What Does "A Better Design" Actually Mean?

tahanson43206 · 2021-07-04 07:19:19

For kbd512 re topic and floating living habitat in particular ...

Thanks for opening a pathway for what ** might ** turn out to be a productive use of the valuable time of those who participate, and especially those who might find future value in reading at least part of the sequence ....

The examples you gave, of large vessels destroyed by enemy action, or just sinking without outside assistance, are certainly worth keeping in mind.

However, I'm trying to take a larger view with a longer stretch of time ....

Your assertion that there is plenty of land is reasonable, as an opening position. However, the fact is that ** all ** land on Earth is claimed.

If someone decides to move inland, there is NO free land ** anywhere ** available for them to set up a camp site, let alone a dwelling.

A floating mini-city on Earth would be a good/useful model for all habitats that are going to be built away from Earth.

it is even a good model for RobertDyck's Large Ship fleet, which I expect will come into being if no one invents artificial gravity.

Your points about carbon consumption are certainly helpful, because they confirm that nuclear power is needed for a vessel like this, and ** that ** is a good idea anyway, as you and Calliban have been maintaining for some time.

The City of New York is just ** one ** large, established coastal city that's facing the prospect of "sinking" into the Atlantic in years to come.

The solution that I've been thinking about for some time is floating living complexes able to provide for most of their occupant's needs, and able to trade with other similar complexes, and with land based entities when that is convenient and advantageous.

***
The question of structure of tall buildings may be worth exploring in this topic, if that subset of knowledge is of interest to anyone.

My general impression is that buildings like the Empire State building were constructed using steel beams to form a welded and riveted cage onto which ornaments such as floors were added.

I get the impression the building in Florida that collapses was a simple pile of concrete elements, similar to what might be build of domino pieces to make a grand tower on the kitchen table.

If my guess about the Florida structure is correct, it is understandable that the entire structure would collapse as it did.

The Empire State building would NOT collapse in such a way, because the steel cage would (and already has) sustain itself when perturbed.

Building by stacking concrete elements is (I suspect) less expensive than building properly with steel frame, but the builder was a fly-by-night operator (according to reports) who was struggling for financing at every stage of construction.

The building lasted 40 years ... that's probably about right for a simple concrete pile.

(th)

SpaceNut · 2021-07-04 09:54:01

With all the land which could be occupied, why do we chose to crowd in so tightly, in the words of the

SpaceNut · 2021-07-04 10:22:11

Hurricane Elsa is moving through the Caribbean with winds of 75 mph. It is forecast to impact the Southeastern United States in the early part of the coming week. Ahead of theHurricane Elsa The rest of the collapsed Surfside condo will be razed. What of the pets left behind?
I am sure if found you could be reunited.
Collapsed Florida condo to be demolished with explosives as storm approaches with another Miami condominium miles from collapsed building evacuated after being deemed ‘unsafe’ as nearby Condo's neighboring building offered payment after complaints

The developers of Eighty Seven Park, the luxury building next to Champlain Towers South, proposed a payment of $400,000 to the association for the now-collapsed condo in exchange for expanded construction hours, a commitment to never publicly oppose the project or the developer, and an agreement to release the developers from all liability

SpaceNut · 2021-07-04 13:53:22

Then again these are some wacky homes

last valued at a jaw-dropping $1.6 million.

it suffers from the same types of decay
BB18tFrM.img?h=416&w=799&m=6&q=60&u=t&o=f&l=f

Calliban · 2021-07-04 15:03:41

I like Tom's idea of a floating city. Probably the easiest way to do this would be using cast concrete cells, pulled together with pre-stressing tendons, which would be periodically replaced. The completed structure would form a dish shape, within which other structures could be assembled. A large city could be built up by accumulation of additional floating concrete structures, which could be linked by cables and under water pipelines. We would probably look to anchor the city to a shallow sea bed. In a shallow enough region, platforms could be built on concrete stilts.

Cellular concrete structures can built quite cheaply, as concrete is cast in a mould and material cost is around $100/tonne. I think that a floating city is a practical proposition. Something similar has been done already in Venice. Before human habitation it was a small group of marshy islands. Building there was expensive, requiring that buildings were constructed on top of long wooden piles driven into the mud. Everything had to be imported. Yet, it grew into one of the great powers of the late medieval Europe.

