False assumptions are what make people get this problem wrong. Look at the thread about "Sanity and Flight Simulation" on this same forum: A great example of why people get this wrong: "THE BATHTUB TEST"It doesn't hurt to take a hard look at yourself from time to time, and this should help get you started. During a visit to the mental asylum, a visitor asked the Director what the criterion was which defined whether or not a patient should be institutionalized."Well," said the Director, "we fill up a bathtub, then we offer a teaspoon, a teacup and a bucket to the patient and ask him or her to empty the bathtub.""Oh, I understand," said the visitor. "A normal person would use the bucket because it's bigger than the spoon or the teacup.""No." said the Director, "A normal person would pull the plug. Do you want a bed near the window?"--Why do people get this wrong initially? It is silly, but people make a simple assumption that is false. You add extra constraints to the problem, because you assumed they should be there. People do that with our treadmill here. They assume that the treadmill MUST stop the forward motion of the airplane, because... well, that's what treadmills are designed to do. Although no treadmill manufacturer ever gave a thought to an airplane on one I would bet...That false assumption gets burned in your brain and you accept it as fact, and everything else that comes from that false assumption is totally false as well.

I am not sure why anyone would think this would work. The aircraft needs to generate lift. This is done by air moving over the wings, and has nothing to do with how fast the wheels are moving over a "treadmill". From what I've read, the point is to enable an aircraft to take off without having to rely upon a long runway, but if that is the case, what would the speed of the aircraft be at takeoff?But even if no one here knew anything about physics, I would have to ask the obvious question: "If this was really possible, wouldn't someone have already tried it?".Thank you to the original poster - it gave everyone at work a lot to laugh at today.- Martin

>The aircraft needs to generate lift. This is done by air moving>over the wings, and has nothing to do with how fast the wheels>are moving over a "treadmill". From what I've read, the point>is to enable an aircraft to take off without having to rely>upon a long runway, but if that is the case, what would the>speed of the aircraft be at takeoff?No, no, no. Again, you are reading things into the problem that are not there. You are not wrong in what you say, but you are creating limits which are not stated in the problem. -We are not saying that a treadmill can magically change the laws of flight-We are NOT saying that a plane will have some sort of vertical takeoff from a treadmill, a plane will still need to move forward over the same amount of takeoff distance. You are picturing a treadmill that is only big enough to hold a plane in place, aren't you? (again, never stated by the original problem) That won't work. The treadmill would have to be at least as big as the takeoff distance needed. There is no real world application to this, it is just a silly riddle that tricks people.

>But even if no one here knew anything about physics, I would>have to ask the obvious question: "If this was really>possible, wouldn't someone have already tried it?".Not really sure what you are implying. To build a huge treadmill that would support a weight of a real size aircraft (even small Cessna) is not an easy engineering task and is not cheap. But yes, someone built a small treadmill and used a model airplane and somewhere on YouTube you can find a video from his experiment - the airplane did take off.Michael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg

Michael...your point is well taken, but...I state again. It matters not a whit what the speed of the treadmill is. That speed, 5mph or 500,000mph will only affect the rotational speed of the wheels, it will not affect the forward velocity of the aircraft, nor will it affect the V1 speed, hence it will not prevent aircraft rotation and liftoffSince we're exploring un-reality here, what if I told you the bearings in the aircraft wheel were "frictionless". Would the aircraft them move backward, or stay in place with the wheels spinning like a whirling dirvish?Someone else here has provided the analogy of the treadmill, well-oiled skates, and a rocket pack. I think if folks would step back and consider that hyposisis, they would see this is truly a non-problem problem.Cheers,btPS...I know we agree on the final outcome, I just am not sure we agree on the details

BT,I can't argue with your point however we are talking about completely different issues. I was only trying to say that his requirements about "treadmill is matching the speed of it's wheels" can not be satisfied by an aircraft accelerating on the treadmill. Nothing more and nothing less. And I have shown why it is the case. I have never doubted nor questioned the physics of the actual takeoff.Michael J.http://img142.imageshack.us/img142/9320/apollo17vf7.jpg

Quote a book, it's the speed of the air moving over the WINGS that matters, not the plane.

Nice to see that even aviators can fall for such simple mind tricks. :)Every aviator groundspeed has absolutely nothing to do with making an aircraft take off. In fact, that's the very reason you take off into the wind, since it gives you an airspeed bonus.

Seems like a lot more votes for "it will take off".Interesting about the R/C model experiment, I didn't know it had been done. As stated in my original post; Mythbusters used an ultralight and a quarter mile conveyer. No mention as to cost yet, but if they had used a Cessna it would have been more...Best Regards, Donald T. :-waveFLYing? It's cool. Trillions of birds and insects can't be wrong.

I can't wait to see it take off...It is on this Wednesday, right? It is kind of sad that a demonstration is necessary to prove such a simple point. It is just a dumb trick question that many get wrong at first, then when you figure it out, it hits you like a 2x4 to the head...I hate to say it but even after it takes off easily, people are still going to argue against it, saying that the light weight of the ultralight throws everything off or something silly like that..

Yup, they'll continue to debate here, they'll write to the Mythbusters telling them what they did wrong and what they should have done to prove the aircraft would just stay still, and the Mythbusters will have to revisit this issue again down the road using bigger aircraft or different belt behavior or different pilot behavior or whatever.... :( (Hey, it happens on a lot of the myths they bust... :()At least this demonstration will conclusively put this issue to rest, whoever's right or wrong... :(

This episode of Mythbusters will be on 12/12 not this Wednesday!

PS: Another of the Myths their busting on this episode, is if a novice without any training land a 747!

No chance, no training at all? absolutely none? Not a snowflake's chance in a volcano. heck I struggle with a PMDG747 with a good couple of thousand hours on FS, let alone a real one with no training.

I agree with you on manual, even for us simmers it takes a lot of practice. However, if the person is somewhat computer literate, I think a controller or pilot could talk him/her into setting up for an autoland!