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tahanson43206,
I can imagine an airship that supports its own weight with a lighter-than-CO2 gas, but obtaining lift greater than weight at the low speeds inevitably required by a giant airship / inflatable flying wing is likely not practical. It may not be infeasible, yet economics- even if it's only the economics of energy and materials generally becomes a consideration at some point. We have high altitude airships that top out around 60k to 70k feet, but those are carrying very modest payloads and they're gargantuan, relative to the payload carried aloft.
For some reason we don't have any lighter-than-air wings that operate at 100,000+ feet here on Earth, which is most likely an indicator that it's not practical and likely infeasible since we generally try everything at least once in the realm of aeronautics, irrespective of whether or not the technology is practical at the time. The primary issue I see is achieving uniform internal load over this inflatable wing, such that the thread doesn't "tear" the gas-tight membrane. The structural members have to be fastened to the gas-tight skin somehow, right? This is actually an interesting design challenge, or at least the part about using fabrics held in tension to support the loads. You'll need a very powerful computer to analyze the design.
You might want to look into aeroelastic structures. There could be something from that field of experimentation that's applicable to this design. If it was my money, I'd stick with well-proven airship designs making use of advanced materials to increase useful load.
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Toy planes use Styrofoam and balsa wood to make light frames for fabric or plastic films to cover. These might be used for a mars wing with wider and thinner wings that have internal balloon for the helium or hydrogen to fill. That gives the buoyancy and the lift would come from the forward motion.
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For SpaceNut re #184 ... thank you for the reminder of the strength of some arrangements of Carbon atoms (in combination with others in your examples).
For kbd512 re #183 ... thank you for your analysis of the potential for ultra-strong, ultra-lightweight wings for Mars. Your point that such wings have not been made for widespread use on Earth is a strong one ... military motivations would surely be driving investigation of high elevation flight capabilities. Another motivation would be the potential private industry of delivery of broadband service using high elevation vehicles that can hold position.
As you know, Google investigated use of high altitude balloons for this purpose but (as nearly as I can tell) has abandoned the initiative.
However, on Earth, flight at the fringes of space is a curiosity, whereas at Mars, it would be a necessity. I expect that when residents have a bit of free time after just surviving, they'll pursue all the "ultra" capabilities that might exist, because their environment demands them.
SpaceNut's reminder of foam structures based on Carbon is an example. Designers may combine multiple lift concepts in a variety of vehicles. On Earth, early aircraft wings were made of Carbon based materials (with steel wire for tensile strength).
Your mention of computer analysis tools is a reminder for the NewMars forum that it would be helpful if one or more persons with access to the software and hardware, and the education and interest required were to take up the questions posed here on behalf of future Martians, who may not have the same tools available.
Google came up with a long list of citations about aeroelasticity and an impressive looking list of books on the subject. I get the impression (from scanning the citations list) that the field is dealing with problems caused by deformations of structures as fluid passes by.
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The equations for lift and even for entry into mars atmosphere are similar. We do have airplane and helicopter topics. Along with mars air breathing engines. With the pesky units of pressure.
Airplanes on Mars
Scouting Mars by Helicopter
Air breathing engines on Mars
Units of Pressure
I think that we have another...
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This item is offered for kbd512 ... it is a nod to his point about the value of traditional design concepts for airships on Mars ...
The item came up in the Yahoo news feed ... the detail about plans for an airship for disaster relief was deep in the article ...
For example, Brin has long been fascinated by the idea of kickstarting a new era of airships. In 2014, he hired an aerospace expert from NASA to build a luxury airship over twice the size of any today—the airborne equivalent of his Dragonfly super-yacht. That effort is managed by a company called LTA Research and Exploration, based in Silicon Valley, where LTA rents the world’s second-largest airship hangar at NASA’s Moffett airfield. A sister company, LTA Galactic, carries out research and development in Akron, Ohio, near the largest active airship hangar in the world. According to emails obtained via public records request, LTA has been interested in leasing this hangar since at least 2018.
A recent job listing at LTA says that it is now developing airships that can improve humanitarian aid delivery in areas struck by natural disasters. Last year, LTA registered an airship called Pathfinder 1, powered by 12 electric motors and able to carry 14 people. LTA’s airships may use hydrogen gas, not for buoyant lift as in the ill-fated Hindenburg, but as fuel to avoid carrying heavy batteries.
https://www.yahoo.com/news/google-found … 33331.html
I'd like to point out the interesting hint about using fuel cells to deliver power for electric motors.
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Seems that balloon rides to space are going to be in again.
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For SpaceNut re #188
Thanks for this additional perspective on the proposed balloon rides.
