As a military officer, I pray these never make it past Test and Evaluation. They took essentially one part and turned it into 1000 parts. Anyone who has seen what 20 year old Marines do with these machines, let alone what happens in war, will appreciate that this is a fantastically horrible idea in a war zone. I need high reliability, not high zoot. Let NASA have high zoot.
These were my thoughts also. During WW II German tanks were technologically superior to Russian tanks. However Russian tanks were easy to repair in the field and that was one of the reasons why Russian armour prevailed over German armour.
Favourite quote: Hence, the Sherman’s grim nickname—Ronson, like the cigarette lighter, because “it lights up the first time, every time.”
Everything was wrong about it and the Russians that got given these on Lend Lease knew that they had been given a death sentence. Aforementioned article just touches the surface, the barrel was too short, the 'tech' for being able to shoot on the move did not work and you needed five of the things to take out one German tank, four as cannon fodder (complete with the guys inside) and one to sneak around the back to get that German tank whilst it was busy taking out the other four.
The 5 Shermans vs 1 Panzer myth is much disputed however where there is smoke there is fire and I would not want to be in one. Plus, by the time that the Americans rocked up to fight WW2 - which was late to the party - the Germans had run out of oil so their tanks were running on recycled coal dust extract rather than the diesel fuel required.
The shoddy design of the Sherman Tank was no matter though, the 'allies' were expected to pay for these useless behemoths after the war so this was the military-industrial-complex and built-in-obsolescence at its finest.
Meanwhile the Soviets had a much more serious war on their hands so their hardware wasn't about making a quick buck. It had to be fit for purpose. The same thinking happens today hence we have toy planes like the F-35 where everyone and his pet congressman is getting a backhander vs. the fit for purpose planes of Russia, as advertised over the skies of Syria and doing much better in the global arms trade.
This is the sort BS stories that capture the imagination of people who don’t know what they are talking about but are trivially disproven by actual facts and statistics. At US entry to the war the Sherman has equivalent tank and crew losses due to fire as similar tanks from other countries and by the end of the war The Sherman was the _least_ likely tank to suffer an ammunition fire of all the major tanks fielded in the war by a very large margin. The biggest tell for this if you look at the stats is to compare vehicle losses and crew losses (e.g. a penetrated Sherman frequently lost one crew member while a T-34 with a similar hit that causes a loss of the tank frequently only had one survivor.) Oh, and the erroneous derogatory term popularized by Belton Cooper's widely discredited book was "Tommy Cooker" and not Ronson.
The T-34 was fit for purpose for certain, as long as the purpose was to leave a trail of broken-down tanks from factory to battlefield. Prior to 1944 more T-34s were lost to mechanical problems than to enemy action.
Tommy Roaster is the translation from German for their nickname for British tanks. The German tanks were much better than the British tanks according to this primary source[0]. I don't know about Sherman tanks.
Infrequently. The US were early proponents of combined arms tactics. Find heavy armour? Call in artillery or air support -- one of the advantages of owning the airspace over the battlefield.
Oh, and the only Tiger tanks that got close to Moscow are the captured ones on display at Kubinka.
The US Shermans were equipped with cannons that had weaker armor penetration by design so that they could fire more potent high energy rounds that would take out infantry since they were expect to meet very little tank resistance. I think part of the 5:1 myth is from the fact that out of a platoon of 5 Shermans only 1 would be equipped with a gun that could penetrate a Tiger from the front.
Correct. US pre-war tank doctrine was that enemy armor should be taken out with AT guns and dedicated tank destroyers (e.g. M10 & M36) while the Shermans were infantry support and to create and take advantage of breakthroughs to flank the enemy or take out supply and ammo depots. For US units all tanks in the platoon of four tended to be the same, but UK tank corps that had Sherman Fireflys available (a Sherman with a British 17 lb gun stuffed into the turret) would often run one Firefly per platoon since the 17 lb gun could engage and destroy at range any German tank it encountered. This was why the longer barrel on the Firefly tank was often camouflaged to look like a short 75/76mm gun to reduce the chance that it would be identified and targeted.
