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#26 2025-05-16 10:20:02
Re: RGClark Postings
For RGClark re adjustable nozzle concept...
Since your latest proposal is for an expendable SSTO, you wouldn't be concerned with re-use of the nozzle.
Perhaps a design that slides out segments along the nozzle as they are needed would help?
https://encrypted-tbn0.gstatic.com/shop … DFl5s73O1_
Update at 1936 New Hampshire time:
For RGClark: https://newmars.com/forums/viewtopic.ph … 48#p231548
GW Johnson sent this image about how to cool two phase rocket engines.(th)
I like that idea. There are several methods of doing variable nozzles. For instance they have been used on jet engine afterburners for decades:
Bob Clark
Last edited by RGClark (2025-05-16 15:56:56)
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
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#27 2025-05-16 12:03:41
- tahanson43206
- Moderator
- Registered: 2018-04-27
- Posts: 21,655
Re: RGClark Postings
For RBClark Re #26 ... thanks for that helpful GIF! Hopefully GW Johnson will find inspiration.
GW Johnson has attempted to respond to the variable geometry nozzle idea, but I suspect you have missed all that input.
Your idea in this post: https://newmars.com/forums/viewtopic.ph … 10#p231710
caught my eye ... I'd never thought about the question before. I'll start looking for answers. I suspect the forum software designers planned for your scenario, but I've never had a need for it. I do recall that on other forums, there can be email notification of replies. I don't think this forum has that feature. You probably haven't noticed, but our senior Administrator is taking some time off to remodel his house, so that source of knowledge is not currently available.
Just FYI ... the reason I set up this topic was so we could communicate with you without placing our IDs on top of your post. It is important for our members to be visible in the Active list as long as possible, so others can see their updates to various topics.
It is available to you if you want to communicate with the admins. You can also use Housekeeping.
Update: I have asked GW Johnson to develop his previously published scenario for his SSTO concept, which I am confident you have never seen. I would appreciate your participation in a serious (non-academic) effort to develop a one-person reusable transport to LEO. I believe there would be a market for such a vehicle, with governments and uber-wealthy individuals as the opening customers, and more later as the vehicles prove themselves. If properly designed, such vehicles could operate just like an airliner, with expense of fuel as the greater part of expenses, just as I suspect it is today for airliners.
We might be able to draw other NewMars members into a serious effort. I am NOT interested in more endless academic discussion. If this can be done, let's set out to make it happen.
(th)
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#28 2025-06-24 14:35:09
- tahanson43206
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- Registered: 2018-04-27
- Posts: 21,655
Re: RGClark Postings
For RGClark re SSTO Engine technology...
Recently kbd512 has been looking at an air breathing system for SSTO.
I am wondering if you might be willing to entertain the idea of using air breathing propulsion for the flight to the top of the atmosphere, followed by traditional rocket engine propulsion. The difficulty of designing for sea level would be eliminated, and the remaining question would be how to design the engine for the optimum performance at the altitude where it begins operation.
In order for you to catch up with kbd512 you might be able to find relevant posts by searching for posts by kbd512.
kbd512 posts in a number of topics, so searching by topic might not work. Or you could just write a note to kbd512 asking for links to relevant posts.
(th)
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#29 2025-06-24 18:25:34
Re: RGClark Postings
For RGClark re SSTO Engine technology...
Recently kbd512 has been looking at an air breathing system for SSTO.
I am wondering if you might be willing to entertain the idea of using air breathing propulsion for the flight to the top of the atmosphere, followed by traditional rocket engine propulsion. The difficulty of designing for sea level would be eliminated, and the remaining question would be how to design the engine for the optimum performance at the altitude where it begins operation.
In order for you to catch up with kbd512 you might be able to find relevant posts by searching for posts by kbd512.
kbd512 posts in a number of topics, so searching by topic might not work. Or you could just write a note to kbd512 asking for links to relevant posts.
(th)
Yes. We know ramjet propulsion is doable as operational ramjets have been fielded since decades ago. What we haven’t been able to do is scramjets that can work for more than just a few seconds of positive net thrust. But ramjets can operate up to Mach 5+, over 1.600+ m/s. This can subtract off a significant amount of the delta-v needed for orbit. This can certainly work for TSTO where the first stage is airbreathing ramjet, and the upper stage being a rocket. This can cut the cost to space since the airbreathing first stage might be reusable for thousands or reuses.
It might also work for a airbreathing/rocket combined-cycle SSTO. I am investigating this possibility.
Bob Clark
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
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