# Another indication of the sad state of scientific/technical knowledge in the US **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [September 21, 2005, 9:57pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782 "2005-09-21T21:57:26Z")\ **Posts on this page:** 14\ **Page:** 2
**Author:** ![JRDelirious](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jrdelirious/32/9531_2.png) [@JRDelirious](https://boards.straightdope.com/u/JRDelirious)\ **Post date:** [September 23, 2005, 2:22am UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/21 "2005-09-23T02:22:29Z")
I’m with **Eonwe** and **David Simmons** on this one. The way that it was phrased makes it at first glance sound like there was half a ton of actual opposing force against every puller. BTW **Simmons** ’ use of the figure of speech “the Karl Rove approach” generated in me the sudden mental image of the assembling of a shady group calling themselves “Marauder Pilots for Truth” 😉 😃 ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [September 23, 2005, 3:44am UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/22 "2005-09-23T03:44:04Z")
> [@JRDelirious](#): > > BTW **Simmons** ’ use of the figure of speech “the Karl Rove approach” generated in me the sudden mental image of the assembling of a shady group calling themselves “Marauder Pilots for Truth” 😉 😃 The “for Truth” is absolutely unneeded. Marauder pilots are for truth by definition. For example, J. K. Havener (a Marauder pilot once of the 497th Sqdn, 344th Group) ends his book on the history of the development and use of the B-26 in WWII with this: > [@](#): > > Maraudermen had always been proud of the fact that they had mastered a 'hot" airplane and were prone to brag about it when in the company of contemporaries flying “that other medium,” lights, heavies, or transports. Just to illustrate how all things change-and sometimes sooner than we’d like to admit-the story was often told during WWII of two macho 'hot pilot" B-26 transition instructors (combat returnees from the South Pacific) emerging from the operations building at LAAF, DelRio, Texas one late summer afternoon in 1943. > > They looked up in admiration as a lone B-26 zoomed across the field in a low pass at tower level, pulled up in a steep bank, and made a tight circle to approach for a landing. The wheels came down as the ship rolled out onto the final, followed by the flaps as its wings leveled for the touchdown, and it greased in for a perfect landing and turned off at the first intersection. > > One pilot tumed to the other and proudly exclaimed: “Now, that’s a man’s airplane!” The second one replied, “You can say that again! Let’s wheel over to the ramp and see who this ‘hot rock’ is who makes a fighter approach.” Imagine their chagrin when out from the nosewheel well dropped a diminutive damsel of the WASP (Women’s Air Force Service Pilot), etc. who had ferried the ship from the Martin factory in Baltimore. > > “Is nothing sacred anymore?” they muttered, as they headed to the club to satiate their deflated egos and wounded pride with shots of bourbon washed down with branch." ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [September 23, 2005, 4:38am UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/23 "2005-09-23T04:38:37Z")
I still don’t see the problem. They had 395 students pulling a 200-ton plane. That’s 1/2 tons per student. That’s a fact, and a useful one too - to get a sense of how difficult (or easy) this achievement is, all you need to do is imagine pulling a 1/2-ton weight on wheels by yourself. Of course different types of wheels have different friction, and friction may not scale linearly, but it’s a decent first-order approximation. ---
**Author:** ![bouv](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@bouv](https://boards.straightdope.com/u/bouv)\ **Post date:** [September 23, 2005, 9:55am UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/24 "2005-09-23T09:55:22Z")
> [@scr4](#): > > I still don’t see the problem. They had 395 students pulling a 200-ton plane. That’s 1/2 tons per student. That’s a fact, and a useful one too - to get a sense of how difficult (or easy) this achievement is, all you need to do is imagine pulling a 1/2-ton weight on wheels by yourself. Of course different types of wheels have different friction, and friction may not scale linearly, but it’s a decent first-order approximation. Well…it’s a fact, but a completly useless fact that actually does NOT give a sense of how difficult it was (which, if my math is anywhere near correct, was not very.) “Weight pulled” is not a valid measure of work done, and for good reason. You said yourself different wheels have different friction. Hell, something with steel wheels on a steel surface (say, a train car) has almost ten times as less friction as something with rubber wheels on concrete. So several people pulling a train car is actually immensely easier for them than if they were to pull a large semi of the same weight on a road. But they are still pulling the same weight, so you see why it’s actually not a meaningful way to express how much work they did. For that matter, imagine pushing your car. Odds are, if it’s a small to medium car, you can push it yourself on a flat surface. So let’s say you are pushing a ton. Now take away the wheels. Can you still push it? Almost certainly not. But why? It’s still just a ton! You pushed a ton earlier, so why is it so hard to do it now? In fact, the _work_ that they did is the meaningful number here. I did not see the story, but let’s say the plane was pulled 100 feet. Well, work is force times distance, and since they all pulled with 20 pounds of force, that’s 2000 foot-pounds of work. That is an actual, measureable, quality. “Pulled 1000 pounds” is not. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [September 23, 2005, 1:04pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/25 "2005-09-23T13:04:12Z")