You mean in an uncontested airspace, with no AA to speak about, disregarding any collateral damage because there is no one to hold them accountable (unlike US forces that are panned by US press)? Right, those plane may be fit for that purpose. Meanwhile, US&allies measure up their planes against each other during Red Flag, where both F-22 and F-35 have stellar performances. FIY, the only time Su-s (of Indian airforce) were there they were outgunned pretty heavily and had a very tough time protecting the engines from foreign object damage. Pretty bleak if you ask me
War is diplomacy by other means, a fundamentally political decision. As long as there are armies, it is politicians who will send men to die, and those politicians are responding to their voting blocs.
Thus senior military leadership is keenly interested in readiness. This requires training, R&D, and intelligence. "Are my officers and troops more physically and mentally prepared than the enemy's?" "What's the best weapon I've got?" and "What's the best weapon they've got?" are critical questions.
See T. R. Fehrenbach's "This Kind of War" for the US's brutal baptism into the darker side of their role as a superpower, a war no American wanted to get involved in. The short-hand in history for this necessity of readinesss is Task Force Smith (2).
Define technically superior? The German tanks had massive reliability problems, not just ease of repair they broke down under non-striker's situations.
OTOH Germany didn't have the resources (raw materials or crews) to field that many tanks, so focusing on fewer but better tanks made sense. Not that it panned out, but it made sense.
As former military, I also concur. There is no time to read a manual or tinker. It must be simple so that anyone in the field can adapt, improvise and overcome. Or at least, quickly limp away from harm. Also, the H1 already breaks enough without adding more crud. I had the H1 wagon and replaced damn near everything on it. I can't even fathom taking that nightmare apart in the mud. CTS and runflats were enough fun.
You could of course just carry a regular spare wheel or two. If your fancy trackwheel fails, unbolt it, and fit the regular spare wheel. You're still mobile, just without the ability to switch to track mode.
I suppose it depends on whether you're more likely to get shot at while changing a broken track wheel, or digging out the vehicle when regular wheels get stuck in the mud/sand.
I think the probability of damage is higher is what they are thinking. I would say that the complexity is far higher in this case, so it is easier to pop 5 bolts and swap a tire then swap.....bolts, then unhook whatever is controlling them.
We're now just guessing how easy or hard it is to swap these wheels. It might be that the replacement mechanism was reinvented as well so it's easier to swap than a standard wheel. But equally you might be right that there are more parts to unhook. Either way it is just guesswork.
It's also pretty annoying if your are stuck in the middle of the desert because you opted not to use wheel 4.0. In the end it's all about statistics. What is more likely to happen? A wheel 4.0 fail, or getting stuck with wheel 1.0 (where 4.0 would have helped)... The first likelyness is constantly decreasing with wheel 4.1, 4.2, 4.9 etc whereas the first one stays constant. At least at some point in time wheel 4.0 should be preferred.
In reliability engineering, the failure rate for a complex system is the sum of the individual failure rates of its components [1].
I will let you do the math.
I somehow doubt that this system would perform so much better than e.g. removing air from a tyre or putting one of those metal boards under it that it would justify the increased complexity (and cost) over normal tires. I mean okay, you don't have to get out anymore, great. For deflating tires that isn't the case either anymore.
- How did you choose this route/destination out of the thousands of possibilities?
- Was there any specific goal beyond spending a bunch of time on a bike and seeing a big chunk of the world?
- Was your time almost entirely spend riding, or did you spend a lot of time in the places where you stopped?
- Camping? Hotels? Staying at friends' houses?
Nothing against 20-year-olds, I was one. I know what I did and what my friends did. I'm no angel. But if was running the engineering team on this, I'd make sure everyone had in their mind "the driver is maximally amped-up, young, and male.
What does them being male have to do with anything?
Are you implying that being male means that they must be reckless? Or that if they were female they would automatically be careful and gentle? Careful throwing around those negative stereotypes.
EDIT:
The driver is likely to be getting shot at. This is going to be an order of magnitude more important than slight gender differences.
"Motor vehicle crash fatalities were higher for males
than females in all age groups, while the male population
is equal to or less than the female population
in all age groups."
Particularly in the 21-30 age group, males had 3x the fatalities of females.
