Shot at some Tesla Roadster SpaceX package stats vs F1 & Top Fuel

Discussion in 'Tesla' started by 101101, Jun 3, 2019.

  1. 101101

    101101 Active Member

    Musk has said the SpaceX vectored thrust package adds 3 g forces to any direction
    and says expelled gas will be immediately replenished depending on power draw. So I will add 3 gs to estimates of all the base roadster's g loading. We have to keep in mind that the tires, and the down force and the weight of the battery limit (even if Maxwell tech lightens) the Roadster S where on the other hand the base roadster matches Top Fuel ftlbs torque by some measures.

    Roadster S vs Top Fuel
    4.5+ gs s off the line 0-60 for roadster S vs Top Fuel's 6 gs off the line, yielding .6 seconds 0-60 for Roadster S, vs .4 0-60 for Top Fuel or 66% of 0-60 acceleration for Roadster S, after that the dragster walks away from the Roadster S hitting 8 gs at 1/8 mile and 200 mph. But not bad to have %66 of Top fuel 0-60 although I am certain an electric dragster could beat top fuel possibly by a large margin- Tesla could do a ultracap enhanced battery demonstrator to shake up Top Fuel. There is apparently also a higher power COPV they could use but I guess that's not deemed safe for land vehicles.

    Roadster S vs F1
    Roadster at 4.5+ gs is 300%-400% of the 0-60 acceleration of F1 and Roadster S at 1.00 second 0-100mph or 400% of F1 acceleration
    Roadster S at 4.7 gs for breaking force is 85% of F1 breaking force
    Roadster S at 5.3 cornering gs is 66% of F1 cornering force

    So it looks like even with the huge advantage on acceleration the Roadster S wouldn't beat F1 on most tracks. But the Roadster S is 1/44th the cost of a F1 car and it is 26000x more fuel efficient than a Top Fuel dragster- top fuel dragster is literally 200lbs of fuel per mile.
    Guessing if the cornering could be improved by about 25% and the braking about about 10% it might be able to compete with F1 on a standard track but my wild guess is couldn't compete if breaking and cornering didn't get within 90% even with huge acceleration advantages. What do more knowledgeable people think? Maybe I did the G calculations wrong for all of it. I used the current hyper car limits for cornering and breaking gs and added the 3 gs for the SpaceX package, I simply added the calculated gs for the base roadster plus 3 for the acceleration.

    I'd like you to contemplate a street-able machine that is totally civilized on the road but can do everything on the track at an average of about 5 gs and that includes, cornering, breaking and accelerating. Its a 5 g machine. A Top Fuel dragster will accelerate at 8 gs but you can't corner in it unless you load it on a truck. A F1 will corner at 8 gs but you can't accelerate more that about 1.4gs. A Tesla Roadster S is like crossing Top Fuel with F1 and making it perfectly street able with a 620 mile ranges and silent off track performance. You don't have to rebuild the engine after every race or replace a bunch of parts as with F1 and top fuel. Also a Top Fuel dragster still costs about 2x what a Tesla Roadster S costs, and neither will self drive and neither is perfectly green with almost no moving parts, neither seats more than 1 or has a trunk.

    I suspect Musk was saying that anything over 3 gs is over the practical limit of human endurance- space shuttle was limited to 3gs going up for comfort and delicate experiments, but really 3 gs is the red out limit for negative gs, Saturn V went 9 gs for much of its flight and fighter pilots sustain 9 gs with gs suits for positive gs.
     
  2. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    I had dismissed the "SpaceX thruster package" for the forthcoming Tesla Roadster Mk II (my term, not Tesla's) as just a rather over-the-top sales gimmick. However, from what George Bower said in his analysis, I guess it really will give a substantial boost to 0-60 times, and thus help with drag racing acceleration. See: "2020 Tesla Roadster With SpaceX Thrusters: What's The Benefit?")

    I'm quite skeptical that it will have any other substantial benefit. Considering the weight-to-thrust ratio, any substantial acceleration will exhaust the thruster pack's gas (not gasoline) capacity within just a few seconds. I was sure that was true just from my general familiarity with basic physics, and George Bower's calculations confirm it.

    I'm quite skeptical that it will be of much, or even any, practical benefit in improving cornering ability. The driver has to be familiar with the way the car handles to be able to get the best performance out of it, and a thrust of up to 3 g's from a gas thruster system would cause the car to perform quite differently. Even if that would in theory help with cornering, it's unlikely to be of any practical use if the driver isn't expecting it. In fact, it would be quite dangerous to have the car perform in a markedly different way when turning at high speed, or when the driver is pushing the limits of the car's traction.

    Also, keep in mind that if the thruster package is using enough energy to recharge the system quickly, it's also using a lot of the battery pack's stored power to do it. Of course, with a whopping 200 kWh of capacity in the pack, that may often not be an issue on the day.
     
    Last edited: Jun 4, 2019
  3. 101101

    101101 Active Member

    Yeah, when I was a kid I read a book on the development of jump jets and how difficult that was. I can see it helping braking but lateral help seems more tricky, as tricky as ABS was but going sideways. Still not ready to count it out because thrust vectoring proved quite effective for a while with Harriers and its well known in rocketry and SpaceX pushes this stuff to the limit. I knew a fighter pilot that used to have to skirmish in a USMC F4 against the Harriers and he expressed respect for the design and they use that thrust vectoring in their maneuvering as much as in take of and landing. I have a feeling if anyone can pull it off SpaceX Tesla. As we know there are also compressed air cars on the market that use the compressed air for range.

