 |
||||||||||||||||
 |
||||||||||||||||
 |
||||||||||||||||
 |
||||||||||||||||
|
||||||||||||||||
 |
 |
|
||||||||||||||||||||
AirplaneDesign.info
This site is still under construction. Most of the links on the left side of the page don't work yet. Please be patient and check again soon. Thanks.
This site will include extensive information about why airplanes are designed the way they are, about why modern airplanes are designed very differently from older airplanes, and why some modern airplanes look very different from some other modern airplanes. During my junior year at Stanford (I hate how pretentious sentences like this sound, but bear with me), I learned of this AWESOME program where an undergrad could design a course and teach it to high schoolers. The course could be taught over five two-hour classes, and be about pretty much anything. The program organizers would do all the “marketing”, contacting 50 schools in the Bay Area and taking care of the registration process. All I had to do was plan a class and teach it. It sounded almost too good to be true. I love teaching, and I love talking about airplanes. I love it when I help people appreciate how cool and intricate the technology around them is. You mean I can spend TEN HOURS talking to high schoolers about airplanes?! That’s AWESOME! And indeed it was awesome. I got nine really great and smart kids, and I planned five interesting, diverse, and quite action packed lectures. We flew my radio-controlled flying wing, flew simulators, and talked about all kinds of airplanes and airplane-related stuff. Few things I have done in my time at Stanford were this interesting, this fun, or this rewarding. The fall after that (senior year), I learned that undergraduates could create and TEACH courses at Stanford! I had heard of Student-Initiated Courses before, but as far as I knew, they involved students working together with faculty to “create” a course that the faculty member would teach. Apparently, some departments made it easy for STUDENTS to teach one- or two-credit courses, especially if those students had gone through the teaching and curriculum-planning workshops put on by the Student-Initiated Course organization at Stanford. And as for the departments that did NOT make this so easy (i.e. the techie ones), faculty members could still teach independent research courses/workshops/seminars. So I would be good to go if I could persuade a member of the faculty that my high-school course would, after some changes, make a good Mechanical Engineering course, and that I would be good at teaching it. My advisor was surprisingly impressed by how much preparation I had put into this course, and at how full of cool stuff it was, so he backed me up and allowed me to make it happen as a Stanford course. Part of the reason that he was so impressed is that I wrote a 170-page book about all the tings I talked about in the class. I am quite unhappy about the fact that this book is now sitting on my shelf instead of getting read by people who might enjoy learning from it. So I’m going to put it all online. I have also written an addendum to the book, about stuff I find interesting but which I did not have time to talk about in my class. Since I wanted to give my students an overview of how aeronautical technologies have evolved, it would not be worthwhile to spend much time talking about VTOL technology or stealth technology, since the impact of these developments on mainstream aviation has been minimal. However, I do know a lot about those technologies, I think they involve some extremely clever engineering, and I did get asked about them in class, so I have written an addendum to my book about those technologies and some other things. I am in the process of converting all the content of my course into HTML and into videos you can watch on the web. All that stuff will be put up on this site once I'm done converting it. Until then, you can download the PDF of my book. (Warning: huge 42 meg file!!!). It does not include the more recent stuff I wrote about VTOL, stealth, etc, just the stuff from the course itself. A lot of the pictures in that book are not mine. I was assured by knowledgeable people that printing those images out in a small size (about 2" on a side, in the middle of a page full of text) for educational purposes at a non-profit school is a kind of use allowed by the "fair use" exceptions to copyright law. However, this is not true if the work is posted publicly on the web for anyone to see. So while this site is non-commercial in nature (there are no ads on AirplaneDesign.info or any other money-making mechanisms), I am in the process of contacting the sources of all the images in my book, before posting the content on this site. So, if you do download that PDF, please remember: It is illegal to use any of those pictures in any way (well, any way that is not "fair use"). They are copyrighted and belong to their respective photographers. When this site is finished, it will contain credits and information on the origin of every image here. The text is all by me. You may use it as long as you give me credit. While I work on converting 170 pages’ worth of text and pictures into HTML, for now here is the course description so you can know what to expect:
Why does a World War 1 biplane look so different from an F-16? Why are the wings of a 747 so different from those on a Cessna? Why are gliders so “thin” while the Space Shuttle is so “fat”? Why does a fighter jet sound so different from an airliner? Why are different, newer, better airplanes always being made? This course would be an overview of the history and diversity of airplanes. A student will understand why planes designed at different times or for different reasons look and perform the way they do. We will go over the development of materials and propulsion technologies which allowed airplanes to evolve from gliders and the Wright Flyer to the Space Shuttle and the F-22. We will start by talking about propulsion and the aerodynamics of lift and drag, and how these considerations affect airplane design. Then we will look at many airplane designs to see why airplanes from different decades look the way they do, and to see why modern airplanes made for different purposes look so different. There are good scientific reasons behind every design feature of an airplane, and they are the topic of this course.
