Helicopter Aerodynamics: Speaker Notes

Helicopter Aerodynamics

speaker notes for Philip Greenspun; revised February 2009

fly low and slow with great visibility (no requirement to stay 500' and 1000' above obstacles)
impress friends; take off and land at an airport and they think you're a hero
cheat gravity; fly in arbitrary directions
land off-airport without ending up on the NTSB Web site

a wing is a wing is a wing; a stalling angle of attack is a stall (figure 2-3 and figure 4-2 from Airplane Flying Handbook)
airspeed + angle of attack leads to lift; easiest way to understand Bernoulli's Principle is conservation of energy; kinetic energy increases as velocity increases, so static pressure must decrease (figure 3-5 from Pilot's Handbook of Aeronautical Knowledge)
helicopter in a hover relies on engine-driven rotation to generate airspeed
pull up on the collective to add angle of attack and the helicopter goes up (explain the swashplate and pitch links here), figure 1-7 shows the controls
move the cyclic and the helicopter translates forward, backwards, or sideways
the anti-torque rotor

three sources of energy: potential, kinetic, blade inertia (assume 500', 70 knots, 400 rpm); figure 3-20
importance of maintaining airspeed to treetop level; figure 11-1
flaring from 70 knots to 0 arrests vertical descent
blade inertia cushions drop from 5', not from 500'

ground school is reading at home and not a major part of the process
10-20 hours of instruction to learn to fly the working helicopter from airport to airport
10-20 hours of instruction to learn to manage emergencies and failures
3-5 hours learning to land in confined areas or on rooftops
10 hours of solo flight
recommendation by your instructor
checkride with an FAA designated examiner