UltimateDelta From United States of America, joined Sep 2007, 1993 posts, RR: 6 Posted (4 years 11 months 2 weeks 3 days 8 hours ago) and read 5120 times:
Hi, everybody. In a sort of response to the thread about taking off on a conveyor belt, I began wondering whether you could land on one. I'd think you probably could, provided that the belt and the airplane slow down at the same rate. By doing this, you could pretty much land a plane in one spot and have no need for a runway. I'm not suggesting airports do this, but I'd certainly like to know whether it would be possible. Thanks for any input you have on this topic.
UltimateDelta
JGPH1A From , joined Dec 1969, posts, RR: Reply 2, posted (4 years 11 months 2 weeks 3 days 7 hours ago) and read 5107 times:
Quoting UltimateDelta (Thread starter): you could pretty much land a plane in one spot and have no need for a runway.
You could also use the same belt to deliver the customers' luggage, and to get people from security to the gate, so it would be a big saving on infrastructure for the airports too.
I disagree for largely the same reasons as why you can take off from a conveyor belt. The belt will not hold the aircraft in place since the primary application of force to move the plane is through the engines. However as you got to idle thrust I would expect the belt to slow the airplane down as friction takes effect. At best it would be a shorter landing distance.
Anyways, I know this is a sensitive and passionate topic, so I'm donning my flamesuit.
Vikkyvik From United States of America, joined Jul 2003, 8200 posts, RR: 28 Reply 4, posted (4 years 11 months 2 weeks 3 days 5 hours ago) and read 5050 times:
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Quoting UltimateDelta (Thread starter): By doing this, you could pretty much land a plane in one spot and have no need for a runway.
Nope, for the same reason you can't take off with the belt in one spot. The wings need to be moving through the AIR to generate lift. They could care less what the ground is doing (except for ground effect).
You can't bring an airplane moving through the air at 150 kts to a stop in one spot. It's a physical impossibility.
"Two and a Half Men" was filmed in front of a live ostrich.
Vikkyvik From United States of America, joined Jul 2003, 8200 posts, RR: 28 Reply 6, posted (4 years 11 months 2 weeks 3 days 4 hours ago) and read 5025 times:
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Quoting Askr (Reply 6):
Actualy it's quite possible... Thugh more populary known as a crash...
Hah, I did in fact think of that after I had written the post.
But I'm assuming you want to stop it so that the energy is absorbed in some way that won't kill people.
Next thread: "Could you crash a plane on a conveyor belt...."
"Two and a Half Men" was filmed in front of a live ostrich.
Wingscrubber From UK - England, joined Sep 2001, 834 posts, RR: 0 Reply 9, posted (4 years 11 months 2 weeks 3 days 2 hours ago) and read 4995 times:
Uh, as a matter of fact... if your runway had a conveyer belt on it, you would save on tyre wear But I don't think michelin or goodyear would like the idea hehe...
Seriously though, all this conveyer belt stuff is nonsense because many centuries ago, some smart alec invented the....
Stratosphere From United States of America, joined Sep 2007, 1613 posts, RR: 4 Reply 10, posted (4 years 11 months 2 weeks 3 days 2 hours ago) and read 4994 times:
Please let this conveyor belt thread die already...I hated the first one and can't believe it had like 800+ posts.
Larshjort From Denmark, joined Dec 2007, 1216 posts, RR: 0 Reply 11, posted (4 years 11 months 2 weeks 3 days 2 hours ago) and read 4983 times:
Quoting Stratosphere (Reply 11): Please let this conveyor belt thread die already...I hated the first one and can't believe it had like 800+ posts.
I actually find it funny to read how people can believe that you can take a 600 ton jet, put it on a convoyer belt, an d it then begins to fly without air moving over the wings
NWADC9 From United States of America, joined May 2004, 4857 posts, RR: 10 Reply 12, posted (4 years 11 months 2 weeks 3 days 2 hours ago) and read 4979 times:
The wheels have nothing to do with motion for the plane. They just sit there and help the plane roll along on the ground. It's the engines that provide propulsion, and they're pushing on the air; the ground is irrelevant.
