tag:blogger.com,1999:blog-7598615455712402973.post1049333585138032853..comments2024-03-25T11:14:45.840-04:00Comments on Polymath: Hovering capability for the reusable Falcon 9, page 3: hovering ability can increase the payload of a RLV.Robert Clarkhttp://www.blogger.com/profile/16114043697010364282noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-7598615455712402973.post-26421167394084276952015-12-29T09:12:37.814-05:002015-12-29T09:12:37.814-05:00Thanks for the link. I had thought there would be ...Thanks for the link. I had thought there would be quite a bit of propellant left at landing because Elon said in the post-flight teleconference MECO was at quite at smaller speed than for the following flights.<br /><br /> According to this simulation the amount left would be enough for it to hover on landing on <i>this</i> flight.<br /><br /> Bob ClarkRobert Clarkhttps://www.blogger.com/profile/16114043697010364282noreply@blogger.comtag:blogger.com,1999:blog-7598615455712402973.post-20279553294419713772015-12-29T07:17:24.010-05:002015-12-29T07:17:24.010-05:00If this simulation is accurate:
https://www.youtub...If this simulation is accurate:<br />https://www.youtube.com/watch?v=b8vzt1PLG5U<br /><br />Then this launch/landing of historic F9 was VERY inefficient. 30t of extra fuel at the landing would mean engine didnt need to throttle much at all...Rokhttps://www.blogger.com/profile/01594627296669652306noreply@blogger.comtag:blogger.com,1999:blog-7598615455712402973.post-31935995927492417152015-12-13T13:20:32.902-05:002015-12-13T13:20:32.902-05:00Idle mode requires tank pressure higher than outsi...Idle mode requires tank pressure higher than outside atmosphere which is a bit hard to do when the tank is empty. And while trying to use propellant residuals.<br /><br />Problem with using residuals in F9 is that its pressurised with helium. Would make more sense with methane engine using a turbopump to scavange gas from the tank.<br /><br />Hover itself doesnt allow bigger payloads as slower descent burns more fuel. Suicide burn is most efficient for a reason. And operating at lower thrust, thus lower chamber pressure, means worse sea level isp.<br /><br /><br />Frankly, if merlin engine could be throttled as far as be3 F9 would have hover capability already. They could design the center engine to drop half of its nozzle and run the pump at less pressure than currently. <br />Rokhttps://www.blogger.com/profile/01594627296669652306noreply@blogger.com