That has little bearing on the cost of fielding/maintaining a vehicle. Fatalities are so rare they won't have an impact maintenance costs unless a sizeable chunk of your fleet is getting driven off a cliff.
In my experience men and women tend to be about equally hard on things. The male outliers tend to create more maintenance work by being hard on chassis/suspension ("hold my beer and watch this"). The female outliers tend to create more maintenance work by keeping quiet about problems (usually having to do with fluids not in their proper places) for far too long.
The most expensive driver is the kind that blindly follows directions/orders into a dumb situation.
Source: Did fleet maintenance in high-school.
edit: The words "in my experience" and "outliers" were used for a reason. I'm not claiming that all men will get a mini-bus airborne if given the opportunity or that all women will ignore an obvious puddle in a parking spot. I am stating what patterns I observed in the noteworthy cases of neglect. There's a million uncontrolled variables, maybe we were just a really scary maintenance department and none of the women wanted to talk to us or something. I'm not claiming that a bunch high school teachers a decade ago is a sample that accurately represents the rest of the population. Maybe the way buses were assigned to teams (pseudorandom) resulted in the observed failure pattern.
I looked for statistics on maintenance cost of equipment for male vs female operators but didn't find any, just the un-documented assertions in https://www.equipmentworld.com/men-vs-women-who-are-the-bett... that basically say women are easier on equipment and specifically
Attention to detail
“I’ve always been impressed by how women take care of
their machines” Smith says. “They keep them clean and
don’t leave trash in the cabs. If there was a drop of
oil coming out of a wheel or something small like that
they let you know about it.”
I'd be happy to look at any statistics you can provide that show "equally hard on things".
I guess it leaves us at, "Statistically, three times as many young adult male drivers have fatal accidents than equivalent young female drivers, despite having a smaller population."
> What does them being male have to do with anything?
Being young and male correlates strongly with high testosterone, the effects of which you can Google for. Being young and male also correlates with higher incidences of road traffic accidents than most other demographics.
But there are millions of young males in the US alone who are more careful than millions of young females.
The effects of testosterone are far from as simple as you suggest. It tends to lead to higher competitiveness. This is not quite the same as recklessness.
Meanwhile during normal usage the driver (of whatever gender) is likely to be getting shot at. This will tend to have a larger affect than their gender.
> there are millions of young males in the US alone who are more careful than millions of young females
Yes, and millions of young men in the US who are shorter than millions of young women. What’s your point? Young men are still disproportionately more likely to be in road traffic accidents.
Re testosterone, the keywords you should be searching for are “risk taking behaviour”.
I’m curious also what percentage of time you think the average military driver is being shot at is.
Looking at a few studies, the data is much more complex. For example, higher levels of circulating testosterone were associated with lower risk aversion among women (r = −0.1793; P = 0.01), but not among men (P = 0.11). However at comparably low concentrations of testosterone the gender difference in risk aversion disappeared, suggesting that testosterone has nonlinear effects on risk aversion regardless of gender.
Or to make a summery of the summery of the study: there is an association of risk aversion when going from low levels of testosterone to very low levels, but "male with high testosterone" is not supported in that study as increased risk taking behavior vs males with normal levels of testosterone.
> Young men are still disproportionately more likely to be in road traffic accidents.
And in the military, given how e.g. the draft has never applied to women. Times are changing, but very, very slowly, and there will always be a gender disparity due to physical differences (e.g. strength, see also: almost every sport)
> Meanwhile during normal usage the driver (of whatever gender) is likely to be getting shot at. This will tend to have a larger affect than their gender.
No -- being shot at is 0-2% of your time deployed. The rest is waiting around.
When I was about 20, I was out driving around and decided to see how fast my Oldsmobile could go, on a long, straight county road. Got up to about 110 and decided to slow down when I popped over a low hill and saw the road making a 90° right turn in front of a tall chain link fence with razor-wire on the top. I made the turn, but I assume emergency medical assistance would have arrived quickly---the fence was Pantex.
It's not. The material used for radioisotope thermoelectric generators needs to have the appropriate half-life (not too long so that it actually produces a useful amount of power per mass, not too short so that it's doesn't exhaust itself) and it needs to not produce destructive types of radiation (which will fry electronics in addition to killing people). The vast majority of nuclear waste doesn't have this property.
