 | | Re: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) And if we were talking about a hovercraft in an elevator - I'd be agreeing with you. Dumb pedantry doesn't work here. The **WEIGHT** of the hovercraft is just as important/relevent/applicable as the **MASS** of the hovercraft when we are (...) (23 years ago, 30-Nov-02, to lugnet.robotics)
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| | Re: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) Ok, remember you asked... Let's take example 1- You're in an elevator. The elevator goes down. Your weight decreases but your mass does not. Q: Where did the weight go? Did you mass change? Example 2- Take a 1lb weight and a scale. Scenario a: (...) (23 years ago, 30-Nov-02, to lugnet.robotics)
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| | Re: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) How? It seems to me that as long as acceleration due to gravity is constant (i.e. same altitude, same planet; in this case, 9.8 m/s/s) then weight and mass have a simple proportional relationship. (23 years ago, 30-Nov-02, to lugnet.robotics)
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| | Re: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) That's a pretty basic physics mistake <shrug>. -- ___...___ We don't see things as they are, ravage@ssz.com we see them as we are. www.ssz.com jchoate@open-forge.org Anais Nin www.open-forge.org ---...--- (23 years ago, 29-Nov-02, to lugnet.robotics)
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| | Re: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) So long as we are down here on the surface of the earth talking about the air pressure under the skirt of a hovercraft and whether it'll lift or not, weight and mass are equivelent concepts. (...) Yes - I understand that. (...) Yes...although (...) (23 years ago, 29-Nov-02, to lugnet.robotics)
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| | Re: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) I think you need a MUCH bigger area under the craft. If all the motors and stuff on top weighed (say) 100 grams, and you have just 16cm diameter skirt then you need a pressure of: 0.1 / (PI x 0.008 x 0.008 ) kilograms/square meter ...in order (...) (23 years ago, 29-Nov-02, to lugnet.robotics)
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| | Re: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) So is Hans Madsen on this list? I'm always skeptical of things that are just throwaway lines like that...was this pure lego? How much cheating was involved? There was a couple of photos of a lego helocopter that could really fly on the list a (...) (23 years ago, 29-Nov-02, to lugnet.robotics)
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| | Re: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) We aren't interested in power, we're interested in moving a volume of air. They are very fast, high rpm. Trade off rpm with suitable gearing. You may need two or more (which is why small may be better). I've never used them myself except for (...) (23 years ago, 29-Nov-02, to lugnet.robotics)
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| | RE: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) Get rid of this fixation with 'lift own weight' (you're -completely- ignoring the -primary- factor of time). Consider the exhaust of a car, pump it into a bag and you can lift the car to change the tire but you can stop the car by simply (...) (23 years ago, 29-Nov-02, to lugnet.robotics)
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| | Re: "real" LEGO Hovercraft ? (with/without batteries/RCX "onboard")
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(...) There's an echo in here ;)...you'll get to the answer faster if you'll think of mass and force instead of weight. (...) Which is where the ratio of the input plenum to the skirt (the output plenum) comes into play. (...) No, that's a function (...) (23 years ago, 29-Nov-02, to lugnet.robotics)
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