The Bombardier C Series CS100 aircraft performed the crucial “Velocity Minimum Unstick Testing”, one of the most fascinating flight tes...
The Bombardier C Series CS100 aircraft performed the crucial “Velocity Minimum Unstick Testing”, one of the most fascinating flight tests in the certification schedule – direct from Salina, Kansas.
This test allows to determine VMU speed - the slowest safe speed an aircraft can go and still achieve take-off, or “unstick” itself from the runway, because the computed take off speeds incorporate some margin above VMU, just as they also do for VS (Stall speed), VMCG (Minimum control speed on the ground) and VMCA (Minimum control speed in the air). These “V” speeds therefore form the basic building blocks of take-off performance.
The optimization of take-off performance is complex. Firstly, the aircraft must be able to get airborne safely, even in the case of failure of one engine. It may also have to overfly obstacles, close or far from the runway end, with sufficient margin, still with an engine failed. The optimization has to be performed for all weights, altitudes and temperatures and obviously some compromises have to be made, as no aircraft can be perfect for all conditions.
During the takeoff, the test aircraft tail will scrap the runway with a lot of sparks coming from the rear fuselage. A specific tail bumper is added to protect the tail from any damage.
