Land propulsion - Tracks, or tires?

Oldfart1939 · 2017-11-16 20:19:52

kbd512-

Thanks for the upgraded info. My experience was in ancient historical times with the then brand new M113s which had an awful tendency to throw tracks. I received training on driving one of the ambulance versions and was continually reminded to never drive in a contour profile on any sort of steep slope or "the tracks are history."

kbd512 · 2017-11-19 19:45:02

Oldfart1939,

The new T150F track links from United Defense have a tested design life of about 19,000km on a 30,000lb M577 variant of the M113, but 10,000km to 15,000km is more realistic life span over the varied terrain such a vehicle may encounter. Each T150F track link weighs 24.3lbs, so 3,086.1lbs for both tracks, 63 (left side) and 64 (right side). These new tracks were also designed to reduce shedding.

The rubber band tracks I proposed using give tracked vehicles ride quality, noise, and vibration similar to heavy wheeled vehicles like semis, assuming a similar suspension system. The minimum design life for rubber band tracks is 8,000km at a 30,000lb GVW. Rubber doesn't last quite as long as forged steel, but the band tracks also incorporate additional design features intended to inhibit track shedding over the T150F. The weight is approximately 50% of the steel track, so basically divide the T150F weight by 2. Segmented band tracks make track replacement easier. The track band is divided into 4 segments per track.

M113A3's equipped with steel or band tracks can attain the same road speed as the Stryker, assuming the governor is removed, but sharp turns at highway speeds would shed tracks. The M113A3 has a road range of 480km with 95 gallons of diesel using the ancient Detroit Diesel 6V53T. The Stryker, a substantially heavier vehicle, achieves an impressive 530km using just 53 gallons of diesel. That said, a substantially heavier hybrid M113 equipped with band tracks achieved a 965km road range. A hybrid Stryker could easily double its road range. The catch is that that is road range. The fuel economy of the Stryker starts to look a lot like the fuel economy of the M113 in an off road environment.

Anyway, the point is that technology for all types of military vehicles has improved greatly since you were in the Army. That's why we have TARDEC. Incidentally, TARDEC and ARPA are responsible for the far more fuel efficient OPOC systems going into the new trucks that Oshkosh is making for the US Army. Eventually, batteries and electric motors will replace the diesel prime mover. These people should be working with Tesla to electrify their trucks to dramatically reduce dependency on fossil fuels, an ever-present danger and logistical nightmare in a war zone, both because the product itself is flammable and because running out typically means a halt to operations in the best case scenario and death if the enemy decides that's a good time to attack.

Terraformer · 2017-11-20 07:27:53

I wonder if a radioisotope generator would work for a long distance truck, whether on Mars or Terra? What power to weight ratio would be needed? I think Strontium-90 could achieve ~0.1 kW/kg. Coupled with batteries, unless you want to continually move to use up the power.

RobertDyck · 2017-11-20 14:13:32

Terraformer wrote:

I wonder if a radioisotope generator would work for a long distance truck, whether on Mars or Terra? What power to weight ratio would be needed? I think Strontium-90 could achieve ~0.1 kW/kg. Coupled with batteries, unless you want to continually move to use up the power.

That's a good idea. As you implied, couple that with modern hybrid technology. Regenerative brakes recover energy from vehicle motion to produce electricity that recharges the batteries. That power is used to accelerate again. That means stopping and starting takes a fraction of the power, reducing power required. Modern hybrids operate the engine at maximum efficiency, even if the vehicle doesn't need that much power right now. The engine runs a generator, that power is stored in batteries. The electricity is used when needed. You can replace the gasoline engine with any generator, do the same thing. Actually, railroad locomotives have done this with diesel for over a century. They stated developing diesel hybrids in the early 1890s, finally got it to work in the late 19-teens, went into production in 1920. All diesel locomotives are hybrids. Some big ocean ships now use azimuthing pods; they do the same thing but with really big engines and electric motors. In the late 1980s, those operating subway systems talked about regenerative breaks, but they wanted to put the power back in the power rails, to power other trains. They didn't think of on-board batteries. That's a relatively new refinement.

