Flight Measurements of Internal Cockpit Pressures in Several Fighter-Type Airplanes

Flight measurements of internal cockpit pressure have been made in several fighter-type airplanes equipped with either conventional or bubble canopies. Data are presented showing the variation in cockpit pressure with indicated airspeed and angle of sideslip for both the canopy-closed and the canopy-open conditions. The effect of admitting the cockpit ventilating air is shown for one airplane. The change in cockpit pressure accompanying a change in engine power is shown to be small. Data are presented showing the variation of cockpit pressure with normal acceleration at a constant value of free-stream impact pressure. At a given lift coefficient the cockpit pressure expressed as a fraction of free-stream impact pressure above free-stream static pressure is shown to be independent of normal acceleration. A method is outlined for predicting the cockpit pressure in accelerated flight from measurements made in unaccelerated flight.