> [@bouv](#): > > Well…it’s a fact, but a completly useless fact that actually does NOT give a sense of how difficult it was (which, if my math is anywhere near correct, was not very.) “Weight pulled” is not a valid measure of work done, and for good reason. You said yourself different wheels have different friction. Hell, something with steel wheels on a steel surface (say, a train car) has almost ten times as less friction as something with rubber wheels on concrete. Yet you yourself used some generic number for coefficient of friction of a rubber wheel on concrete, and multiplied it by the “weight pulled” number to calculate how hard this task was. That seems to demonstrate the usefulness of that number. But you don’t even need to do any math. If you hear “airplane” and “1/2 per person”, all you have to do is imagine (or recall) 2 people pulling a smallish car, because most of us know that airplanes and automobiles both have rubber tires and a small car weighs roughly a ton. And most of us have pushed cars, or at least seen it done. That will instantly give you a decent idea of how hard the job is. Which, as you said, is not very. > [@](#): > > In fact, the _work_ that they did is the meaningful number here. By that argument, “ran a marathon in 2:10” isn’t a meaningful number either, because it doesn’t tell us how many joules of work was done. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [September 23, 2005, 1:31pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/26 "2005-09-23T13:31:54Z")
> [@scr4](#): > > By that argument, “ran a marathon in 2:10” isn’t a meaningful number either, because it doesn’t tell us how many joules of work was done. Bad comparison. The whole point of running the marathon is to find out who can run it in the least time on that day. I think that 1/2 ton/person is bad because it give the wrong impression. If the writers of the script want to give some sense of the effort to the non-technical I think the simple statement that the plane weighed 200 tons would do the job. I’m sticking with my original claim. (smug smilie would go here but we don’t have one) ---
**Author:** ![Rocketeer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rocketeer/32/4437_2.png) [@Rocketeer](https://boards.straightdope.com/u/Rocketeer)\ **Post date:** [September 23, 2005, 2:06pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/27 "2005-09-23T14:06:13Z")
> [@bouv](#): > > Because in no way is it 1/2 ton for each person. The force needed to pull the plane is equal to its weight (well, technically the normal force from the ground as a reaction to the plane’s weight, but whatever…) times the frictional coefficient of its wheels on the ground. That force is going to be a lot less than 400,000 pounds. > > [This site](http://www.roymech.co.uk/Useful_Tables/Tribology/co_of_frict.htm) places the coefficient of rolling friction between hard rubber and concrete (I am assuming it was concrete, someone correct me if i’m wrong) at 0.01-0.02. Using the large estimate, the frictional force the people had to overcome was only (0.02)(400,000 lbs) = 8,000 pounds. > > 8,000 lbs/395 people = ~20 lbs each. > > Twenty pounds. Sounds a lot less impressive than 1000, doesn’t it? The World’s Second-Best Selling Commercial Jet Airliner Company has this to say about the matter: "To estimate the pulling force, a simple calculation can be made. The coefficient of rolling friction for an airplane is about 0.0165. If we assume that the airplane weight is 100000 pounds, it would therefore take about 1650 pounds of horizontal force to pull the aircraft: ``` 0.0165 X 100000 = 1650 pounds ``` This coefficient of rolling friction is the value required to sustain rolling motion. To initiate airplane motion (break it loose from a stop), a higher force is required. While this break-away force is much more difficult to quantify, it is reasonable to assume that the coefficient of rolling friction would be increased by a factor of about 1.5. So to initiate motion, it would take about 2500 pounds of horizontal pull force for our assumed aircraft weight of 100000 pounds: ``` 0.0165 X 1.5 X 100000 = 2500 pounds ``` In order to minimize the break-away force required to initiate aircraft motion, we can offer the following suggestions: 1. Inflate the tires to the high end of the allowable range. 2. If the airplane is parked overnight, the tires tend to take a “set” in their deflected state (cold set). This can dramatically affect the ability to initiate aircraft motion. To minimize this cold set problem, we recommend that the aircraft be towed into position reasonably soon prior to the pulling event so minimal time elapses with the aircraft sitting in one position (a few hours is acceptable). 3. Use as light of an airplane weight as is practical. For your information, the Operating Empty Weight (OEW) for the 737-300 is about 70000 pounds and about 85000 pounds for the 737-700." They also recommend figuring on each person providing maybe 25 pounds of force and the airplane’s hydraulic pumps be turned on or the brake accumulator charged so that the airplane can be stopped after the pull. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [September 23, 2005, 6:42pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/28 "2005-09-23T18:42:27Z")