    There is still the possibility that the Roadster S is a 5 g-force machine all around, a F1/dragster hybrid stamina titan

    By 5 g-force machine as above I mean average 5 gs in acceleration, in cornering and in breaking even if somewhat intermittently. The main intermittentancy we think of what electrics is eliminated with the Roadster S, probably charge it pretty quick with a mega charger plug or even without one and with 620 miles of range it's luxurious. And below I show why its much less intermittent than those true race cars all around. I get your point, though with a 1 or more tire changes during a 190mile race a F1 car can corner at close to 8 gs and even with the vectored thrust running the Roadster S would come up short by a substantial margin and can the thrust vectoring even be sustained meaningfully throughout a race, and without the gas no car can compete with a dragging on the ground 4 wheel motor cycle which is what F1 is. I think I read somewhere the roadster will have 90 seconds of gas and we don't now how quick the recharge is. Musk makes it sound quick. Must be an amazing recharge system because it can take a few minutes to charges a 3000psi scuba tank and this is a 5000psi COPV.
    But for about 50lbs guessing total weight 40 liter COPV or about 3.5 scuba tanks worth.
    Have to remember to these types of thrusters systems have exquisite precision that a huge amount of super expensive space stock relies upon every day. I wonder if the SpaceX idea came about when Musk and crew were thinking about positioning his Roadster in space to aim at Mars.

    On intermittancy you can only run a Top Fuel about 950 revolutions light to light before you need an engine rebuilt that takes a crew of 9 close to 40 min and maybe minimum $4500 in parts but also need labor and machine shop. The dragster is good for about 1000ft or maybe pushing it to the old limit of 1/4 mile- but probably not any more. After not too many dragster runs you'll need a new engine at about $60K and 2K for tires. But you can run the Roadster S all day long even though you only get about %66 percent of the speed 0-60 of the dragster. The F1 will give you maybe 3-5 races before you need a new engine, really you want to play it safe you'll need a new engine after 568 miles, but you'll need engine work at 189miles or a single race and you'll go through tires. The Roadster S with regen (if used in much in race mode) and thrust braking might do well with the brakes as a limiting factor but would presumably go much farther if the tires would hold up. Probably not going to beat a F1 on a typical track even with radically better acceleration in the Roadster S vs the F1, because of the better cornering in F1 and better braking in F1. But regardless you can drive it on the street and you could do a bunch of brutal races presumably without needing much if anything in the way of maintenance outside of tires. And again its dirt cheap. I got it wrong elsewhere the efficiency of the Roadster S vs dragster is something like 3200x in favor or the Roadster S.

    In my mind there is still the very real possibility that thrust vectoring and the Tesla Maxwell lighter tougher more resistant and resilient dry electrode batteries plus possibly Maxwell supercaps and the rest of the Tesla tech would totally upend F1 and Top Fuel if Tesla decided to do so with Formula E and Electric Dragsters. I hope Tesla does this because I think Formula E is being set up to not embarrass legacy ICE companies and Tesla doesn't play that.
     
  4. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    I agree that with a lot of training, on the level of a fighter pilot or a professional race driver, there may well be an advantage to using the SpaceX thruster pack for such things as assisting in steering and lateral movement of the car. What concerns me is someone trying to use it who's unfamiliar with the different way it's going to handle when the thrusters are pushing in any direction other than straight forward or straight back. IMHO that's just an accident waiting to happen.

    No, there aren't any past the prototype stage. None "on the market"... unless you're talking about a toy, where the range is measured in feet rather than miles!

    [​IMG]

    There was a long-running scam from a company known as "MDI" (Motor Development International) which announced various attempts in various countries, over the course of 20+ years, to put into production a car powered by compressed air. But for some odd reason :rolleyes:, they never actually went into production. After folding their tent and sneaking away into the night in one country, they would pop up a bit later promoting the same scam in another country.

    I think the closest any air-powered car ever got to production was the announcement in 2009 by Tata Motors of India, that they would be producing a car with an MDI-developed compressed-air motor starting in 2011. Tata claimed a highly unlikely 80 mile range for the car, despite third-party assessments that estimated the car would have a real-world range of about 5 miles. Of course the Tata air car didn't actually go into production, because... physics. Shockingly, according to Wikipedia, Tata was still claiming to be working on a production model as late as 2017. Not sure what's going on there; is it corporate groupthink, unable to admit that they were fooled by MDI's scam and have wasted a lot of time and money on something that is unworkable? Or are there people at Tata who are actively and knowingly involved with, and promoting, the scam? I hope it's a case of ignorance and incompetence, rather than greed and conspiracy.

    "Never attribute to malice that which can be adequately explained by stupidity, but don't rule out malice." -- Heinlein's Razor

    Here's a 2014 article on the subject: "Whatever Happened To That Compressed Air Car Anyway?"

    And hey, 101101, gotta say here: For someone who's as deeply devoted to all kinds of outlandish conspiracy theories as you are, it's rather ironic that you seem to have utterly missed that promoting development of an "air car" is a real conspiracy!
    :eek:
     
    Last edited: Jun 5, 2019

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