An experimental investigation of lift engine inlet total pressure recovery and total and static pressure distortion during simulated hover and transitional flight has been conducted on a full-scale XV-4B model. The objectives were to develop fixed-geometry inlets for the four vertical-mounted lift engines that were independent of inlet closure door considerations and to provide satisfactory inlet pressure conditions for all modes of VTOL flight. The results indicate that satisfactory inlet pressures can be achieved with a design having single fixed auxiliary lips only in the forward inlets. Engine stalls, surges, and critical vibration levels were absent throughout the test program, which included numerous starts and accelerations at 200 knots relative wind speed. The total pressure recovery at static hover conditions was optimum, while total and static pressure distortions were always less than 13% and generally less than 10% in the VTOL transitional flight regimes for the final inlet configuration. A compact and flexible method of correlating inlet performance data is presented.