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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

#11
post #5

Earlier quoted context omitted.

Air freight is phenomenally inefficient compared to rail.

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.

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

#13
IANAAE (...not an aerospace engineer), but I smell a metric boatload of utterly delusional thinking here.

> ...remarkably simple way to slash air cargo costs as much as 65% – by having planes tow autonomous, cargo-carrying gliders behind them, big enough to double, or potentially triple their payload capacity.

A 65% cost reduction via tripling the payload would require that costs not increase, no? Are these huge cargo gliders free to purchase/operate/maintain? And hauling them around puts zero additional load on the engines of the air freighter that's towing them, to increase maintenance or fuel costs?

> ...payload-carrying gliders were towed toward combat zones in World War 2, full of troops and/or equipment, then released to attempt unpowered landings in the thick of things – with widely variable results, particularly where stone-walled farms were a factor.

True, but glider losses due to mishaps (starting with broken tow ropes) were damned high even before they got to the target area. What % of cargo being lost in transit do these folks figure is acceptable, in the modern air freight business?

> These "Aerocarts" will be pulled down the runway by the lead plane just like a recreational glider. They'll lift off more or less together...

Ask anyone with a pilot's license about this. Especially if he has experience with taxiways at large & busy airports, or with taking off in anything less than picture-perfect weather, or with airplanes that lack "sporty" thrust/weight ratios.

> With no propulsion systems, you save all the weight of engines, motors, fuel, ...

Even if your towing airplane magically does not need larger engines or more fuel to haul 2x or 3x the weight around - what happens when you land, and the tow plane engages its thrust reversers?

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

#14
post #5

Earlier quoted context omitted.

>rail Wrong niche. This is in the same market as conventional air freight.

Air freight is phenomenally inefficient compared to rail.

Travel time of 8 hours vs 3 weeks... most things being transported by plane are ones where time is of the essence.

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

#15
post #11

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.

How is building a rail system for transporting freight to and from the U.S. that runs through Russian territory a good/feasible idea?

Even if Russia agreed, Putin or whatever strong-man dictator they have next could suddenly decide it was a bad idea, and to block U.S. freight. Then we have no rail transport AND a grounded air fleet that would take time to get operational at the same output it is today.

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

#16

What the US needs is to fix its rail system. eminent domain the whole thing, pay off the robber barons and just run it like it matters to get shit from here to there.

When it comes to freight rail, the US is in the top handful of countries in the world by pretty much any metric.

We’re not great at passenger rail, but we beat all of Europe when it comes to the amount of freight shipped via rail per capita, and all of Europe except Switzerland based on the percentage of total freight transported by rail.

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

#17
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.

How is building a rail system for transporting freight to and from the U.S. that runs through Russian territory a good/feasible idea? Even if Russia agreed, Putin or whatever strong-man dictator they have next could suddenly decide it was a bad idea, and to block U.S. freight. Then we have no rail transport AND a grounded air fleet that would take time to get operational at the same output it is today.

I didn't mean tomorrow ("if we ever.."), or the day after. I meant one day when the US and Russia get along as well as China and the US do. It's not like we'll be at not-war war long into the future. Building the bridges and tunnels would take probably a decade or two, the way we build things. But if we did, then much of China's trade that goes over airfreight could come over via rail... one day.

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

#18
post #5

Earlier quoted context omitted.

Air freight is phenomenally inefficient compared to rail.

Travel time of 8 hours vs 3 weeks... most things being transported by plane are ones where time is of the essence.

There’s such a huge time gap between our current rail and air that many things that are somewhat time sensitive end up flying which would use a reasonably quick rail network. NYC to LA is well under 2,800 miles so getting just about anywhere in the continental US on rail in under 48 hours is a completely reasonable standard.

Yet, people moving from Texas to Florida don’t just park a U-Haul on a flatbed and fly, because it’s not just slow but also unpredictable. It can take weeks or even months in some cases because the network is optimized for coal and wheat etc which don’t care about delays just cost.

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

#19
post #11

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.

Where is Mr Wilford when you need him?

Sorry couldn’t resist the Snowpiercer Reference - where they connect alaska to russia with a long ass bridge.

To be fair it does look like a “technically possible but ruinously expensive” kinda project.

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

#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 double the volume of cargo you could carry, it seems unlikely that it would allow you to double the weight of the cargo, since the engines and the airframe have all been designed around the same set of engineering requirements. The best case scenario would be a decrease in the cost of volumetric cargo, with dense cargo staying the same.

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