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GW Johnson just posted a couple of studies on Single Stage to Orbit and Two Stage to Orbit ....
The spreadsheets can be provided if anyone is interested in seeing them.
Attached are copies in pdf format of two articles I wrote and just recently published on "exrocketman". They are bounding calculations on what can be done toward expendable and reusable vehicles to reach Earth orbit from the surface. One investigates and bounds what can be done SSTO. The other investigates and bounds TSTO. If you want to post these in the drop box thingie, go ahead.
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This is very simple rocket equation stuff, done in a couple of spreadsheets. The ascent-averaged Isp data come from other stuff I have recently published on "exrocketman", about estimating rocket engine performance. Some of that was done with a version of the bell nozzle rocket spreadsheet used in the orbits+ course. The free-expansion stuff came from a post on "exrocketman" dealing with aerospike nozzles. If anyone wants the spreadsheets, they can have them.
GW
The first file is to be linked from here (SSTO):
https://www.dropbox.com/scl/fi/hu5zc3qc … 3lptv&dl=0
The second file is to be linked from here (TSTO):
https://www.dropbox.com/scl/fi/4dnyyqjn … gsvmd&dl=0
Here is an update:
This is the one that supports the other two you just posted for me. I meant to post this on "exrocketman" some time ago, but never got around to it until today.
It shows vividly just how easy it is to use the "r noz alt" worksheet in the "liquid rockets.xls" spreadsheet file, plus the Paintbrush-made "engine sizing report.png" file to very rapidly size multiple engines and run trade studies. This is where I got my recommendations for how to size a fixed "compromise" bell nozzle to get really good ascent performance out of it.
That spreadsheet file is an update of the one that is part of the orbits+ course materials. I took that one, deleted the extraneous worksheets, added an altitude performance calculation block with automatic plots, and added a output data block that works perfectly with a "Paintbrush"-made engine sizing report. It becomes cut-and-paste with some minor edits to report a design.
The multiple engine designs I sized for the trade study also make a good data library. Pdf document file attached. It should go with the other two, which were "Bounding Calculations for SSTO Concepts" and "Bounding Calculations for TSTO" that you just posted for me.
Link to pdf goes here:
https://www.dropbox.com/scl/fi/s8v6c0zc … upmdo&dl=0
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Despite the clouds, we got to see the eclipse right here in our front yard near McGregor. That's first one I ever actually saw with my own eyes. And I thought I saw a large flare during totality, at bottom right of the sun's image. An orange speck against the corona.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Not sure where to post this. Two news items. (1) the last Delta-4 heavy-lift launcher has flown. (2) The Russians finally on the 3rd attempt got some kind of a heavy-lift launcher to fly.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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We have two new videos arriving soon at exRocketman1 YouTube channel...
I'm in the process of uploading two new MP4 videos to my youtube channel. One of these is the study I did for landing 40-ton cargoes directly on Mars, as 1-way trips. The other is a "how-to" video for using the latest version of the rocket engine performance spreadsheet that was used in the orbits+ course, plus my compressible flow course. This latest version includes the calculations and plots for performance vs altitude, and a sizing of chamber length and diameter (downstream of all the turbopump drive cycle stuff, which is not addressed in the spreadsheet). Cycle needs only the dumped bleed flow fraction to model it effectively in terms of thrust and Isp. These should be visible on the channel after midnight tonight or tomorrow. Youtube has to do its thing processing the MP4's, and each one needs about 3/4 hour to complete. They are about that long.
GW
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For GW Johnson re new phpBB3 test account ....
I understand that members of the forum do not have time to read every post, so you may not be aware of the test account that the Admins have set up for evaluation of newer forum software.
Please connect to the Azure test account using the information in the Azure topic.
If you encounter an SQL timeout message please just refresh the page. Azure is a Virtual Machine that goes to sleep and has to be re-awakened.
I'd appreciate your feedback on the site.
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For all...
