My last "They didn't go moon trip".
09-05-2007, 01:32 PM
#121
Registered User
Thread Starter
Join Date: Jun 2005
Posts: 996
We see two sets of tire tracks comming down the hill.
Then before it stops the front wheels lift skipping 6 feet or so and comes to a rest.
That is amazing!
The front wheel skips the entire lenght of the wheel base. How convenient!
Then before it stops the front wheels lift skipping 6 feet or so and comes to a rest.
That is amazing!
The front wheel skips the entire lenght of the wheel base. How convenient!
09-05-2007, 01:39 PM
#124
Registered User
iTrader: (1)
Join Date: Jan 2003
Location: Union City/San Diego, CA USA
Posts: 4,682
Car Info: The Thundercougarfalconbird
i looked up the lunar rover weight and assuming that wiki is right (463lb on earth) it comes out to ~20lb. At empty and with astronauts weighing approx 160lbs ( i think they weighed even less than that), that would be ~26 lbs per wheel (take the sigma pi calc and divide by 2). Still small beans.
09-05-2007, 01:40 PM
#125
Registered User
Thread Starter
Join Date: Jun 2005
Posts: 996
you forgot this image. This is the rover in motion with 1 astronaut. Look at the dust fall off the tire. This disruption would leave an inprint. I would beleive that the front wheel would lift in this case more so then lifting when the LR is comming to a stop. Even so this shows that the tire displaced moon dust on initial movement a should continue to do so comming to a stop.
Last edited by Ichinobu; 09-05-2007 at 01:44 PM.
09-05-2007, 01:49 PM
#126
Registered User
Thread Starter
Join Date: Jun 2005
Posts: 996
The above picture is a good example of how far fetched the idea that the front tire lost contact a full wheelbase length before coming to a stop and not embedding the front wheel in the dust.
They are implying that the LR did a wheelie to a stop.
They are implying that the LR did a wheelie to a stop.
09-05-2007, 01:49 PM
#127
The force of the astronaut is concentrated straight down from his CG to 2 legs into the ground. The CG of that rover is not at the wheels and (depending on the weight distribution) the force of the astronauts and the car is distributed to 4 wheels.
W=mg/2 (human for 2 legs)
W=mg/4 (for 4 wheels and assuming equal weight distribution)
and note that g is not 9.81m/s^2. On the moon its... 1.63m/s^2 about 7x less.
Assuming sigma pi weighs 300lb, he'd be ~50lb on the moon. that translates to approximately 12lb per wheel. Thats like a nudge on the shoulder. And the astronauts, i'm safely assuming, weighed less than sigma pi.
W=mg/2 (human for 2 legs)
W=mg/4 (for 4 wheels and assuming equal weight distribution)
and note that g is not 9.81m/s^2. On the moon its... 1.63m/s^2 about 7x less.
Assuming sigma pi weighs 300lb, he'd be ~50lb on the moon. that translates to approximately 12lb per wheel. Thats like a nudge on the shoulder. And the astronauts, i'm safely assuming, weighed less than sigma pi.
i looked up the lunar rover weight and assuming that wiki is right (463lb on earth) it comes out to ~20lb. At empty and with astronauts weighing approx 160lbs ( i think they weighed even less than that), that would be ~26 lbs per wheel (take the sigma pi calc and divide by 2). Still small beans.
you forgot this image. This is the rover in motion with 1 astronaut. Look at the dust fall off the tire. This disruption would leave an inprint. I would beleive that the front wheel would lift in this case more so then lifting when the LR is comming to a stop. Even so this shows that the tire displaced moon dust on initial movement a should continue to do so comming to a stop.
09-05-2007, 01:57 PM
#128
Registered User
iTrader: (1)
Join Date: Jan 2003
Location: Union City/San Diego, CA USA
Posts: 4,682
Car Info: The Thundercougarfalconbird
I forgot to say that this was a static assumption. Dynamically, it could hit a bump and the rover could go flying. Dynamic behavior can change drastically when the grav pull is different. Statically it stays the same.