Last edited by Calliban (2021-07-04 15:08:43)

kbd512 · 2021-07-04 16:20:42

tahanson43206,

I'm of the view that humans don't naturally exist in water, much as they don't naturally exist in airless voids better known as "space". The people who live in such places must have a high degree of technical competence and the physical ability to overcome that. A ship or boat or barge is not a particularly good place for a senior citizen or women with children to live. Some obviously do live aboard boats or yachts, but they tend to be independently wealthy, in good health, and they learned how to swim at a very early age. While all of the land may be claimed by someone, people also routinely buy and sell land. There's no shortage of land available for purchase here in Texas, for example.

The sorts of nuclear power sources that Calliban and I have advocated for are dirt-simple low operating pressure reactors that consume all or most of the initial fuel load over time because they don't use fuel rods and water as a coolant, but instead make use of a fissionable slurry that can be chemically cleaned to remove fission products. Naval nuclear reactors are still feasible for civilian ships, but space is at a premium so lots of shielding is typically required for humans to be able to walk right up to the edge of the reactor vessel. That shielding material will either be very costly (Tungsten or depleted Uranium) or very cheap and very heavy (sand and sea water). It's absolutely doable, but using nuclear power dictates that humanity has taken a long-term view of power generation, in much the same way that the French have.

When I think about the best way to use nuclear power, it's the implementation of small modular reactors that don't use high pressures or water as coolant, that either don't need to be refueled or don't need more than a nominal amount of fuel present in the core, periodically topped up with fresh fuel, combined with a small chemical separation unit that strips neutron abosorbing fission products.

I think of practical reactors as thick-walled little pots / kettles made from ductile cast iron, small enough to be shock-mounted in a concrete containment pit or inside a ship's hull, filled with a Thorium-based fuel slurry that doesn't produce long-lived fission products, with either a molten salt or molten metal coolant so they operate at very low pressure, implementing a primary and secondary loop with a heat exchanger in order to keep the nuclear side shielded and the non-nuclear side separated, and with passive safety that uses a neutron moderator to immediately stop the fission process if the fissionable slurry leaves the core. These design characteristics are night-and-day different from most of what we're currently doing with nuclear power.

The Russians used the cheapest quality steel in their reactors that they could lay a hand to, rather than the most expensive super-grade ultra-pure / ultra-refined alloys, with the net result that their reactor vessels don't suffer from thermal and radiation induced cracking that the use of said super grade alloys caused in western-designed reactors. In other words, sometimes much simpler and cheaper technology ultimately proves to be "better" than the newest "hot-ness" from science, and in ways that actual matter to the sustainability and practicality of the complete solution.

tahanson43206 · 2021-07-04 16:31:04

For Calliban re #30

(With a nod to kbd512 in #31 whose post arrived as this one was in preparation)

A few years ago I was given the opportunity to serve as an officer of one of the many reboots of the Living Universe Foundation.

The LUF was itself a spinoff of the Third Millennial Foundation, which was structured in a way that the IRS found problematic.

Both organizations achieved significant membership, but by the time I got involved, the membership had dwindled to just a few dozen or so.

Here are links in the NewMars archive to the topic, with mention of see based living.

http://newmars.com/forums/viewtopic.php … 02#p181702 (th) 2021-06-30

http://newmars.com/forums/viewtopic.php … 54#p129154 Tom Kalbus 2016-04-24

http://newmars.com/forums/viewtopic.php … 90#p117690 Tom Kalbus 2013-11-26

Apparently Tom Kalbus got into hot water with the Administrators of this forum. hmmm... pun not intended but probably apt.

***
For kbd512 ... I need to take time to read your recent posts more carefully.

I did note some encouragement of the use of nuclear fission to provided for sustained living in large habitats, whether at sea or in space.

***
The most recent post is still visible on the screen above this reply, so I am able to see (and remember) the paragraph about the Russian use of cheap quality steel as more practical than high strength alloys used in the West.

***
Back to Calliban ... I thought your idea of concrete is interesting, as you will see when you look at the Kalbus links.

Edit#: I am confident I am the only member of the forum who knows that there is a blend of glass that floats.

It was patented (or rather, still in patent) the last time I checked.

This material is just about perfect for walls of floating cities.

(th)

kbd512 · 2021-07-04 20:13:07

Calliban and tahanson43206,

I take no real issue with these various thought experiments, as I find them fun to think about, but while our brain power is focused on not solving the underlying problem of energy depletion and the increasing complexity of purported substitutes continually requiring more energy that we don't have, we are, in point of fact, not actually solving the underlying problem. It seems like we keep retreading through very fundamental logical fallacies.

