Icing trials on the front fuselage and engine intakes of helicopters at conditions simulating forward flight

One of the large test chambers of the Altitude Test Facility at the NGTE has been successfully used for full-scale trials on the front fuselage and engine intakes of the Westland Sea King and the Westland/Aerospatiale Lynx helicopters under simulated wet icing conditions. The Paper describes tests made to examine the effects of air temperature, air speed, water concentration and aircraft attitude on the extent of ice accretion. The possibility of ice ingestion by the engines during melt-off has also been studied using high-speed videotape recordings. Data are also presented from non-rotating tests on full-scale sections of main rotor blade made to examine the effects on accretion of blade speed, pitch angle, air temperature and water concentration. The effects of cyclic pitch change have also been examined and typical results are presented. The Paper includes general comments on the use of an altitude cell for helicopter icing investigations and the accumulation of data leading to clearance for flight in icing conditions.