RSSOrigami Flying Disc
Read this article in MAKE:
10: Home Electronics, Page 167.
To get MAKE, subscribe or purchase single volumes.
Subscribers—read this article now in your digital edition!Understand Bernoulli's principle of flowing fluids and gases with a paper flyer.
From the column 123
By Cy Tymony
Illustrations by Tim Lillis
MAKE: Noise — Discuss this article
You must be logged in to post a talkback.[ Display main threads only] [ Oldest First]
Showing messages 1 through 3 of 3.
- Incorrect theory
You must be logged in to reply.
The explanation for the lift is not correct. Bernoulli's equation is true, but the longer upper surface does not explain the increased speed of air.
A wing is just deflecting air particles down (both upper and lower surfaces contribute to this), so the wing must go up.
Typical wing shape, as seen in fig 3 also, is designed to minimize the drag and turbulent airflows around it, while deflecting as much air as possible (or needed). Making one surface longer than the other is not the target.
Posted by pnu on July 23, 2007 at 07:31:10 Pacific Time
- Incorrect theory
You must be logged in to reply.
The commonly used term for the lift (bird, airplane, frisbee, boomerang) effect is the Bernoulli principle.
In a short one-page, how-to column (with 14 illustrations) there's no room to bring up: the angle of attack, the Coanda effect, reducing the strength of turbulence with flaps, how airplanes can fly upside down, how sailboats use the "Tacking technique" to sail into the wind, curveballs and how Beckham "bends it."
The fundamentals won't please everyone but they open the door to investigate more.
Cy Tymony
Posted by Sneakyuser on August 02, 2007 at 16:02:37 Pacific Time
- Incorrect theory
You must be logged in to reply.
Pnu is correct: I can't believe Ty has dragged out these old cliches; blowing across a piece of paper demonstrates the Coanda effect, not Bernoulli's principle (It is the curvature of the paper, not the faster flow of air, which makes it lift; it is only coincidence that gravity supplies a curve which appears to support Bernoulli. Try turning the paper strip on its side, so that it does not curve. There will be no movement towards the air stream).
Second, the molecules which travel above a wing have no "memory" thus have no idea they have farther to travel. There is no "rejoining" of air molecules at the trailing edge of the wing--there never was. This concept is in many aerodynamics books--but not any recent ones! Typical way to see the error of this view is to think about planes which fly upside down--Ty's explanation cannot explain this; pnu is accurate.Posted by kiteship on July 29, 2007 at 15:48:29 Pacific Time
|
Showing messages 1 through 3 of 3. |
Join the conversation -- every MAKE article has an online page that includes a place for discussion. We've made these RSS and Atom feeds to help you watch the discussions: subscribe.
Explore More in Make Magazine
Search the pages of MAKE
Raves for MAKE!
“Now we've got geek DIY (do it yourself) porn. Just as would-be Emerils pore over lushly illustrated cookbooks with recipes involving hard-to-find morels and complicated instructions for roux, Tom Swift wanna-bes are devouring MAKE.”
— Steven Levy, Newsweek
“...O'Reilly Media recently launched what has already become the bible of this new movement, a magazine called MAKE.”
— Daniel Roth, FORTUNE
“If you're the type who views the warnings not to pry open your computer as more a challenge than admonition, MAKE is for you.”
— Rolling Stone
“One of the most innovative magazines I've seen in a long time.”
— Steve Riggio, CEO Barnes & Noble
“The kind of magazine that would impress MacGyver”
— Marcus Chan, San Francisco Chronicle
