# error in the "will the plane take off" **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [August 14, 2007, 11:05am UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537 "2007-08-14T11:05:17Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [August 21, 2007, 3:03pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/21 "2007-08-21T15:03:54Z")
[QUOTE=wevets] Just a note - lift is generated by more than just the Bernoulli Principle - from what I understand, planes have to deflect enough air downwards to provide an upward lift force, and lift can be generated from Bernoulli, the Coanda effect, and in some other ways. > **[Lift (force)](https://en.wikipedia.org/wiki/Lift_%28force%29)** > > When a fluid flows around an object, the fluid exerts a force on the object. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to counter the force of gravity, but it may act in any direction perpendicular to the flow. If the surrounding fluid is air, the force is called an aerodynamic force. In wate... [http://www.straightdope.com/mailbag/mairplanesfly.html](http://www.straightdope.com/mailbag/mairplanesfly.html) [/QUOTE] He doesn’t actually mention the Bernoulli principle. Regardless of whether air is “deflected downwards” (which understates the importance of what happens over the top of the wing), or “travels faster over the top compared to the bottom” (which is true even for a flat plate, but the reason given is flawed), or “turned”, the ultimate effect must be the same: for a wing to generate lift there must be an area of lower pressure above it compared to the pressure below it. This is all he has said and it is about as accurate as you can be without offending someone somewhere. And yeah, in real life prop aircraft, the lift generated by the propwash over the wing is minimal. It has a small effect on the behaviour of the aircraft as the wing stalls but that is about all. Otherwise I’d be in danger of lifting off the ground when doing full power engine runs against the brakes! ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [August 21, 2007, 3:05pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/22 "2007-08-21T15:05:35Z")
[QUOTE=John W. Kennedy] Actually, I don’t think a normal prop airplane will take off while not moving relative to the atmosphere, but that is because a normal takeoff depends on the ability of the aircraft to accelerate to rotation speed; the props alone won’t send enough air over the wings. But an overpowered plane could, assuming that the weight of the additional engines and additional frame and struts doesn’t spoil it. [/QUOTE] And you’d be better off rotating the engines 90 degrees and calling the thing a helicopter. ---
**Author:** ![John\_W.Kennedy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_w.kennedy/32/1031_2.png) [@John\_W.Kennedy](https://boards.straightdope.com/u/John_W.Kennedy)\ **Post date:** [August 21, 2007, 8:37pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/23 "2007-08-21T20:37:08Z")
[QUOTE=The Sonoran Lizard King] Then why don’t they put big fans on sailing ships, and go anywhere they want, independent of wind? [/quote] Ever visit the Everglades? ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [August 22, 2007, 2:02am UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/24 "2007-08-22T02:02:53Z")
[QUOTE=John W. Kennedy] Ever visit the Everglades? [/QUOTE] Missing the point, I think, John. Those work by pushing air. They don’t work by pushing air into the sails of the ship. ---
**Author:** ![Khampelf](https://avatars.discourse-cdn.com/v4/letter/k/8e7dd6/32.png) [@Khampelf](https://boards.straightdope.com/u/Khampelf)\ **Post date:** [August 22, 2007, 2:35am UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/25 "2007-08-22T02:35:45Z")
[QUOTE=DSYoungEsq] Missing the point, I think, John. Those work by pushing air. They don’t work by pushing air into the sails of the ship. [/QUOTE] Yes. Thank you. ---
**Author:** ![Defective\_Detective](https://avatars.discourse-cdn.com/v4/letter/d/d2c977/32.png) [@Defective\_Detective](https://boards.straightdope.com/u/Defective_Detective)\ **Post date:** [August 22, 2007, 2:51am UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/26 "2007-08-22T02:51:56Z")
Would one be allowed, outside of the pit, to respectfully call someone an idiot and kindly suggest they return to whence they came? Because if one were, I might be inclined to say so to Dr Max (or whatever his screen name is). Although that might be rude, so perhaps I’ll refrain. ---
