Ray Garrison Posted January 31, 2008 Share Posted January 31, 2008 Marvel really got me thinking, and I had this cool rhyme about this guy... ... but somehow it just seemed, I dunno, inappropriate somehow... Quote Link to comment Share on other sites More sharing options...
oldtimer Posted January 31, 2008 Share Posted January 31, 2008 Hey nice pic! I've been enjoying the occasional sighting in our backyard of the tufted titmouse. Can't imagine what rhyme you mean though (insert smiley type face of choice). Been seeing a lot of dark-eyed juncos lately, along with the regulars that stay year round... Quote Link to comment Share on other sites More sharing options...
oldtimer Posted January 31, 2008 Share Posted January 31, 2008 After this is resolved, can we PLEASE solve the age old question of the Woodchuck and the amount of wood said woodchuck could chuck? Is the woodchuck on a conveyor belt, designed to move as fast as the woodchuck chucks? I've always wondered...How much ground could a groundhog grind if a groundhog could grind ground? The thing is marvel, without a conveyor belt, no one seems to care. Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted January 31, 2008 Share Posted January 31, 2008 i missed it. did it take off or not?in Christ, because of God's grace,roy Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted January 31, 2008 Share Posted January 31, 2008 How many licks to the center of a tootsie pop if the licker is on a tread moving at 7 miles an hour? (Tell that damn owl to keep his beek shut) Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted January 31, 2008 Moderators Share Posted January 31, 2008 i missed it. did it take off or not? in Christ, because of God's grace, roy Both the model and full size plane did take off. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted February 1, 2008 Share Posted February 1, 2008 i missed it. did it take off or not? in Christ, because of God's grace, roy its up on bittorrent if you want to watch it Quote Link to comment Share on other sites More sharing options...
Deang Posted February 3, 2008 Share Posted February 3, 2008 http://mythbustersresults.com/episode97 I applaud the effort, but I'm with those who say the test was flawed. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted February 3, 2008 Share Posted February 3, 2008 which part of it was flawed? Quote Link to comment Share on other sites More sharing options...
oldenough Posted February 3, 2008 Share Posted February 3, 2008 When i attached my flying model Piper Cub to a spring balance and applied power it pulled a total of 17lbs of thrust(approx) When i placed the plane and spring balance attached and secured on my wife's tread-mill, the tread-mill could only produce a force of around 1lb in the opposite direction. Though not a scientific experiment does anybody think that the 1lb of force the tread-mill could exert through the planes wheels could over-come the 17lbs of forward thrust the plane was able to produce ? Quote Link to comment Share on other sites More sharing options...
Moderators Travis In Austin Posted February 3, 2008 Moderators Share Posted February 3, 2008 It is like the Mythbuster guys said at the end, some people simply cannot wrap their heads around the fact that airplanes do not derive power from the ground like cars do. They even did an example with the car on the conveyer and then applied thrust (a hand) from behind. I am the first to admit I was like the pilot who thought for sure it would not take off. Then someone pointed out to me that the problem was really asking. Flawed? The only flaws could be that the speeds were not matched with precision, or that the plane was lighter then normal, lower take off speed, etc. However, the experiments showed that the plane moves forward regardless of the speed of the converyer belt. Thats the whole point, if the plane moves forward it takes off if you can make the stuff big enough or long enough. Now what I want to know is how many Peter Piper pecked, on a conveyor belt while chasing a woodchuck. Travis Quote Link to comment Share on other sites More sharing options...
soundbound Posted February 3, 2008 Share Posted February 3, 2008 The original post states, a plane is standing on a movable runway( something like a conveyor).as the plane moves the conveyor moves but in the opposite direction.the conveyor has a system that tracks the speed of the plane and matches it exactly in the opposite direction. the question is will the plane take off or not? If the conveyor matches the plane's speed exactly. Wouldn't the plane have no forward motion? The video shows it moving forward at a good speed. It seems to me the original question is asking if the plane can take off standing still with just the lift from the air from the propellers lifting the wings and weight of the plane standing still. A helicopter can do this because its lift pushes it upward, but doesn't a plane need some forward motion for lift or an up lifting air current like a glider needs for lift? Can just the propellers air current be enough to lift the plane off the ground standing still? Quote Link to comment Share on other sites More sharing options...
oldenough Posted February 3, 2008 Share Posted February 3, 2008 if the plane can take off standing still with just the lift from the air from the propellers lifting the wings and weight of the plane The propeller DOES NOT provide lift, it provides forward momentum by producing thrust. The conveyor has absolutely no part in this. The conveyor for all intents and purposes is a useless component. A Red Herring if you like. Quote Link to comment Share on other sites More sharing options...
soundbound Posted February 3, 2008 Share Posted February 3, 2008 The propeller DOES NOT provide lift, it provides forward momentum by producing thrust. I see. If the conveyor matches the plane's speed exactly. Would there be forward motion? Quote Link to comment Share on other sites More sharing options...
oldtimer Posted February 3, 2008 Share Posted February 3, 2008 There would be forward motion because with freely spinning wheels the conveyor really does not matter. The power of the planes engine(s) acts upon the air, not the ground. The conveyor can run as fast as it wants, it does not impart a negative force upon the planes forward motion. Keep in mind that the plane's wheels are free spinning. There is no transmission from the engine to the wheels as in an automobile. Quote Link to comment Share on other sites More sharing options...
soundbound Posted February 3, 2008 Share Posted February 3, 2008 Thank you. That makes since. [ap] Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted February 3, 2008 Share Posted February 3, 2008 He sees but he don'ts believes its Quote Link to comment Share on other sites More sharing options...
mas Posted February 3, 2008 Share Posted February 3, 2008 If you understand the scenario, in a larger sense, you can construct an equivalent force diagram with any plane that common sense says will fly instead of not flying. That is done simply by realizing that the earth is spinning (and moving through space), and a plane remains stationary relative to the earth as it is sitting on a runway. . This is essentially equivalent to a plane's wheels matching the converyor belts speed and remaining motionless relative to the conveyor belt. But since we tend to ignore the motion (as we have nothing to compare it to experientially), we treat it as stationary and focus soley on the plane and its application of force relative to the air. The only thing that matters (given that the wheels can move freely and not create additional drag opposing the applied acceleration) is the ability to accelerate the plane relative to the air - that which provides the lift. Since the scale of the example with the earth is large, we tend to ignore it. But it is nevertheless real. But no one (nowdays!) expects that airplanes cannot fly, or that they even have to take off in a direction opposite the direction of the earth's rotation. Instead, planes generally take off into the wind ;as by the wind opposing the direction of the applied thrust, it adds additional lift. As it has been mentioned, you have essentially two force systems at play, and the motion of the converyor and the wheels sum to zero - all the while being a red herring as the means of acceleration for the plane has nothing to do with the wheels. The entire problem is stated akin to what any good magician does as they intentionally divert your attention to focus on an inconsequential portion of the act while the 'trick' occurs elsewhere. Quote Link to comment Share on other sites More sharing options...
oldenough Posted February 3, 2008 Share Posted February 3, 2008 Seems to me this is a thread where the likes of Mas&Srobak could put their amazing intellect to work. Uh..on second thoughts... Quote Link to comment Share on other sites More sharing options...
oldenough Posted February 3, 2008 Share Posted February 3, 2008 My apologies mas, seems we had the same idea at the same time.[Y] Quote Link to comment Share on other sites More sharing options...
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