According to you and the people you quote quite frequently, excessive energy usage to produce things we can't afford to produce, from an energy availability standpoint, absent more cheap energy from fossil fuels that we can't produce since the cheapest sources from an EROEI standpoint have already been depleted, is the very definition of the problem we actually need to solve, but the "solution" in this case is to use more energy to produce something that humanity doesn't actually need at the present time. Let your mind marinate on that for a bit.

Maybe you and most other people wonder why nothing ever changes, but I certainly don't. I know that few of you see how silly this has all become (not this topic, not this proposal, but what all of our "solutions" to the underlying problems entail), but I think SpaceNut and I do. Our proposed solutions to the problem of economic prosperity (the ability of the average citizen to become wealthy enough to purchase and develop land) that only comes from energy abundance (because the economy is a physical entity, not a metaphysical one, as you and many others with actual engineering knowledge have already noted numerous times), all seem to require more of the one thing we don't have.

It has historically been a mistake, paid for in terms of human lives, to build a city right on the shoreline of a waterway. That was historically done for sake of convenience and ease of travel / trade, not because erecting large buildings in places subject to periodic flooding makes much sense if the ultimate goal is to protect human life from the most singularly lethal extreme weather event, namely flooding.

If you erect massive buildings mere feet from an ocean or river or lake, then by the very definition of what you're doing, you're putting anyone inside at the mercy of the water. We already know what the solution is to that problem, and it doesn't involve better engineering or better materials or floating cities- you don't construct large buildings so close to the water's edge!

The one thing humanity is desperately short of, and needs far more of, that doesn't require any resource we're incapable of obtaining, is better critical thinking skills. If you want to expend a massive amount of capital / labor / energy to solve the disappearing coastline problem, then do that by moving all of those buildings several miles away from the edge of the coastline. That's the ultimate solution. Don't put anything on the coastline that you're unwilling to allow nature to destroy, because soon or later that will happen.

Similarly, the solution to the problem of energy expenditure to import cars from overseas is to stop that practice and build your own cars domestically. Every industrialized nation should make their own food, water, medicine, textiles, appliances, and vehicles, then you don't need massive container ships shuttling cargo all over the planet, which means you also don't need the energy to make the steel to make the ships, nor the energy to make oil rigs to extract and refine the fuels that power the massive ships, the crews to fabricate and man the ships, etc. This is a classic "snowball rolling downhill effect". You, as an engineer, should be fully aware of that.

We can still share our ideas without transporting the physical artifacts of our ideas half way around the world. The machinery that forms the foundation of technologically advanced human civilization is now pervasive enough for us to do that. Every industrialized nation has computers, the internet, CNC machines, mining equipment, etc.

Anyway...

I would like to ask whether or not this concrete preform structure we anchor offshore would be in compression or tension or a combination of the two? The strength of concrete in compression is very impressive, but very pedestrian when in tension. As such, how do we ensure that this concrete structure is always in compression, the way the Romans did?

If we can't assure that this concrete structure is adequately supported to prevent failure, then how about applying a thin layer of concrete over a galvanized steel support structure?

Is there a cost effective way to fabricate a steel reinforced concrete exoskeleton for a hollow semi-submerged structure?

My intent is to avoid the use of less durable paints and plastics, and to instead use something that becomes stronger with exposure to sea water, the way Roman concrete does.

tahanson43206 · 2021-07-05 07:00:38

For kbd512 and Calliban ...

I'd have to go back to the "Millennial Project" by Marshall T. Savage to be sure, but Tom Kalbus reminded us of "seacrete" ....

Sea creatures that pull Calcium from sea water to make shells are able to make strong, long lasting structures and surfaces.

I ** think ** (again without checking the source) that "seacrete" may have been imagined as similar to the natural material.

***
Regarding a question by kbd512 re compression for concrete flotation devices ... sea water provides plenty of compression.

A structure the size of a New York sky scraper would be mostly underwater like an ice berg. All the surface under water would be under compression. The surface at the water line and above would need to be designed for the air/water/solar interface.

***
I mentioned floating glass in a post recently, but the point bears repeating .... glass has distinct advantages for use as a structural material in this setting, and the ability to float in sea water is a definite plus.

kbd512 reminded us of the potential of traditional ship designs to sink, due to displacement of sea water by a thin shell of material, such as wood or steel, or in some cases aluminum.

