Article 5973 of rec.models.rockets: Path: samba!concert!gatech!emory!wupost!uwm.edu!ogicse!sequent!muncher.sequent.com!coryc From: coryc@sequent.com (Cory Carpenter) Newsgroups: rec.models.rockets Subject: Public domain simulation programs Message-ID: <1993Feb19.075203.8886@sequent.com> Date: 19 Feb 93 07:52:03 GMT Article-I.D.: sequent.1993Feb19.075203.8886 Sender: usenet@sequent.com (usenet ) Organization: Sequent Computer Systems, Inc. Lines: 73 Nntp-Posting-Host: crg8.sequent.com A friend I met at LDRS-XI wrote the programs to follow, and has placed them in the public domain. Also available is a non-public domain program called simply "ROCKET" that seems to do a good job of simulating flights based on commercial motors and rocket designs, or on user-specified motors and rocket designs. It includes graphical output of thrust vs. time, velocity vs. altitude, and mass vs. acceleration, as well as numeric output of a plethora of variables. The program also includes support for multistage rockets, supersonic flight, and clustered engines. I don't know what his company is charging for the software, since I received it in exchange for a copy of the video I shot at Black Rock. For more information, contact: Cambridge Group 1921 N Gaffey, Suite D San Pedro CA 90731 (213) 832-8836 Here's the information on the shareware programs to follow in separate postings. (I hope someone will archive these, as I don't remember the address of the r.m.r server, and don't know whether anonymous uploads are allowed.) PARA.EXE This program calculates the descent rate of a parachute. You are prompted for the barometric pressure, temperature, and altitude. The density altitude is computed. Next, you are prompted for the diameter, load, and drag coefficient of the parachute and the descent rate is computed in feet per second. Reasonable default values are suggested at the beginning of the program. The source code, PARA.BAS, gives all the mathematical formulas necessary. NODRAG.EXE This program computes the projected speed, altitude, and delay times for rockets without considering aerodynamic drag. These are computed without using iteration, so the program runs very quickly. Aerodynamic drag is, however, a major factor for most model rockets, so the program is useful mostly for rapid comparison of different designs. The results are closer to reality for heavy payloads, low speeds, or large-diameter rockets. Again, all the formulas are available in the source code for the mathematically inclined. SHOCK.EXE This program calculates the force and amount of stretch in a shock cord, given the mass of the rocket and the speed at parachute deployment. Knowing the stretch of the cord and attachment point, and also the maximum amount of stretch that the cord can withstand, it is possible to be sure the system is strong enough before launch. I hope these programs come in handy for someone. If you have suggestions for improvements, I would advise you to contact the Cambridge Group. If enough interest is shown I suspect they would consider making "ROCKET" available as shareware, rather than as commercial software, but I definitely can't make any promises on that score. I am not affiliated with the Cambridge Group in any way, and neither they nor I make any guarantee as to the accuracy or reliablility of this software. -coryc -- | >> Disclaimer: I speak for Sequent only in our hardware manuals << | | Cory R. Carpenter, Tech Writer | "Never trust ale from a god-fearing | | Sequent Computer Systems, Inc. | people..." | | coryc@sequent.com | --Quark, Deep Space Nine |