tag:blogger.com,1999:blog-36913768.post7080023803003226857..comments2024-03-27T22:31:22.146-07:00Comments on Unreasonable Rocket: Calculating...Paul Breedhttp://www.blogger.com/profile/11024641086551653462noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-36913768.post-83633240609701005932016-05-25T00:11:19.672-07:002016-05-25T00:11:19.672-07:00PMI-001 braindumps - DumpsPortal assures you of ex...<a href="http://www.dumpsportal.com/PMI-001-braindumps.htm" rel="nofollow">PMI-001 braindumps</a> - DumpsPortal assures you of exam success with money back guarantee. No need to bother of losing time and money. You are 100% safe with DumpsPortal.Anonymoushttps://www.blogger.com/profile/06595359784543137039noreply@blogger.comtag:blogger.com,1999:blog-36913768.post-8765493690588046702012-06-18T09:18:01.314-07:002012-06-18T09:18:01.314-07:00Quite worthwhile info, much thanks for the post.Quite worthwhile info, much thanks for the post.jordanhousesc.orghttp://jordanhousesc.orgnoreply@blogger.comtag:blogger.com,1999:blog-36913768.post-3072181066126453842010-05-07T06:56:19.178-07:002010-05-07T06:56:19.178-07:00Paul, I'm trying to get an estimate for the r...Paul, I'm trying to get an estimate for the required delta-V to orbit under these conditions:<br /><br />1.)use a dense propellant such as kerosene/LOX; dense propellants are known to reduce gravity losses.<br /><br />2.)use a moderate to high liftoff thrust/weight ratio, say, 1.4 and above; high liftoff T/W also reduces gravity losses.<br /><br />3.)launch near equator to get the ca. 460 m/s tangential boost.<br /><br />4.)only get to 100 km, the altitude considered space, to just launch satellites or make orbital transfers, not for long term orbits.<br /><br /> Can your program do that?<br /><br /><br /> Bob ClarkRobert Clarknoreply@blogger.comtag:blogger.com,1999:blog-36913768.post-18446918874722709762010-05-04T16:42:09.413-07:002010-05-04T16:42:09.413-07:00Hey, I was just curious to know how much you spent...Hey, I was just curious to know how much you spent on unreasonable rocket compared to some of the competition. Also, I was also wondering what it takes to get a rocket into low earth orbit as compared to escaping the earth's orbit and getting it to the moon. I'm a Ron Paul fan too. I'm so glad to see a Ron Paul guy working to get things into outer space.Watasha_Joshhttps://www.blogger.com/profile/00006122206073885815noreply@blogger.comtag:blogger.com,1999:blog-36913768.post-55752002408745623952010-04-27T06:54:07.642-07:002010-04-27T06:54:07.642-07:00Regarding base drag with motor on/off:
A lot of p...Regarding base drag with motor on/off:<br /><br />A lot of programs, like AeroDrag and RASAero will give you curves of Cd vs Mach number with the motor on & off.Carl Tedescohttps://www.blogger.com/profile/06410117998639382093noreply@blogger.comtag:blogger.com,1999:blog-36913768.post-33818699824114241802010-04-21T21:50:19.695-07:002010-04-21T21:50:19.695-07:00Drag is= 1G + A Cd roe V^2
Lost Delta V is Drag *t...Drag is= 1G + A Cd roe V^2<br />Lost Delta V is Drag *t<br />Distance is V *t<br /><br />we want to maximize<br /><br />V*t/(1G +A* Cd *roe *v *v)*t<br /><br />So we want the maximum of<br /><br />V/(1G + A* Cd * roe *v*v)<br /><br />let k=1G <br />and a=A*Cd*roe<br /><br />Maximum of <br />V/(k+aV^2)<br /><br />1/(k/v _aV)<br /><br />or find the minimum of <br /><br />k/V +a*V<br /><br /><br />Complicated by the fact that Cd is actually a function of VPaul Breedhttps://www.blogger.com/profile/11024641086551653462noreply@blogger.comtag:blogger.com,1999:blog-36913768.post-10401258015043497442010-04-21T09:27:28.593-07:002010-04-21T09:27:28.593-07:00Cool graph man.
I did a similar study a few years...Cool graph man.<br /><br />I did a similar study a few years ago, and the real take-away is that the optimum vertical speed (i.e. most energy efficient) for a given altitude is equal to the terminal velocity at that altitude. So to get the most altitude, start off slow and speed up as you get higher in altitude. It's the old-skool gravity-drag vs. aero drag fight.Davehttps://www.blogger.com/profile/17134486793106322094noreply@blogger.comtag:blogger.com,1999:blog-36913768.post-45108573548121597302010-04-19T14:31:51.611-07:002010-04-19T14:31:51.611-07:00not worth further optimization for this parameter....not worth further optimization for this parameter... I hope to enhance the quality of the simulation to be a tool for evaluating a lot of stuff in the trade space, IE <br /><br />Tank pressure and Tank mass vs ISP.<br /><br />Optimum expansion ratio etc...<br /><br />this is a simple 1d simulation, in parallel I'm working on a 6DOF sim to work on guidance and do some hardware in the loop simulations.Paul Breedhttps://www.blogger.com/profile/11024641086551653462noreply@blogger.comtag:blogger.com,1999:blog-36913768.post-51980540263721008042010-04-19T13:31:12.949-07:002010-04-19T13:31:12.949-07:00From the graph it looks like any peak drag between...From the graph it looks like any peak drag between 250 and 325 gets you above 50km, within 1% of optimal. Maybe it's not worth doing much more calculation.Bob Steinkenoreply@blogger.comtag:blogger.com,1999:blog-36913768.post-59168138690130671532010-04-19T12:06:00.988-07:002010-04-19T12:06:00.988-07:00The Cd you are using would seem to include the bas...The Cd you are using would seem to include the base drag component, if the data follows the writeup in that report. When your engines are firing you will be pressuring your base region and a portion of the base drag will go to zero. You might want to break out the base drag and allow it to go to zero when the engines are firing. The rule of thumb is that the ratio of nozzle area over base area is the amount of base drag that 'goes' away due to base pressurization.<br /><br />If have the motors on for some appreciable amount of time, this will make a difference.Anonymousnoreply@blogger.com