Floating glass is expensive (I understand) and the patent is still in effect (to the best of my knowledge) but if a building (to live at sea) is intended for occupancy for 100 years or more, expense at the front end will pay off with rent for many decades to come.

(th)

tahanson43206 · 2021-07-05 07:54:10

For anyone who might be interested:Seacrete

Reference: The Millennial Project by Marshall T. Savage

First off ... I was surprised to (re-learn) that the original word used by Savage was "sea-ment'

The common translation to sea-crete is understandable. It's an example of a person hearing a term, integrating it with previous knowledge, and jumbling the original just enough with the earlier neuron settings so the permanent memory is a meld of the two.

The section of interest is on page 73 in the chapter on Aquarius..

SearchTerm:seament
SearchTerm:seacrete

Paragraph title: Sea Shell

Aquarius will not be built so much as she will be grown. Like many man-made structures, Aquarius will be made of reinforced concrete; but instead of being poured or assembled, her cement will be accreted out of sea water--like a seashell.
The accretion of 'sea-ment' is accomplished by applying an electric current to a metal grid; calcium carbonate and other mineral ions dissolved in sea water bond electrochemically to the charged metal, forming a cement-hard coating.
Most surface waters, particularly in tropical seas, are saturated with calcium carbonate, (CaCO3). This mineral is very familiar in its common forms: calcite, marble, limestone, seashells and Portland cement.

The author goes on for page after page, detailing chemistry and construction techniques.

If readers of this post do not already have a copy of "The Millennial Project" in their libraries, I am pleased to be able to report that used copies are available. I just ran a Google search for the millennial project book for sale.

The result set includes offerings for $4.00 and $4.10 (no doubt plus shipping).

For anyone interested in human future in space, this is a bargain!

In addition, the book is still available at Amazon:

There the offerings start at $24. There are (apparently) 14 copies available.

If there is an expression of interest, I can imagine being persuaded to add a paragraph or two more of quotation.

Because the price for the original work is so low, I'm hoping at least a few members of this forum will snap one up.

out of curiosity, I asked Google about online availability of the book and discovered this intriguing link:

e-Book Download The Millennial Project: Colonizing ... - Google Docs
docs.google.com › document
e-Book Download The Millennial Project: Colonizing the Galaxy-In 8 Easy Steps by Marshall T. Savage, Keith Spangle pdf. Download ...
The Millennial Project - Wikipedia
en.wikipedia.org › wiki › The_Millennial_Project
The Millennial Project: Colonizing the Galaxy in Eight Easy Steps by Marshall T. Savage is a book in the field of ... The book's thesis · The steps of the project · Criticisms · See also
The millennial project (1994 edition) | Open Library
openlibrary.org › books › The_millennial_project
The millennial project. colonizing the galaxy in eight easy steps. by Marshall T. Savage. 0 Ratings; 7 Want to read; 0 Currently reading; 0 Have read ...
Read The Millennial Project Colonizing the Galaxy in Eight Easy ...
www.dailymotion.com › video
Jun 18, 2018 · Read Free Ebook Now http://mediabooks.club/?book=0316771635Read The Millennial ...Duration: 0:34
Posted: Jun 18, 2018
[PDF Download] The Millennial Project: Colonizing the Galaxy in ...
www.dailymotion.com › video
Mar 14, 2017 · Read Free Full Ebook http://readebookonline.com.e-bookpopula … 0316771651[PDF ...Duration: 0:05
Posted: Mar 14, 2017
The millennial project : colonizing the galaxy in eight easy steps ...
www.worldcat.org › oclc
Summary: The blueprint for the future of the American Space Programme. This book is both an argument for why humankind has an obligation to explore and ... Summary: The blueprint for the future of the American Space Programme. This book is both an argument for why humankind has ...
The Millennial Project: Colonizing the Galaxy in Eight Easy Steps by ...
www.goodreads.com › book › show › 778041.The_Millennial_Project

Recently SpaceNut said "Holy Batman!" when GW Johnson came back online ...

I'm quoting that expression now ... I clicked on the Google docs link and a teaser for The Millennial Foundation popped right up!

The Download button has this link: http://camimbu.com/?book&k=The+Millenni … google.com

Following that link gave this: http://ebookbit.xyz/book?k=The+Millenni … ps&lang=en

At that point I got a 404 error.

It is entirely possible this happened because the computer I start on each day is vintage 2000 and I don't update it, so a more modern browser might be able to pull it down.

It would be nice to have an electronic version to be able to quote more easily and accurately.

