Mach Crit (Mcrit)?
May 10, 2024
Ref FAA PHAK 5-45
What’s Mcrit – Mach Crit?
Ans: airflow over any part of the aircraft or structure under consideration first reaches (but does not exceed) Mach 1.0.
Design of increase Mcrit (delay occurrence of shock wave) ?
- Thin airfoil (reduce the thickness)
- drawbacks: reduce the wing tank volumn
- Sweepback
- drawbacks: need to fly faster to compensate, and that is why the aircraft need high lift devices to maintain T/O performance
- vortex generators
function: delay the onset of separation by creating a vortex which mixes boundary airflow with high energy