As had been previously reported, the tickets would cost an (estimated) $125,000.00 USD
Tickets would cost roughly $125,000, Poynter said. By comparison, tickets for Richard Branson's Virgin Galactic are estimated to cost $250,000 for a brief rocket flight 50 miles high. But no space tourism flights have left the ground yet.
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Sub orbital is a cash cow waiting if the prices are low enough for the average joe to be able to go.
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tahanson43206,
Yes, some people are finally accepting that basic math does not favor the use of batteries, given present energy densities, for anything that must fly. I understand the appeal of the energy efficiency of batteries, but in aircraft weight and energy density matter greatly. In rocketry, weight and energy density are, more or less, the driving force behind everything you do.
So... In the immediate future a fuel cell powered airship would be a boon to the shipping industry by at least halving transit times with acceptable increases in fuel consumption over the slow boat from China. Reasonably cheap and fast shipping is a real cash cow that every business in the world would benefit from.
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For kbd512 #191 in reply to my #187
Thanks for noting the promising sounding work on fuel cell powered air ships!
***
This next posting to Technology Updates is a two-fer ...
The article is about a new design for an electric aircraft.
However, it is the ** client ** for this new aircraft I thought members of the forum might find interesting ...
https://www.yahoo.com/lifestyle/electri … 01052.html
“Our primary objective is to meet our first customer’s mission, reliable organ delivery when and where it’s needed,” Clark said. “We couldn’t have an aircraft that had any possibility of being grounded for repairs due to a complex system.”
That client, United Therapeutics, is developing manmade organs for human transplant. The goal is to have a reliable, environmentally friendly mode of transport for the organs.
There have been posts in this forum in the past, about 3D Printers enlisted to build tissue scaffolding for research.
I am encouraged to see a hint in this article that research may have led to actual organ development, with the prospect of actual delivery to actual patients.
If someone in the contributing membership runs across anything more than this little hint, I'd be quite interested.
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This evening's post to Technology Updates may be of interest to NewMars forum readers for a couple of reasons ...
First, since Kevlar is under consideration as a component of a space elevator for Mars (at Phobos) I was intrigued to learn that the new research reported in the article is descended from the invention/discovery of Kevlar itself.
Second, the techniques reported for making a material of a foam of nanoscale threads may be of interest for a variety of applications on Mars.
Rather than suggest a specific web site, I am offering the search string. Google will find a number of sites ...
super-material-game-changer-firefighters
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Here is an announcement that (I am hoping) will be of interest to Louis !!
https://www.yahoo.com/finance/high-eart … 49234.html
This article describes an innovative startup that plans to use existing space assets to provide valuable information to customers, by capturing images of customer satellites when they are in view of otherwise unused Earth pointing satellites. Earth point satellites spend most of their time over water, so there is a lot of potential opportunity in terms of asset availability. However, the coincidence of intersection of the customer satellite and the potential asset is a technical challenge.
The article mentions the potential to help with orbital garbage cleanup, but (as far as I can see) the business case for that is not strong at present. Insurance carriers might be a potential cleanup funding source, because the loss that can occur in the event of a collision with orbiting debris could be significant.
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This post is for Calliban ....
While trying to find the story reported in Void's ice/brine topic, Google showed me a collection of imaged Popular Mechanics magazines from 1927 and 1928 which contained articles about steam engines active in that period. Electric locomotives were giving the steam designs a good run for their money, but it was still early in the competition at that point. The article I found caught my attention, and I read for far longer than I had intended, because I can still remember the last days of steam after the end of World War II.
I have not thought about steam engines at all for some time, and not at all about the details of design to try to wrestle increasing power/speed combinations out of the limited capability of simple steam propulsion, while staying within the limitations of bridges, tunnels, rails and curves of the time.
The article included images of British monster locomotives as well as American ones.
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Thanks TH.
There are several basic problems that render rail based steam engines impractical as a mode of propulsion, compared to diesel and electric engines.
1. They rely upon heat transfer into a separate working fluid, which limits power to weight ratio, as heat transfer is rate limited and boilers are heavy.
2. They are non-condensing and non-regenerative cycles, hence much energy is wasted in the residual energy of saturated steam, which carries away a substantial amount of enthalpy. This makes them inefficient.
3. The low efficiency and high inherent weight, raise the requirement for huge quantities of fuel, which add even more to weight. Range is also limited, requiring frequent and time consuming refuelling stops.
4. The high inherent weight and low power of the system, results in poor acceleration and limits to speed.
5. The high consumption of solid fuels, incompletely combusted, raises severe problems with air pollution in urban areas.
It was this final problem that led to the replacement of steam power by DC third rail in London, South East England, Merseyside and Newcastle, between about 1900 and 1960. People were literally dying in their thousands in toxic smogs, in large part due to steam engine pollution. I find it mildly humorous that so many people consider steam to be a romantic age. They were archaic, slow, dirty, stinking things. In just one night in London in 1952, smog from steam engines and open fires killed more people than all of the radiation released by Chernobyl.
