SOME PERFORMANCE AND OPERATING CHARACTERISTICS OF CONVERTIPLANES 570157

The place of the convertiplane in the VTOL aircraft spectrum between the helicopter and the jet direct-lift airplane is discussed. Performance and operating characteristics are compared for four turbine-powered convertiplane designs having a range of disc loadings from 10 to 160 lbs/sq ft, and capable of hovering flight at 5000 ft on a 95°F day. It is shown that a marked increase in installed power requirement and in hovering fuel rate and downwash velocity occurs with increasing disc loading. Speed capability increases, with disc loading) however it was also found that for equal installed power, speed capability is largely independent of disc loading. Cruising range was found to be higher at low disc loading.

The use of fixed vs tilting wings in convertiplanes is considered. Test data on the download on a fixed wing in hovering flight is presented, including the effect's of plain flaps. The influence of disc loading on the characteristics of tilt-wing types during conversion is discussed.