The Use of Marine Gas Turbines in an Amphibious Hovercraft, the USN AALC JEFF(B)

The Navy’s air cushion landing craft LC JEFF(B) is one of two full-scale advanced development craft that was developed and is being tested under the Amphibious Assault Landing Craft (AALC) program. The JEFF(B) was designed and built by Bell Aerospace Textron under contract to the Naval Sea Systems Command. The JEFF(B) is powered by six Avco Lycoming TF-40 gas turbines. The engines are coupled together in two sets of three engines each. The loading and control requirements resulting from this configuration, and the associated high-density spray environment, result in some unique capabilities and problems. Initial phases of development and testing of the JEFF(B) have uncovered and solved problems related to control and power matching of coupled engine systems, and to protecting the engines from the deleterious effects of salt-spray ingestion. On-line engine health monitoring systems have been developed to record compressor performance degradation due to salt ingestion.