**Author:** ![John\_W.Kennedy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_w.kennedy/32/1031_2.png) [@John\_W.Kennedy](https://boards.straightdope.com/u/John_W.Kennedy)\ **Post date:** [August 22, 2007, 3:17am UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/27 "2007-08-22T03:17:22Z")
[QUOTE=DSYoungEsq] Missing the point, I think, John. Those work by pushing air. They don’t work by pushing air into the sails of the ship. [/QUOTE] Yes, but that’s not what he said. Anyway, I already pointed out the problem with his logic in my previous posting. Pulling yourself up by your bootstraps or using fans on your own sails is a zero-net-force situation. Airplane propellers are not (if they were, no plane would _ever_ take off). (And yet the “using fans on your own sails” situation is actually more complex than that. Ever hear of a Flettner rotor ship?) ---
**Author:** ![Cyberhwk](https://avatars.discourse-cdn.com/v4/letter/c/7993a0/32.png) [@Cyberhwk](https://boards.straightdope.com/u/Cyberhwk)\ **Post date:** [August 22, 2007, 8:50am UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/28 "2007-08-22T08:50:01Z")
Nothing to add, just wanted to say it’s realizations like this thread that make me glad I re-upped earlier today. ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [August 22, 2007, 3:11pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/29 "2007-08-22T15:11:26Z")
[QUOTE=DSYoungEsq] Missing the point, I think, John. Those work by pushing air. They don’t work by pushing air into the sails of the ship. [/QUOTE] True and true. Problem here is that neither analogy is really equivalent to what happens with the airplane wing, although **John** ’s is closer. Problem is, with both swamp boats and self-propelled sailing ships, we’re talking about purely horizontal airflow, thrust, and motion. However, with the airpalne, the question is whether a prop thrusting _horizontally_ will create enough flow over the wing to lift the plane _vertically_. Different set of vectors. [In an earlier thread](http://boards.straightdope.com/sdmb/showthread.php?p=7064728#post7064728), guest \*\*smellsofbikes \*\* says, > [@](#): > > When you’re practicing _very_ short take-off and landing in a Piper Supercub, a tailwheel aircraft (as in two big wheels up front, one small one in the back) you stomp on the brakes, and bring the engine up to near-full-power, and the air from the prop is sufficient to lift the tail so you’re balanced on two wheels. But you’re nowhere near flying. That pretty much seems to match with **John** ’s intuition that a normal aircraft won’t fly with just the engine backflow, but an overpowered one might. ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [August 22, 2007, 3:21pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/30 "2007-08-22T15:21:00Z")
Yes, well, I wasn’t saying that the propeller wash over the wing thing wouldn’t work, just pointing out that the analogy used was based upon an inaccurate understanding of what the prior poster had said. 🙂 ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [August 22, 2007, 4:42pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/31 "2007-08-22T16:42:52Z")
[QUOTE=DSYoungEsq] Yes, well, I wasn’t saying that the propeller wash over the wing thing wouldn’t work, just pointing out that the analogy used was based upon an inaccurate understanding of what the prior poster had said. 🙂 [/QUOTE] Sorry; I wasn’t necessarily disagreeing with you, just using your post as a jumping-off point to continue the conversation. ---
**Author:** ![DiggitCamara](https://avatars.discourse-cdn.com/v4/letter/d/df788c/32.png) [@DiggitCamara](https://boards.straightdope.com/u/DiggitCamara)\ **Post date:** [August 22, 2007, 5:42pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/32 "2007-08-22T17:42:24Z")
[QUOTE=Defective Detective] Would one be allowed, outside of the pit, to respectfully call someone an idiot and kindly suggest they return to whence they came? (snip) [/QUOTE] Not needed (nor would it be heeded). Dr Max came, answered and left (victoriously, at least in his mind). ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [August 23, 2007, 4:13pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/33 "2007-08-23T16:13:35Z")
[QUOTE=Defective Detective] Would one be allowed, outside of the pit, to respectfully call someone an idiot and kindly suggest they return to whence they came? [/QUOTE] No, that would not be allowed. But I think you knew that. Insults, whether direct or implied, are not permitted in this forum. Don’t try this ploy again. bibliophage moderator CCC ---