I would suggest Potassium-40. That's a radioactive isotope that's so low level it isn't regulated. You can buy it without any special license. It decays by beta decay, so a beta-voltaic cell could capture the radiation. The interesting thing about this isotope is it's sensitive to a modulated magnetic field. Properly modulated, the magnetic field causes the atoms to decay much faster. This is something science said shouldn't happen, but it does. Traditional science believes nothing changes the rate of decay of any isotope, but this one can be affected. That means you can cause rapid release of energy when you need it, turn it off when you don't. And beta radiation is so weak it can be blocked by a single sheet of paper, or a single layer of plastic film. A beta-voltaic cell works on the same principle as photovoltaic, but obviously uses beta radiation instead. Potassium-40 will be consumed as you produce energy, it will have a limited range, but the range should be much greater than chemical fuel.

RobertDyck · 2017-11-20 18:46:37

Hmm. Technical details of the K40 reactor are sketchy. Few people are working on it. One wants to enhance electron capture by bombarding it with electrons. One periodic table claims K40 has half-life of 1.277 x 10^9 years, another says 1.248 x 10^9 years. It naturally decays 89.28% via electron capture (EC), 10.72% via beta emission (β+). The EC mode can be further divided, over 99% really is electron capture, less than 1% is via positron emission (β-). There is some question about how EC happens, some people think this is actually positron (β-) emission, but it gets annihilated by impact with an electron (β+) in an electron shell.

If increased K40 decay is in the form of EC or β-, then a beta-voltaic cell could not capture the energy. This becomes nothing but a radioisotope heater, so the heat would have to be utilized like any other RTG.

Forum discussion
PeriodicTable.com
WebElements.com

kbd512 · 2017-11-21 10:22:53

People obsess over the heat energy that a radioisotope can produce and fail to consider the magnetic energy that the material generates, which is orders of magnitude greater. Thermal conversion processes are inherently inefficient and even though recent developments are promising, they'll still fall far short of making an alpha or beta power cell a practical device for a vehicle.

Beta Radiation in a Magnetic Field

This is a very simple and well-known effect. The principles for using it may not be widely known, but they're well understood by electrical engineers and aren't unique to radioactive materials. The radioactive materials simply provide a current source using ionizing radiation.

JoshNH4H · 2017-11-21 16:44:30

The problem with beta voltaics is that in a solid material the electrons tend to bounce around and have most of their energy converted into heat anyway.

One thing I've always wondered about is the potential for preventing K-capture decays by stripping these isotopes of their electrons entirely and storing them in a vacuum chamber. Wikipedia mentions that things of this sort may happen in nature (although it doesn't cite that claim so it's not very credible), but it does cite that Be-7 (decays by K-capture with a half life of 53 days) may have its half life affected with the presence of an insulating/conductive matrix.

I was originally thinking about this in the context of rocket propulsion. Basically you'd have an electrostatic or magnetic cage full of stripped ions which you would introduce (micrograms at a time) into your combustion chamber. When they mix with the normal matter in the combustion chamber (let's say water) they would steal a few electrons and decay rapidly, releasing huge amounts of heat (relative to chemical fuels) in the process.

There are three major problems with this idea that make it probably impossible, even in theory: Isotope selection, isotope production, and isotope storage.

For this to work, you need a combination of properties that are sort of contradictory. You need an isotope whose decay energy is low (because any isotope with a decay energy above 1.022 MeV will also decay via positron emission) but decays quickly (ideally on the order of milliseconds). The best you can do with K-capture is half-lives on the order of a few seconds, although I don't remember offhand which ones were best. I want to say isotopes of Chlorine and Argon were my top two, and they had half-lives of a few seconds (which would be a pretty long residence time for propellant in a fuel chamber).

