Welcome to the Home Page for:
HELICOPTER AERODYNAMICS I
The objectives of this course are to provide an introductory treatment of the aerodynamic theory of rotary-wing aircraft, including basic performance, control, and basic rotor dynamics. Prerequisites are a understanding of elementary aerodynamics and dynamics. Students should have taken two courses in aerodynamics at the undergraduate level. Students should also have an elementary background in computer programming.
Homework Problem Sets
History of Rotorcraft
Prof. J. Gordon Leishman, Room 3179C,
Open. Unavailable Tuesday and Thursdays until 11am (Reserved for ENAE 488A students). Only by prior appoinments on Fridays. Otherwise, you are welcome to come and see the instructor at anytime during regular office hours, workload permitting. Call or email first!
Students may use email as a means of interacting with the instructor. Make sure you have a computer account. Class announcements will often be made by email. Click here to email: J. Gordon Leishman.
Please do not send homework assignments by email (see homework requirements below).
- Homework (70%)
- Technical Essay (15%)
- Final Exam (15%).
- Homework is assigned (posted on the web page) about every other week, usually on a Tuesday.
- Homework must be submitted one-week after it is assigned.
- Submission of homework is mandatory.
- Homework is expected to be done carefully and neatly, and submitted on-time.
- Improperly done homework will be returned for correction and resubmision. Resubmissions may not be graded until the next batch of homework.
- Students taking the course over instructional television (ITV) MUST submit all their assignments through ITV, or can mail the assignments directly to the instructor by regular US mail if submission through ITV is not possible. The homework must be dated as received by ITV or postmarked by the due date. DO NOT send homework by FAX.
- Time-extensions for homework submissions will be granted, but only on a case by case basis. Homework submitted after the due date and without a time extension will receive no credit.
Homework Problem Sets (posted here when made available)
Homework #1. Posted 9/1/05. Due 9/13/05.
Homework #2. Posted 9/16/05. Due 9/27/05.
Homework #3. Posted 10/7/05. Due 10/17/05
Homework #4. Posted 10/18/05. Due 11/1/05
Homework #5. Posted 11/17/05. Due 11/24/05
Homework #6. Posted 11/29/05. Due 12/08/05
Download Introductory Slides for ENAE 631 here:
- For Part 1 of the introductory slide presentation click here.
- For Part 2 of the introductory slide presentation click here.
- For a paper on the technical development of the autogiro, click here.
- The Technical Essay will be due for submission on 11/22/05. NO EXTENSIONS.
- The essay title must be submitted to the instructor for approval no later than 9/30/05
- The essay can be on any subject related to rotorcraft technology, but must have relevance to aerodynamics.
- For further details on the essay requirements, click here.
- There is no mid-term exam for the Fall 2004 semester.
- The final exam is 12/16/04 at 10:30am.
- Primary textbook is: Principles of Helicopter Aerodynamics (Hardback) Cambridge University Press, ISBN: 0-5216606-0-2 or Paperback edition ISBN: 0-5215239-6-6.
- 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.
- A primary reference text will be Helicopter Theory by Johnson. This is the definitive reference for modern helicopter analyses. An inexpensive Dover publication of this book is now available.
- Other useful books 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.
HISTORY OF ROTORCRAFT:
The ideas of vertical flight can be traced back to early Chinese tops, a toy first used about 400 BC. Amongst his many elaborate drawings, the Renaissance visionary Leonardo da Vinci shows what is a basic human-carrying helicopterlike machine. His sketch of the "aerial-screw" or "air gyroscope" device is dated to 1483 but it was first published nearly three centuries later. Da Vinci clearly did not build his machine, except perhaps for some small models, but his idea was clearly far ahead of its time. Read more....
- Article on Breguet Quadrotor
- Article on Cornu Helicopter
- Singles versus tandems versus coaxials
- Vortex ring state
- BERP rotor.
