Space X Option Package

[serverguy247]

you may have forgotten ambient air viscosity in your calculations. It occurs we don't need to depend on specific impulse only for a thruster designed for mostly sea level operation. With the right geometry thrusters, you should be able to get the same order of magnitude energy back as you inserted in COPV .

I'm going out on a limb here; but perhaps you could add little compressors and bypass fans to the thrusters to increase their "grip" of the air, the way a jet has bypass fans to multiply its thrust. Although I don't know if there would be too much inertia to spool up fast enough.

Or skip the fan and just have an outer cowl... A bit like a ramjet / dyson air multiplier type affair.

If we had around 150Kg of air (as A X 3 found with the off-the-shelf COPV from SpaceX) with an ISP of 70 in a vac (possibly more?). That is a significant amount. 1000n thrust over 10 seconds, maybe?

 

[jeremyz]

On a related note, this electric, ducted fan go-kart goes 0-60 in 1.5 seconds. It's nice to get rid of the limits of tire traction.
Insane Electric Go Kart Does 0-60 In 1.5 Seconds - Videos

 

[jaguar36]

I made up a spreadsheet to calculate how the pressure levels and tank sizes would effect the forces that thrusters would be able to put out. Its all rough numbers with lots of assumptions, but I think it should be ball park accurate (assuming I didn't muck it up, which is quite likely given how long its been since I had fluids).

By my calcs if you put in a 18"x40" air tank (something that could fit in the back seat) at 10,000psi (which is what some hydrogen fuel cell tanks run at) you can get enough force to drop the 0-60 time from 1.9s to 1.5s. Depending on where you put the nozzles you could of course use this to improve braking or cornering very easily as well.

The tank would be empty at that point and unfortunately as others have noted the issue is then refilling the tank with a compressor that doesn't weigh a ton.

Here's a screenshot, I'd be happy to send it to anyone who wants to check my work or try some different scenarios.

 

[J X 3]

You need a canoe paddle to steer that go-kart lol

 

[J X 3]

@ jaguar36

On the compressor side, the air intake is of a certain area and the flow will depend on speed assuming no fans sucking air. So how long it takes depends on that area and the vehicle's speed.
The intake air flow has a force that they need to try to harvest, at 200km/h some 189N if area is 0.1m and at 400km/h some 756N.
So what pumps are there that can take advantage of this and how efficient are they? Is there any pump that is this flexible or do they have to build their own state of the art pump?

PS did you notice how close the ejection speed is to the speed of sound or was that intentional?

 

[thegruf]

intriguingly this solution uniquely provides additional performance that reduces not increases the load on the tyres.
Fascinating to see how weight, recharge time, consistency and noise in particular are managed.

@jaguar36 - what is the total energy required to recharge your example size vessel?

 

[dhanson865]

apparently you lose the rear seat in the 2020 roadster if you want this option.


Elon says:

Trade is just that Roadster becomes a 2 seater instead of a 2+2. COPV in place of the kid seats, which is prob wise for many reasons

 

[kbM3]

So maybe he’s not joking (but the “flying” part is certainly a joke).

Elon never jokes.

 

[slipnslider]

Quite the opposite , this is a major asset with autonomous vehicles as it increases safety dramatically.
It also enables higher peak and average speeds so that is a plus with car as a service where time is money for both the customer and Tesla.
If done right, this triples Roadster revenue while boosting margins so the return on this investment is quite high even if you don't factor in the long term upside and this being in every car.
The fact that others aren't doing it is great and Tesla has an advantage on the tech side that helps here.
The marketing upside is huge too.
So all in all, this might end up being the biggest Tesla news in a long while, even if some folks might need 5 to 10 years to get it.

Yes, in a place without traffic or speed limits, rocket thrusters could have some advantages. Where is that exactly?

 

[Zoomit]

Where is that exactly?

The places where sports car records are broken.

 

[J X 3]

Yes, in a place without traffic or speed limits, rocket thrusters could have some advantages. Where is that exactly?

That's not quite true, just because you have a lot of thrust at your disposal, doesn't mean you have to use it at maximum potential.
It's also only needed when the car is pushed beyond its limits, you are not gonna use it at city speeds because the car is far from its limits.. However, in a low speed emergency, you might want to use it as it's less dangerous than not using it. The autonomous vehicle will need to be aware of it's surroundings and manage its resources accordingly.

You are clearly very angry at something but this is nothing more than better aero. They take a mass, they accelerate it, they redirect it, just like any aero feature. It is far more flexible and powerful than traditional solutions though.
A huge upside is that unlike everything else, they can take that mass and energy, store it and use it even at low speeds. Drag and lift scale with the square of speed so at low speed, they are pretty useless. This solution works.even at low speeds because you saved that mass and energy and can deploy it at will and in any direction.

 

[slipnslider]

The places where sports car records are broken.

So not for use on public streets. Sounds like a real worthwhile use of tesla's limited resources doesn't it?

