Tom
From the Hawker manual, V2: take-off safety speed. V2 is equal to VR plus the increment in speed attained prior to reaching 35 feet with an engine failure.
VFTO: The final take-off climb speed. "When a positive rate of climb has been established, retract the landing gear. Raise the flaps at approximately 160 kts but not below final take-off climb speed. With both engines operating at take-off thrust, the airplane should be allowed to accelerate to an airspeed of 160 KIAS, this airspeed being maintained until obstacle clearance height is reached."
VERC: en route climb speed.
So for a two engine noise abatement departure we aim for 160kts whilst adjusting power so as not to exceed the maximum mandated pitch of 20 degrees. Flaps are then raised, the aircraft accelerated to VERC and climb power is set.
So for the Hawker, V2 plus 10, whilst unlikely to make the aircraft fall out of the sky, is not the most efficient speed to raise flaps whilst maintaining the close-in obstacle clearance profile (second segment). Or, put another way, retracting flaps at V2 plus 10 in the climb will degrade climb angle as opposed to waiting until VFTO. From the manual.
AP