- Tail rotors
Course outline (not necessarily covered in order stated):
1. Introduction: A History of Helicopter Flight
- Early Attempts at Vertical Flight
- The Era of the Autogiro
- The First Successes With Helicopters
- Maturing Technology
- Tilt-Wings and Tilt-Rotors
2. Fundamentals of Rotor Aerodynamics
- Flow Near a Hovering Rotor
- Conservation Laws of Fluid Mechanics
- Application to a Hovering Rotor
- Disk Loading and Power Loading
- Induced Inflow Ratio
- Thrust and Power Coefficients
- Non-Ideal Effects on Rotor Performance
- Figure of Merit
- Induced Tip-Loss
- Rotor Solidity and Blade Loading Coefficient
- Power Loading
- Axial Climb & Descent
- Working States of the Rotor in Axial Flight
- Momentum Analysis in Forward Flight
- Induced Velocity in Forward Flight
- Numerical Solution to Inflow Equation
- Validity of the Inflow Equation
- Rotor Power in Forward Flight
- Other Applications of the Momentum Theory
3. Blade Element Analysis
- Blade Element Analysis in Hover and Axial Flight
- Integrated Rotor Thrust and Power
- Thrust Approximations
- Torque/Power Approximations
- Tip Loss Factor
- Blade Element Momentum Theory
- Ideal Twist
- BEM Theory - A Numerical Approach
- Distributions of Inflow and Airloads
- The Optimum Hovering Rotor
- Circulation Theory of Lift
- Power Estimates
- Prandtl's Tip Loss Function
- Figure of Merit
- Compressibility Corrections
- Thrust Weighted Solidity
- Power/Torque Weighted Solidity
- Weighted Solidity of the Optimum Rotor
- Weighted Solidities of Tapered Blades
- Mean Lift Coefficient
- Blade Element Analysis in Forward Flight
- Blade Forces
- Induced Velocity Field
4. Rotating Blade Motion
- Types of Rotors
- Equilibrium About the Flapping Hinge
- Equilibrium About the Lead/Lag Hinge
- Equation of Motion for Flapping Blade
- Physical Description of Blade Flapping
- Coning Angle
- Longitudinal Flapping
- Lateral Flapping
- Dynamics of Blade Flapping with a Hinge Offset
- Blade Feathering and the Swashplate
- Review of Rotor Reference Axes
- Dynamics of a Lagging Blade with Hinge Offset
- Coupled Flap-Lag Motion
- Introduction to Rotor Trim
5. Basic Helicopter Performance
- Hovering and Axial Climb Performance
- Forward Flight Performance
- Induced Power
- Blade Profile Power
- Parasitic Power
- Climb Power
- Tail Rotor Power
- Total Power
- Effect of Gross Weight
- Effect of Density Altitude
- Lift-to-Drag Ratios
- Climb Performance
- Speed for Minimum Power
- Speed for Maximum Range
- Range-Payload and Endurance-Payload
- Factors Affecting Maximum Attainable Forward Speed
- Performance of Co-Axials and Tandems
- Autorotation Revisited
- Autorotation in Forward Flight
- Height-Velocity (HV) Curve
- Autorotation Index
- Ground Effect
6. Conceptual Design of Helicopters
- Design Requirements
- Design of the Main Rotor
- Rotor Diameter
- Tip Speed
- Rotor Solidity
- Number of Blades
- Blade Twist
- Blade Planform & Tip Shape
- Airfoil Sections
- The BERP Rotor
- Fuselage Design
- Fuselage Drag
- Vertical Drag or Download
- Fuselage Side-Force
- Empennage Design
- Horizontal Stabilizer
- Vertical Stabilizer
- Design of Tail Rotors
- Physical Size
- Thrust Requirements
- Pushers Versus Tractors
- Design Requirements
- Aerodynamic Interactions
- Typical Tail Rotor Designs
- Other Anti-Torque Devices
- High Speed Rotorcraft
- Compound Helicopters
- Tilt Rotors
- Other High Speed Rotorcraft
Go back to the Rotorcraft Aerodynamics main page