On Wed, May 02, 2007 at 05:54:22AM -0400, DataPacRat wrote: >The current design I'm fiddling with is 83% fuel. I suppose if the >fission-fragment has the best Isp, the only options I have left are to >increase the fuel-to-payload ratio, and/or use some staging to get rid >of some of the unnecessary structural mass in mid-thrust.
That seems like a very low fuel fraction; designs I've heard about are 99% or more. >(My mistake in typing that out - that's supposed to be fully-loaded >sAccel times burn-time.) Of course, you should also bear in mind that the mass of the drive will be a factor - you may want to stick with Orions in the end, because that f-f thruster itself weighs 140lb/lbthr as opposed to 0.125lb/lbthr for the Orion. Certainly worth considering both. >On 02/05/07, Roger Burton West <[EMAIL PROTECTED]> wrote: >>Um, no. The whole point is that you lose mass as you go along. >I'm quite aware, but the 'Simplified Delta-V' is a bit quicker for an >order-of-magnitude comparison between different drives. But goes increasingly wrong as the fuel fraction increases... >I'm not quite up to fiddling with GVB's formulas in that manner yet. :) It's really easy. Trust me on this. (1) Make sure your drive and fuel tank are in the same subassembly (or package). (2) Right-click the package and select "new link node". (3) Select in the four list windows: the drive, "vFUEL_WEIGHT", the fuel, "TotalPayload". Leave the multiplier at 1. That's all it takes, and you'll get an accurate delta_V readout. R _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
