," Michitsch said. "We will wait to see industry proposals ... We have not decided on a turbine engine or on any engine."

Speaking for the Crusader program office, Fahey denied that there is any bias for or against any type of engine. "We do not have a preference," he asserted. "We are looking for a common engine that reduces the Abrams O&S costs, satisfies the Crusader space and weight requirements and satisfies [both vehicles'] performance requirements."

The turbine entry in this competition will be the LV100, which was developed originally for the Crusader by a joint venture of Honeywell and General Electric.

The LV100 is a 1,500 horsepower engine, 51 inches long, 35 inches high and 37 inches wide. It weighs 2,300 pounds.

Joe Militano, spokesman for Honeywell's Defense and Space division, Phoenix, said that the LV100 is 30 percent more fuel efficient than the current AGT 1500. It also has 43 percent fewer parts than the older engine and is 500 pounds lighter.

One Honeywell official at the company's Washington, D.C. office said the relatively low weight of the LV100 gives it an edge over diesel systems. He speculated that, by changing the engine in Crusader to a turbine, the Army could shave 2 tons off the vehicle's weight.

Experts interviewed for this story noted that the Army routinely does not use the same engine for different vehicles. So, in the case of the Abrams-Crusader program, there is a limited selection of engines that meet both vehicles' requirements.

Traditionally, diesels have worked best in the 900 to 1,000 horsepower range. "Above that, there are challenges in weight," said one expert. "That is why the AGT was successful-it can get a lot of power and it's lighter. Diesels are heavier."

Diesel engine suppliers, however, disagree.

Walter E. McCandless is an engine product manager at Caterpillar Defense & Federal Products, Mossville, Ill. The company will compete for the Abrams-Crusader award with the CV-12 Perkins, which had been selected for the Crusader before the Army decided to redesign it. The U.K.-based engine maker Perkins subsequently was acquired by Caterpillar.

"The requirement for Abrams is 1,500 horsepower. It would appear that now, because the weight of Crusader will be lowered, that will reduce the power requirement," McCandless said in an interview. "We would do some things to take some weight out of the cooling system package for the Crusader. We can get a lot of weight reduction compared to the original concept."

For the combined Abrams-Crusader package, he said, "we would propose a new engine and transmission and diesel with cooling system ... We think we can put the diesel in, with transmission upgrade, and meet the range requirements for the tank and have no weight penalty compared to the current turbine."

The fuel economy achieved with diesel engines, he said, not only means buying less fuel, but also cutting on the manpower needed to transport fuel to the battlefield.

"With a turbine, typically you need an auxiliary power unit because the turbines use a good amount of fuel when they are idling. With the diesel, you let the engine idle and you don't need an auxiliary power unit."

McCandless noted that the Perkins engines are used in British military vehicles and they also are used as generator set engines. The CV-12 is a commercial engine widely used in electric power generators. He said Caterpillar acquired Perkins because it wanted to use the small Perkins engines in its commercial equipment.

Options Considered
General Dynamics Land Systems, meanwhile, is considering entering the engine competition with a diesel system the company manufactures at a facility in Muskegon, Mich.

"We are reviewing our options" on proposing the MTU 883, under the name GD 883, for the Abrams-Crusader program, said Keating. The company is licensed to build these engines by the German engine conglomerate MTU München.

General Dynamics currently is competing for a possible purchase of up to 1,000 tanks by the government of Turkey. The company is offering an M1A2 Abrams equipped with an MTU 883 diesel engine, which is part of a power pack called Europack. The Turkish government specified a diesel engine as part of the tank's requirements.

Besides the GD 883, another candidate could be the AVDS 1790, used in M1 tanks by Israel and in the Abrams' predecessor, the M-60 tank. It also powers the Army's M8 Hercules recovery vehicle.

Being the prime contractor for the tank, one industry expert observed, could translate into significant advantages in the engine competition. "General Dynamics can make a case that it will lower retrofit costs and life-cycle costs," the source said.

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