 

[slipnslider]

That's not quite true, just because you have a lot of thrust at your disposal, doesn't mean you have to use it at maximum potential.
It's also only needed when the car is pushed beyond its limits, you are not gonna use it at city speeds because the car is far from its limits.. However, in a low speed emergency, you might want to use it as it's less dangerous than not using it. The autonomous vehicle will need to be aware of it's surroundings and manage its resources accordingly.

You are clearly very angry at something but this is nothing more than better aero. They take a mass, they accelerate it, they redirect it, just like any aero feature. It is far more flexible and powerful than traditional solutions though.
A huge upside is that unlike everything else, they can take that mass and energy, store it and use it even at low speeds. Drag and lift scale with the square of speed so at low speed, they are pretty useless. This solution works.even at low speeds because you saved that mass and energy and can deploy it at will and in any direction.

Aeros are a simply plastic cover over the wheels. This is an elaborate, expensive, intricate system that will be difficult to develop and maintain. Every dollar spent on this toy is a dollar not spent on telsa's many other higher priorities.
Telsa doesn't get to whine "we had to only sell the most expensive cars first or else we wouldn't survive as a company!" and then go and waste money on boondoggles like this.

 

[mongo]

Aeros are a simply plastic cover over the wheels. This is an elaborate, expensive, intricate system that will be difficult to develop and maintain. Every dollar spent on this toy is a dollar not spent on telsa's many other higher priorities.
Telsa doesn't get to whine "we had to only sell the most expensive cars first or else we wouldn't survive as a company!" and then go and waste money on boondoggles like this.

Ummm.... Tesla has a bunch of money in Roadster reservations to spend on development. Including founders series cars at 250k up front.

 

[J X 3]

Aeros are a simply plastic cover over the wheels. This is an elaborate, expensive, intricate system that will be difficult to develop and maintain. Every dollar spent on this toy is a dollar not spent on telsa's many other higher priorities.
Telsa doesn't get to whine "we had to only sell the most expensive cars first or else we wouldn't survive as a company!" and then go and waste money on boondoggles like this.

How do you brake from 60mph to 0 mph in 50 feet? How do you jump over obstacles in case of an emergency?
How do you travel safely on the highway at 400km/h if you can't brake and turn at 3g to avoid death?

Another thing that traditional aero doesn't get you is efficiency if you optimize for safety and perf. If you make a car with very sticky tires, very high drag and very high downforce all the time, that's not good at all when it comes to fuel.
This kind of super-active aero allows Tesla to have low drag and downforce under normal conditions and a great flexibility to deploy just what is needed, when needed while using a lot less fuel.
This is like finally getting access to an opposable thumb.

 

[gjunky]

Would you do it if you had a cop car behind you?

Many places have exhibition of speed laws: Exhibitions of Speed Laws | LegalMatch Law Library

Other places would consider it reckless driving.

Wouldn't he always be behind you....

I've hear of people being ticketed for wasting resources but that is a tough argument to make with an electric car

 

[J X 3]

I made up a spreadsheet to calculate how the pressure levels and tank sizes would effect the forces that thrusters would be able to put out. Its all rough numbers with lots of assumptions, but I think it should be ball park accurate (assuming I didn't muck it up, which is quite likely given how long its been since I had fluids).

By my calcs if you put in a 18"x40" air tank (something that could fit in the back seat) at 10,000psi (which is what some hydrogen fuel cell tanks run at) you can get enough force to drop the 0-60 time from 1.9s to 1.5s. Depending on where you put the nozzles you could of course use this to improve braking or cornering very easily as well.

The tank would be empty at that point and unfortunately as others have noted the issue is then refilling the tank with a compressor that doesn't weigh a ton.

Here's a screenshot, I'd be happy to send it to anyone who wants to check my work or try some different scenarios.
View attachment 308765


View attachment 308765

I can't figure out how you got to that force.
In the thrust equation just the mass flow x speed is 8500+ and then you would add almost 400k from pressure differential x area.

 

[jbcarioca]

What comes after plaid mode?

Just for accuracy: Maximum Plaid could only be reached in the Winnebago IIRC. If they really do offer the rockets maybe they’ll need to ask Mel Brooks if it could be Kaminsky drive.

 

[mongo]

Just for accuracy: Maximum Plaid could only be reached in the Winnebago IIRC. If they really do offer the rockets maybe they’ll need to ask Mel Brooks if it could be Kaminsky drive.

COPV will be label Schwartz?

 

[scaesare]

Aeros are a simply plastic cover over the wheels. This is an elaborate, expensive, intricate system that will be difficult to develop and maintain. Every dollar spent on this toy is a dollar not spent on telsa's many other higher priorities.
Telsa doesn't get to whine "we had to only sell the most expensive cars first or else we wouldn't survive as a company!" and then go and waste money on boondoggles like this.

You assume "either/or", when it appears possible for "either/and".