A NASA View
Most of the improvements over the past 40 years have been as a result of propulsion technology, primarily higher by-pass ratios and turbine inlet temperatures, nearly tripling seat mules per gallon. Advanced configuration concepts have, in general not been investigated in depth nor implemented.
The thickness ratio
The thickness ratio is the ratio of the maximum thickness of an airfoil to the chord and often varies between the root and tip.
Aircraft Design: Synthesis and Analysis
This internet-based version of Aircraft Design: Synthesis and Analysis is an experiment. It is a new type of textbook whose pages may be distributed throughout the world and accessable via the world-wide-web. The text will be evolving and new items will be added continually.
Why a Digital Textbook?
There are several reasons for using this format for the course notes:
- They are easily updated and changed — important for aircraft design so that new examples and methods can be added.
- Analysis routines can be built into the notes directly. The book permits you to build up a design as you progress through the chapters.
- The format permits easy access to information and organizes it in a way that cannot be done in hardcopy.
- It is inexpensive to include color pictures and video.
- It is possible, by providing just a couple of custom pages, to tailor the textbook for a particular course. If the material on supersonic flow is not appropriate for the class, a new outline and contents page may be created that avoids reference to that material.
Taking Notes
- Shock waves in supersonic flow create a new source of drag called wave drag.
- To minimize the strength of the shock wave, all supersonic airfoil profiles are thin, with respect relatively sharp leading edges.
- Total drag = Skin friction drag + Pressure drag (due to flow separation) + wave drag (only for transonic and supersonic speeds)
- Skin friction drag + Pressure drag called Profile Drag
Pilot Induced Oscillations
Pilot Induced Oscillations (PIO) are defined as sustained or uncontrollable oscillations resulting from the pilot’s efforts to control the aircraft.
Definition - Pilot Handling Qualities
Pilot Handling Qualities are quantitative measures of the acceptability of the stability, controllability and manoeuvring performance of an aircraft which can be utilised by an engineer during the aircraft design process.