Flying an aeroplane with only a single propeller to keep you in the air. Can you imagine that? -Capt. Picard
787atPAE From United States of America, joined Oct 2006, 143 posts, RR: 4 Reply 13, posted (4 years 11 months 2 weeks 3 days 1 hour ago) and read 4974 times:
Sounds like some folks need to go to college and take this course called DYNAMICS. It's one of the first actual engineering courses I enrolled in. It's been 15 yrs since I've taken this course, and I still shake my head at topics like this...
In this course, the topic of relative motion is discussed. I'm not talking about Einsteinian relativity, but rigid body motion.
If the knowledge of relative motion is applied to an airplane and airflow (and maybe a little bit of common sense aerodynamics), many things will become apparent.
For example:
Quoting Vikkyvik (Reply 5): wings need to be moving through the AIR to generate lift.
Boeing4ever From , joined Dec 1969, posts, RR: Reply 14, posted (4 years 11 months 2 weeks 3 days 1 hour ago) and read 4970 times:
Quoting Larshjort (Reply 12): I actually find it funny to read how people can believe that you can take a 600 ton jet, put it on a convoyer belt, an d it then begins to fly without air moving over the wings
Take an R/C car and put it on a treadmill. Run the car on the treadmill with the belt moving against the car. Now, run the treadmill, but with your hand, push the car. The car moves forward. That's becaue the force is applied at a different location instead of the wheels.
Cars move due to wheel friction.
Airplanes move due to thrust from the engine. Thus the airplane will move forward regardless of the conveyor belt/landing gear interaction...free stream velocity will move over the wings, and the aircraft will lift off.
SlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 71 Reply 15, posted (4 years 11 months 2 weeks 3 days 1 hour ago) and read 4953 times:
Quoting Boeing4ever (Reply 15): Airplanes move due to thrust from the engine.
Give it up.
He apparently believes in the "magic" version of the conveyor belt. The one that can stop an airplane by spinning its wheels.
Happiness is not seeing another trite Ste. Maarten photo all week long.
He apparently believes in the "magic" version of the conveyor belt. The one that can stop an airplane by spinning its wheels.
There's hope for him.
The worst the conveyor belt will do is cause the tires to disintigrate. If it were true the wheel friction alone would prevent the airplane from taking off, then I can think of a lot of fixed gear GA planes that would have problems as the free stream acts on their wheels.
Kalvado From United States of America, joined Feb 2006, 471 posts, RR: 0 Reply 17, posted (4 years 11 months 2 weeks 2 days 23 hours ago) and read 4922 times:
Quoting Wingscrubber (Reply 10): Uh, as a matter of fact... if your runway had a conveyer belt on it, you would save on tyre wear Smile But I don't think michelin or goodyear would like the idea hehe...
I'm sure they would start supplying conveyor belts to make up for used profit!
And to add some more fun to the thread:
is it possible to land a plane into a wind tunnel? Say we fly a plane into 150 knots (or whatever landing speed is) stream of air. Then, wings still have enough lift, but the plane is stopped with respect to tarmac while still floating above ground.
apply chokes and turn off wind tunnel..
Starlionblue From Hong Kong, joined Feb 2004, 15869 posts, RR: 66 Reply 18, posted (4 years 11 months 2 weeks 2 days 23 hours ago) and read 4919 times:
Quoting Kalvado (Reply 18): Then, wings still have enough lift, but the plane is stopped with respect to tarmac while still floating above ground.
Sure. In fact Popular Mechanics (cue laughter) had this picture of a hovercraft aircraft carrier a few decades ago. No need for catapults since the carrier would go so fast that there would be very significant lift generated for the planes.
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
Vikkyvik From United States of America, joined Jul 2003, 8200 posts, RR: 28 Reply 19, posted (4 years 11 months 2 weeks 2 days 21 hours ago) and read 4895 times:
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Quoting Kalvado (Reply 18): And to add some more fun to the thread:
is it possible to land a plane into a wind tunnel? Say we fly a plane into 150 knots (or whatever landing speed is) stream of air. Then, wings still have enough lift, but the plane is stopped with respect to tarmac while still floating above ground.
On this forum, I've read posts by people who've flown Cessnas into strong headwinds - so much so that the airplane was stationary relative to the ground....or even moving backwards.
