receive data and video with all Army UAVs. Lots 5 and 6 will have Link 16 data-links. The AH-64E is to be fit for maritime use. The Army expressed interest in extended-range fuel tanks for greater endurance. As of April 2020, 500 AH-64Es have been delivered. AH-64F In 2014, Boeing conceptualized an Apache upgrade prior to the introduction of the U.S. Army's anticipated attack version of the Future Vertical Lift (FVL) aircraft, forecast to replace the Apache by 2040. The conceptual AH-64F would have greater speed via a new 3,000 shp turboshaft engine from the Improved Turbine Engine Program, retractable landing gear, stub wings to offload lift from the main rotor during cruise, and a tail rotor that can articulate 90 degrees to provide forward thrust. In October 2016, the Army revealed they would not pursue another Apache upgrade to focus on funding FVL; the Army will continue buying the Apache through the 2020s until Boeing's production line ends in 2026, then FVL is slated to come online in 2030. Compound Apache In October 2018, Boeing began testing the AH-64E Block 2 Compound, a compound helicopter design which added a larger fixed wing and a pusher propeller to the Apache airframe to provide additional lift and thrust, respectively. In addition, the engine exhaust was redirected downwards. Collectively, the modifications were anticipated to improve speed to , range to , payload to , and fuel economy. A 30% scale model completed wind tunnel testing in January 2019. The Compound Apache has been pitched as an interim replacement for the Apache before its replacement under the Future Vertical Lift program. Sea Apache During the 1980s naval versions of the AH-64A for the United States Marine Corps and Navy were examined. Multiple concepts were studied with altered landing gear arrangements, improved avionics and weapons. The USMC conducted a two-week evaluation of the Apache in September 1981, including shipboard operation tests. Funding for a naval version was not provided; the USMC continued to use the AH-1. The Canadian Forces Maritime Command also examined naval Apaches. In 2004, British Army AgustaWestland Apaches were deployed upon the Royal Navy's , a Landing Platform Helicopter, for suitability testing; there was U.S. interest in the trials. During the 2011 military intervention in Libya, the British Army extensively used Apaches from HMS Ocean. In 2013, US AH-64Ds were tested on several U.S. Navy ships. Export Apaches Several models have