Once you've selected an isotope, production is a big issue too. Isotopes that decay via K-capture are universally lighter than stable isotopes of the same element. We don't have a good way of reliably producing this kind of isotope, especially in an electron-free environment. You might try bombarding isotopes with high-speed protons, but that's not a selective process and probably 99.9% of the protons (or more!) will end up wasted. That's not necessarily a problem if you're looking at a rocket launch but it's certainly not desirable.

There's also the problem of storage: As it turns out, it's really hard to strip heavy ions of all their electrons. The energy involved is comparable to and maybe larger than the actual decay energy. With such high energy potentials it can be really, really hard to keep electrons from jumping over virtually any potential barrier (especially with quantum tunneling). Again, I haven't done the calculations but the magnitudes involved are way beyond even the physical limits of what we can do right now.

Some of these aren't as bad if you're storing energy for transportation (half-life is less important, for example, and something on the order of hours would be totally fine), but others are much worse (if you're losing 99.9%+ of your input energy, you might consider just using a battery).

Lastly,

RobertDyck wrote:

The interesting thing about this isotope [K-40] is it's sensitive to a modulated magnetic field. Properly modulated, the magnetic field causes the atoms to decay much faster. This is something science said shouldn't happen, but it does. Traditional science believes nothing changes the rate of decay of any isotope, but this one can be affected. That means you can cause rapid release of energy when you need it, turn it off when you don't. And beta radiation is so weak it can be blocked by a single sheet of paper, or a single layer of plastic film. A beta-voltaic cell works on the same principle as photovoltaic, but obviously uses beta radiation instead. Potassium-40 will be consumed as you produce energy, it will have a limited range, but the range should be much greater than chemical fuel.

Seeing as this does in fact defy just about everything we know about radioactive decay, I am extremely skeptical of this claim unless you can provide some rock solid evidence that this is actually true. There were similar claims that X-ray bombardment could cause the expedited decay of metastable radioactive isotopes, but further experiments showed that this is in fact not true.

Terraformer · 2017-11-21 17:14:20

Roberts mention of K-40 reminded me of my suggestion to bombard Ca-40 with neutrons to produce Ca-41, which would then decay and release energy. But I don't think the cross section would be good enough, even if you could produce neutrons cheaply (a D-D fusor set up specifically for that purpose?). Of course, if you had a cheap way of producing a fuel with a suitable half life and energy production rate, you could use it for power generation until you're ready to launch, and then switch to a thermal rocket for launch, then plug it back in on orbit to add to a massive power station...

JoshNH4H · 2017-11-21 21:37:27

Producing neutrons with a low energy input is a tough one that I've been kicking around for a long time. The neutron production problem is what killed NILFiR in the end, I just couldn't come up with a way to get neutrons for less than the 16 MeV energy of reaction

elderflower · 2017-11-22 04:08:12

D/T fusion produces neutrons, helium and a huge amount of energy.

JoshNH4H · 2017-11-22 07:31:38

In theory it produces a large amount of energy, but in practice every device so far has actually produced a negative amount of energy at fantastic cost

elderflower · 2017-11-22 08:52:28

Hydrogen weapons use this reaction. They produce huge amounts of energy. the problems arise from the need to contain and sustain the reaction. In twenty years time.....

JoshNH4H · 2017-11-22 10:16:08

I've got some pretty strong opinions on fusion power that maybe aren't appropriate for this thread. I'm either going to start a new thread or dig up an old one and explain them there.

JoshNH4H · 2017-11-22 14:47:45

Fusion post here

SpaceNut · 2020-05-11 19:32:54

https://www.marsdaily.com/reports/The_l … s_999.html

SpaceNut · 2020-08-08 07:39:47

bump

SpaceNut · 2020-12-11 18:50:22

This definitely is a repair issue for mars whether we are using either for a mars vehicle.
Next would be the manufacturing of replacement parts from insitu materials rather than waiting for a mars flight cycle which might not be in time to get your request for parts to be shipped to mars in time....

