Solar-powered aircraft flown for nearly three weeks without landing
eandt.theiet.org
eandt.theiet.org
My favorites atm are the yachts that are capable of sailing just about anywhere in the world without a drop of fuel. The price is prohibitive, but considering that you might not need a house anymore it is actually getting close to possible for a reasonably senior tech employee.
[full disclosure: no affiliation]
Other options like kites and wind turbines can work well but they all all significant upfront costs as well as ongoing maintenance issues. Spending that same money on a bigger boat gets you much more space, and of course a generator can give you redundancy or higher top speeds.
If you're living on your boat 365 then I imagine avoiding severe weather becomes more important?
Most people living in boats actually live on ports and don't get very far from the coast most of the time.
For those that do not really stray far from the shore or who are willing to take more risk for more comfort, they use a slower boat.
This is a net positive. The alternative is to roll back and forth with the waves. It’s much nicer with the sail up and ata bit of a heel.
Also, just to throw this in, one of the world cruising sailing couples which wrote for the magazines switched to a diesel powered boat as they aged and found that they spent less of fuel than they had on new sails. Sails are consumables if you care about performance.
Your point on the diesels still stands. Properly designed cats are unsinkable and don't readily capsize, but not weathering a storm is worth every penny invested in diesels. Besides one needs them in marinas anyway.
It's an interesting question, where does the wear come from. But sails are a very active part of the boat; every tack is going to drag the sail across the deck of the boat, rub against fittings. When a sail luffs, head-to-wind it's whipping around with the weight of the sheets (control lines), and then when you're taking the sail down it's getting folded (best case) or stuffed into a bag (worst case) [EDIT: some sail materials like being shoved in a bag!]. And of course even when a sail is just sitting there powering the boat it's under a tremendous amount of force, which stretches it over time.
Sails do fail, and yes often by ripping in half. I've personally never heard of a sail failing at the control points (e.g. the tack of a jib), probably because those areas are heavily reinforced.
Those areas where the sail needs to be strongest is where they are re-inforced doubling up the layers (and not just 'two', a corner can easily be 10 ply or more thick), on older boats further re-inforced with leather or heavier grades of fabric. The panels are carefully laid out so that the highest stress aligns with the warps. A large sail can be made up from many 10's of panels, which are joined in a variety of manners (glue (typically for very fast boats or as re-inforcement of stitching), stitching, sometimes ultrasonic welding for special applications). On the very high end there are even laminated custom laid out fibre pattern sails (for instance: a sandwich of Kevlar wire between two layers of bonded fabric or plastic).
At one time I worked for a competitor of North Sails, who by the way were pioneers in the digitization of sail manufacturing.
The cheapest ones last the longest but offer the worst performance.
Yes, but it makes less noise.
In the netherlands they have flaoting houses in the canals, but stationary AFAIK
I wonder now with post-covid remote working options and starlink if you could actually make it work.
I do wonder though if sailing the ship is basically a full-time job in itself (navigation channels? Docking at foreign countries? Getting food etc?).
That said, unless you are able to drop anchors, I am guessing that you would spend most of your working hours at a dock or with a partner piloting instead.
It will not work either far away from the shore.
On certain routes, packets will be artificially delayed so that high-speed traders can pay big bucks to get their packets through first, ahead of fiber. And, maybe pay even bigger bucks to prevent their competitors from getting their packets through as fast. Imagine tiered pricing, where each millisecond ahead of the rest of the pack is ten times the price.
So, for example, orbits inclined near 70 degrees pass near New York and London/Frankfurt. Packets going by satellite laser links can get there many milliseconds ahead of those poking along on subsea fiber. Somebody in London who finds out 10 ms before everyone else about a price change in New York gets to make a killing trading on the exclusive information.
Regardless I just don't see SpaceX as the company that doesn't evolve with times tbh.
"Evolve with times" does not seem to mean anything. In markets where Starlink is viable, they have no effective competition, and can charge as much as the market will bear. As long as they have more potential users than bandwidth to sell them, they are under no pressure to reduce prices or give up profit. A goal to subsidize Martian colonization provides a very strong incentive to maximize income. We should expect to see very high gross margins until other constellations begin to compete.
London/New York doesn't seem like the distance that there is going to be huge wins for back bone connected entities. But I guess that even if you can land a percentage of packets quicker via starlink, then there is some value in the trading world?
