Recent content by gggnano

  1. gggnano

    Surely this will NOT work: violation of conservation of momentum?

    The rotating ball should push the vehicle first to the right and once it hits the airbag - to the left?? Even if this works, how are you going to automate it and repeat it?
  2. gggnano

    I may need 29 megawatts just to lift 180 kgs with ion thruster...

    ^ I know, and it's a shame I mean the reason I was hoping for them to be usable on earth was: 1. Quiet, unlike anything that flies on earth and uses spinning rotors (helicopters, boeing, chesna, f16), ok excluding gliders and zepellins, but come on... 2. Safe, unlike spinning rotors + kerosene...
  3. gggnano

    I may need 29 megawatts just to lift 180 kgs with ion thruster...

    So after reading a great paper from Utah university (or so) they include the following equation which should apply at least to some type of electric thrusters: P(power) = T(thrust in N)*S(specific impulse in secs)*G/(2*Efficiency) x=(1800*1000*9.8)/(2*0.3) x = 29,000,000 watts needed to lift a...
  4. gggnano

    Collection of Science Jokes P2

    God to his son: "Hey Jesus, wanna see a cool reaction using quantum fluctuation?" Less than a Planck second later: "Oh damn, it says spontaneous reactions are not reversible". bonus joke: Electron says: "Hurry up we have no time!" "Tell me about it"...said the Tau.
  5. gggnano

    Are Hovering Cars the Future of Transportation?

    Um yeah...it's called gravity and gravity is a big problem for flight on earth. To the best of my knowledge the cheapest method for a single-person transit these days isn't a car but electric scooter which is even more efficient than say solar car and obviously fossil fuel cars or bikes and to...
  6. gggnano

    I Is it possible to have "ideal surface" whose highest peak is ~1 nm?

    I was planning to use one of my 3d printers + arduino YET it seems as if arduino isn't going to work in a vacuum sooo... Apparently all of the requirements are super difficult to meet: 1. El. Conductive 2. Absurdly flat area with 5-10nm highest peak 3. In a vaccum 4. Moved by electronics that...
  7. gggnano

    I Is it possible to have "ideal surface" whose highest peak is ~1 nm?

    ^ Yet quick google suggests that they're indeed exceptionally flat even beating the sil. wafers? Yet I'm not too sure about the transparency and it's insulator...it's very cheap too and harmless...
  8. gggnano

    I Is it possible to have "ideal surface" whose highest peak is ~1 nm?

    ^ yes but no parameters mentioned I have to guess maybe...5 inches or 10 cm or so for each one will be ok - squared.
  9. gggnano

    I Is it possible to have "ideal surface" whose highest peak is ~1 nm?

    ^ I was looking for mica months ago but compared to wafers of silicon it isn't easy to find it online. Also how do I clean it?? I am planning to put it in a vacuum chamber but before that I bet it will be covered with moisture, dust if not even bigger things like fingerprints...maybe with...
  10. gggnano

    I Is it possible to have "ideal surface" whose highest peak is ~1 nm?

    Oh I had no idea, good info! So the claim it's 0.5 average may be true yet again nothing said about maximum, and it turns out it is coated of SIO2 (so it's sand??) with 200 nm of SIO2 which I assume is where the the 0.5 average roughness comes from? Normally I wouldn't that much since it's not...
  11. gggnano

    I Is it possible to have "ideal surface" whose highest peak is ~1 nm?

    I just discovered this paper which illustrates my concern: https://www.epj-conferences.org/articles/epjconf/pdf/2017/31/epjconf_incape2017_01055.pdf " ZnO thin film using granular source for deposition of e-beam. The highest peak is 150nm with average roughness of 28.74 nm" So from the quote...
  12. gggnano

    I Is it possible to have "ideal surface" whose highest peak is ~1 nm?

    I mean you could buy a mirror or silicon wafer but they give say 0.5 nm or 5nm 'roughness' which I suspect is the mean average roughness but this doesn't rule out a high "bump" way above the mean average such that for example 1 million bumps of 1 nm and just one of 5 will result in...
  13. gggnano

    Can the thrust of Ion Thruster be increased at the cost of speed?

    ^ Tantalum-Hafnium-Carbide has close to 4000 C melting point so I suspect 2000 C can be handled yet given the weight of the gas with earth's gravity...I've no idea. Which is why I am giving twice lower than it's melting point. As to Xenon: it's the heaviest non-radioactive gas, non-corrosive...
  14. gggnano

    Can the thrust of Ion Thruster be increased at the cost of speed?

    Just to elaborate on the obvious: I am using 1000 N, 1 kN as the thrust where things are "about to get interesting" as you're entering human-level of flight at this point albeit you will need several thousand at least for realistic scenario (aka anything other than a child flying on small...
  15. gggnano

    Can the thrust of Ion Thruster be increased at the cost of speed?

    So I had more time today and found this fantastic paper from NASA, long story short: No. https://descanso.jpl.nasa.gov/SciTechBook/series1/Goebel_02_Chap2_thruster.pdf Have a look at page 23, the equation basically: Thrust in mN = 1.65*amperes*Squareroot(Volts) So assuming insane amperage of...
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