This is meant to be an exposition of the simple, yet elegant models used to understand the working and performance of a helicopter. Using first principles, thought experiments and the occasional Hollywood video, learners will understand how to gauge the efficiency of a rotor, and how to predict its performance (even on distant planets!). They will grasp how a rotor operates in climb and how to produce the universal inflow curve. They will gather the necessary tools and techniques to predict the descent rate of a maple seed when it is in an 'autorotative' state. The asymmetries inherent to forward flight will also be covered in detail. Using a hybrid model, they will be learn how to compute the inflow variation across the rotor disk. Students will finally be exposed to the fundamentals of efficient rotor design ('optimum' vs 'ideal' rotors) before an in-depth look into the calculation of typical helicopter performance metrics (maximum speed, service ceiling etc).

The course will cover and use the following three models in a variety of conditions:

(1) Momentum Theory

(2) Blade Element Theory (BET)

(3) Blade Element Momentum Theory (BEMT)

When applicable, lectures will be accompanied with optional Python scripts for interested students to run and extend.