Hello, fellow RV-ators.
At Oshkosh this past summer, I gave three talks at the forums. I finally got around to posting the videos online, and I think you would enjoy them.
Note: Each talk has a link to a page where you can download a PDF of the slides.
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The first, and arguably most RV-centric, is about the uses of 3D printing in aviation
. As you'll see, quite a bit of that content came from Van's Air Force. (At the end of my slides
, I credit all you creative people who have come up with 3D printed parts for your RVs, Pipers, etc.). But the scope of the talk goes far beyond kitplanes: It covers the history of how aviation companies have used 3D printing (e.g. stereolithography for wind-tunnel models, fused filaments for flight-test parts), how they use it now (e.g. SLS air ducts and interiors parts, powder-bed titanium engine parts, early structural applications, and UAVs that are almost entirely 3D-printed), and the research that will make more substantial structural applications in the future (e.g. fatigue testing, surface-smoothing, computerized tomography X-rays that can detect tiny internal imperfections). The bulk of the presentation shows dozens of 3D-printed parts currently flying in aircraft made by Boeing, Airbus, Lockheed, Bell, Cessna, Piper, Van's, Sonex, Evektor, Kamov, NASA, and in various spacecraft from cubesats to manned capsules to SpaceX rockets. Did you know that each F/A-18F Super Hornet has about one hundred 3D-printed air ducts?
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The second talk discusses a topic that is near and dear to the heart of many RV pilots: the physics of aerobatics
. (Before Oshkosh, I also gave this talk at the Society of Experimental Test Pilots symposium). Here's the general idea: There are many analysis methods (i.e. equations) out there that will predict airplane performance (e.g. range, required runway lengths, climb rate, etc.), but none for predicting an airplane's aerobatic capabilities. Given some basic facts about an airplane's design (e.g. how many Gs the structure can take, how fast it can fly, its stall speed, etc.), could it do a roll? Could it do a loop? These questions become especially interesting when it comes to "marginally aerobatic airplanes", i.e. airplanes not built for aerobatics, such as jetliners and small single-engine Cessnas. (Note that this talk discusses what is PHYSICALLY POSSIBLE, not what is legal or necessarily advisable). This talk sets up some aerobatic maneuvers as simple high-school physics problems and does the math to figure out what characteristics/capabilities are required for an airplane in order for it to be able to do a roll, and in order for it to be able to do a loop. Even for pilots of very capable airplanes like ours, I hope that my approach helps you think about whether you are flying aerobatics safely and about whether there's anything you can do to perform acro better.
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The third talk is about as general as it gets. Ever since I was a little kid, I had certain questions about why airplanes are designed the way they are
: Why are most airplanes NOT flying wings or canard airplanes, since those are supposedly so efficient? Why do most airplanes have a horizontal stabilizer that pushes downwards? Why do small airplanes have propellers and big airplanes have jet engines? How exactly do winglets reduce drag? And so on. Then I went to college and learned the answers to these questions. The thing is, these answers are hidden inside thick textbooks full of intimidating equations, but it is perfectly possible to explain them to a normal person who doesn't feel like doing calculus. So I created an "airplanes 101" course, which I call Understanding Airplanes, that explains why an airplane is designed the way it is, for non-engineers. I started teaching it even before I graduated with my Bachelor's, and nowadays I teach it mostly at Boeing and at Seattle-area air museums. Although the course is 8 to 10 hours, I have a one-hour "hits and highlights" that addresses the most common questions that people have about airplanes, and that's what I presented at OSH. Look at the questions below, which are addressed in the video. How would you answer them?
- How exactly do winglets reduce drag?
- Why do smaller airplanes generally still have propellers while bigger airplanes usually have jet engines?
- Why do stealth airplanes have flattened fuselages, straight parallel edges, and no right angles?
- Will we ever have supersonic transports again?
- Why are there so few electric airplanes? What about solar?
- What are the pros and cons of composite materials?
- Why do wider jet engines, and wider propellers, allow for better fuel efficiency?
- Some transport airplanes (mostly bizjets and military cargo planes) have T tails, engines in the back, and/or high wings, but most airliners do not. Why?
- When must an airplane be retired?
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