[Spaceships] FWIW: Semi-Hard Science Boost Drive

DaltonS · 05-23-2015, 11:06 AM

I've had this idea for a more “realistic” boost drive for some time, but had to work out the equations and numbers first.

Mass Conversion Boost Drive (TL10^) [Any!]

This drive is a Reactionless Engine (SS1:p24) that directly converts fuel mass into directional kinetic energy instantaneously applying it to the ship and its contents boosting it to a c-fractional velocity. The kinetic energy of a ship travelling at relativistic velocities is the difference between the total energy of its rest mass (M) and that of its relativistic mass (M/τ) where τ=sqrt(1-(v/c)²) (also known as the tau factor). Thus, with K=Mc²(1/τ-1), the mass converted to kinetic energy would be m=M(1/τ-1), making τ=M/(M+m) and (v/c)=sqrt(1-τ²). The table below assumes that for safety, the fuel tanks contain mass for two boosts; one to accelerate, the other to decelerate. (For this I used M=sqrt(1-0.05*N) and m=r*(1-M) where N is the number of fuel tanks and r is the rate of mass conversion.) The conversion rates are 60% at TL10^, 80% at TL11^ and 100% at TL12^. Use Subwarp drive prices.

Code:

_____________________________________________________________________________________
 Fuel  |           Velocities/Tau Factors for Mass-Conversion Boost Drive            |
 Used  |  60% Conversion (TL10^) |  80% Conversion (TL11^) | 100% Conversion (TL12^) |
(Tanks)|  v/c   v(AU/hr) τ-Factor|  v/c   v(AU/hr) τ-Factor|  v/c   v(AU/hr) τ-Factor|
-------+-------------------------+-------------------------+-------------------------|
  1/3  | 10.03%  0.7233  0.99496 | 11.56%  0.8341  0.99329 | 12.91%  0.9314  0.99163 |
  2/3  | 14.21%  1.0254  0.98985 | 16.37%  1.1811  0.98651 | 18.26%  1.3172  0.98319 |
   1   | 17.45%  1.2591  0.98465 | 20.08%  1.4484  0.97964 | 22.36%  1.6132  0.97468 |
   2   | 24.88%  1.7947  0.96856 | 28.50%  2.0563  0.95852 | 31.62%  2.2814  0.94868 |
   3   | 30.71%  2.2158  0.95166 | 35.05%  2.5284  0.93657 | 38.73%  2.7941  0.92195 |
   4   | 35.76%  2.5801  0.93386 | 40.63%  2.9315  0.91372 | 44.72%  3.2264  0.89443 |
   5   | 40.33%  2.9096  0.91506 | 45.62%  3.2913  0.88987 | 50.00%  3.6072  0.86603 |
   6   | 44.58%  3.2160  0.89515 | 50.19%  3.6210  0.86492 | 54.77%  3.9515  0.83666 |
   7   | 48.60%  3.5061  0.87397 | 54.45%  3.9286  0.83873 | 59.16%  4.2681  0.80623 |
   8   | 52.46%  3.7846  0.85136 | 58.48%  4.2191  0.81116 | 63.25%  4.5628  0.77460 |
   9   | 56.21%  4.0548  0.82710 | 62.32%  4.4963  0.78203 | 67.08%  4.8395  0.74162 |
  10   | 59.87%  4.3195  0.80094 | 66.02%  4.7628  0.75111 | 70.71%  5.1013  0.70711 |
  11   | 63.50%  4.5809  0.77254 | 69.59%  5.0208  0.71810 | 74.16%  5.3503  0.67082 |
  12   | 67.10%  4.8408  0.74146 | 73.08%  5.2720  0.68264 | 77.46%  5.5882  0.63246 |
  13   | 70.71%  5.1012  0.70712 | 76.48%  5.5178  0.64423 | 80.62%  5.8164  0.59161 |
  14   | 74.35%  5.3641  0.66870 | 79.83%  5.7596  0.60219 | 83.67%  6.0360  0.54772 |
  15   | 78.06%  5.6317  0.62500 | 83.15%  5.9986  0.55556 | 86.60%  6.2478  0.50000 |
  16   | 81.87%  5.9067  0.57417 | 86.44%  6.2361  0.50280 | 89.44%  6.4527  0.44721 |
  17   | 85.84%  6.1926  0.51303 | 89.73%  6.4736  0.44139 | 92.20%  6.6513  0.38730 |
  18   | 90.03%  6.4950  0.43528 | 93.05%  6.7129  0.36632 | 94.87%  6.8441  0.31623 |
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Dalton “who thinks this makes boost drives relatively realistic” Spence