It's why airplanes take off and land into headwinds. Less ground speed required when you're on the runway for the same amount of lift.
Also why windshear is so dangerous on landing. If you're flying into a 10 knot headwind, and it suddenly turns into a 20 knot tailwind, that's 30 knots of airspeed, and the equivalent amount of lift, that you suddenly just lost.
"Two and a Half Men" was filmed in front of a live ostrich.
Kalvado From United States of America, joined Feb 2006, 471 posts, RR: 0 Reply 20, posted (4 years 11 months 2 weeks 2 days 21 hours ago) and read 4889 times:
Quoting Starlionblue (Reply 19): Sure. In fact Popular Mechanics (cue laughter) had this picture of a hovercraft aircraft carrier a few decades ago.
Quoting Vikkyvik (Reply 20):
On this forum, I've read posts by people who've flown Cessnas into strong headwinds
That was partially to illustrate earlier post
Quoting 787atPAE (Reply 14): In this (DYNAMICS ) course, the topic of relative motion is discussed.
Still, now I have to discard popcorn I got ready expecting some show
Askr From Poland, joined Mar 2008, 45 posts, RR: 0 Reply 22, posted (4 years 11 months 2 weeks 2 days 13 hours ago) and read 4818 times:
Quoting HAWK21M (Reply 22): Provided the Belt runs in the opposite direction & at the speed required Smile
But what if the belt runs in the same direction as the plane is landing... Oh gosh, the wheels will be sationary while the plane will be movig foreward... How come will this be possible?
Or worse case - the belt will be running faster than the plane...
Okok, I'm shutting up!
But I do warn you all, I have an extinguisher under my desk ;d;d
ATC-PL Wanabe :) - 2nd application is in... 11 July...
Flexo From St. Helena, joined Mar 2007, 405 posts, RR: 0 Reply 24, posted (4 years 11 months 2 weeks 2 days 12 hours ago) and read 4803 times:
Actually, if the belt was to move in the same direction as the landing aircraft and would exactly match its speed, you wouldn't even need wheels and brakes any more. That would mean some great weight savings!
Then, on top of that great advantage, you could connect a generator to the belt to generate electricity from braking the landing aircraft.
I don't see any cons do you?
25 David L: Well, I've been beaten to the juicy answers but... Me? Of course I could but no-one will let me demonstrate. Yes, the patented Conveyor Belt Isolating
26 Scooter01: I'm sure 2H4 might come up with something.... Scooter01
27 Askr: Check out the original thread... fair bit of magic, the Force, Schwartz, Bermuda-riangle-type forces there... ;>
28 David L: I know, I even classified the variations. However, no-one ever suggested an aircraft would fly with no air flowing over the wings. The problem was th
30 Bond007: Well, #1 can't possibly take off... if the speed of the conveyor matches the speed of the wheels ... because the wings will hit the posts. #2 is a wh
31 SlamClick: Actually they do all the time. The air doesn't go much of anything. It just gets lifted out of the way for a moment. We fly because the wings cut thr
32 Vikkyvik: It doesn't matter what's stationary and what's moving, though. The air could just as well be moving, and the airplane stationary. Hence wind tunnels.
33 2H4: There's already a version in operation. It allows very fast jets to land in several hundred feet, and has allowed Cessna O-1s to hover in place befor
34 David L: Well, yeah... OK. And that means air only flows over the wings of the aircraft I'm flying in. Tough luck for everyone else.
35 AirframeAS: Suggested to the mods to lock or delete this thread. This is getting ridiculous.
36 Flyf15: What I really want to know is if you put a treadmill in a plane and took off... would you be able to run on it?
37 2H4: It's not as though people are being forced to open the thread.... 2H4
38 RoseFlyer: As an aircraft design engineer who specializes in brakes/wheels/tires among other things, I will weigh in. You really have no benefit using a conveyor
39 RussianJet: I think that the words 'conveyer belt' should be banned from all fora on airliners.net
40 Dragon6172: If we just built conveyor belts between all destinations we would not need to worry about whether the plane took off and landed.