Mars_B4_Moon · 2022-03-21 09:27:42

Tracks would make it easier to hook up to some power grid maybe a mix of Solar and others or have the Train lines powered by Energy from some Nuclear Reactor. Biodiesel is a good idea for an engine that is going to be mobile but Battery power is getting better each year.

Algae fuel, algal biofuel, or algal oil is an alternative to fossil fuels that uses algae as its source of energy rich oils. Corns are also known biofuel sources, such as corn and sugarcane. Department of Energy estimates that algae fuel replacing all petroleum fuel in the United States, it would require 15,000 square miles (39,000 km2), which is only 0.42% of the U.S. map, or about half of the land area of Maine. When made from seaweed (macroalgae) it can be known as seaweed fuel or seaweed oil. Corn for Fuel, biochemical engineers are currently trying to find a way that we can also use the nonedible parts, such as the husks.

Hard lessons from bio-fuel
https://www.greentechmedia.com/articles … uel-bubble

Could we make cars out of petroleum residue?

https://techxplore.com/news/2022-03-car … sidue.html

Other Algae topics Life support systems, Algae
http://newmars.com/forums/viewtopic.php?id=9947
Algae based solid propellant?
http://newmars.com/forums/viewtopic.php?id=10001
Utilization and Issues of Algae for Martian Colonization
http://newmars.com/forums/viewtopic.php?id=8799

Last edited by Mars_B4_Moon (2022-03-21 09:34:49)

Mars_B4_Moon · 2022-06-26 08:50:21

Canada's railway giants are going battery and hydrogen.

Steam engines were once a symbol of progress. Now, CP and CN look to electric for the future
https://www.cbc.ca/news/science/freight … -1.6440766

Rail Construction Machines
https://www.youtube.com/watch?v=wK9eNvj4zJ0

previous discussion
Trains on Mars - Could a rail system provide martian need
https://newmars.com/forums/viewtopic.php?id=3501

Tunnel Transportation on Earth, Mars or Luna
https://newmars.com/forums/viewtopic.php?id=9843

Calliban · 2022-06-26 10:33:50

One problem with trains on Mars is that the huge temperature swings would result in thermal expansion that would tend to warp the rails. We could deal with that by having expansion joints, but it would make the journey a bit noisy. Another problem is that carbon steels get progressively more brittle as temperatures decline beneath -20°C. That means more ductile alloys will be needed to avoid brittle fracture problems.

Mars_B4_Moon · 2022-08-15 04:18:03

China’s "Sky Train" levitates power-free on permanent magnet tracks
https://newatlas.com/urban-transport/ch … t-magnets/

Switzerland’s Brilliant Plan For Underground Cargo Delivery Tunnels to Reduce Traffic is Now Underway
https://www.goodnewsnetwork.org/switzer … t-started/

argo Sous Terrain (CST), or ‘Underground Cargo,’ will begin with a 46-mile (70 kilometer) stretch between Zurich and a major logistics hub in Härkingen/Niederbipp. It could grow to as many as 310 miles of tunnels (500 km) connecting all the Swiss cantons.

https://www.youtube.com/watch?v=htTo-_5X8gA

Elon Musk Says Boring Company Will Build Underground Hyperloop
https://futurism.com/the-byte/elon-musk … -hyperloop

Natural Tubes and Tunnels?