And here’s the syllabus, so you know specifically what this part of the site will talk about:
I -- A brief history of aviation -Balloons, dirigibles, gliders, failed attempts. Wright, Dumont (what a record means), Blériot, Curtiss. Records. Airliners. WW1. Bombers, fighters. Air races. Metal and cantilever. Seaplanes. WW2. Jets. The sound barrier. Swept wings. Stealth. Materials. Computer control. Spaceplanes. II -- Science behind design Forces
Control: Pitch, roll, yaw. Elevators, ailerons, rudders. Exceptions (V-tails, drag rudders, elevons, wing-warping, differential thrust, RCS, hang gliders, powered chutes, thrust vectoring, canards). Trimming (center of lift moves back. Fuel pumping in REAL sleek planes). Stability: Pitch. Balance of moments. CG forward with respect to surfaces, so engines forward, wings back, tail way back (that means nose-down, so how do you get a nose-up to balance? Low engines, tail pushes down). Fly-by-wire, fighters, computers, the Shuttle (and why it probably crashed). Roll stability, dihedral. The Envelope: Min t-off to max speed at sea level (low end). Slow end: less air, less viscosity and less loading mean higher alpha and easier stall. Fast end: less drag and same thrust till you climb till all air is used (Stoich.), then less thrust cuz less air, so less speed until you’re both stalling and maxing the engines. Compare envelopes. 747. Cessna. F-22. Osprey. HH-60. Performance, ratios and angles
- Features (winglets, flaps, slats, VGs, spoilers, variable geometry, thrust reversers, landing gear) - Exceptions in controls, engines, and layout – exotic airplanes. III -- A More Technical History Early days – bad engines – slow flight – LIGHT planes – little material, thin – LOW loadings and stresses or else they break. (Wright, Dumont, Bleriot, Fokker Triplane, Curtiss, Vickers Vimy). 30’s – much, much better engines and lighter, more precise metal work means A) Faster planes and B) More robust planes and in consequence C)heavier planes (a few times heavier, on average). So no need for wires and struts. Cantilever wings. Enclosed canopies for faster, higher flight. (Gee Bee, T-6, P-36, Me109, Ford Trimotor, Macchi/Supermarine racers, Boeing 314, Vega/NYP) 40’s – even better engines – even faster – possibly even heavier – even more robust – more agile, or more load / more range. (P-47, Spitfire, DC-3, B-29, Connie, Sea Fury) 50’s – Jets. Sound barrier. Swept wings. MUCH more robust planes. Much higher drag. Temperature becomes an issue. Stubby wings set back for agility, or swept high-aspect-ratio wings for range. (Me262, F-80, F-86, F-100, F-102, B-58, F-104, B-47, 707, SR-71). All the stuff AFTER this in nowhere near that important, and has mostly military applications, except of course for the turbofan. By 1960, jets were aerodynamically equivalent to modern jets. So the 60s experimented with spaceplanes and rockets, with insanely fast planes, and with cold war bombers and interceptors. (Lifting bodies, X-13, X-14, F-4, B-52, 747, MiGs) 70’s – Stealth, computer control, turbofans. (F-16, F-117, Shuttle, F/A-18, HiMAT). 80’s – Light materials for everyone (Rutan planes, ultralights, gliders) 90’s – computers for everyone (777, next-gen fighters, manufacturing) Late 90’s / Early 00’s – Spaceplanes. Everyone wants satellites, no one wants to pay for an ICBM. Hypersonic ramjets. Also, cheaper general aviation. Kitplanes, ULs, etc. Anyone can become a pilot. (X-33, Roton, X-40, X-47, RVs, WAR replicas, ULs, powered parachutes (since 007 The World is not Enough), trikes…) So now, planes are lighter, stronger, safer and cheaper than in the 60’s, but look the same and are not any faster. So all the advances since then allowed us to build the same planes, but better (compare fuel consumption of, say, 747 and F-104, or 777 and 707, or F-22 and a century-series jet, compare weights of 777 and 707…). Then, the NEXT generation: Thrust vectoring, F-22 and 777 engines (and structures), sonic cruiser, ramjet to space (or to Japan), UAV’s. Notice how progress is always driven by the desire to make use of a more powerful (or efficient) engine or of lighter/stiffer materials. Engines and materials are what allow airplanes to become better. And aerodynamics, to a smaller extent, but mainly only during some periods of innovation.
Thanks for your patience. Hopefully this course will all be online soon. Valeu! Sincerely, Bernardo
| |||||||||||||||||||||
 |
|
||||||||||||||||||||
 |
||||||||||||||||
 |
||||||||||||||||
 |
||||||||||||||||
 |
||||||||||||||||
|
||||||||||||||||
 |