The closest thing to what you're looking for appears to be Americium-241, discussed in the above link, which apparently can be extracted from nuclear waste, but it's not a very good choice.
Command and Control (by Eric Schlosser) is a great book if you're interested in the history of US nuclear weapons.
According to the author, most warheads in the US arsenal are (or were) equipped with single-use thermal batteries that are activated during the firing sequence.
Thermal batteries were originally developed by German scientists, but the concept was taken further in the 1950s when the US armed forces were looking for a more reliable and less maintenance intensive power source for their nuclear weapons once fired.
That's pretty much the diametrical opposite of the book's message, at least in my reading of it. Most of the book has been spent, as I remember it, decrying features that look cool for developers but useless for the users, such as overly-complex configuration panels, or interfaces that emphasize "cool" features at the expense of reliable basic function, etc.
Yes, you are absolutely right about the book's message.
That was not what I was talking about. I was talking about HN attitude toward that book and HN attitude in general regarding the position wrt users/developers. Crowd here are happy to cry about user hostility because of the walled gardens, closed source, whatever, but given a choice many will go the path of the least resistance and choose the technologies and approaches that make it easier to have some kind of result without much consideration about UX or accessibility of said result. Fast and cheep to develop is winning agains enjoyable to use.
Sure, it is not 100% true, but the trend is quite obvious, imho.
In case anyone here thinks I was not long enough on HN to criticise it: I've been here for the 9 years now.
Nobody also peed on their wheels either. But they do need to handle quite a bit of dust and there is no one around to grease them. The APCs I had to use wouldn't survive that long without service.
Internet of Things means that we can enable new synergies with Web Scale techniques, like making each tread run its own software package with logging, analytics, self-maintenance, and the normal operational features, each implemented as a reliable, portable Electron app.
What if the failure mode was it just being a regular wheel again? I suppose it's competing against letting the air out of the tyre so it might still be worse
You cant guarantee such a failure mode. That thing has to be full of little gears, actuators and electronics to make it work. Any of those break; and it freeses, stays as is or falls apart.
But what if test and evaluation prove they are more reliable than tires filled with air?
I understand what you are trying to say but maybe the same discussion happened when they started using air tires instead of solid wheels: "What if your drive over a rock and all air floats out!? I pray they never start using air tires!".
>But what if test and evaluation prove they are more reliable than tires filled with air?
That won't happen. Just the fact that there are so many moving parts, controlled by microcontrolelrs, all with multiple independent fail points makes the idea that these are more reliably just absurd.
The only question is, is the trade off of less reliability worth the advantage they provide.
I don't see it, but maybe there are some applications which I'm not aware of were you really really need these abilities.
One major difference, reliability-wise, of modern vehicles is electronic engine management---electronic fuel injection, electronic ignition, etc. These are, in fact, much simpler than their previous mechanical counterparts.
Materials are better, as are engineering, but those are a wash complexity-wise.
The major complexity increase has been antilock braking/traction control/stability control, all of which are (I hope!) designed to fail back to their older mechanical state. Their reliability has improved considerably, but my 2004 Corvette may need another brake controller rebuild and the brake controller on my 1995 BMW motorcycle's primary purpose seems to be to test for low-voltage conditions when I start the bike.
Eh, if we want to look at mechanical complexity increasing reliability, I'd point at exhaust valves. Have you owned a vehicle with valves you had to adjust? man, life was different before hydraulic lifters. Adding a fancy complex part means I don't have to fiddle about adjusting my valves every so often. (except on my motorcycle... Perhaps BMW of the '90s thought adjusting your valves built character or something.) And valve timing has gotten a lot more complex during my lifetime, at least last time I looked, was mechanical/analog. I came of age as VVT-I/VTECH variable valve timing was hitting the mass market, and I'm pretty sure those systems were not electronically actuated. (I can't say I really have looked at this sort of thing in the last decade, so they might be electronically actuated now) I'm sure there's a bunch of other mechanical bits that got both more complex and more reliable.
I do like the example of fuel injectors vs. carburetors. The carburetors were a lot more mechanically complex, and quite difficult for a non-expert to get right. Fuel injectors are easy. a good example of just how much a simple micro-controller can make a system seem a lot more simple.
