In aerodynamics, the flight envelope defines operational limits for an aircraft with respect to maximum speed and load factor, given at a particular atmospheric density.
To calculate those limits we use te "V-n diagram
The V-n diagram is a graph that summarizes an aircraft's structural and aerodynamic limitations at a particular weight, altitude and configuration.
- The horizontal axis is indicated airspeed.
- The vertical axis of the graph is load factor, or G's.
The vertical line on the right side is called the redline airspeed, or VNE (Velocity never-to-exceed).
- Main rotor blades stalls and helicopter loses lift,
- Stalling main rotor blades creates excessive vibrations,
- Helicopter might suffer from structural damage.
In forward flight, the tip of advancing balde will have the highest speed. If forward speed exeeds maximum speed, it will reach M1.0 and start a stalling.
The top and bottom of the V-n diagram are established by the structural limit line, or limit load factor.
ULTIMATE LOAD FACTOR
There will be some permanent deformation at the ultimate load factor, but no actual failure of the major load-carrying components should occur.
An aerodynamic limit of rotor thrust exists at speeds less than maneuver speed because air mass flow through the rotor is decreasing and the rotor can't generate high transient thrust levels.
- Naval air training comand CNATRA P-401 (Rev. 10-09)
- VID 241036 - Creation
DATE OF SUBMISSION
- 12:33, 23 February 2021
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