tag:blogger.com,1999:blog-7598615455712402973.post8647763839384126265..comments2024-03-25T11:14:45.840-04:00Comments on Polymath: Altitude Compensation Improves Payload for All Launchers.Robert Clarkhttp://www.blogger.com/profile/16114043697010364282noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-7598615455712402973.post-46975428321974745612016-01-26T09:31:47.505-05:002016-01-26T09:31:47.505-05:00Given that expansion ratio on D4H is 21.5 with noz...Given that expansion ratio on D4H is 21.5 with nozzle diameter of 2.34m and that booster core diameter is 5.1m, maximum expansion ratio would be about 80. According to thrust coefficient curves I have that would put vacuum isp at 436s. <br /><br />But at 10km, a 21.5 expansion ratio nozzle still has more thrust than ratio 80 nozzle.Rokhttps://www.blogger.com/profile/01594627296669652306noreply@blogger.comtag:blogger.com,1999:blog-7598615455712402973.post-62507125564794159872016-01-13T13:59:59.745-05:002016-01-13T13:59:59.745-05:00I would doubt these numbers.
The engines start o...I would doubt these numbers.<br /><br /> The engines start off with expansion ratios of 21.5 while upper stage has expansion ratio of 250. Adding extensions would increase mass by a few tons per core. <br /><br />Second point is that calculator does not accout for the fact that the rocket would still start with usual expansion ratio. What is the altitude where switch would be done? 10km? 20? By that time the rocket would burn about half of the fuel in the boosters. With that sea level isp...<br /><br />Rokhttps://www.blogger.com/profile/01594627296669652306noreply@blogger.comtag:blogger.com,1999:blog-7598615455712402973.post-30067169521508084912016-01-12T05:56:22.953-05:002016-01-12T05:56:22.953-05:00The SLS would be under major pressure if the Falco...The SLS would be under major pressure if the Falcon Heavy can lift 100 mT for $120 million.Andrew Swallowhttps://www.blogger.com/profile/10945854011042065256noreply@blogger.com