Were the Lunar Rovers faked?

[smartcooky]

The wheel with 57lbs of weight on the moon has to move the equivalent of 342lbs of mass horizontally on the moon, and the testing shows it can't be done.

I am not saying they should have put 342lbs of weight on the wheels, I m saying the wheels have to get enough traction to be able to pull 342lbs horizontally in order for the rovers to move on the moon, and not only does the testing show that the wheels slip well before that, but the equipment is not even sufficient to test it fully.

http://www.hq.nasa.gov/alsj/PerfBoeingLRVWheelsRpt1.pdf

I missed this earlier, so let me address it now.

This, more than anything else you have posted, shows that

a) you have little if any understanding of the principles of force, weight and mass.
b) you have a propensity to read a technical/engineering document and draw totally incorrect conclusions from it.

My car is a Subaru Impreza SW; it has a dry weight of about 3000 lbs. If I lean on it with all my weight, I can apply a force of about 40lb; sufficient to move the car on level ground. Why is this? Simply because its not the mass of the car that I have to overcome to get it moving, its overcoming friction that is the issue. You simply do not need 3000 lbs of force to move a 3000 lb vehicle horizontally. That friction can be down to a number of things. If mass is a constant, then the type of surface and the size of the wheels are the biggest issues.

I struggle to push a 3000 lb car along a road, but a 3000 lb loaded two-wheeled horse cart is easy to move and maneuvre because its wheels are four and a half feet in diameter

[Noldi400]

A theme that keeps repeating in Anywho's posts seems to be that while he has a superficial understanding of the difference between weight and mass, he doesn't understand how that difference affects things in the real world.

Reminds me of Heiwa and the Magic Disappearing Propellant.

[Tedward]

Ever see those strong men competition programs where they pull lorries? Then there is one fella that pulls an aircraft. Just looked up the record, some guy has dragged a Globemaster.

[anywho]

The wheel with 57lbs of weight on the moon has to move the equivalent of 342lbs of mass horizontally on the moon, and the testing shows it can't be done.

I am not saying they should have put 342lbs of weight on the wheels, I m saying the wheels have to get enough traction to be able to pull 342lbs horizontally in order for the rovers to move on the moon, and not only does the testing show that the wheels slip well before that, but the equipment is not even sufficient to test it fully.

http://www.hq.nasa.gov/alsj/PerfBoeingLRVWheelsRpt1.pdf

My car is a Subaru Impreza SW; it has a dry weight of about 3000 lbs. If I lean on it with all my weight, I can apply a force of about 40lb; sufficient to move the car on level ground. Why is this? Simply because its not the mass of the car that I have to overcome to get it moving, its overcoming friction that is the issue. You simply do not need 3000 lbs of force to move a 3000 lb vehicle horizontally.

I never said that the wheels had to apply 342lbs of force, I said they have to pull (a) 342lbs (mass) horizontally. I included the extra words to make my point clearer.

The testing shows a drawbar pull (pull/weight) of .5 to .6 before slipping becomes too problematic, this means that the rover wheel can pull it's own weight plus 50 to 60% more.

This would be fine on earth, but on the moon the wheel needs to pull an additional 500% above and beyond the weight it has on it.

[Jason Thompson]

We'll add graph reading to the list of things you don't know how to do properly.

[RAF]

... on the moon the wheel needs to pull an additional 500% above and beyond the weight it has on it.

Please show us the numbers you "crunched" to arrive at that 500% figure.

If you can't/won't provide that, then your most recent claim is just like the other claims you have made...just a lot of "smoke-blowing".

Still awaiting the evidenced that the Landings were faked....what is taking you so long?

[Jason Thompson]

To expand on my earlier comment, they are looking at slip on increasing slope angles and at constant speed. Their level surface test is testing a system that has already overcome the inertia of the vehicle and brought it to speed. The wheels don't have to 'pull' the mass of the vehicle any more. It's already moving and will keep moving according to Newton's first law. On a slope the wheels constantly have to pull the vehicle against its own weight, which is pulling it back down the slope, against the direction the wheels are trying to move it in. That's what is being tested. What anywho has called the 'drawbar pull' of 0.5 - 0.6 is actually the force acting to oppose the wheels in their efforts to drive the rover up a slope: the proportion of the weight acting to retard the motion. And that really is weight, not mass.

The test says nothing about the ability of the wheel to get the vehicle moving from a standing start and overcome the inertia of the static rover through controlled acceleration.

You have to identify what the test is actually testing before you can make sense of the results.

[JayUtah]

This would be fine on earth, but on the moon the wheel needs to pull an additional 500% above and beyond the weight it has on it.

Wrong.

[twik]

This would be fine on earth, but on the moon the wheel needs to pull an additional 500% above and beyond the weight it has on it.

Like others, I would like to know how you determined this.

[smartcooky]

The testing shows a drawbar pull (pull/weight) of .5 to .6 before slipping becomes too problematic, this means that the rover wheel can pull it's own weight plus 50 to 60% more.

This would be fine on earth, but on the moon the wheel needs to pull an additional 500% above and beyond the weight it has on it.

I'd be interested to see the force - mass - friction - -inertia calculations you carried out to arrive at that figure, because it sounds like utter BS to me.

You are still not understanding the difference between weight and mass. You obviously do know that an object in a 1G field with a mass of 100kg has a weight of 100kg, while that same object in a 1/6th G field, while only weighing 16kg, nevertheless still has a mass of 100kg. However, you are drawing all the wrong conclusions from this and failing to understand its implications.

