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Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

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Re: Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

#71

Post by JKCalhoun »

readthenotes1 wrote: post #54
JKCalhoun wrote: post #32

Earlier quoted context omitted.

What would that be? Not doubting you, just can't think of collateral damage.

The interstate system comes to mind, with neighborhoods torn apart. "Wrong side of the tracks" used to be a phrase with meaning for a reason.

I assumed the interstate system would benefit from no longer being in a constant state of needing repair.

And I'm not sure if you're suggesting more train tracks would be laid in cities to divide communities? I assumed the discussion was about better utilizing the infrastructure we already have for rail.

Re: Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

#72

Post by bjterry »

kelnos wrote: post #26
bjterry wrote: post #20

The cargo a plane can carry isn't limited only by the volume of the interior, but also by the amount of weight that can be carried safely in the plane. Airlines try to balance the amount of dense and non-dense (a.k.a. volumetric) cargo to solve for the joint constraint by charging different prices for cargo depending on the greater of its weight cost vs. its volume cost. Even if it turned out to be practical to doubl…

The article is about having a completely separate plane (glider, really) that is towed by a conventional plane. The glider gets to ride in the powered plane's wake, and presumably the fuel cost to tow the cargo plane is less than the cost of flying two independent planes. This isn't about making a larger conventional plane that has more volume to put cargo in.

Right, but if a plane has a maximum takeoff weight of 600k lb, I doubt if it can safely takeoff while being 600k lb AND towing another x00k lb in a glider, which is what would be required to reduce cargo costs by 65%.

Re: Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

#73

Post by ethagknight »

mc32 wrote: post #11
ethagknight wrote: post #7

Earlier quoted context omitted.

Rail is phenomenally inefficient crossing oceans compared to air freight

Hmm, if we ever built the Alaska-Siberia overland railway connection (bridges + tunnels) it would become a possibility to make efficient from what is now an impossibility. It’s doable. Tunnels and bridges necessary would not be beyond what we have built elsewhere with current technology. The weather may be challenging in Winter though.

That’s several thousand miles of additional journey on your way to Shenzen or wherever? Massive amounts of track, tunnel and bridge that has to be maintained in extreme conditions and across multiple nations at odds with each other?

Or just put it on a boat?

Re: Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

#74

Post by newsclues »

r00fus wrote: post #10
newsclues wrote: post #6

Earlier quoted context omitted.

Most of the time but some remote locations it is not nor does it require rail volume. Rail is less efficient than water transport most of the time but it does not always apply to the local situation.

Pareto principle means you should prioritize the 80%+ use case. Most of the time is what you want to spend all your time/money optimizing while making also the other use cases possible.

I think this is a terrible way to apply the Pareto principle.

80% of the time a hammer is a better tool than a screwdriver does not mean you should not use screwdrivers and just get better with a hammer.

Different tools for the job is more effective than one universal tool for everything

Re: Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

#76

Post by mc32 »

ethagknight wrote: post #73
mc32 wrote: post #11

Earlier quoted context omitted.

Hmm, if we ever built the Alaska-Siberia overland railway connection (bridges + tunnels) it would become a possibility to make efficient from what is now an impossibility. It’s doable. Tunnels and bridges necessary would not be beyond what we have built elsewhere with current technology. The weather may be challenging in Winter though.

That’s several thousand miles of additional journey on your way to Shenzen or wherever? Massive amounts of track, tunnel and bridge that has to be maintained in extreme conditions and across multiple nations at odds with each other? Or just put it on a boat?

I don't think it would be as problematic as you suggest. The Trans-Siberian railway already operates at similar distances. Also China is building their belt-and-road network. We could get goods from China, Japan, Korea and Russia all on this rail system.

The one sticky point might be gauge. We'd want something all agree upon. We'd want to avoid variable track gauge bogies.

Re: Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

#77

Post by DoesntMatter22 »

Retric wrote: post #65
DoesntMatter22 wrote: post #52

Earlier quoted context omitted.

You think a completely reasonable standard is for a train to average 58 mph all the way across the united states without stopping? What about all the slowdowns due to extremely rough terrain? The fact people have to be swapped out? The fact that not all cars are going all the way across the country and also have to be swapped out? 58mph average is insane.

Train’s don’t need to slow down for rough terrain because they can’t handle rough terrain and either route around it or tunnel through it. What they do need to slow down for is the rail network itself. Poor track conditions, missing block signal systems, and Trains without an automatic cab signal, automatic train stop or automatic train control system "may not exceed 79 mph." Freight trains really could travel a most…

So as you said it's not actually reasonable to think a train is going to get across the US in 48 hours.

Trains have to slow down a lot when going through rough terrain because there are curves involved. You can't go 80mph.

Re: Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

#78

Post by BizarroLand »

londons_explore wrote: post #57
nradov wrote: post #46

Earlier quoted context omitted.

Only sport gliders carrying a maximum of 2 people achieve those speeds fuel free. A large, heavy cargo glider carrying a full load is just going to crash without a tow rope, regardless of winds or thermals.

You probably wouldn't go totally fuel free - you'd go mostly fuel free. And yes, the craft would have to be absolutely huge for a decent payload - and it might make sense to use different construction techniques considering that - for example an inflatable fully pressurised craft.

Could probably add relatively inexpensive drone systems to the gliders with some solar and a battery to enable it to assist in landing and taxiing, as well as dealing with weather and the inevitable crashes.

I am aware that flying is the safest form of mass transportation but crashes do still happen and should be accounted for, after all, and it would be nice if the autonomous glider drone systems had a touch of brains in it to try to not land on a house or into a highway or something.

Re: Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

#79

Post by dredmorbius »

ZeroGravitas wrote: post #64
dredmorbius wrote: post #53

Earlier quoted context omitted.

This is true, and I've made the point myself previously on HN. But US freight tonnage is dominated by cheap bulk goods, most notoriously coal, though grain and bulk liquids (petroleum, industrial).[0] There's also a lot of intermodal / containerised freight, but this is almost exclusively long-haul "land bridge" traffic, with very little trade or viability for short-haul freight ( Cross-country carriage still takes 1…

There a US startup that has been featured here that is aiming for this market you identify. Small autonomous train carriages fitting into the gaps of the bigger system and making use of abandoned/underused spurs. I think this is them: https://intramotev.com/ Interview with CEO on exactly what they offer at the moment: https://www.railway-technology.com/interviews/i-dont-see-a-f...

Thanks!

Re: Unpowered cargo gliders on tow ropes promise 65% cheaper air freight

#80

Post by BirAdam »

nradov wrote: post #38
BirAdam wrote: post #24

Earlier quoted context omitted.

When goods stop crossing borders, soldiers start crossing borders. The easiest way NOT to go to war is to have open trade.

That's a nice little platitude but it's not supported by the historical record.

Eh, the USA’s history seems to confirm it. I’m not really sure about others, but I’d be surprised if countries that are dependent upon one another were at war with one another.
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