The UK hung onto the steam engine for too long. The steam railways simply weren't able to compete with private cars for people transport and they were too slow, expensive, inflexible and cumbersome to compete in goods transportation.
Last edited by Calliban (2020-07-10 16:21:31)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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tahanson43206,
Although it wouldn't be practical on Earth due to air resistance, I wonder if Stirling engines and solar concentrators could be used on Mars to provide motive power for a train by supplying each rail car with its own motors and solar concentrator array.
Infinia has a 30kW 6-cylinder free piston balanced Stirling engine that produces that kind of power using a 10m to 12m reflector dish using a 1kW/m^2 solar radiation flux. We'd get less than half of that on Mars, but Mars also has 38% of Earth's gravity, so the train would require less than half of the motive power of an Earth-bound train for equivalent performance.
As you can see, Infinia and NASA have been working on this for quite some time:
REPORT ON STATE-OF-THE-ART DISH-ENGINE APPLICATIONS
30 kW Maintenance Free Stirling Engine for High Performance Dish Concentrating Solar Power
It's not compact or lightweight, but it's extremely durable and reliable.
The production 6-piston Stirling engine is expected to weigh around 540kg. I've been trying to figure out how much the solar concentrator would weigh, but I'm guessing lightweight materials could make something in the 2,250kg range feasible using Aluminum alloys. That power-to-weight ratio is nothing to write home about, but this is a distributed propulsion system (1 or 2 dishes per rail car) mounted to 45t steel rail cars or perhaps lighter composite rail cars with Aluminum rolling stock with steel rims.
I based my weight estimate for the dish off of this design, admittedly not very mass-efficient for a number of reasons:
Solar Concentrator (Solar Dish) Dimensions
I was trying to factor in worst case scenario numbers to the total mass of the system. Note that the 9m dish is only 292kg on its own and it only weighs 111kg on Mars and doesn't have to be stiff enough to withstand Earth-associated wind pressures. There won't be any infrastructure or trees or other obstacles around the railroad track, either. It's entirely conceivable that the complete system would produce better power-to-weight performance than Earth-based diesel electric locomotives.
An Earth-bound diesel electric locomotive weighs just shy of 200t and produces 6,000hp. This distributed system would require 150 cars to produce 6,000hp, but the propulsion would be highly redundant and long haul freight trains routinely have at least 100 cars here in America. We could also make the cars from rock wool-based composites to reduce the weight of individual cars to compensate for any relative increase in mass over the steel-based cars and locomotives used here on Earth to produce equivalent power-to-weight performance to an ordinary diesel electric locomotive.
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For kbd512 re 197
Bravo for your ** inspired ** response to the steam train idea that popped up in one of Void's topics!
This topic is a good place for your ideas to appear, although it would probably make sense to put a copy over in the train topic just brought back from the depths of the archive.
I hope you (or someone) will follow up your initial ideas with more details about how this interesting concept would work, and where (on Mars) it would be most useful for initial deployment.
(th)
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tahanson43206,
It's pretty simple. You bolt 2 of these solar concentrator dishes to each rail car and they provide about 30kW of power per rail car. Earth-bound diesel electric trains provide about 60hp or 45kW per rail car with 100 cars. If you figure each rail car has a loaded weight of around 100t, that works out to about .45kW/t. If the Mars-bound train weighs 38% of the Earth-bound train as a function of the gravity difference, then the Mars-bound train has 1.25kW/t. Alternatively, you use a smaller power system that provides 20kW of power per rail car and that still works out to .53kW/t. Overall, your power provisioning system still ends up weighing less than a diesel electric locomotive producing equivalent power. There are some limitations such as only operating during daylight hours, obviously, but between the lighter propulsion system, no stops for refueling, and lighter rail cars, you end up with equivalent performance. I figure this system is good for a rated speed of around 120km/hr and 720km/sol.
A standard boxcar is 16.9m in length and the long ones are 20.6m in length, so the overhead solar concentrator dishes would be staggered on either side of a rail car. Each bogie would have its own electric motors, so individual cars could move under their own power, as required, or in series, if operating as part of a train. This would allow us to run trains of arbitrary lengths with no requirement for specialized locomotives to move them around.
A rock wool fiber has roughly 6 times the tensile strength of a mild steel, so it's entirely possible to build lighter railcars using composite beds and boxes, and maybe even tanks, dependent upon what you're hauling (water, mostly, though industrial chemicals would probably still require stainless steel). So the rail cars would be made from rock wool composite and Aluminum to roughly halve their empty weight, which would have the knock-on effect of further reducing the size and weight of the solar power system to provide equivalent power-to-weight.