41 Askr: That is true, but now we would have to work ut a way of keeping a plane on the conveyor while it accelarates or decelerates. Now we could use brakes
42 Tdscanuck: Not having to pack the weight of the brakes around seems like a pretty huge benefit to me. Plus, if the brake is on the conveyor belt, you lose most
43 Kalvado: Then you would have to ban word "treadmill" as well. and then we'll anll miss a horror story about someone who tried to bring a full-size treadmill a
45 Metroliner: What if a conveyor belt landed on a plane? Could the plane take off? Pure genius Is this how Airbus are getting the A320NG to shed a few pounds...? To
46 David L: Well said. Even if no "good idea" comes of it, some people enjoy the theoretical discussion. If others don't like it that's tough luck. I'd be happy
47 Aogdesk: Not to stir things up too much, but now that I've spent countless seconds pondering this question, I bring up this issue: Could a conveyor belt take o
48 David L: Whoa! You want the top of the aircraft to move without the landing gear rotating? Are you going to arrange a conveyor belt under the aircraft, too, o
49 Aogdesk: Purely a hypothetical. Ok, perhaps a drug induced hypothetical....but.... j/k.....that other thread got sooooo way out of hand that I figured I'd tes
51 Flexo: The answer to both of these questions, and, in fact to most of the questions in this fun thread is most likely 42.
52 Translatoryboy: Now, if you took all the hot air expended in this thread and applied it to a balloon.... or did someone already beat me to the punch. (sorry, new here
53 Allstarflyer: Surprised no one mentioned ground effect.
54 UltimateDelta: How'd we get started with the belt on top of the plane?
55 Mir: Indeed, but is that in knots or zoidlorks? -Mir
56 Motopolitico: Hey, I know how to make it as though this thread never existed... Demand Media Demand Media Demand Media Thread deletion in 3... 2... 1...
57 HAWK21M: What happend in case we eliminate all conveyor belts from these threads on Anet......Problem solved regds MEL
58 Aogdesk: Welllllllll.....it was my post that started the "belt on top of de plane" thing. I was merely trying to point out the sheer absurdity of the entire t
59 2H4: Fun as the conveyor threads are, I must admit....I enjoy the "hovering birds in the cabin" thread more. 2H4
60 Aogdesk: Ah, I vaguely recall that thread. Please tell me though, did anyone claim that the birds would violently slam into the aft bulkhead??
61 2H4: Oh, I'm sure someone mentioned it at some point! I particularly enjoyed the concept of wing-mounted pods filled with hovering birds to provide extra
62 BWI757: Another problem to consider: f there was a cow on the belt when the aircraft landed on it, we'd have a heck of a mess since the cow would be drawn und
63 DaBuzzard: Hmmm, that looks like something that would be useful in some parts of Africa Far more useful than a conveyor belt at the very least
64 Scooter01: If the conveyor belt was moving the the same speed and direction as the landing aircraft, the aircraft would not need the heavy and expensive landing
65 Wingscrubber: Rosebud - I'm a landing gear engineer too! Although a junior one... I can't say who I work for in case you take my opinions to be that of my employer
66 Sovietjet: Excellent! My thread has been resurrected and lives on
67 WPIAeroGuy: Hovering birds aren't lighter than air, they are just creating a downforce equal to their weight in order to stay alot. A lighter-than-air craft gene
68 Wingscrubber: Video to illustrate my earlier point- http://www.youtube.com/watch?v=rELFSGei3hE
69 GST: But by deffinition every major airport in the world will need to replace its runways with 2 mile long conveyor belts somehow made to be able to take
70 Keesje: .. some fun on my sunday evening thnx in another thread I proposed to put the conveyor belt up side down under the aircraft, for take-off and landing.
71 CFMTurboFan: Couldn't have said it better myself!!!!!!!!!!!!!!!!!!!!!!!!!!!!
73 UltimateDelta: For clarification: This is only theoretical. I´m not suggesting that anyone study this for years and try to make it work; I just wanted to see what y
74 2H4: Well heck...NOW you tell me...I've gone through 7 airplanes already, trying to make it work! 2H4
75 David L: If you're happy enough to let all the aircraft pile up in a heap at the end of the conveyor belt, yes.
76 Wingscrubber: I think generally everybody participating in this thread understands that the 'landing on a conveyer belt to eliminate landing gear' principle is feas
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But I don't think michelin or goodyear would like the idea hehe...
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