(th)

Mars_B4_Moon · 2022-06-14 07:13:14

Researchers at The University of Tokyo create vertical field-effect transistors that can be used to store information in a 3D array, which may lead to faster and more energy-efficient data storage

https://techxplore.com/news/2022-06-dat … emory.html

kbd512 · 2022-06-26 13:30:23

Does anybody else see the problem with allowing one group of engineers to run amok?

82611937cbf37e47e56e1f77a0694eb3--engineering-aviation.jpg

This is what you end up with when one group is allowed to dictate all aspects of a given design.

Calliban · 2022-06-26 13:38:45

Kbd512, this is always the problem with big projects, with different design teams with difference specialisms having to interact on a common design. It is why huge amounts of time has to go into design integration meetings with 3D CAD models. Systems engineering of complex things like submarines, ships, aircraft and spacecraft, ends up being difficult for precisely this reason.

kbd512 · 2022-07-28 03:19:39

There's been a lot of debate on the effectiveness of stealth technology, so I'll post this here from the user named "dwightlooi" on F-16.net:

In general, the radar aperture (antenna area) doubles with a 1.41 times increase in diameter. With all else being constant it takes an increase in aperture of 10x to double the range of a radar. Technologies like AESA antennas increase the output and sensitivity of a radar for any given size. Advanced T/R module technology and smaller T/R modules also do that. PESAs generally reduce sensitivity. Both types of ESAs allow instantaneous beam steering and high beam focus. Only the AESA can form multiple beams simultaneously.
The problem with radar improvements is that while output and sensitivity gains have increased radar performance by about 20~30x in the past 30 years translating to an increase in range for a given physical aperture of up to 2.6 times. The advent of VLO airframes has reduced RCS to roughly 1/1000~1/10000th that of 4th generation jets. To make up for this through radar improvements will require an improvement of radar performance by 1000~10000x which is not projected to be possible with known and projected technological road maps.

That post was made about 15 years ago, in response to how physically large the radar systems of modern fighter jets were. 15 years later, there's still no radar that can compute a firing solution to down a stealth aircraft from any significant distance. The F-117 shoot-down in Serbia was a function of following the ingress and egress routes using HUMINT, complacency amongst air crews, no EW support from EA-6Bs, and manipulating the radar set to make it barely capable of determining where the stealth aircraft was while it was exposing itself via opening its bomb bay doors in preparation to drop on the target. Basically, what transpired was a non-repeatable event, even if it engendered some humility amongst the stealth aircraft pilot community to treat all enemies as competent, capable, and always waiting to capitalize on any mistake a pilot makes, however slight.

An In-Depth Analysis of how Serbs Were Able to Shoot Down An F-117 Stealth Fighter during Operation Allied Force

Take note from the article that the lowest frequency the radar set was capable of operating over was only able to "see" the F-117 when its bomb bay doors were opened and it flew within 5 miles of the emitter (point-blank range for anything but MANPADS), but was otherwise incapable of tracking the aircraft. The F-117 had no operable RWR equipment, either, although the pilot was able to visually determine that he was being shot at. This was later rectified in the F-22 and F-35 programs by devising RWR antennas that did not compromise the stealthy airframe. One of the missiles fired at his aircraft guided to the target but then failed to detonate, possibly because it lost signal entirely as it neared the aircraft by flying above the portion of the aircraft that was radar-reflective, whereas the other missile, which presumably flew under the F-117, did detect when it was within lethal range and its warhead detonated. The two other F-117s in the strike package were never shot at. There could be various reasons for this, but their bomb bay doors were also closed, which is the most probable explanation.

This point is emphasized to show that even radar and missile systems designed in the 1950s and fielded from the 1960s onwards were able to accurately track and shoot down any non-stealthy aircraft that flew within range, even if it was merely the bomb bay of an otherwise stealthy aircraft. The F-117 was also designed in the 1970s, so it was very primitive as stealth aircraft go. The B-2 design was considerably more advanced, the F-22 a bit more, and the F-35 was the first design where all the fundamentals were thoroughly worked out and tested and materials technology finally caught up to make stealth a practical design feature.

