Thanks, that makes sense. Still not totally clear on how "Dead Mass" and "Liftoff Mass" relate to stage masses before and after separation. I might claim that "Liftoff Mass" is something of a misnomer.
Some possible terminology: - (m_L) Payload mass - (m_p) Propellant mass - (m_i) Initial (fueled) mass - (m_f) Final (burn out) mass - (m_r) Mass of rocket These could be further subscripted w/numbers indicating a particular stage. Ex: - m_i1 Mass of 1st stage only, including fuel - m_f2 Mass of 2nd stage only, excluding fuel I think maybe (m_1) can be short for (m_i1) etc. The (m_r) designation always refers to the rocket as a whole: - m_rb1 Burn out mass of stage 1 + fueled mass of stages 2 & 3 - m_ri2 Initial mass of stages 2 & 3, this would be after stage 1 separation -- Even if this isn't the greatest terminology, it's important to specify which masses are being referred to. (2011.01.29) ben...@gmail.com: > Total terminology gaffe on my part! "stage seed" refers to the weight > of the stage above the stage for which we desire fuel numbers. Eg, for > stage three, the seed should be 1kg, the payload weight. For stage 2, > the seed should be 4 kg and some change (stage three's wet weight, you > see!). > > the stage velocities are as calculated on lines seven and eight of the > section titled 'iterative approach'. > > I'll clear those details up as soon as I return to a computer! > > On 1/29/11, rq1...@q7.com <rq1...@q7.com> wrote: > > Looks good! > > > > I can't check the iterative output 'cuz the stage speed ("Stage Seed") > > is missing from the table. (Or i don't understand it, or my browser > > isn't rendering it, etc.) But if the stage speed was known you could > > just use the first equation as a simple check. > > > > -- > > We should (do?) have a symbols page to define the meaning of these > > symbols, and/or define them as they are used. > > > >> http://psas.pdx.edu/staging/ > > -- > > http://psas.pdx.edu/news/2000-11-02/RA_PSAS_Lecture.PPT > > http://psas.pdx.edu/RocketSim/ > > http://psas.pdx.edu/2012_liquid_motor_notes/ > > http://psas.pdx.edu/simplerockets_1d/ > > http://psas.pdx.edu/RocketSimPhysics/ > > > > (2011.01.29) ben...@gmail.com: > >> I was curious to see what it would take to get a 1 kg payload into orbit, > >> so > >> I did some math and wrote some code! Forgive me if this duplicates work > >> elsewhere on the wiki, but in lieu of a page on "Staging", I created my > >> own > >> and populated it to some degree. > >> > >> Please, kick tires and poke holes! I wrote a small bit of code with the > >> intention to calculate and iterate fuel needs. I have no idea if it > >> works, > >> but simple delta-vee calculations on its outputs are encouraging. _______________________________________________ psas-team mailing list psas-team@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-team This list's membership is automatically generated from the memberships of the psas-airframe, psas-avionics, and psas-general mail lists. Visit http://lists.psas.pdx.edu to individually subscribe/unsubscribe yourself from these lists.