A car in the moon...

  • Thread starter AlexGTV
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the best heat exchangers i can think of would be to use a water to water, ie have the radiators submerged in water, have this 'bath' water take have values that regulate the relese of water to the vacum of space, the relesed water would evaporate and absorb energy (heat) from the tank. this is the same method of cooling that was used in the spacesuits used by appollo astronuts.

I was actually hoping compressed or liquified air would do the trick... since we'd be using a lot of it and throwing it away through the exhaust, anyway (how much extra exhaust scavenging do you think we can get when venting to vacuum? :lol: ). The main worry is how cold is cold enough? We'd have too much cooling unless we regulated the amount of liquid air getting into the heat exchangers.

the oscilation motion shoudl be engineered out with the use of dashpots (shock absorbers)

Hmmm... add a few weeks of testing to the schedule... Branson can!

there is no sound in space (not strickly true but it is in this case)

George Lucas didn't get rich from making silent movies... I think artistic license can be used in the filming of the attempt. Or better yet... use microphones mounted on the road surface to pick up the vibrations of the car as it passes.
 
To answer the original post: The car would hit a much higher velocity on the way to the moon than it ever would on the moon. :dopey:


You're onto something!


If we loaded the Veyron onto a rocket of some sort and fire the rocket very near the moon, we can launch the Veyron at an even higher speed, and with exact precision, make the Veyron's path essentially tangent to the moon. For a tiny, tiny, tiny, fraction of a second, the Veyron is going very very very very fast on the moon. :dopey:
 
This thread is excellent. :D

I was actually hoping compressed or liquified air would do the trick... since we'd be using a lot of it and throwing it away through the exhaust, anyway (how much extra exhaust scavenging do you think we can get when venting to vacuum? :lol: ). The main worry is how cold is cold enough? We'd have too much cooling unless we regulated the amount of liquid air getting into the heat exchangers.


I think you are missing the scale of this problem. :lol:


Let's ignore all the other reasons that this engine may not work correctly and just think about the thermal problem.

Let's aim to keep the engine at a temperature which, on the compression stroke, just barely prevents the fuel from auto-igniting - we'll run it hot (I don't think there's any choice :D). And because the engine will run hot, let's give it the benefit of the doubt and say it has a thermal efficiency of 33%. It's a nice round number and not so far-fetched for a modern engine using modern materials. That means the 736 kW (1000 hp) engine produces 1472 kW of waste heat. I realize this isn't a constant value, but I'll say that it is for dramatic effect.
1472 kW of heat is an unfathomably large number in the space industry.

From what I've read, the ISS isn't capable of rejecting any more than 100 kW of heat from its numerous enormous deployable radiators.
15x less than we're talking about here (at least).

Hubble's solar arrays can generate about 6kW of power, so its peak imaging power (and consequently, its thermal dissipation) is probably quite similar.
250x less than we're talking about here.

Small to medium imaging or communications satellites don't usually generate more than 2 or 3 kW.
500x less than we're talking about.


If I buy into this 'bring convection with us' idea of yours, and I crunch a few numbers, I find that for every one minute you want to run the engine at this output, you need at least 120kg of liquid oxygen to keep it from overheating -and I've been very very forgiving with my assumptions.

edit:That's much more oxygen than will be used to actually run the engine for that minute, using the numbers aLLeKs posted earlier.
 
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If I buy into this 'bring convection with us' idea of yours, and I crunch a few numbers, I find that for every one minute you want to run the engine at this output, you need at least 120kg of liquid oxygen to keep it from overheating -and I've been very very forgiving with my assumptions.

edit:That's much more oxygen than will be used to actually run the engine for that minute, using the numbers aLLeKs posted earlier.

120 kilograms a minute. Hmmm... at top speed, the Veyron, which drinks 5.3 liters a minute at full blat (according to wikipedia) should need around 40 kilograms of regular air per minute (nitrogen+oxygen). We're wasting too much.

So, we'd be adding two tonnes of mass to the Veyron in fuel, about a ton in tanks, and various retrofitting...

About five tonnes? Not really that bad... Still less than a ton of weight, but we'll definitely need to reinforce the hell out of the suspension and tires.

It shouldn't take more than two minutes of fuel to reach 400+ mph.

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But what else can we do? We're still dumping the exhaust out into space... hopefully contributing in a small way to a greenhouse effect that will pave the way towards a habitable moon... :lol: ...so let's use that. We can run the exhaust inordinately cold (run the engine extremely rich)... then run that through some of the heat exchangers. I know... exhaust can't really be cold, but you can still use it as a heat dump.

And instead of dumping the LOX, let's keep it circulating, and merely vent some as the pressure rises (like a steam engine)... vent it backwards, actually... the first steam rocket on the moon. :D Should lower our LOX requirement.

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C'mon... the engine will work. We just need to enclose the Veyron in a bubble of atmosphere and keep the ambient temperature between 10 - 40 degrees C. Hmmm... can we make fishbowls on the moon? :lol:
 
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C'mon... the engine will work. We just need to enclose the Veyron in a bubble of atmosphere and keep the ambient temperature between 10 - 40 degrees C. Hmmm... can we make fishbowls on the moon? :lol:

:lol: Awesome.