It should be readily apparent, given that radar sensitivity and missile accuracy and lethality have improved by orders of magnitude during the intervening decades, that all non-stealthy aircraft are not survivable over a modern battlefield if the enemy has IADS (Integraded Air Defense Systems- air defense systems that are networked and talk to each other electronically, so the appropriate missiles and guns are employed against the threat aircraft). Russia and China field hundreds of these systems. That means all 4th generation non-stealthy F-15s, F-16s, F-18s, A-10s, B-1s, Tornadoes, EuroFighters, Mirages, Rafales, Sukhois, and MiGs are highly vulnerable to modern IADS. If the enemy has a healthy supply of SAMs, then losing 10% to 40% of every strike package, per mission, is par for the course. Red Flag exercises conducted at Nellis AFB, involving American, European, and Indian (they use the latest Russian-built Sukhois) pilots flying those 4th generation jets, has proven as much. American / US Army and USAF IADS operators inflict 10% to 40% casualties on the attacking strike package, every single mission, no matter how good the pilots are. It should go without saying that an unaware pilot is highly vulnerable to virtually any missile system, which is the entire reason for the sensor fusion technology that the F-35 pioneered.

What this really tells us is that all of our current jets that aren't B-2s / F-22s / F-35s / B-21s are obsolescent. A Strike Eagle is still a Strike Eagle, and still capable of inflicting crippling damage with its large bomb load and considerable combat radius, but if it runs into something like a S-300, then it's survival is dependent upon the quality of its ECM suite and stand-off distance from the threat IADS. If we pit our legacy jets against modern Russian or Chinese IADS, even if their operators aren't the best-trained in the world, a 10% minimum casualty rate per mission is what we should expect. I don't think that's sustainable for more than a week or two, certainly not a month or more, before there are no jets left, even if you have replacement pilots available. Russian air losses in Ukraine have been considerable, despite the fact that Ukraine doesn't have a functional Air Force and operates most of the same old Soviet era equipment arrayed against them, with respect to air defense systems.

That is why I asserted that replacing our existing F-4s / F-104s / A-6s / A-10s, with very expensive F-14s / F-15s / F-16s / F-18s, which mostly offered improved kinematics, was such a monumental waste of tax money. Our pilots would have been much better served with improved engines, sensors, and weapon systems, which all but nullified the perceived advantages of the newer 4th gen fighter jets. There's a highly persistent belief that newer automatically means better. Newer is almost always more expensive, but stealth was the only paradigm shift in fighter jet design. When the GE F-110 engines became available to power the F-15 and later F-16, the existing F-4s and F-104s should've been retrofitted with those new engines. The older airframe designs would then out-climb the then-new F-14s / F-15s / F-16s, achieve very similar sustained turn rates (the newer jets still would've been slightly better on this metric), and kept existing production lines open and turning out fresh airframes. The F-4 and F-104 were the correct heavy and medium fighter concepts. They could've been refined to the point where they did nearly everything that the newer jets did, except for spending more tax payer money. Starting from scratch with a clean sheet design is seldom, if ever, less expensive than taking a well-proven existing design and upgrading it as time progresses.

The CL-1200 variant of the F-104 Starfighter could've been equipped with the same radar as the F-16 and the same weapons, albeit fewer of them, and done just as well in combat as the F-16. Oddly enough, the CL-1200 (17,250lbs) had an empty weight almost identical to the modern F-16 (18,900lbs), an identical wing area (300ft^2 for both), same basic wing design (tapezoidal delta with LERX for both), rate of climb some 10,000fpm greater than the F-16, same conventional tail design as the F-16 (not the T-tail of the original Starfighter), so there's little reason to believe that kinematic performance would dramatically differ. CL-1200's combat radius with internal fuel and 4,000 pound bomb load was 420 miles vs 339 miles for the F-16. Both carried a similar quantity of internal fuel.

The Air Force instead selected the far less-capable F-5 Tiger II instead of the CL-1200. The F-5 was subsequently replaced by the F-16, because it couldn't do what the USAF needed it to do with the technology of the era, which was obvious even back then according to those involved. After the tax money was spent, it was determined that turning the F-5 into the F-16 that they needed meant producing the F-20 Tigershark, another all-new design, albeit privately funded, that offered similar kinematic performance but less payload-to-distance than the F-16. F-20 was very modestly less expensive than the more capable F-16. F-404 and F-110 engines, then new designs, were not dramatically different in terms of procurement cost, avionics and sensors were always going to cost the same, and airframe fabrication costs are by weight, which meant no dramatic cost savings were offered. In short, USAF embarked on a series of inordinately expensive diversionary side projects in search of the perfect medium fighter, which squandered the program investment into the F-104 and F-5 designs.