Here is a link to Dr. Johnson's 42 minute very detailed presentation on how to land 40 (or more) tons on Mars...
https://www.youtube.com/watch?v=lsCZmEiDOB4
At 36 minutes in there is a detailed plan for a mission between Earth and Mars for a reusable transfer stage.
The mission would use liquid hydrogen and liquid oxygen and storable propellant for orbit changes.
The plan assumes a 3+ year flight plan.
At 40 minutes in the summary affirms that 40 tons can be done without a prepared field.
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Update on latest videos in exRocketman1...
The view count for the long video reported in Post #281 is now up to 1 - that would be my view yesterday
Today I am watching/listening to the video on rocket design ... I would like to point out that since Dr. Johnson learned how to use the on-screen "laser" pointer, he has become increasingly skilled in it's use.
In this video, which is a deep dive into the spreadsheets anyone can use to perform these calculations for design of rocket engines, GW has circled text or cells he wants to emphasize, and he moves the pointer to show where the viewer might focus.
The pace of the presentation in all these videos seems comfortably slow to me, and in any case, the YouTube viewer allows for repetition of sections as desired.
Note for GW Johnson: It occurred to me (while watching the video) that I don't know where to find the spreadsheet, and then up popped a screen showing that the spreadsheet is available at about minute 30 ... I'll wait until the video ends to test the links!
I'm happy to see you are advertising the course offerings, via the links in this slide.
Update a few minutes later... Dr. Johnson! We have a problem! The links do not work from the youTube video.
You might be able to add a page as an appendix to show the links so people can copy them by typing.
For GW ... the links may have pointed to NewMars for folks to pick up materials. It that is the case, please considering including NewMars as a reference.
I'd like to encourage other NewMars members to watch and comment upon these videos.
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For All regarding links to resources from YouTube video...
Does anyone know how to offer live links from YouTube videos?
Can they be offered via text about the videos?
There may be a convenient way to do this?
For GW Johnson ... there may be a way for you to do this...
No views Apr 12, 2024
This is a quick "how-to" guide for using a spreadsheet file that I developed, which easily and quickly and accurately estimates rocket engine performance. The user does not have to be a rocket engine expert in order to use this spreadsheet. Pretty much anyone could do this.
Transcript
Above is a quote of the description you created for the video... You may be able to put the links in there, or one link to a NewMars post where all the links are stored. You may be able to use this method for all your videos.
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I just did the best I could, with my very limited understanding of all this internet/computer stuff.
The recent posts now show numbers of views. The old one about the Lionel train has 1300 views now, but it's been up there for many years. My son put it there.
For me, it's monkey-see, monkey-do. And the funny part is that I really do like bananas.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For GW Johnson!
Congratulations on all you've accomplished!
Please see if you can put the links to your spreadsheet in the description field of your video.
I have an offer for you ... if you will put the link to this post into the description field, I will fill it up with all the links you want to provide to your viewers.
You don't have to do ** anything ** other than put the link to ** this ** post into the description field.
The link you want to insert is: https://newmars.com/forums/viewtopic.ph … 34#p221834
You can do this for each video, or for all of them if that makes sense.
NewMars.com has plenty of room for posts so please take advantage of the generosity of Executive Director James Burk and Society President Dr. Zubrin.
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For All... GW Johnson was successful in registering with the new test forum this evening.
Every current member of the forum is welcome to register with the new test forum.
The address is published at the top of the Azure topic. There are a couple of quirks that everyone should know about ...
Because this is a virtual machine, we are seeing error messages that (I think) are caused by the virtual machine waking up out of a sound sleep, waiting for you to knock on the door. When you ** do ** knock on the door, the Virtual Machine will grumble because it has to load a copy of the MySql server which it only loads when someone needs it. You'll see a complaint that the database missing. Just refresh the page and say Yes to the question if you really want to refresh the page. At that point, it appears grumpy will have had time to load the database.
When you first open the site, you will have to Register. Register is up in the upper right, to the left of log in. The procedure should seem familiar or at least reasonable.