>Today's cars are so much more complex than old cars. Yet almost all of them are much more reliable than old cars.
That's debatable. Evey person who owns a vintage car, pre electronics area will tell you that. I'm sure there are improvement in new cars which made them more reliable but not because of increased complexity. Maintainability of modern cars is a mess.
And maintainability is exactly the argument here. I do not know everything about these new tires, but like many people advocating here, I would rather just let the air out of my tires to get through the mud and re-inflate them then deal with the complexity that seems to be shown here.
Nothing against 20-year-old Marines. I was 20 once too and recall some choice decisions I made, friends made, others made. It's not their ability I'm worried about. It's their judgement.
To a point, looking at the political landscape today I’d say I trust the 20 year olds over the 65 year olds. Even if you can’t get the 20 year olds to pay attention.
I agree, but not when it comes to self driving vehicles. For those better than normal wheels is enough. There's no way to change a brocken wheel anyway.
I’ve never heard this. What is the connection between the Willys Jeep and the Land Cruiser? Superficially they look similar but do they have any actual mechanical or design connections?
In WW2 the Japanese sent a captured American Jeep to Toyota for them to copy. This was the Toyota J. The J was redesigned into the 40. The 40 was redesigned into the 70.
Other than the overall 4WD front engine body-on-frame design, I do not believe that there are any carryover components nor unique design features of the Willeys in the 70.
I am not easily wowed but I got to say it.WOW.
The transition from track to round again had a couple of bumps. Its amazing what we can do these days.
I wonder if it's a pneumatic, hydraulic or an electrically actuated assembly. Looks like a hydraulic braking system.
Isn't the advantage of using tracks supposed to be the increased surface area for traction and weight bearing? This seems to only slightly increase the surface area. It doesn't seem that this would have enough traction advantage to make the complexity worth it.
I feel like, having been really introduced in the WW1 tank, that tracks were mostly about keeping motive force over a much longer distance, which is almost but not quite surface area/traction.
Seems like they could get most of the benefit at much less cost and complexity by going with side-by-side "dualies"
If one of the tires goes flat, then there's built-in redundancy from the other ones and it could be replaced in the field if needed, but no one's going to be able to overhaul this track mechanism without a shop.
It does help with traction, though. That's an improvement over tires.
However I wonder why they accept the complexity/reliability problems I assume come with this solution instead of going with added (engageable on demand) tracks.
Since it's DARPA it's pretty far from being fielded, so I should think they're only worried about proof of concept at this point. But if you could modularize and ruggedize the wheels and make them easily replaceable and compatible with existing vehicles, then I could certainly imagine this being quite practical in certain situations.
One car weighs ~3500 lbs. If I keep 35psi of air pressure in the tires, that works out to ~100in^2 of contact patch. With four wheels, that's 25in^2 per wheel or 5in square.
This looks like the tread-extended contact patch is more like 12in long times the original width, or 60in^2. That halves the weight per square inch.
And how often do humvees get stuck anyway? I like the product, but it’s obviously wasteful. During the Iraq insurgency what was wanted was armor plating. Literally just 1/4” slabs of steel.
The US donated (I’m sure with wink wink strings attached) to us, Slovenia, some years ago and it was quickly found that they are too large and cumbersome for our foresty mountanous terrain. They’d get stuck all the time on tiny roads or between trees.
I think these days they’re used for paraded to show we have them but day to day the military keeps using their trusti Puchs from who knows when. Tiny and manouverable.
Given how much money the US spends on its military I'd expect them to be prepared to fight just about anywhere.
Certainly in "foresty mountanous terrain" since that isn't particularly rare. Exists inside of the US. Exists on both borders of the US. Etc.
Producing a military optimized for "blowing up unsophisticated enemies in desserts" seems like a very shorted sighted way to spend the military budget.
(None of the above should be taken as me defending spending so much on the military as a whole, just on the allocation of the budget within the military to all sorts of terrain when taking the size of the current budget as a given).
The US military has divisions that specialize in "foresty mountainous terrain". There are parts of the world (and US) that are effectively inaccessible to any mechanized units and the US military has large combat units that are setup to operate effectively in those environments. Terrain that is prohibitive to mechanized units is traditionally the domain of "light infantry" divisions (e.g. 10th Mountain Division), distinct from mechanized infantry divisions.
