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” 
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:
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.
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.
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)
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:
Inflate the tires to the high end of the allowable range.
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).
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.
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?
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?
I dunno. I see it as the sad state of the price of jet fuel in Japan.
And if there were two of you I guess you would say that you had each pulled 1000 lb. up the driveway.
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.
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.
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.