Pros and Cons to the M1 Abram's Honeywell AGT 1500 Multifuel Engine

The Honeywell AGT 1500 engine is a multifuel gas turbine developed for use in the UH-60 Blackhawk helicopter.  After losing that contract, Honeywell entered the AGT 1500 into the contest for the SH-60 and AH-64, but lost those two also.  Finally, the engine snagged a victory in the contest for the Abrams, whose designers decided that its acceleration was key to fulfilling the role the Abrams would be given.  For logistical reasons, the Abrams generally runs on JP-8 fuel, and it is the AGT 1500:JP-8 combination that this post will discuss to determine whether or not keeping the AGT 1500 in the Abrams is a good idea.

Pros:

• Fuel tankers don't need to carry diesel engine specifically for the Abrams
• Can siphon fuel off of most damaged/disabled Army and Air Force vehicles without contaminating its fuel supply
• Unmatched top speed and acceleration
• Very good for the Cold War scenario of a war most likely in Germany

• JP-8 does not wax over in cold weather
• Lighter and smaller than a diesel engine
• More room for fuel and ammo

Cons

• ~1,000°F (535°C) engine exhaust
• Massive IR signature, allowing for detection and tracking at much longer ranges via infrared sensors
• Requires a lot of cooling to prevent a heat buildup
• JP-8's auto-ignition point is roughly 248°F (~120°C), meaning that any failure with the cooling units or engine heat shield could easily result in an engine fire
• Infantry cannot operate close to the tank, disrupting old tank-infantry operations and complicating transport
• Very bad for operations in urban environments where the infantry otherwise would be near the tank to reduce its vulnerability to point-blank attacks
• Gets 3 gallons per mile (~7 liters per kilometer) off road at half-load
• Requires a larger gas tank, negating the small engine bonus
• Performance with diesel not much better, as the engine is not optimized for diesel
• Range (not combat radius) of ~120 miles (~190km) off-road at full load and ~250 miles (~402 km) in optimal conditions with a full load
• Tanks need to wait for tankers to catch up, negating the top speed and acceleration bonuses
• Downtime allowed a portion of the Iraqi Republican Guard to retreat during the First Persian Gulf War
• Smokers, which create a smokescreen to obscure the tank's visual and IR signatures, removed to prevent engine flameout due to the heat they generate and the low auto-ignition temperature of JP-8
• Smoke grenades used instead, but at a lowered effect and amount
• Very expensive to maintain
• ~25% of the US Army's maintenance budget goes towards the AGT 1500's.  Another 25% goes towards the rest of the tank
• Unclear how much of the maintenance cost of the rest of the tank is due to exhaust heat
• Engine not optimized for any fuel, resulting in a lower efficiency when compared to other engines

Conclusion

In short, the AGT 1500:JP-8 combo has some advantages, namely in situations where the war would take place largely near the bases of the Abrams' operator, but it does not fit the current needs of the US military.  I cannot offer up another engine to possibly replace it, but a new engine should definitely be considered for the Abrams if, for no other reason, to increase its range.  Currently, the Abram's need for constant refueling makes it more difficult to deploy in Afghanistan, and, should we find ourselves in Iran, the Abrams would have the same problem it had in the First Persian Gulf War where it would run out of fuel prior to accomplishing its objective.

The US Army should also consider using a fuel better suited for ground operations, even if the logistics behind the switch would be very difficult.  Engines should be optimized for diesel or other fuels more suited for ground ops, but still accepting of fuels such as JP-8 for cold weather operations.