The US military has dedicated units and training facilities for virtually every environment on Earth.
Except maybe the western European nations like Germany. But it may be that Germany has had USAEUR there long enough so that they have cut wider roads in their forests for military vehicles. I was stationed there when they were introduced to the theater in the 80's and they didn't have any significant problems.
> US is not fighting in areas where getting stuck between trees is a big issue.
They need equipment for future wars, which are very difficult to predict. Also, the military's main purpose is to deter enemies by having capability. Enemies would be thrilled if the US military couldn't operate in wooded areas.
We can sell you some lightly used units from our last imperial war. They have excellent maintenance records. And comes with a 5 year, or 50,000 mile warranty, whichever comes first.
I saw one get stuck so bad in the sand it took three tanks to pull it out over in Saudi. Was sitting with the frame on the ground so no way to dig it out (trust me, they had us try).
> Was sitting with the frame on the ground so no way to dig it out (trust me, they had us try).
A vehicle beached at the frame on sand is a very common occurrence in the desert, and it's fairly trivial to get out if you have a shovel, brains, and are physically well. It's just some work, but sand is incredibly easy to excavate by hand, even from underneath a vehicle.
Maybe the track version is meant to be used only rarely, when the vehicle is truly stuck. So you’re either wasting time digging yourself out with a shovel and saving on maintenance, or you switch to tracks to get out of the ditch and then perform maintenance right after you get back to the base. So long as maintenance is not deferred it seems preferable to do the latter.
I would think this will need way more maintenance than a regular wheel/tyre combination even if only used in the ‘round’ configuration.
I also worry about what a hand grenade or small IED will do to this contraption, compared to what it will do to a conventional tyre. Even if it is as strong, it likely still will increase mean time between repairs, as, when one breaks down, it’s more likely that one will have a regular tyre at hand than that one has one of these.
This. Humvees are probably just what's readily available as a test platform.
If such a wheel/track is ever used for real, it might be on something very different, and not on the front lines. And possibly larger or smaller than this.
I'm hardly an expert, but I believe caterpillar treads have been in regular use for over a century and still take loads of maintenance compared to wheels. However effective it may ultimately be, it seems unlikely that this team will solve that particular problem.
The vehicle in the video was already wobbling around madly at low speed, as it is it’d be completely uncontrollable at highway speed and at whatever frequency the wheel and suspension resonate.
We add grams to balance wheels to prevent damage to suspensions etc, this thing seems just a dream for vehicle applications.
Note that the whole assembly rotates when in wheel mode. Making it radially symmetric (i.e. a triangle) in track mode means that it can switch modes with at most a 120 degree rotation rather than having to rotate through up to 360 degrees to get the flat bottom into position.
I didn't say anything about the design of it, which is by the way, very cool. I don't understand the point of the triangle. The same mechanism could be used to change the geometry of the wheel only at the bottom.
Changing it only at the bottom adds complexity: Which side is at the bottom right now? How can we know this; how can we know this in a way that will survive the tough conditions we expect this to be driven in? And then we need to have three separate actuator paths to transform just one part of the wheel.
We would also need to deal with the fact that just flattening one side of the wheel would make for a shorter perimeter than that of the circle; the tread is a loop of a constant length, and it needs to be kept fairly taut to function in both wheel and tread mode.
Considering that this is a rather a rounded triangle, I doubt it has anything to do with tightness, and more with convenience, esthetic. A symmetrical displacement is also slightly less constraining in term of keeping the overall circumference/periphery (i.e. less deformation).
A better design would have been to flatten the wheel into an more oblong or even an egg shape, like snowmobiles or tanks have. However, it requires more mechanical displacement and adjustements.
"Better" is meaningless in isolation. The design you propose is better in some aspects, but likely not in the areas the designers of this wheel are optimizing for (simplicity, reliability, etc)
I suspect it may apply torque from the drivetrain to the mechanism with the most optimal geometric leverage against both the mechanisms internal frame and the contact patch on the ground during transition into and out of tread mode.