In a similar show of silliness, the US Navy inadvertently designed and operated the USAF's first F-15s, which also first flew in 1958. This aircraft was the A-5 Vigilante. A-5s were powered by a pair of J79 engines, which also powered the F-4 and F-104. It carried more internal fuel, at 3,600 gallons, than any other US-built fighter-type aircraft except the F-111B, which was also rejected by the Navy, in favor of the inordinately expensive F-14 which was designed and built two decades later. As a result, the A-5's un-refueled combat radius on internal fuel alone exceeded anything produced since then. The only somewhat similar aircraft with similar range are the F-111B, Blackburn Buccaneer, A-3 Skywarrior, and Tupolev Tu-128. This airframe had fly-by-wire control, the first HUD, radar navigation, and a truckload of ECM and radar warning equipment. Oddly enough, it has a slightly lower wing loading than the F-15 when equipped with 4 AIM-7 and 4 AIM-9. In test flights, despite having about half the available thrust of the F-15, it proved to be Mach 2.5 capable on high speed record flights across the Atlantic, even if the Navy said it could only achieve Mach 2. If the production line was left open long enough to see F110 engines, then this aircraft would've significantly exceeded the climb performance of a totally clean F-15, while carrying 3,600 gallons of fuel and 8 air-to-air weapons.

The real question is how many times the tax paying public will allow the US military to create and then re-create the capabilities of existing aircraft or other weapon systems until they demand that the services stop reinventing the wheel. We've kept the M1 Abrams and AH-64 Apache production lines open since about the mid-1970s. By continuously upgrading those weapon systems, they're as relevant today as they ever were, although I'd argue that even those machines were extravagant wastes of money to pursue wunderwaffe. A purpose-built version of the Little Bird could do what the Apache does, perhaps not quite as well in specific cases, but well enough to get the job done.

In closing, the argument that WWII-era radar systems can "detect" stealth aircraft is quaint, and while it has a small kernel of truth to it, it's still an absurdity that requires a definition of what such a radar can actually do after the stealthy jet is detected. It certainly can't guide a missile to the target, because to do that you need much higher frequency radars that are much more accurate. Can you shoot a missile into a 15 cubic mile volume of airspace, which is the accuracy that the WWII-era radar provides, and still expect it will hit something? Anything is possible by chance, but the probability is astronomically low. No other F-117s were shot down before or since, despite extensive use in Iraq during the early stages of the war when all Iraqi air defense systems are still active. That was the most primitive that stealth technology will ever be. Meanwhile, all existing aircraft and air defense radar systems will have to grow in size by multiple orders of magnitude or suffer from multiple orders of magnitude reduction in tracking and locking distances, rendering them about as effective against stealthy aircraft as the most primitive WWII-era radars were for tracking non-stealthy aircraft in order to vector fighters or bombers onto a target. There are electro-optical systems on the horizon that will restore some of the lost tracking and locking range, but they must also have a clear line-of-sight to the aircraft they're engaging, and atmospheric conditions can render them useless, which is why we still use radio beacons versus optical beacons for precision landing of airliners in bad weather. Stealth represents the proverbial "once-in-a-lifetime" paradigm shift for combat aircraft, where everything that came before is suddenly obsolete. Stealth is as significant as the switch from piston to jet engines.

Mars_B4_Moon · 2022-09-02 08:23:41

Nasa Moon rocket launch unlikely to be ruined by weather, Space Force says
https://www.independent.co.uk/space/nas … 58433.html

Lawyers awarded $70M+ fees in deadly Florida condo collapse
https://abcnews.go.com/US/wireStory/law … e-89008495

Mars_B4_Moon · 2024-05-18 18:42:58

F-4 Phantom jets hold farewell flight after over five decades of service

https://en.yna.co.kr/view/AEN20240510008500315

a 2013 article on the other Korea

North Korea’s Illegally Supplied Helicopters Emerge After 30 Years In The Dark
https://www.businessinsider.com/north-k … rge-2013-7
Their presence confirms long-held beliefs that Hughes helicopters first traveled from the United States to a legitimate arms dealer in Germany. Then the helicopters made their way through a convoluted, geographical and legal laundering process, in which they ended up loaded onto Russian transport ships in three separate cities — Hong Kong, Rotterdam, Antwerp.

