GE aircraft engines in maritime use
By Edward Lundquist
General Electric helicopter engines have applications that have proven to be successful in the maritime sector. The latest GE engine to do double duty aboard aircraft and marine vessels is the GE38.
According to Lee Wilkerson, marketing director for GE Marine in Cincinnati, Ohio, the proven GE38 engine materials have been used extensively on other GE military and commercial engines. “These materials have been proven in both commercial applications where millions of hours and cycles are accumulated in revenue service and in military applications operating in severe environments including salt water, sand and combat operations.”
The GE38 was designed with materials and coatings that have proven corrosion resistance and have been selected based on lessons-learned from GE’s extensive experience with marine operations for engines such as the F414, F404, T700, TF34, LM2500, J79, T64, and T58. In particular, the engine’s alloys possess excellent sulfidation /corrosion resistance as evidenced by these engines having successfully passed Navy Corrosion Susceptibility Testing.
“As a result, very little is required to marinize the GE38 beyond the application specific items related to controls and package design,” Wilkerson says.
Wilkerson says that GE has a long and storied relationship with US Navy programs that we would like to continue with SSC. “We are celebrating our 40th year of service on US Navy surface combatants on a myriad of platforms and our LM2500 has set the standard for gas turbine reliability with an MTBR of over 23,000 hours in the DDG51 class operation.”
“Drawing on our legacy of success within the Navy’s Surface Warfare community, GE seeks to bring this same level of excellence to the Navy and Marine Corp’s Amphibious Warfare capability.” Wilkerson says. “The selection of the GE38 for the CH53K was based on its ability to thrive in the amphibious warfare environment while delivering superior mission operability. This is precisely the characteristic required for a successful Ship-to-Shore Connector (SSC) propulsion gas turbine. GE has purposely maintained a strict adherence to engine configuration commonality to allow for a high degree of maintenance, logistic footprint, personnel training and installation interchangeability.”
Should the GE38 be selected for the SSC then the US Navy will have made a decision to invest in a fleet of over 900 gas turbines (CH53K fleet=600 plus units, SSC fleet = 300 plus units). This investment in material assets serves to minimize the investment required in personnel training, tooling, spare engine/component provisioning and shipboard stowage required to facilitate deployment of the propulsion system with the fleet, he says.
The GE38 design draws on the highly successful CFE738 commercial turbofan engine and the US Navy T407 turboprop engine with proven technology improvements to the hot section. The GE38 engine design builds on the proven T700 architecture and military pedigree, say Wilkerson.
According to GE, the GE38 will meet or exceed the operational requirements established for the SSC program, with significant savings of fuel and maintenance cost over the life of the engine.
The company cites key GE38 characteristics:
• Low risk, proven design based on the T700 and CFE738/T407/MTDE engines
• Fuel efficient thermodynamic cycle resulting in 17% better specific fuel consumption than the T64, an engine of similar technology vintage as the existing LCAC ETF40B engine
• Modern, simple design with 63% fewer parts than the T64
• Corrosion-resistant coatings and materials
• Sand tolerant design, coatings, and materials
• Minimal support equipment enabling a small logistics footprint
• Highly reliable, derivative design approach
• Easily maintainable, modular design.
Should the US Navy select the GE38 Marine Gas Turbine Engine to power its envisioned Ship-to-Shore Connector (SSC), it would be the first marine application for the engine.
Hybrid-Electric Drive
Looking further down range, Wilkerson says the US Navy’s decision to restart the DDG-51 production line and the potential DDG-51 Flt III present an opportunity for the Navy to use the GE38 in a generator set to address the growth in shipboard electrical power requirements. “These requirements are driven by, but not limited to, the Navy’s desire for increased sensor capability, directed energy weapons development and the enhanced operational flexibility made possible by hybrid propulsion architectures that effectively blend mechanical drive and electric propulsion and power options,” he says.
A number of shipboard propulsion & power architectures can be envisioned wherein Main Propulsion prime movers coupled with enhanced Ship Service Gas Turbine Generators (SSGTG) would generate operational mission flexibility with reduced operating expense.
“A GE38 powered SSGTG delivering 4 MW of electric power would provide an immediate increase of up to 3 MW of shipboard electric power in the current propulsion system model. Couple the more powerful and fuel efficient GE38 SSGTG with a the Hybrid Electric Drives (HED) currently under evaluation and the potential for enhance operational economy and mission flexibility increase exponentially,” Wilkerson says.
“Generally speaking,” Wilkerson says, “there are a couple of fundamental approaches in how we can generate the aforementioned enhancements: Design changes to system components (engines, motors, generators, control’s, etc.) and/or modification to how we operate the systems composed of these components. A blend of hybrid architectures and enhanced products appear to offer the best pathway to success.”