Tesla Roadster is going to be able to hover over the ground, says Elon Musk | Hacker News Reader

Tesla Roadster is going to be able to hover over the ground, says Elon Musk

electrek.co

31 pointsdevy19 comments

With compressed air? No. I don't care how "not joking" he is, the power density is just not enough to lift a car for more than a few seconds even if the entire car were filled with tanks. It's just common sense. Have you ever seen compressed air VTOL on anything?

He also claims it will allow the car to accelerate "at the limit of human endurance" which would imply thrust vectoring also.

Perhaps he's testing the limits of human credibility...

Even if it would work... what would hovering even do that is beneficial? Without tires touching the pavement, you won't turn or stop well at all. You will bottom out over every speed bump and driveway and parking lot entrance, unless you're hovering like a foot off the ground. The efficiency gains from the decreased rolling resistance will certainly not overcome the juice that these things will suck down...

Parallel parking?

(There are no "efficiency gains from decreased rolling resistance" if the tires aren't even touching the ground. Your wheels will spin without moving the car, an efficiency of 0%)

> With compressed air?

Nope, with cold gas thrusters: https://twitter.com/elonmusk/status/1083128521801822213

That's a fancy word for compressed air.

It works better if you add water as reaction mass. :)

http://aircommandrockets.com/water.htm

I think we need to have a conversation about Elon Musk and gas-lighting.

I think we can all agree that some people are demonstrably taking what Musk has said to be a genuine statement about a feature in a new product. You can observe this from the people discussing in detail how it will work. Now, I'm not going to argue about that. Let's assume it turns out that this feature is not in the next Roadster. Can someone convince me that this isn't market manipulation? He's lying about features in his future products in a way that will clearly effect the market if they were true. And when it turns out to be untrue he'll throw his hands up and say it was a joke - despite literally saying he's not joking and going into details of the implementation.

Tell me, how does this differ from when Elon Musk called someone a pedofile, repeatedly, then claimed that his accusations must be true because the guy didn't sue him, and then filed court documents claiming that it was clearly all a joke to defend himself from libel claims.

Does anyone else feel uncomfortable handing ANY money or control to this person? I personally feel like Elon Musk seems to have started to cross a line into actively attacking some of the fundamental norms in our society in some sort of effort to avoid ever having to have any responsibility. This is genuinely starting to feel dangerous to me, maybe I'm being overly sensitive, but we've let this stuff slide in the past and it has been catastrophic.

I saw this tweet and immediately became concerned that the SEC would consider this a problem with disclosure, as there's a world in which people take this seriously (given his history with successful rockets) and thus would take action financially because of it.

In my mind it was a silly offhand joke - aka there is no world in which he's not joking about this. HOWEVER there may exist people who took it seriously and then went out and bought TSLA.

I think it’s safe to announce features for your product

It is if they are reasonable and not total fabrications that are deceptive. That's not to say that musk was being deceptive, I don't think he was.

I think even this thread shows that people take Musk's jokes or snide comments as truth.

Here’s the tweet that the article makes reference to:

> SpaceX option package for new Tesla Roadster will include ~10 small rocket thrusters arranged seamlessly around car. These rocket engines dramatically improve acceleration, top speed, braking & cornering. Maybe they will even allow a Tesla to fly...

[Emphasis mine.]

https://twitter.com/elonmusk/status/1005577738332172289?s=12

Ok, some thoughts of mine:

1. Reactive thrusters for aiding turning - Bosch is playing with this concept already for motorcycles, and is an interesting idea. Effectively firing a thruster against the direction of turning. Would be interesting to see implemented, RIP to whoever was riding a bike next to the car that does a hard turn all of a sudden.

2. Braking - having a reverse-thrust system in emergencies would be interesting, but I'd imagine you'd need an awful lot of thrust... Again, RIP to the small child who's crossed the street and required you to emergency brake.

3. Acceleration. We have rocket powered drag cars already. Do it. Please.

4. Sustained flight of a car. I think that reefer over at Joe's office may have affected him deeper than we'd like to have thought.

As a consumer, at this point (unless they can make it fly), I'd rather have them add reliability and reduce the total cost of ownership.

Anything that would replace the back seat of the car that generates thrust downward I would expect would cut into area that would be allocated for battery. So less area for battery but a major demand for the battery being added? Sounds like wishful thinking to me unless it’s just a few USB fans with spaceX written on the side of them facing down.

Maybe they reduce the >600miles range to 60?

Some time ago, Eaton invented a hydraulic hybrid system that stored hydraulic fluid under compressed air tanks from braking. It was incredibly efficient because of minimal conversion losses in a simple system. It didn't take off, sounds like what's mentioned

Reading only the headline, I thought this was going to be a claim that it'd accelerate so fast it would lift its front wheels off the ground--like this... https://youtu.be/_59wxPsC9NU?t=142

But what he actually said... that's just crazy.

Musk is technically very clever (have you seen SpaceX rockets landing in tandem?)s o it's likely he has something that comes close to what he's saying.

If so, I expect the real problem with this system will be safety. Sure you might be able to squirt a high density gas or liquid at high enough speed to move this car but then what is that high speed fluid going to hit? Probably it would tear up roads, cut down trees, decapitate passersby and create all kinds of mayhem.

Stick handling this through a government approvals process looks like a non-starter.

> Musk is technically very clever (have you seen SpaceX rockets landing in tandem?)s o it's likely he has something that comes close to what he's saying.

This was done in the 90s, there's nothing special about landing rockets upright. https://en.wikipedia.org/wiki/McDonnell_Douglas_DC-X

Also, being technically clever includes being able to navigate the problems that you brought up, such as the need to meet government standards, meet safety requirements and actually be useful.

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