Compare to fiber. Best ping time is 76 ms, or 38 ms one way. So, our budget margin is 10 ms. Suppose, instead of a direct downlink, packets are dumped to a nearby hub and carried via 1000 km of fiber to the destination, with various routing delays, adding 5 ms, leaving a 5 ms lead, 5000 microseconds.
In finance, we say a microsecond is an eon, a millisecond an eternity. That is because in a microsecond we can do >1k multiplications. 5 ms is time for >5M multiplications, many more than needed to evaluate a position and choose a response.
The only routing choices are which satellite to uplink to, and whether to forward or downlink each packet. Whatever choices are made don't need to be re-evaluated more than per second. Packet queuing delay can be negligible; modern switching equipment will start forwarding a packet while the rest is still arriving; this would happen when forwarding via laser link.
The latency advantage for New York/London/Frankfurt <-> Singapore/Tokyo/Hong Kong would be even more compelling.
There are many things rich people can do, poor cannot. You gotta have money, to make (real) money. Thats the harsh truth and most of us who do not have it, have to struggle hard, to make some wealth and very, very hard and be very lucky and gifted, to get rich by it (without negating all ethics).
I'm not a full-time liveaboard, but I have been on-board for the last couple of months and you can definitely make it work.
Sailing is labor intensive, but not in the ways you imagine. Navigation, docking and provisioning are all straightforward.
Where it can sometimes feel like a full-time job is maintenance. Everything on a boat wants to break all the time. Doesn't matter if the vessel is brand new or 40 years old; finding a balance between maintenance and life is difficult.
Pipes are made from plastic and last decades, but they're generally not too hard to replace though.
I'd argue the biggest maintenance jobs to a house is keeping everything clean, basically the same as a boat. The other one would be painting every couple of years, and of course garden maintenance.
Someone should always be on watch if possible. It doesnt always happen as people do solo voyages. Open ocean most vessels would have transponders but if you're anywhere coastal you couldn't take the chance as smaller vessels don't always have and you can't rely on radar either.
I do think you could make it work though. Similar to van living. Plan your legs based on availability. You down time will be part maintainance etc.
Wind is more consistent than sunshine.
It looks like shit though. The other yacht looks much nicer.
Considering loitering is a very important goal for military drones, I expect them to be using solar power extensively too.
edit: remember the context. This is about an abstract optimization to find the minimum viable aircraft.
A fully charged battery would necessarily have more mass than a fully depleted battery, but the difference should be so tiny as to be immeasurable. Or am I wrong? We're essentially talking about the sum weight of a bunch of electrons, which are extremely light. There's no other exchange of matter going on when charging/discharging a battery, just the creation/destruction of chemical bonds, and associated movement of electrons.
However it has less potential energy. And therefore you change mass by the mass associated with that potential energy.
see: https://physics.stackexchange.com/questions/34421/does-the-m...
For example, an aircraft could "start" at 50% battery state of charge, then charge to 95% over the course of the day, then come back 24 hours later at 51%, and that would be valid. There are other ways around this, but this is what I came up with at the time.
This is similar to why the starting altitude is allowed to float. The gravitational potential energy of the aircraft can be used as another "battery", but the aircraft is only a valid solution if it's not losing altitude over the course of 24 hours.
Various metals can be used. Iron is cheap, whilst aluminium-air cells actually offer some of the best performance in kWh/kg of available materials, exceeding that of LiON cells.
https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemi...
Is it feasible to operate these at lower altitudes?
e.g. can we have solar/air drones posted every 100 miles of interstate highway?!
What's the usefulness of this or was it just a random example?
Nobody likes photo radar.
> When asked by a reporter if he would ever replicate the stunt, Cook replied: “Next time I feel in the mood to fly endurance, I’m going to lock myself in a garbage can with the vacuum cleaner running, and have Bob serve me T-bone steaks chopped up in a thermos bottle. That is, until my psychiatrist opens for business in the morning.”
Source: https://www.airspacemag.com/daily-planet/airborne-for-64-day...
Here's an account that popped up on Google.
https://www.aopa.org/news-and-media/all-news/2008/march/01/e...
They don't specify the "cruising" altitude, but I assume it's ~10 kilometers at most, probably less?
