XPost: sci.electronics.design, sci.physics, sci.space.policy   
   From: krw@nowhere.com   
      
   On Tue, 8 Nov 2016 07:13:09 -0000, jimp@specsol.spam.sux.com wrote:   
      
   >In sci.physics mike  wrote:   
   >> On 11/7/2016 7:39 PM, jimp@specsol.spam.sux.com wrote:   
   >>> In sci.physics mike  wrote:   
   >>>> On 11/7/2016 1:46 PM, jimp@specsol.spam.sux.com wrote:   
   >>>>> In sci.physics Phil Hobbs  wrote:   
   >>>>>> On 11/07/2016 01:37 PM, jimp@specsol.spam.sux.com wrote:   
   >>>>>>> In sci.physics Robert Clark  wrote:   
   >>>>>>>   
   >>>>>>>    
   >>>>>>>   
   >>>>>>>> If you know of a means to provide 50,000 V at *lightweight* then you   
   will   
   >>>>>>>> have solved the problem of an independently flying lifter, using the   
   >>>>>>>> macrosized wires currently used. You would need about a power to   
   weight   
   >>>>>>>> ratio for the power source of better than 1 watt per gram, while   
   being able   
   >>>>>>>> to provide these ca. 50,000 V voltages.   
   >>>>>>>>   
   >>>>>>>>    Bob Clark   
   >>>>>>>   
   >>>>>>> Trivial; look at any camera flash unit built in the last several   
   decades.   
   >>>>>>>   
   >>>>>>> However you have totally missed the point; voltage and the weight of   
   the   
   >>>>>>> converter is irrelevant as it is the total power that determines the   
   >>>>>>> weight of it all.   
   >>>>>>>   
   >>>>>>> BTW, here are some real world power to weight ratios:   
   >>>>>>>   
   >>>>>>> Boeing 777 engine 10 kW/kg   
   >>>>>>    1985 Chevy Celebrity 300 W/kg <-- So for a 1000 kg car, that's 402   
   >>>>>> horsepower?  Sign me up! ;)   
   >>>>>>   
   >>>>>> Cheers   
   >>>>>>   
   >>>>>> Phil Hobbs   
   >>>>>   
   >>>>> No, that is the power to weight ratio of the engine, not the power to   
   >>>>> weight ratio of the car.   
   >>>>>   
   >>>>>   
   >>>> Power is a red herring.  What's important is the total energy produced   
   >>>> by the   
   >>>> engine AND the fuel supply.   
   >>>> It doesn't get the least bit interesting until the engine can lift   
   >>>> itself and a FULL tank of whatever powers it AND the vehicle AND the   
   >>>> payload to reach the destination.   
   >>>> I can't imagine that ever happening 1000 feet off the ground on this ole   
   >>>> earth at a cost anywhere near the cost of other forms of transportation.   
   >>>   
   >>> Are you trying to say airplanes aren't going to make it in the commercial   
   >>> world?   
   >>>   
   >>>   
   >> Yep, that's exactly what I'm saying: "Airplanes with ion drive are not   
   >> going to make it in the commercial world."  Whatever technology can make   
   >> that work will be FAR less costly applied to something that rolls along   
   >> the roadway.   
   >   
   >I doubt there is any technology that could ever make it work in an   
   >atmosphere.   
   >   
   >> But that misses the point that it's ENERGY that's the concern.  Doesn't   
   >> matter how light or powerful the airplane engine is if it still can't lift   
   >> enough fuel to reach the destination.  It takes a given amount of energy   
   >> to get from here to there.  Changing the engine only affects the efficiency   
   >> of the process that converts the available fuel source to whatever it takes   
   >> to motivate the vehicle.  Maybe we'll see terrestrial ion engines, but   
   >> the efficiency   
   >> improvement won't be huge.   
   >   
   >Aircraft engines don't lift anything.   
      
   Harriers aren't aircraft?  Well, they do look a little like bricks.   
   -)   
   >   
      
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