Lava tubes on Mars could provide shelter for streets and towns
https://www.digitaltrends.com/space/mars-lava-tubes/

Entire cities could fit inside the moon's monstrous lava tubes
https://www.livescience.com/lava-tubes- … table.html

PDF
old basaltic Mars lava flows associated with shield volcanism
https://web.archive.org/web/20131002050 … aFINAL.pdf

Subway Cave: Old Lava Tube in Lassen National Forrest
https://californiathroughmylens.com/sub … l-forrest/

Mars_B4_Moon · 2022-08-24 17:42:12

Fleet of hydrogen passenger trains begins service in Germany

https://abcnews.go.com/International/wi … y-88791423

Mars_B4_Moon · 2022-08-25 15:11:21

Some news on the Lunar Cars

A quick guide to the new lunar landers and rovers
https://www.fastcompany.com/90770975/a- … and-rovers

More on China’s New ‘Sky Train’

China’s New ‘Sky Train’ Doesn’t Need Power to Levitate on a Magnetic Track
https://www.yahoo.com/video/china-sky-t … 00936.html

kbd512 · 2022-08-26 00:42:38

Mars_B4_Moon,

If it's feasible to mass-produce Iron-Nitride (Fe16N2) permanent magnets, then at least the possibility exists to develop long distance permanent magnet railway systems to drastically reduce railcar weight and eliminate rolling resistance leaving only air resistance as something that the train must overcome. This would be desirable to reduce power requirements to something comparatively trivial for primarily low-speed cargo transport. Cargo trains presently use 10,000hp or more to move around, but this could make rail-based cargo transport one of the cheapest possible ways to deliver sheer tonnage of materials. Standard types of cars could be fabricated similarly to an aircraft fuselage, and become much lighter than the steel behemoths rolling around these days. The cargo could potentially become the majority of the transported weight, unlike current train designs, aircraft, or ships. Permanent magnets do not require cryogenics or other maintenance-intensive / power-hungry technology. Even if they're not as strong as cryogenically-cooled electromagnets, the maintainability of the solution is also much better. The non-contact nature of the vehicle levitation also eliminates steel-on-steel wear and tear.

Calliban · 2022-08-26 02:45:35

That is an interesting idea. Track wear is an issue but appears to be highly variable. The figures of 400 million to 2 billion gross tons are given on this rail enthusiast forum for the average life of a freight rail. The higher end is achievable with modern metallurgy. Some lightly used railways are still good after a century. But the wear and tear will be a function of both speed and curvature, so these figures are only crude estimates.
https://cs.trains.com/trn/f/111/t/247004.aspx

To determine the value of maglev in this application, we would need to weigh a lot of factors. The capital costs of the respective tracts. Maintenance and replacement costs. Energy costs, reliability. Labour costs of faster vs slower trains.

On an energy basis, rail freight in the US is already 12x less energy intensive per ton-mile than heavy truck. About 200KJ per tonne-km. That is about 200 tonne-km per litre of diesel. To put it another way, over a distance of 250km, a single kg of diesel will move 1000x it's own weight. As fuel economy goes, the only thing that beats that presently, is inland water transport. But rail combines energy efficiency with speed, in a way that water based transpirtation cannot.
https://en.m.wikipedia.org/wiki/Energy_ … _transport

If politicians and businessmen in the US and Europe are serious about decarbonising transport, they don't need revolutionary BEV trucks or maglev, although this may add extra value. Just extend conventional railways so that every settlement of any size has a rail freight hub. This means having a coirdinated national strategy for freight transportation, which isn't straight forward. But the technologies you need are all long established, with existing manufacturing lines that are almost entirely domestic. This is a case of scaling up something that you already do, rather than inventing something new.