Here is the next quirk... Create a post and you will cause me to see a notification that you have arrived. I will approve your post, and I will also lift you from Newby to Registered member.
At that point, you will be able to help the Admins to evaluate the new system. Please remember that everything we do is temporary, so put your permanent posts into NewMars as usual.
If you have any questions, please post them in the Azure topic.
This topic is supposed to be about GW Johnson's many publications, including the exRocketman1 YouTube videos.
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This post is reserved for a set of files created by Dr. Johnson in support of the exRocketman YouTube videos, and in support of the course on Basic Orbital Mechanics including rocket design.
There are three files to be linked here:
1) An updated spreadsheet
https://www.dropbox.com/scl/fi/9nqdv47z … f6avf&dl=0
2) A slide show about the spreadsheet
https://www.dropbox.com/scl/fi/uxhf343c … j1suw&dl=0
3)_ A User Manual for the spreadsheet
https://www.dropbox.com/scl/fi/dw1o8end … 0c208&dl=0
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What Tom posted for me in post 287 just above is a revised version of my entry spreadsheet that embodies the 1953-vintage by-hand analysis of H. Julian Allen, used for warhead entry back then. I've had a version of this spreadsheet for some years now, and it is part of the multiple lessons in the "orbits+" course series. What I have done is clean it up of extraneous stuff not used, add a worksheet set up for Venus entry, and I added a model for plasma radiation heating at the stagnation location (which I validated against Apollo experiences).
This is a cleaner-looking, and more complete version. It does radiation heating in addition to convective heating, something not needed in the 1950's with warhead entry. There is the Excel spreadsheet file with worksheets for each of 4 worlds, plus a pdf document that is a user's manual, written to be very detailed and complete. Both of these are better than the original versions. I also created a set of powerpoint slides that is also a sort of user's manual. Those are the 3 things Tom posted for us.
The new spreadsheet file actually has 6 worksheets in it. The 4 "operational" ones for general use are named "Earth", "Mars", "Titan", and "Venus", each being set up with that world's atmosphere model from the Justus and Braun paper on entry, descent, and landing. All you need to analyze an entry are the entry conditions (speed and angle-below-horizontal), and the object characteristics (ballistic coefficient and effective nose radius). You do need to adjust the altitudes in the list (1) to get a denser point spread where things are changing rapidly, and (2) to make the final altitude in the list the one where speed is at local Mach 3, where it is no longer hypersonic (each worksheet has a recommended value listed on it). Plots are generated automatically, but un-annotated.
The other two spreadsheets are copies of the "Earth" model in which I analyzed Apollo coming back from LEO versus Apollo coming back from the moon, in order to "calibrate" the plasma radiation model to match Apollo experiences. I left them in place so all could see how good a match was achieved. But, if one wants to delete them as redundant, that's OK. From LEO, radiation heating was negligible, while it dominates coming back from the moon at just under escape speed. The model predicts just under the nominal 11 gees coming back from the moon, which is just about right.
I would encourage any forums user to download these items and try them out. In particular, the user's manual document shows exactly how I copy the plots to a "Paintbrush" png file and annotate them for clarity. It makes a really good presentation of the results. Earth, Titan, and Venus pretty much come out of hypersonics at high altitudes. It is Mars where you come out low, because of the thin atmosphere. Which in turn makes it very sensitive to ballistic coefficient (higher coefficient is very close to the surface indeed). But all these entries (except Titan) must take place at shallow angles, or else the deceleration gees and heating get too high.
GW
Last edited by GW Johnson (Yesterday 09:21:15)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For GW Johnson ....
Per our discussion in the Google Meeting 2024/04/28...
http://newmars.com/forums/viewtopic.php … 67#p222467
Please insert the link above into the description field for the video Mars Direct Landings...
Please provide me with the details I need to insert into the post so that your viewers can easily pull spreadsheets, pdfs and whatever else you want them to have. Please provide text to help your viewers understand what the resources are and how to use them.
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