**Author:** ![John\_Kavanagh](https://avatars.discourse-cdn.com/v4/letter/j/d78d45/32.png) [@John\_Kavanagh](https://boards.straightdope.com/u/John_Kavanagh)\ **Post date:** [August 31, 2007, 2:37pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/34 "2007-08-31T14:37:46Z")
On the thread about [Human Cannonballs](http://www.straightdope.com/classics/a4_069.html) Cecil, peace be unto him, mentions the first such projectile, a “Young woman named Zazel”. Actually it was a young man who at that point in his career posed as a woman becasue his mentor, The Great Farini, thought it made better theatre. “Farini” was a Canadian, an early tightrope walker and the first person, I think, to walk a tightrope over Niagara Falls. The story of both of them (including their real names, which I forget) is in the book “The Great Farini”, a good and interesting read. ---
**Author:** ![John\_Kavanagh](https://avatars.discourse-cdn.com/v4/letter/j/d78d45/32.png) [@John\_Kavanagh](https://boards.straightdope.com/u/John_Kavanagh)\ **Post date:** [August 31, 2007, 2:41pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/35 "2007-08-31T14:41:12Z")
Sorry, this was meant ot be a new thread. Forgive a newbie. ---
**Author:** ![Cervaise](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cervaise/32/16693_2.png) [@Cervaise](https://boards.straightdope.com/u/Cervaise)\ **Post date:** [October 31, 2007, 6:18pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/36 "2007-10-31T18:18:25Z")
Bumping this thread (chose it because it’s recent, and because it contains **zut** ’s definitive post on the subject) to report that Mythbusters has decided to take on the question. The episode will air in December, [sez this story](http://seattletimes.nwsource.com/html/television/2003983863_webmythbusters.html). Set your TiVos, people! 🙂 ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [October 31, 2007, 6:31pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/37 "2007-10-31T18:31:28Z")
[QUOTE=The Sonoran Lizard King] All Hail the magical treadmill!! The mighty force that keeps planes stationary in the face of all physics. Hail! [/QUOTE] It’s the same mighty, magical force that keeps threads like this popping up when everything has been wrung out of the topic long ago. ---
**Author:** ![DanBlather](https://avatars.discourse-cdn.com/v4/letter/d/f4b2a3/32.png) [@DanBlather](https://boards.straightdope.com/u/DanBlather)\ **Post date:** [October 31, 2007, 6:40pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/38 "2007-10-31T18:40:18Z")
[QUOTE=John Kavanagh] On the thread about [Human Cannonballs](http://www.straightdope.com/classics/a4_069.html) Cecil, peace be unto him, mentions the first such projectile, a “Young woman named Zazel”. Actually it was a young man who at that point in his career posed as a woman becasue his mentor, The Great Farini, thought it made better theatre. “Farini” was a Canadian, an early tightrope walker and the first person, I think, to walk a tightrope over Niagara Falls. The story of both of them (including their real names, which I forget) is in the book “The Great Farini”, a good and interesting read. [/QUOTE] The only reason it was a man was because they couldn’t find a woman of the right caliber. 🙂 ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [October 31, 2007, 7:15pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/39 "2007-10-31T19:15:50Z")
[QUOTE=Cervaise] Bumping this thread (chose it because it’s recent, and because it contains **zut** ’s definitive post on the subject) to report that Mythbusters has decided to take on the question. The episode will air in December, [sez this story](http://seattletimes.nwsource.com/html/television/2003983863_webmythbusters.html). Set your TiVos, people! 🙂 [/QUOTE] > [@](#): > > “We put the plane on a quarter-mile conveyor belt and tested it out,” says Savage about the experiment using a pilot and his Ultralight plane. “I won’t tell you what the outcome was, but the pilot and his entire flight club got it wrong.” So the plane didn’t take off? 😉 Guess they screwed up somewhere. ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [November 1, 2007, 12:48pm UTC](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537/40 "2007-11-01T12:48:57Z")
> [@](#): > > “We put the plane on a quarter-mile conveyor belt and tested it out,” says Savage about the experiment using a pilot and his Ultralight plane. “I won’t tell you what the outcome was, but the pilot and his entire flight club got it wrong.” [QUOTE=Colophon] So the plane didn’t take off? 😉 Guess they screwed up somewhere. [/QUOTE] Knowing Mythbusters, I suspect the plane revved up, lurched forward, slewed off the runway, careened wildly toward the camera crew, tipped onto its nose, and exploded in a ball of flame. [Previous page](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537.md?page=1) [Next page](https://boards.straightdope.com/t/error-in-the-will-the-plane-take-off/415537.md?page=3)