09-05-2007, 02:02 PM
#129
Registered User
Thread Starter
Join Date: Jun 2005
Posts: 996
i looked up the lunar rover weight and assuming that wiki is right (463lb on earth) it comes out to ~20lb. At empty and with astronauts weighing approx 160lbs ( i think they weighed even less than that), that would be ~26 lbs per wheel (take the sigma pi calc and divide by 2). Still small beans.
the rover is 463lb on Earth an astronaut weighing 175 pounds. wears the complete suit, the total weight is then about 485 pounds (310 + 175 =495)
astronaut + rover = more weight. They are riding the thing!
There are tracks all over the place except behind the wheels.
09-05-2007, 02:05 PM
#130
Registered User
iTrader: (1)
Join Date: Jan 2003
Location: Union City/San Diego, CA USA
Posts: 4,682
Car Info: The Thundercougarfalconbird
Ah this is funny.
the rover is 463lb on Earth an astronaut weighing 175 pounds. wears the complete suit, the total weight is then about 485 pounds (310 + 175 =495)
astronaut + rover = more weight. They are riding the thing!
There are tracks all over the place except behind the wheels.
the rover is 463lb on Earth an astronaut weighing 175 pounds. wears the complete suit, the total weight is then about 485 pounds (310 + 175 =495)
astronaut + rover = more weight. They are riding the thing!
There are tracks all over the place except behind the wheels.
which AGAIN amounts to 26 static pounds per wheel. The acc constant is less, but the gravitational constant is less so again, the dynamics won't be what we are used to seeing here on earth.
Last edited by samurai; 09-05-2007 at 02:10 PM.
09-05-2007, 02:05 PM
#131
VIP Member
Join Date: Aug 2003
Location: running track
Posts: 3,018
Car Info: 2004 Wagon
so you're saying 26lbs on the wheel won't leave tire marks on lunar dust? but a 300lb astronaut (with all the gear) = 43 lbs on the moon --> 21.5 lbs per foot leaves those huge footprints?
yeah! that's the pic i was talking about. the dude is ON the rover and there are no tire marks.
yeah! that's the pic i was talking about. the dude is ON the rover and there are no tire marks.
09-05-2007, 02:09 PM
#132
Registered User
iTrader: (1)
Join Date: Jan 2003
Location: Union City/San Diego, CA USA
Posts: 4,682
Car Info: The Thundercougarfalconbird
If the weight were distributed to the rear, then adding 15 pnds to the rear would be ~34lb per wheel while the front would be at ~18lb per wheel with a quick calc.
09-05-2007, 02:11 PM
#133
Registered User
Thread Starter
Join Date: Jun 2005
Posts: 996
The force of the astronaut is concentrated straight down from his CG to 2 legs into the ground. The CG of that rover is not at the wheels and (depending on the weight distribution) the force of the astronauts and the car is distributed to 4 wheels.
W=mg/2 (human for 2 legs)
W=mg/4 (for 4 wheels and assuming equal weight distribution)
and note that g is not 9.81m/s^2. On the moon its... 1.63m/s^2 about 7x less.
Assuming sigma pi weighs 300lb, he'd be ~50lb on the moon. that translates to approximately 12lb per wheel. Thats like a nudge on the shoulder. And the astronauts, i'm safely assuming, weighed less than sigma pi.
W=mg/2 (human for 2 legs)
W=mg/4 (for 4 wheels and assuming equal weight distribution)
and note that g is not 9.81m/s^2. On the moon its... 1.63m/s^2 about 7x less.
Assuming sigma pi weighs 300lb, he'd be ~50lb on the moon. that translates to approximately 12lb per wheel. Thats like a nudge on the shoulder. And the astronauts, i'm safely assuming, weighed less than sigma pi.
sounds nice but if there is going to be skipping it should have happened on this hoop tee doo but notice all tracks
09-05-2007, 02:16 PM
#134
Registered User
iTrader: (1)
Join Date: Jan 2003
Location: Union City/San Diego, CA USA
Posts: 4,682
Car Info: The Thundercougarfalconbird
perhaps, but you're not going to tell an astronaut that went to the moon to drive exactly at the same speed all the time. Some times, they gunned it, sometimes they kept it slow, sometimes it was loaded with one person, etc etc etc. It all makes a diff in a reduced grav field. Also, note that they were going up on a hill here. I would think it would be as hard to skip going up a hill on earth as well as the moon.
09-05-2007, 02:19 PM
#135
Registered User
Thread Starter
Join Date: Jun 2005
Posts: 996