From: eripe.dk@gmail.com   
      
   Was reading this paper on an interstellar drive   
   https://arxiv.org/pdf/1808.02019.pdf   
      
   and then had the thought what if instead of the paddle design, use a propeller   
   design.   
      
   For instance, I have a propeller for a machine   
      
   0,63 m diameter, - area   
   1465 rpm   
   289 Pa   
   4,61 m3/s   
   3140 W   
   1,46 kg/m3 air density   
   Force = p x A = 90 N   
      
   If interstellar density is 1e-16 kg/m3, this fan would scale to F = 6,2e-15 N,   
   but extend the wings to 1000 km diameter and you get a force of 0,015 N (rim   
   speed is now 0,26c) but the power cost is only 0,54 W, if my calculations are   
   correct.   
      
   Apart from the issue of making a 1000 km massless propeller, do you see any   
   holes?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)