I'm guessing the triangular track mode is the default mode. If the track gets damaged the whole thing can be switched to the wheel mode and continue working that way.
Makes me wonder why nobody checked their work, parachute failures get investigated pretty thoroughly so it's not like you're going to get away with burning in a few hummers.
Though "Never attribute to malice that which is adequately explained by stupidity." Back in '90 or so I was on the ground crew for a jump they were doing to impress some Soviet generals and they jumped with too high winds which resulted in two arty canons and a sheridan tank burning in (they got to oscillating so bad the chutes collapsed) and three planes worth of troops ending up in the trees. Bad day to jump but made for an interesting day on the ground.
I think the wind died down temporarily just in time for the go/no go call...was on a jump where that happened and it was nowhere near a fun landing.
Thinking further on the heavy drop thing, from what I remember the crew who's vehicle it was were the ones doing most of the rigging with the riggers mostly just checking their work. Too many eyes for it to be an accident methinks.
"Johnny Lodern:
One issue is they where dropped from seperate aircraft, each crew is supposed to inspect cargo before drop, so there is more than 1 person at fault if it was not equipment failure."
Glorious news for all privates who’ve ever had to haul a Humvee out of a mud-filled ditch
I’ve seen plenty of tanks get stuck but honest to god I don’t ever recall a HMMWV getting stuck. I used to try to get my HMMWV stuck. That thing is geared so low it just walked out of soup up to the hood. Tracks are advantageous when more surface area is needed to spread the weight out, like soft wet ground (mud) or very fine loose (think sand dunes). It will be nice to have the added mobility for certain missions but I don’t see this becoming organic to most units. The vast majority of missions just don’t need these wheels and they look like they’ll break.
They could support tracks on existing vehicles by making new hubs/shafts. You remove the hub, add a shaft extension, replace the hub, then get spare rims and tracks out of the boot and do an Indy 500-style fast wheel change. If you hustled my bet is you could do this in 2 minutes with four people. Would add significant unsprung weight but would support existing vehicles.
If you modify the vehicle you can support this without changing the hub and shaft/extension, just change the wheels and add tracks. But I'm assuming they wanted to work with a mostly stock vehicle.
Interesting concept, but it looks like it wobbles around quite a lot in "wheel-mode"; and this is at the very low speeds shown in the video. I think it's reasonable to assume that it would be almost uncontrollable at higher speeds (leading to damage to itself and other components over time). As others have already mentioned, maintenance would be much more complex too with so many moving parts, all of which could potentially be damaged; and it certainly would be more expensive than a simple wheel.
As a previous soldier (commander of a hummer unit), there are serious challenges that the terrain offers. Bits of sand and rock get into EVERYTHING when you're driving over them. All those small complex moving parts could easily become a nightmare if they got stuck full of grit. Hopefully their engineering takes this into account.
This is some good work, shows that taking a new approach to things can sometimes be delightfully tantalizing. But remember, the guys at DARPA want to go home and have a beer as well :-)
As with any tracked vehicle: Larger, flat surface area touching the ground results in better grip on soft ground and is less prone to sinking in. Small track-sections like here obviously aren't as good at that as full, tank-style treads, but easier to add to a wheeled vehicle and allow normal steering.
There's all kinds of companies making conversion kits to such (non-shape-shifting) small tracks for trucks and SUVs, not sure if there's a military example of that exact style.
The benefit of filming in the parking lot of the engineering building is that you don't have to drag your prototype and a film crew out to the nearest swamp.
There’s something deeply poetic to this that DARPA didn’t understand the wisdom in what the “reinvent the wheel” phrase means. This seems to embody every bit of its meaning. Replace rubber tires which are brain dead simple and work very well with zero maintenance with this complicated monstrosity that I have many doubts about even being an improvement.
It's literally DARPA's job to fund pie in the sky projects, in the hope that maybe some of them might be practical.
The internet was born of a DARPA project, Siri was made with technology spun off from another. Project MAC was filled with groundbreaking research and development of AI and operating systems. All modern operating systems can trace their lineage back to Project MAC. The origins of GPS are also from an earlier DARPA project.
Most DARPA projects will never be used in an operational environment, but the technology discovered and lessons learned inevitably find their way into other projects and technologies.