Last edited by Mars_B4_Moon (2024-05-18 18:46:36)

kbd512 · 2024-08-16 01:33:55

tahanson43206,

I came back to your concept of a floating city after reconsidering how to power it. If trompes were used to provide power from compressed air, then the energy savings over time would be tremendous. The generation of air power from gravity would also be a way to make this entire endeavor pay for itself. Photovoltaics and conventional wind turbines are hurting for raw materials, but Iron is plentiful. We would have these "floating cities" offshore to maintain the air compression infrastructure required to power both the floating cities and land-based cities. We need enough people to make this work, but offshore jobs pay well and this ties in well with my concept about how to repower the major infrastructure pieces without hydrocarbons, nuclear energy, or intermittent and weak output from photovoltaics and electrical wind turbines. The operative buzzword here is "synergy". We need more reliable power, so we use gravity to compressed air. We need people to maintain all the ships and floating cities, so we revitalize our marine industry to employ them. They need homes for them and their families, so we create floating cities. The floating cities need to be paid for, so they generate electrical power and compressed air power for vehicles.

Calliban · 2024-08-16 12:22:22

A trompe powered by wave energy would have no moving parts aside from flap valves.

As the wave enters the funnel, it sends a pulse of high velocity water through the tube forcing open the flap valves. The resulting pressure drop pulls air through the vertical tube into the water stream. As the wave dissipates, the flap valves close and air is trapped beneath them until the next wave arrives. Air is driven into the tank at the bottom of the tube, accumulating there under hydrostatic pressure.

Last edited by Calliban (2024-08-16 12:26:55)

tahanson43206 · 2024-08-19 06:18:32

For Calliban re #43 ....

In last night's Google Meeting, kbd512 took the time to explain your drawing, and the concept you've described, of using wave action to drive air bubbles and sea water down a tube to a tank where the air would be collected.

Now that I understand the concept, I am hoping you might add a few details to the design.

The mass of water to drive the column down would arrive at the surface float at the crest of each wave. The total displacement available at any given time would be the difference between the crest of the wave and the trough. The float itself would be somewhere in between those limits at that time. kbd512 reminded me that hydrostatic pressure in the ocean increases with depth, so the maximum depth to which the float mechanism drives the new water would be where the hydrostatic pressure matches the pressure provided by water over the surface of the float. Can you (would you?) provide some numbers to go with your design?

How much air might such a system produce over time, given various sea conditions, and what pressure might that collected air experience inside the concrete tank?

An application for air collected in this manner might be to supply an underwater shelter (for example) which would otherwise have to use a snorkel of some kind to pull air down into the habitat.

(th)

kbd512 · 2024-09-26 20:25:57

To illustrate how ridiculously strong and hard maraging steel is, a little engineering simulation:
APFSDS-T VS Various Armor (AL Alloy, RHA, Tungsten Alloy, Depleted Uranium, Titanium, Plastic, Iron)

It's not an acceptable substitute for a real test, but I think we're going to find that the real world is at least similar to those simulations.

Against a simulated 700mm thick block of different armoring materials, at 1,500m/s the Tungsten penetrator produced a cavity depth of:
Tungsten: 324mm
Depleted Uranium: 329mm
Maraging Steel: 340.1mm
Rolled Homogenous Steel: 444mm
4340 Steel: 476mm
Titanium (alloy unspecified): 584.1mm
Aluminum (alloy unspecified): 700mm
Armaco Iron: 700mm
Polyethylene: 700mm

Maraging steel rates only slightly behind Tungsten and Depleted Uranium, insofar as its ability to resist penetration from a Tungsten long rod penetrator. This would seem to indicate that maraging steel is one of the most practical and inexpensive solutions for maintaining the structural integrity of our large interplanetary transport ships, and limiting structural damage from orbital debris that does manage to penetrate through the multi-layer ballistic fabric coverings. As long as we maintain them above cryogenic temperatures to prevent the steel from becoming brittle, the hull should be good to go for a very long time.

Calliban · 2024-09-27 07:53:55

Marageing steel is hard to beat in strength and has good strength-weight in spite of its high density. The only lingering question in my mind is brittle fracture performance. That is a big deal when designing pressure vessels for a life support function. It is why reactor pressure vessels are made from low alloy steels, even though there are much stronger options available. Also, marageing is heavily alloyed. Can we weld it without creating heat effected zones where alloying elements have migrated to grain boundaries? That is what tends to cause cracking in alloy steels. It is why so much money ends up being spent on NDT of welds in high hazard industry.

kbd512 · 2024-09-27 19:07:20

Calliban,

RPVs cycle to very high temperatures and pressures though. We're going to build this thing in space, using lasers or electron beams to minimize the HAZ. Conceivably, we could also "weld" the metal without applying any heat, only friction.

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