Senior level aerospace elective. The objectives of this course are to provide an introductory treatment of the aerodynamic theory of helicopters. including basic performance, control, and basic rotor dynamics. Prerequisites are a understanding of elementary aerodynamics and dynamics.
Dr. J. Gordon Leishman, Room 3179C,
Homework is assigned about every other week (due for submission 1-week after it is assigned). Submission of homework is mandatory. Homework is expected to be done properly and neatly and submitted on-time. Homework that does not meet the required standard will be returned and must be resubmitted. The Technical Essay will be due about the 12th week of class. The essay can be on any subject related to rotorcraft technology.
A set of printed class notes will be distributed to students. In addition, there are several textbooks that will be used for this course. The classic text on the subject is: Aerodynamics of the Helicopter by Gessow and Myers. Although the nomenclature is a little out of date, this text provides a solid coverage of the basic material. The main secondary text will be Helicopter Theory by Johnson. This is the definitive reference for modern helicopter analyses. An inexpensive Dover publication of this test is now available. Other useful texts are: Rotary Wing Aerodynamics by Stepniewski and Keys, Helicopter Performance, Stability and Control by Prouty, and The Foundations of Helicopter Flight by Newman. The latter text is very modern and provides excellent coverage for an introductory course.
Some history
The difficulties in attaining vertical flight
Rotorcraft configurations
Helicopter design features
Basic flight characteristics of the helicopter
Differences between propellers and rotors
Notation
Momentum considerations
Actuator disk
Rotor thrust and power
Rotor figure of merit (FM)
Blade element considerations
Effect of profile drag on FM
Complexity of the real rotor wake
Momentum theory for climb
Momentum theory for descent
Flow states of the rotor
Combined blade element/momentum theory
Ideally twisted blades
Weighted solidity
Numerical computation of rotor performance
Comparison with measured performance
Tip loss effects
Effects of blade twist and taper
Optimum hovering rotor
Effects of climb on induced power
Ground effect
Energy balance in autorotation
Forces on the blade element in autorotation
Autorotation diagram
Most efficient angle of attack for autorotation
Rotor drag in vertical descent
Equilibrium of hinged blades
Blade flapping and blade motion
Coriolis effects
Rotor types
Control of a hinged rotor in hover
Rotor angle of attack
Rotor induced velocity
Blade element angle of attack
Control of a hinged rotor in forward flight
Calculation of flapping coefficients
Basic performance equation
Climb performance
Range and endurance
Optimum speeds
Maximum level speed
Rotor operating envelope