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
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
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
The 4 forces: origins, basic physics/aerodynamics, components of each, how to maximize or minimize them:
-1) Weight (and density) – weight is bad for range, speed, altitude, efficiency…
-2) Lift – airfoils, camber & crest, pressure, air down = plane up, changes w speed & density, Euler-N & Bernoulli.
-3) Drag – parasite and pressure – most obvious – sonic and induced – less obvious.
Pointy planes, swept wings, high aspect ratio, smooth surfaces, teardropping. Cruise speed.
-4) Thrust. Engines: in line, radial, rotary, (then back to in line), turbojet, turbofan,
turboprop, ramjet, and miscellaneous (time allowing): rocket, pulsejet, electric, man-powered…
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
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
- Wing Aspect Ratio
- Wing Loading, biplanes
- Wing Sweep
- Thrust to Weight – Lift to Drag – Glide slope
- Lift distribution, Twist/washout (vortices & tip stall), Taper
- Noise (engine, turbulence)
- 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.