1. Figure 7 compares loiter time, mission radius, loiter altitude, and loiter Mach number capabilities between the interim study vehicle with the PW150 engine, and the final aircraft with a VAATE-based engine. The final aircraft met the six hour loiter and 200 nautical mile mission radius goals, though it loitered at a slightly lower altitude and Mach number than the interim aircraft. Lift fan aircraft results similarly improved for loiter time and radius, meeting the goals, but loiter altitude and Mach number increased by approximately 20% compared to the interim aircraft. These increases were due to the engine growth required to match the tandem fan system thrust/weight at takeoff.
2. The parametric cycle deck user could specify fan diameter with fan pressure ratio automatically determined, or FPR with fan diameter automatically determined. Both front and rear FPR could be set independently, though both fans always had the same diameter. A technology level flag was available that set component efficiencies. Bypass ratio could be specified, though this feature was not used for this program, but was allowed to default. Conventional compressor bleed was available, with a user-specified airflow. A number of losses could be input, including main and auxiliary inlet total pressure recovery, pressure drop across the fans, loss between fans, loss across the blocker valve, pressure drop to the lift nozzle throats (front and rear, separately), nozzle gross thrust coefficient (Cfg), and losses in the aft bypass duct, supercharging duct, and main nozzle. Losses were specified appropriate to lift or cruise mode.
3. Figure 14 compares loiter time, mission radius, loiter altitude, and loiter Mach number capabilities between the interim study vehicle with the T-55 engine, and the final aircraft with the optimized engine cycle. The final aircraft met the six hour loiter and 200 nautical mile mission radius goals, loitering at exactly the same altitude but at a 21% lower Mach number than the interim aircraft. Honeywell lift fan aircraft results similarly improved for loiter time and radius, meeting the goals, with loiter time increasing by 71% relative to the earlier aircraft. Final loiter altitude was reduced by 5000 feet, and loiter Mach number dropped by the same amount as the tandem fan system, compared to the interim aircraft.