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For GW Johnson re latest attempt to compile XYTRAJ to run on a modern computer.
https://www.dropbox.com/scl/fi/klzugg3a … 7fp5g&dl=0
The link above will provide a zip file that contains the entire application ready to run on a Windows computer with .NET 8.0 installed.
There are five files in the set. so they should go into a folder and not onto the desk top.
Update Thursday: An attempt to create a setup file failed. However, the set of files provided in the download above appears to be working. It is possible to create a link to the program that shows up in the desktop.
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For GW Johnson re .NET inquiry
The command we tried was: reg query "HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP"
The response I got on the new Windows 11 machine was:
HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft\NET Framework Setup\NDP\CDF
Same and \v4
Same and \v4.0
I'm not sure what that means. I assume you saw something similar, if the command worked.
Update: Here is the actual text. It turns out that Windows 11 implemented a new feature ... Now, when I highlight text in the command window, it goes into the copy buffer automatically. That is going to take some getting used to.
C:\Users\tahan>reg query "HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\CDF
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4.0
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To quote the computer from the command prompt window:
"The system cannot find the path specified"
This is the 4th time tried. All results identical.
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 re post on calculator that SpaceNut showed us...
https://newmars.com/forums/viewtopic.ph … 17#p233717
Would you like to see the calculations? I ask because the site appears to be "open source" which implies the code is visible to the public.
In addition, if the site is running as I think it is, the code is actually running on your computer in your browser, using a language called JavaScript.
We have a topic in this forum about JavaScript.
offtherock turns out to be a computer guru, but I don't know details yet. His range appears to be wide and deep. I am buried in projects so can't take this on right now, and perhaps offtherock can't either, but the key question is now is whether your would like to see how the calculator is working.
I can't ** guarantee ** we can answer the question, even if we can access the code, but at least (I'm pretty sure) the option is available.
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I'd like to know exactly how t figures its estimates, and from what inputs. It might well be better than what I do, which is just a approximation.
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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This post is about Rocket Nozzles...
While we wait for a solution to the problem of display of images, here are links to two images GW created to explain how rocket nozzles work.
Thrus Image 0
https://www.dropbox.com/scl/fi/v6xry0w6 … d9u9c&dl=0
Thrust Image 1
https://www.dropbox.com/scl/fi/2j8xx37k … s2m7v&dl=0
Thrust Image 2
https://www.dropbox.com/scl/fi/p76qn2g5 … 3x2ka&dl=0
Thrust Image 3
https://www.dropbox.com/scl/fi/47j6gvk8 … 6g9hq&dl=0
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This post contains an excerpt from private correspondence...
I hope it might be helpful to NewMars members who might be designing SSTO space planes ...
As for the behavior of inlets, there is an exrocketman article that goes into it, although not quite as deeply as what's in my ramjet book. This took 3 chapters in my book. The article is "Fundamentals of Inlets", posted 9 November 2020, search code 09112020.
In that article, the 6 possible cases for pitot/normal shock inlets are illustrated in Figure 4, and the 9 possible cases for supersonic inlets are illustrated in Figure 6. What you do with these inlet components is different with ramjets than with gas turbine engines, afterburning or not.
And that complicated difference is why using a common inlet and afterburner nozzle for a combined gas turbine with a ramjet, is so very hard to accomplish, while preserving most of the performance of both! And these geometries are fundamentally compatible, while scramjet is not!
If you look further down that article, you can get some idea of the complexity involved in addressing real-world aerodynamic problems with inlets. The ramjet book goes far deeper into all of this.
GW
I had asked about trying to use the same air inlet for all three air-breather engine types.
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There are no scramjets that will ever use a pitot/normal shock inlet. There are probably no ramjets that will use one, if the flight speed is to exceed Mach 1.5. Gas turbines, usually afterburning, will use a pitot/normal shock inlet if max flight speed is under about Mach 1.5, at the very most 2. These kinds of designs must use very volatile gasoline as fuel, although the octane number is irrelevant.
The supersonic inlets only work above Mach 1.8 at the very minimum, and perform like crap below their shock on lip speeds, if at all. Things that fly in the Mach 2 to Mach 3.5-or-more range can use shock-on-lip speed inlets of about Mach 2. These can use air cooling below about Mach 3 to 3.5 in the stratosphere, slower lower down. Above that, everything must be protected by ablatives, and you can only use dump stabilization for your flameholding. With a Mach 2 shock-on-lip inlet, your max speed potential is still only about Mach 3.5 to maybe at most 4. These will require a wide-cut fuel like JP-4 or Jet-B. More volatile than a straight kerosene.
If you are using a Mach 2.5 shock-on-lip design, your min takeover Mach is very close to Mach 2.5, and your top speed can be anything from about Mach 4 to just a bit above Mach 6, if the exit nozzle is a big enough percentage of the total frontal blockage area. You can use a straight kerosene fuel, like JP-5 or JP-8, or Jet-A or Jet-A1. There are also kerosene-like synthetics available, like RJ-5/Shelldyne-H, which resembles kerosene, but is very slightly denser than water. It does freeze too easily, though!
All of these supersonic inlets feature external compression features (spikes or ramps), and they have some min inlet throat area, either at or close downstream of, the inlet cowl lip capture feature. Flow at the min area and slightly downstream is sill supersonic, but just barely. That is followed by a terminal normal shock-down to subsonic flow, followed by divergent area increase to accomplish the diffusion to the needed degree of well-subsonic compressible flow in the duct.
Scramjet can use the same external compression spike or ramp features, and a similar cowl lip stream-tube capture feature, but there is only some modest internal contraction in duct area to something close to Mach 2.8 supersonic speed. There must be 5-10 duct diameters length of this supersonic "isolator duct", to maintain stable combustion in the scramjet combustor, however that fuel might be injected, and however that flame stabilization might be obtained. Further, there can be no bends at all in this straight "isolator duct". Doing so immediately causes shock-down to subsonic flow.
GW
Last edited by GW Johnson (2025-08-24 15:35:42)
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 re image storage....
As you know, imgur.com no longer accepts files for display. I'm pretty sure I have run out of the free space they provide, and since I haven't paid them for storage, it makes sense they would put a limit on the free service.
It appears I may have found a partial solution.
https://newmars.com/forums/viewtopic.ph … 44#p233944
The link above takes you to an experiment I ran, to see if I could host images on the phpBB3 site we set up for testing last year.
It turns out the answer is yes, but the service is similar to dropbox.... Your viewer will still have to click on a link to see the image.
However, we are ** paying ** for storage so we don't have to worry about running out of room.
I'll investigate to see if it might be possible to serve the files directly, but in the mean time, if there are images you would like to show to forum readers, we can begin to deal with the back log. The procedure to store images is similar to what we have to do to save at Dropbox. We have to log in and go through some preliminary setup, after which we can upload files. Then we copy a link and paste that into the FluxBB post.
In fact (as I think about it) I think you could actually perform this operation with a bit of training.
I just checked, and you are ** indeed ** set up on the phpBB3 site. Here is the link for login. Please check it.
http://40.75.112.55/phpBB3/ucp.php?mode … =index.php
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then there is this.
https://postimages.org/
but off course its a 3rd party and one never knows what they decide to do in the future.
Last edited by offtherock (Today 11:34:03)
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