Railways can be electrified, though rail freight is so energy efficient anyway, that you might wonder if there is any point. And electrification may complicate loading and unloading. Freight needs overhead AC electrification. Third rail delivers a maximum of about 3MW (5000HP) to a train at 750V. It might work for some local freight lines, but it won't deliver the 10,000HP you need unless voltage is increased, which starts to get dangerous and leaky. But railways and buses, together, only account for 2.6% of transport energy use in the US. We can fuel trains with diesel, heavy oil, gasoline, LPG, CNG, or synthetic fuels. For more volatile fuels, a gas turbine-electric hybrid system may be more efficient than diesel engines. But compression ignition engines coukd be adapted to any of these. Energy consumption is low enough that we don't really have the fuel sustainability problems with rail that we have with road transport. The entire US rail network could be fuelled with biofuels if neccesary, without placing unsustainable burdens on farmland.
https://www.eia.gov/energyexplained/use … -depth.php

Battery electric trucks could have niche applications in a world where rail dominates inland freight transportation. The railways can bring products to your town, but not to your front door. There is value in developing a low emmission end use distribution vehicle system, that can take freight from rail hubs to regional customers. That might be a distance ranging from 5-30 miles. Small to medium capacity BEV trucks (and other stored energy vehicles) would be suited to this application. They would be cleaner and quieter, which is valuable in an urban setting and the shorter distances work within their range limitations. Discussions around BEVs tend to get stupid when idealistic people start assuming they are going to replace trains and long-range heavy trucks. These people will bend facts to fit theories, rather than the other way round. A cool look at transportation economics, suggests that liquid fuels are becoming more expensive and will remain so. The solution is to extend tried and proven fuel efficient technologies that already have demonstrated excellent fuel efficiency and competitive cost overall.

In North America, railways cannot completely displace diesel powered trucks, because parts of Western USA and Mexico, have mountainous topography. Whilst you could in theory dig tunnels and gourges, this would be a long and expensive programme. But a sensible transport strategy would look at reducing the need for diesel powered trucks by extending railways to greatest extent that is practical. Ultimately, the better fuel efficiency becomes, the easier it will be substituting synthetic fuels into the transportation system. In most of Europe, the barriers to extending rail freight have more to do with the high saturation of passenger rail and competition over already busy track.

On Mars, we have the advantage of zero air resistance and only 2/5 the gravity. Railways should be at least twice as energy efficient on Mars. We could feasibly power freight rail using DC third rail on Mars, using local solar arrays to provide direct current at 750V. But hilly topography will be just as problematic for rail as it is on Earth.

Last edited by Calliban (2022-08-26 03:55:20)

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#101 2017-11-16 20:19:52

Re: Land propulsion - Tracks, or tires?

#102 2017-11-19 19:45:02

Re: Land propulsion - Tracks, or tires?

#103 2017-11-20 07:27:53

Re: Land propulsion - Tracks, or tires?

#104 2017-11-20 14:13:32

Re: Land propulsion - Tracks, or tires?

#105 2017-11-20 18:46:37

Re: Land propulsion - Tracks, or tires?

#106 2017-11-21 10:22:53

Re: Land propulsion - Tracks, or tires?

#107 2017-11-21 16:44:30

Re: Land propulsion - Tracks, or tires?

#108 2017-11-21 17:14:20

Re: Land propulsion - Tracks, or tires?

#109 2017-11-21 21:37:27

Re: Land propulsion - Tracks, or tires?

#110 2017-11-22 04:08:12

Re: Land propulsion - Tracks, or tires?

#111 2017-11-22 07:31:38

Re: Land propulsion - Tracks, or tires?

#112 2017-11-22 08:52:28

Re: Land propulsion - Tracks, or tires?

#113 2017-11-22 10:16:08

Re: Land propulsion - Tracks, or tires?

#114 2017-11-22 14:47:45

Re: Land propulsion - Tracks, or tires?

#115 2020-05-11 19:32:54

Re: Land propulsion - Tracks, or tires?

#116 2020-08-08 07:39:47

Re: Land propulsion - Tracks, or tires?

#117 2020-12-11 18:50:22

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#118 2022-03-21 09:27:42

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#119 2022-06-26 08:50:21

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#120 2022-06-26 10:33:50

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#121 2022-08-15 04:18:03

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#122 2022-08-24 17:42:12

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#123 2022-08-25 15:11:21

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#124 2022-08-26 00:42:38

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