At some point the engineering feat of turning on the car is much more impressive than driving an extra couple of hundred mph.
 
In space, there are 3 temperatures; absolute zero, damn near absolute zero, and full-bore solar radiation. It's just like a hot pocket.

Do you guys know what absolute zero is? That's the temp where there is a complete lack of kinetic energy, things are frozen on a nano scale. Do you know what unfiltered solar radiation feels like? Think Hiroshima.

So depending on what side of the moon you're on, you're either getting the deepest freeze mathematically possible or you're getting nuke'd. So forget about radiators and anything else you'd expect on a land vehicle to operate in those extremes.

On weight; what weighs 1000lbs on Earth weighs about 165lbs or so on the moon. Keep that in mind.

Here's a better question; what would the terminal velocity be of a Veyron in space "if" 1001hp (work/time) were continuously applied to it and spooky things like gravity and solar winds didn't get in the way?

Extra credit: how long would it take said Veyron to reach Mars assuming you're starting from 0 velocity just outside the Earth's atmosphere?

Bonus question: how much fuel would you use to travel the same distance on roads?

Bonus Bonus question: how many lap dances could you buy with the money you spent on fuel? (not including tips)
 
Bonus Bonus question: how many lap dances could you buy with the money you spent on fuel? (not including tips)
You'd have the entire club in bed with you long before you shelled out that much money.
 
You guys are trying too hard, why not go with a simple hydrogen or other gas powered rotary. Also a radiator wouldnt work too well when there is no air. I would say insulation alone should be good enough.
 
Let's pretend there was air and oxygen on the moon... said Veyron would maybe surpass the Earth's landmark because it would weigh a lot less on the moon (less gravity on the moon...) or at least accelerate a lot quicker... but in theory the Veyron is only built to withstand the top speed it reaches on Earth... so who knows how well the tires, chassis, engine etc would hold on the moon under intense speed...

If there was air and oxygen on the moon then you'd have the air resistance the exercise was apparently trying to do without and the whole thing would be futile anyway...
 
If there was air and oxygen on the moon then you'd have the air resistance the exercise was apparently trying to do without and the whole thing would be futile anyway...

If the question isn't 'how fast can a Veyron travel in outer space/lunar surface' but a question of how much does aerodynamic drag affect the top speed of a Veyron, that last question is easy to answer.

Pop a Veyron on 4 very low resistance rollers, strap it down, and mash the pedal. Bingo, no wind resistance.
 
If the question isn't 'how fast can a Veyron travel in outer space/lunar surface' but a question of how much does aerodynamic drag affect the top speed of a Veyron, that last question is easy to answer.

True, but the original question asked how it'd perform in no atmosphere with no wind resistance, and then the wind resistance was added back in so that the car would function.

Defeated the purpose, really...
 
You guys are trying too hard, why not go with a simple hydrogen or other gas powered rotary. Also a radiator wouldnt work too well when there is no air. I would say insulation alone should be good enough.


Radiators work perfectly fine when there's no air. :sly:




...Oh, but convectors don't.


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Danoff
:lol: Awesome.

At some point the engineering feat of turning on the car is much more impressive than driving an extra couple of hundred mph.

Yup.

I actually posed the question at lunch of how you would get a car safely to the moon to a few of my coworkers today. (to those that don't know, I design and build satellites so I'm talking with the right crowd)
I got a few laughs, some strange looks, but no solid leads. 👎:indiff:
 
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Radiators work perfectly fine when there's no air. :sly:




...Oh, but convectors don't.


edit:


Yup.

I actually posed the question at lunch of how you would get a car safely to the moon to a few of my coworkers today. (to those that don't know, I design and build satellites so I'm talking with the right crowd)
I got a few laughs, some strange looks, but no solid leads. 👎:indiff:

Ask 'em how they'd make a satellite run on 93 octane and how big a turbo you can run. (after your performance review & any drug testing of course)
 
So depending on what side of the moon you're on, you're either getting the deepest freeze mathematically possible or you're getting nuke'd. So forget about radiators and anything else you'd expect on a land vehicle to operate in those extremes.

Hence the fishbowl,. Depending on how we treat the surface, we can make it radiate heat into space or act as a greenhouse. More likely we'll use it as a greenhouse. Then heat dissipation would be taken care of by the exhaust and excess air vented into space. (Astronauts do not do this because: 1.) they don't have internal combustion exhaust coming from their electric buggies, and 2.) it's a waste of compressed/liquid air)

The titanic engineering hurdles of actually building at least twenty kilometers of road on the moon, mind you, far outweigh the rather trivial matter of making a Veyron vacuum-proof. :D
 
You just need to apply the same engineering that the Veyron is getting to a team of dump trucks, excavators, steam-rollers, and so forth.

This is starting to look cost-efficient. Look at the technology sharing!
 
Hey... how big a fishbowl would you need to cause significant drag given the atmosphere on the surface of the moon? :lol:
 
There is one. Just not enough of a one to matter. :D

Remember... we're not relying on an atmosphere to carry away heat. We're going to vent it out with the waste gases and a pressure relief valve. Something that NASA does not do because air is a bit too precious for them.

But not for Richard Branson!
 
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