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For kbd512 re #199
Here is what we set up as a guess for what you might want to focus on in the Sagan City 2018 virtual community:
0007 kdb512 Proposed: Nuclear power facility
However, the solar powered train system you've invented might be an alternative you'd be willing to consider?
The idea is to set up Plot 0007 as a record in the NewMars database, and build it up over time.
There is nothing that would preclude your setting up another plot for Nuclear power, or anything else you want to develop as documentation for a "real" community able to not only survive on Mars, but to thrive there.
As a suggestion ... sizes of components of a railroad for Mars could be patterned after those of Earth, or they could be adjusted for the new setting.
Shipping containers have been standardized on Earth, and potentially their dimensions might be carried forward into interplanetary commerce.
Were that to happen, it would be a natural fit to design a railroad so that standard shipping containers would plop right into railroad cars.
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tahanson43206,
I'm not for or against any idea because I came up with it or somebody else came up with it or anything like that. The math behind the basic engineering involved with making something work either checks out or it doesn't. If it doesn't, then it doesn't matter how enamored anyone is with the idea, including me. There are no trees or power lines or other terrain obstructions on most candidate overland routes in most places on Mars and very little air resistance that something of the size of a 10m solar concentrator dish would otherwise create at Earth sea level. That's why I proposed this. It's technically feasible because it would meet the power-to-weight requirements for a train on Mars, it uses very robust and thoroughly proven Stirling engine technology, and it would be relatively simple to maintain without computers or other advanced electronics.
I would think that we'd use Earth-standard train component and shipping container dimensions and call it a day, rather than starting over from scratch. There are good reasons to use lighter fabrication materials, but not many good reasons to "reinvent trains" or "reinvent cargo containers", as NASA would no doubt try to do. The shipping industry has already figured out the dimensions and weights of cargo for optimal shipment using existing infrastructure and designs. They already have steel, Aluminum, and fiberglass shipping containers.
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Pressurised cars will have round bodies, like earth aircraft fuselages, because this is efficient structurally. Therefore the railway must be built with this in mind, so as to allow passenger transits without suiting up. Such a car could mate directly with an airlock assembly. With such a railway the cargo transport arrangements would also mimic earth aircraft cargo arrangements, rather than marine/terrestrial containers, I would expect.
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tahanson43206 asked a question related to trains and I responded with something that could feasibly work on Mars.
All of which have been copied to the topic Trains on Mars - Could a rail system provide martian need
Can we continue there...thank you all.
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For SpaceNut re #203
I am delighted to see a subtopic that blooms in "Technology Updates" moved (transplanted) to a prepared environment! Congratulations on your management of the forum!
Here is an report on new technology that I am seeing as a significant missed opportunity!
Bearing in mind that Tyson Foods is owned by investors from many nations, it is probably not surprising that the direction chosen was to move toward pure robotic workers to cut meat, but I see this as a significant missed opportunity to give humans the opportunity to take part in the process by operation of teleperation equipment.
Business
Tyson Foods is ramping up development of robots that can cut meat in response to coronavirus outbreaks in meatpacking plants
insider@insider.com (Bethany Biron)
July 11, 2020 2:12 PM
That snippet showed up in the Yahoo News Feed this morning.
For SpaceNut ... a reasonable place for you to transplant that item is Poverty in America topic.
There are new (and challenging) jobs for robot designers, for both hardware and software, and there will be new (and challenging) jobs for robot installers and maintainers, but as with teller machines replacing human bank tellers, the jobs folks have today will soon be gone.
The challenge for entrepreneurs today and for ever, is to think of ways of using unskilled humans to make a reasonable return on investment.
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Last edited by tahanson43206 (2020-07-12 08:07:32)
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This update is about materials science, and specifically materials used for manufacture of computer chips.
I was surprised to learn that tungsten has been a material of choice for manufacture of logic chips. The article at the link below is short on details, but it reports on work done by Applied Materials to accelerate the flow of signals inside dense chips.
https://www.yahoo.com/news/applied-mate … 00373.html
I'd appreciate someone exploring this subtopic a bit, and reporting a bit more detail.
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For SpaceNut ... do you have a topic specifically about fusion?
Here is an update (no breaking news ... just an update) on work in Europe to build a large fusion reactor test article.
https://www.yahoo.com/news/infinite-car … 00034.html
The level of investment by multiple nations is impressive. The sales pitch by the engineers and scientists who are designing this machine must be persuasive.
This is a brute force approach, if there ever was one.
Hopefully, if this attempt succeeds, it will point the way for less costly system.
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The trick for the magnetic field is keeping the temperature low enough so as to be below the curie temperature where the field goes away....
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