Why Do Jets Fly so High? Intro to Thrust and Jet Engine Design
Propulsion and flight module exploring the thrust equation
This module explores the concept of thrust and the relevant equations for jet engines in an introductory course about “flight”. When implemented at the University of Dayton, the “Introduction to Flight” course had 28 students in their sophomore and junior level studying Mechanical Engineering. Each assignment in this class includes EML objectives. The module took 2.5 weeks (5 classes each 1 hour and 15 minutes) to be complete where the students explored the question, “Why do jets fly so high?” and big picture view of “thrust” and jet engine design.
This module involved the 3C’s by guiding students through a process of inquiry, exploration and discovery. In classroom, students were exposed to the fundamental equation of thrust derived from conservation of mass and momentum. Then, the students were asked to find opportunities to increase thrust from an engine by influencing parameters in the thrust equation. The open ended question encourages students to make connections between theory and practice. After understanding the equation, students discuss opportunities for improvement and societal impact. This module would work well for anyone teaching flight, jet engines, or propulsion.
- The nominal thrust of a large modern commercial jet engine, and the approximate cost, lifetime, and fuel consumption
- How components (inlet, diffuser, compressor, combustion chamber, turbine, and nozzle) are interconnected and contribute to thrust
- Why cruising altitude is an important parameter for optimizing efficiency
- An understanding of engines to devise a laboratory experiment, measuring thrust of a simple electric fan with force sensors
- Which type of jet engine produces greater thrust/cost
- Opportunities to increase thrust with an assessment of both feasibility and viability
- A collaborative space encourages collaboration and participation in group discussions
- More hands-on activities would help students make connections with day-to-day flight
- Have multiple assessments spread throughout the module rather than at the end