> [@David Simmons](#): > > Bad comparison. The whole point of running the marathon is to find out who can run it in the least time on that day. And the point of a plane pull is to move a really big plane, isn’t it? > [@](#): > > I think that 1/2 ton/person is bad because it give the wrong impression. If the writers of the script want to give some sense of the effort to the non-technical I think the simple statement that the plane weighed 200 tons would do the job. Fine. But if they just said “200 tons, 395 people” that doesn’t really mean anything to me other than “big plane, lots of people”. Once I divide one by the other to get “1/2 ton per person” I can imagine how difficult it is. ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [September 23, 2005, 6:57pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/29 "2005-09-23T18:57:16Z")
> [@scr4](#): > > And the point of a plane pull is to move a really big plane, isn’t it? > Fine. But if they just said “200 tons, 395 people” that doesn’t really mean anything to me other than “big plane, lots of people”. Once I divide one by the other to get “1/2 ton per person” I can imagine how difficult it is. I agree. Let’s break down this English. I tie a rope to the front of my car and pull it up my driveway. I say: “I just pulled a 2000 lb. car up my driveway”. Is that worng? Let’s shorten it: “I just pulled 4000 lbs. up my driveway”. Is that part wrong? If so, why? If not, what is the difference when there are multiple people involved? ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [September 23, 2005, 6:57pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/30 "2005-09-23T18:57:24Z")
> [@scr4](#): > > And the point of a plane pull is to move a really big plane, isn’t it? > Fine. But if they just said “200 tons, 395 people” that doesn’t really mean anything to me other than “big plane, lots of people”. Once I divide one by the other to get “1/2 ton per person” I can imagine how difficult it is. I agree. Let’s break down this English. I tie a rope to the front of my car and pull it up my driveway. I say: “I just pulled a 2000 lb. car up my driveway”. Is that worng? Let’s shorten it: “I just pulled 2000 lbs. up my driveway”. Is that part wrong? If so, why? If not, what is the difference when there are multiple people involved? ---
**Author:** ![Plynck](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Plynck](https://boards.straightdope.com/u/Plynck)\ **Post date:** [September 23, 2005, 9:47pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/31 "2005-09-23T21:47:31Z")
I dunno. I see it as the sad state of the price of jet fuel in Japan. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [September 23, 2005, 11:16pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/32 "2005-09-23T23:16:49Z")
> [@Shagnasty](#): > > “I just pulled a 2000 lb. car up my driveway”. Is that worng? And if there were two of you I guess you would say that you had each pulled 1000 lb. up the driveway. ---
**Author:** ![bouv](https://avatars.discourse-cdn.com/v4/letter/b/bc8723/32.png) [@bouv](https://boards.straightdope.com/u/bouv)\ **Post date:** [September 23, 2005, 11:41pm UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/33 "2005-09-23T23:41:25Z")
> [@scr4](#): > > Yet you yourself used some generic number for coefficient of friction of a rubber wheel on concrete, and multiplied it by the “weight pulled” number to calculate how hard this task was. That seems to demonstrate the usefulness of that number. > > But you don’t even need to do any math. If you hear “airplane” and “1/2 per person”, all you have to do is imagine (or recall) 2 people pulling a smallish car, because most of us know that airplanes and automobiles both have rubber tires and a small car weighs roughly a ton. And most of us have pushed cars, or at least seen it done. That will instantly give you a decent idea of how hard the job is. Which, as you said, is not very. It may have been a generic coefficient, but according to **Rocketeer’s** link, it was accurate. ANd I didn’t multiply it by the “weight pulled” (because that’s a irrelevant number,) I multiplied it by the weight of the plane. > [@](#): > > By that argument, “ran a marathon in 2:10” isn’t a meaningful number either, because it doesn’t tell us how many joules of work was done. It IS a meaningful number, because that is what is being measured. Time (or, if you prefer, the average speed of each runner) is what determines who wins the race. But “weight pulled” does not determine if the plane moves. How about this for a way to phrase it: “The plane weighs 200 tons, and there were about 400 people pulling it. That actually means that each person had to do about the same amount of work you would do if you were pulling your car up the driveway with a friend.” Gets the EXACT message across, without conveying any mis-information or bad science. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [September 24, 2005, 3:32am UTC](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782/34 "2005-09-24T03:32:58Z")
> [@bouv](#): > > It may have been a generic coefficient, but according to **Rocketeer’s** link, it was accurate. ANd I didn’t multiply it by the “weight pulled” (because that’s a irrelevant number,) I multiplied it by the weight of the plane. You then divided it by the number of people. That’s equivalent to multiplying coeff. of friction by “weight pulled per person.” And I never said it’s inaccurate. All I meant was that if we know the “weight pulled per person” (= 1/2 ton per person) and description of load (“airplane”, which implies pneumatic rubber tires), that’s everything we need to know to do the calculations you did. [Previous page](https://boards.straightdope.com/t/another-indication-of-the-sad-state-of-scientific-technical-knowledge-in-the-us/322782.md?page=1)