PART II-HANDLING
          
                The acceleration in a steep dive is rapid but slower when
                carrying blunt nosed external stores.
          (ii)  The elevator is light and powerful and should be used
                with care during the recovery.
          (iii) Compressibility characteristics may vary between dif-
                ferent aircraft but no difficulty in control should be
                experienced if the limitations are not exceeded.
          (iv)  Above 10,000 feet, warning of the approach and
                effects of compressibility will probably be given by the
                following characteristics :
                (a)  A progressive nose up change of trim occurs between
                     approximately a Mach number of .71 and .76.  The
                     push force to maintain the dive at a Mach number
                     of .76 is considerable and lateral stick forces are
                     very light.  Lateral buffeting and wing dropping may
                     also occur at this speed.
                (b)  If speed is increased further, the lateral buffeting
                     may increase and pronounced longitudinal porpois-
                     ing occurs at an approximate Mach number of .77.
                     The forward push-force to maintain the dive is still
                     heavy but at a Mach number of .78 the porpoising
                     increases until the aircraft tends to recover by itself
                     by breaking away in a series of sudden pitching
                     oscillations in an upward direction.
                (c)  When carrying 500 lb. bombs the lateral buffeting
                     and wing dropping referred to in (a) above may
                     occur at an indicated Mach number as low as .71.
          (v)   Below about 10,000 feet the characteristics will probably
                be as follows :
                (a)  There is a progressive nose up trim change to a Mach
                     number of .75 but not so pronounced as at high
                     altitude and the lateral buffeting may not occur.
                (b)  At about a Mach number of .76, stick forces may
                     fluctuate and there is strong longitudinal buffeting
                     accompanied by a nose down change of trim which
                     may be pronounced.  The aircraft may break away
                     either in a series of sudden pitching oscillations
                     or in an upward or downward direction.  On
                     some aircraft the nose down change of trim may
                     occur at a Mach number as low as .7.
          (vi)  Recovery from compressibility is almost immediate with
                use of the dive brakes, or on throttling back, but there
                is a slight nose down change of trim on throttling back at
                low altitudes.  Opening the dive brakes produces a

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