Were the Lunar Rovers faked?

[Glom]

Well the NASA hoaxers could do anything... except proof read.

[Tedward]

Quick bit of engineering here...the spokes on a bicycle wheel are under tension.  The hub does not "press" on the lower spokes, it "hangs" from the upper ones.  That tries to pull in/bend the rim, but since the rim is a circle, any attempt to flatten it merely increases the tension tangential to the load.  Gets a little more interesting under dynamic loads, and a little sheer comes into play, but at no point are the spokes under useful compressive load.  They aren't shaped for it.

Back in the day, we used to knock on them lightly with a metal tool to listen for the right tone.  Any dull ones weren't tensioned right.

Aye, I was picking more on the fragile item doing something strong, regarding the claims on the rover. Bit obtuse maybe whilst I was asking about gearing.

[nomuse]

I lose track of the original comment in all the quotes unquotes and quotes, but I can never resist trying to brainstorm the physics of something.  Especially when I have such talented people to come along after and explain where I got it wrong!

[raven]

If the rover didn't work, Anywho, what were they driving?
While by no means an expert, I do like old school special effects, like stop motion, and stop motion, especially then, looks nothing like the rover moving.  This scene, while effective, highlights a problem, the lack of motion blurring. COmpare that to to the famous Apollo 16 'Grand Prix'. To my eye, they look nothing alike in technique, the rovers motion being far, far, smoother, yet Clash of the Titans was almost 20 years older.
OK, let's look at another technique, CGI. Even now it would be tricky, but then?
This was at the forefront, the absolute bleeding edge of technology back then. Shading was primitive, textures were unknown, bump mapping, what's that?
So no dice.
Traditional 2D animation, do I even need to give an example?
So, again, if the special effects of the time weren't up for it, you need an actual working 'prop', something that could be driven. So just what were they driving?

[Tedward]

I lose track of the original comment in all the quotes unquotes and quotes, but I can never resist trying to brainstorm the physics of something.  Especially when I have such talented people to come along after and explain where I got it wrong!

I don't mind, this is a great place for learning. I know the spokes are weak this way and strong that way, that is the end of what I know about spokes. That and too tight thet are going to go.... I did not consider the rest of it would not not claim it.

[gwiz]

...1hp to accelerate 1500lbs is ridiculously low.

Tell that to a horse.

[gwiz]

I used to rally a 1974 Ford Escort RS1600. On loose gravel, I would typically hit top speeds of around 130 km/h with average stage speeds of about 80 km/h. The Ford Escort was a rear-wheel drive, making a lot harder to handle than modern AWD rally cars.

My rallying was back in the 1970s too, mainly involving Escorts.  On occasion, I navigated for a friend who had a 240Z.  Now that really was a handful, with a distressing tendency to terminal understeer.

[cjameshuff]

Do I need numbers to say that a fall from 1inch puts more stress on the frame than the static weight weight of an astronaut?

So what if it does? You've done nothing to demonstrate that the rover couldn't withstand such stresses.

[Glom]

Do I need numbers to say that a fall from 1inch puts more stress on the frame than the static weight weight of an astronaut?

So what if it does? You've done nothing to demonstrate that the rover couldn't withstand such stresses.

Do we even have a citation for the loading limits of the LRV? Or is it just a bit of hyperbole taken too literally, which is often a trap HBs fall into.

[Trebor]

Can I make a general plea to everyone to use the right units for mass and weight.
Every time you talk about weight in kg or mass in lbs you make a unicorn cry.

[Chew]

Can I make a general plea to everyone to use the right units for mass and weight.
Every time you talk about weight in KG or mass in lbs you make a unicorn cry.

Did you just capitalize the symbol for kilogram?

[Trebor]

I have spend quite a bit of time looking to see how they tested the rovers for 1/6g, and all I can find is a comment that the wheels were tested on some machine but I cannot find any more about what that was, and also that they used a scale model for testing.

This youtube clip has a sequence at the 2:04 mark showing how they tested for 1/6g.
https://www.youtube.com/watch?feature=player_detailpage&v=FVMfjPXwRO4#t=124s

[Trebor]

Can I make a general plea to everyone to use the right units for mass and weight.
Every time you talk about weight in KG or mass in lbs you make a unicorn cry.

Did you just capitalize the symbol for kilogram?

whoops

[Nowhere Man]

In response to Trebor's plea...

Weight only equals mass in a 1G environment. When you take the environment away, mass and weight are no longer equal.

Weight does not equal mass anywhere.  Weight is the effect produced by mass in a gravitational field.  Weight = mass times gravitation.

In SI, the unit of weight is the newton.  It is defined in SI as mass * gravitation.  1 newton is 1 kilogram*meter/second².  Thus, on Earth, 1kg weighs 9.81 newtons.  One pound is 4.45 newtons; one newton is 0.225 pounds (3.56 ounces) (all values rounded to 3 significant digits; pounds here refers to "pounds force").

In Zero G, an object with a mass of 1kg has a weight of 0kg

In zero g, the weight of 1kg is 0 netwons.

On the moon an object with a mass of 1kg has a weight of approx 167g because its a 0.167 G environment

On the moon, 1kg weighs 1.62 newtons.

On Mars an object with a mass of 1kg has a weight of approx 380g because its a 0.38G environment

On Mars, 1kg weighs 3.71 newtons.

So, your 1500kg LRV, while it only weighs 250kg on the moon, its mass remains 1500kg. However, that isn't the kicker.

1500kg weighs 1500kg * 1.62m/s² = 2430 newtons.

Fred

[Not Myself]

In Zero G, an object with a mass of 1kg has a weight of 0kg

In zero g, the weight of 1kg is 0 netwons.

Funny thing is, we can fix that one in another way as well.

"In Zero G, an object with a mass of 1kg has the weight of an object with a mass of 0kg"