Try this thought experiment, and give me an answer

You place a perfectly smooth 100kg block on a perfectly level 100% friction-free surface*. You place this arrangement in a vacuum chamber on the Earth.

It will take "x" amount of force to move the block one metre.

If you now set up an identical arrangement on the moon, how much force will it take to move the block one metre?

CLUE: you won't need engineering calculations to work this out.

*PS: I know there is no such thing as 100% friction free, but humour me!

[Count Zero]

Why is it so hard to understand that a properly-designed wheeled vehicle (even a top-heavy one) can drive in a controlled manner under complete control at 10-15kph on a surface with a very low friction co-efficient?

Video proof

[smartcooky]

Why is it so hard to understand that a properly-designed wheeled vehicle (even a top-heavy one) can drive in a controlled manner under complete control at 10-15kph on a surface with a very low friction co-efficient?

Video proof

Did you hear the one about the Irish Zamboni driver?

He wanted to take the Zamboni on a hill-climb, but he abandoned the idea when he couldn't find an Ice Hockey rink on a hillside.

[anywho]

On a slope the wheels constantly have to pull the vehicle against its own weight, which is pulling it back down the slope, against the direction the wheels are trying to move it in. That's what is being tested. What anywho has called the 'drawbar pull' of 0.5 - 0.6 is actually the force acting to oppose the wheels in their efforts to drive the rover up a slope: the proportion of the weight acting to retard the motion. And that really is weight, not mass.

They are measuring the drawbar pull on a level surface and extrapolating those figures to estimate the slope climbing abilities

"All the wheel performance plots shown herein reflect the assumption that the pull coefficient measured at a given slip on a level surface with a slngle wheel is roughly equivalent to the tangent of the slope that a vehicle equipped with similar wheels can climb"
http://www.hq.nasa.gov/alsj/PerfBoeingLRVWheelsRpt1.pdf

This would be fine on earth, but on the moon the wheel needs to pull an additional 500% above and beyond the weight it has on it.

Like others, I would like to know how you determined this.

For simplicities sake we will use a 600lb vehicle, and all measurements in lbs, and ignore rolling
resistance.

A 600lb vehicle on earth weighs 600lbs and has a mass of 600lbs, on the moon it weighs 100lbs but still has a mass of 600lbs. Each wheel on earth has 150lbs of weight on it, and on the moon each wheel has 25lbs of weight on it.

In both cases the same mass has to be moved horizontally, and the forces needed to accelerate the vehicle horizontally are the same in both cases ("x" for smartcooky), but relative to the weight on the wheels it is not the same.

On earth the wheel has 150lbs of weight on it an has to move 150lbs horizontally so it does not need any drawbar pull to move (it only has to move the weight on it).

On the moon that same vehicle wheel has only 25lbs of weight on it, but it still has to move 150lbs horizontally, so if you base the drawbar pull on the weight on the wheel (which they clearly did in the test) then you need to be able to pull an additional 125lbs on top of the weight of 25lbs, or 500% more.

In the test they lost usable traction at 50 to 60% over what it takes to drive the weight of the wheel, but on the moon the need enough traction to pull an additional 500% more than the weight of the wheel, or a "pull coefficient" of 5, not .5 like they got.

[Jason Thompson]

Once again, anywho, look at the graph and the testing regime. At 0% slip they have defined a 0% pull coefficient. They are NOT testing the ability of the wheel to get the mass of the rover moving, they are testing the abilities of the wheel once steady state has been reached, i.e. at a constant speed over a level surface, and making it slip deliberately to see what it could do on a slope where it does have to pull its weight (not mass) against gravity. At this point the rover does not have to pull its mass in the way you are describing.

The only thing that test tells us about the rovers ability to get moving is that if you started to spin the wheels at that speed the rover would likely slip and not make a clean start in its motion. Well so what? Cars do the same thing. You get round that by using a slow initial acceleration to give the wheels a chance to grip and get the mass of the vehicle moving.

You're taking a test that is designed to assess one aspect of performance and applying it to the one you think it should be testing, just as you did with the footage of the rover going over the test bed.

[nomuse]

In both cases the same mass has to be moved horizontally, and the forces needed to accelerate the vehicle horizontally are the same in both cases ("x" for smartcooky), but relative to the weight on the wheels it is not the same.

On earth the wheel has 150lbs of weight on it an has to move 150lbs horizontally so it does not need any drawbar pull to move (it only has to move the weight on it).

On the moon that same vehicle wheel has only 25lbs of weight on it, but it still has to move 150lbs horizontally, so if you base the drawbar pull on the weight on the wheel (which they clearly did in the test) then you need to be able to pull an additional 125lbs on top of the weight of 25lbs, or 500% more.

In the test they lost usable traction at 50 to 60% over what it takes to drive the weight of the wheel, but on the moon the need enough traction to pull an additional 500% more than the weight of the wheel, or a "pull coefficient" of 5, not .5 like they got.

Wait, what?

You seem to have proven that ion engines are impossible.

What do I mean?  I mean that acceleration = force/mass.  Always.  In most real-world situation, there are addition forces to consider; friction force, air resistance, rolling resistance, etc. 

But at the very basics, it does not matter how large the mass is.  ANY force will produce an acceleration.  And ANY acceleration over time produces velocity.

Which is how ion engines work.  Or how solar sails might work.  The force is very small.  The acceleration is very small.  But it is not zero.

IF the bearings in the LRV were perfect, and the wheels infinite in size relative to impeding terrain features (another way of saying, if the surface were perfectly flat), then the beating of a gnat's wings would be sufficient to put the LRV in motion.  And if continued for a long enough interval, to reach any desired velocity.