Airbus would need quite a few of these in order to build a global internet connectivity service then.
Edit: https://en.wikipedia.org/wiki/Airbus_Zephyr says ~20 km.
Starlink sats (will) operate at ~540-570 km:
https://spaceflightnow.com/2021/04/29/spacex-launches-60-mor...
Very high quality visual/signals surveillance seems like a much more obvious market fit.
Second, all you have to do is make these aircraft compatible with cell phones. So your target population already has "end user terminals" literally in hand.
Third, this is not a one-time need. Local disasters happen fairly regularly, and sometimes can be predicted in advance. (For example hurricanes.) There is real value to an instant telecommunications network that can be deployed on short notice.
Now I don't claim that this is actually economically viable. But it is not exactly crazy, either.
They should probably look into partnering with e.g. Ericsson Response (https://www.ericsson.com/en/about-us/sustainability-and-corp...).
Oh, yeah, there are already companies the provide complete surveillance of cities or large areas of cities so that even if a crime scene is discovered hours or days later, they can just go back to that time and track vehicle movement to and from the crime scene to wherever it ends up as long as it's in the same (large) area.
Reducing the cost of the equipment that does the recording of the area will only make it more accessible to more police departments, for better or worse.
I suspect the greater issue is vehicle cost, lifetime, and safety. A starlink satellite is much smaller (and as result cheaper) and is rumored to have a 5+ year lifetime. Also, at end of life it burns up in the atmosphere. No worry about pushing the life on a component and having it crash and kill someone as a result.
https://www.airbus.com/newsroom/press-releases/en/2018/09/ai...
I’m confused by the article and the above comment. Isn’t a glider by definition unpowered?
The economics here just seem wrong.
60 Starlink satellites per Falcon 9 launch [1]
= + USD2021$250,000 in launch costs per satellite (+ manufacturing / ops costs)
[0] https://www.elonx.net/how-much-does-it-cost-to-launch-a-reus...
[1] https://space4peace.org/starlink-gears-up-to-launch-nearly-1...
[1] https://www.forbes.com/sites/erictegler/2021/04/28/prices-fo...
A new Cessna vs a used Falcon 9 launch hardly seems like a fair comparison. The cost of the rocket is written off as externalized. The actual satellites are not factored in at all. Really what we are comparing here is the cost of an operation vs the cost of an airplane. The economics still seem dubious.
And because Starlink is building thousands of satellites it has economies of scale that no previous satellite/spacecraft had.
> Airbus would need quite a few of these in order to build a global internet connectivity service then.
Yes it would require more units, but with a much smaller cost per unit for build, launch and maintenance. That's where it will start to get interesting: Which will have the lowest cost per GB, per user, per square km of coverage etc?
I suspect even if it's cheaper it would still remain less global, since having massive swarms of these would probably be even more of a logistical nightmare than starlink. i.e they would supplement other technology... which is pretty much what Airbus is quoted suggesting in the article.
Somebody further down in the comments estimates $250k in launch costs for each Starlink satellite^[1]. Elsewhere, I found a claim that SpaceX execs said in 2019 that the per-satellite cost was "well below" $500k^[2]. So let's say $400k per satellite including manufacturing and launch, just to pick a number.
Once it's in orbit, you need to pay for operations, but not maintenance (except on your ground-based infrastructure). And multiple factors (e.g. cheaper launch) stand to bring that price down.
Realistically, how much do we expect one Starlink satellite's worth of telecom UAS to cost on an ongoing basis, including the maintenance and operations costs that don't apply to Starlink? Where is the analysis? OP's article makes the "cheaper" claim with (AFAICT) absolutely nothing to back it up, and the fact is that full size aircraft are not cheap.
The service density flexibility and possibility for additional radio bands Starlink can't provide might be a good argument for this system to exist, but all this talk of it being cheaper seems very vague and presumptuous. What am I missing?
^[1] https://news.ycombinator.com/item?id=28832257
^[2] https://www.teslarati.com/spacex-starlink-satellite-launch-s...
It's not a full sized aircraft. 1 small autonomous plane is cheaper than 1 small satellite in general - in almost all respects. The article didn't claim anything beyond this:
> The unmanned glider [...] is cheaper and more environmentally friendly than a satellite.
This is fairly obvious and uninteresting, what is interesting is cost per GB/user/km2, in other words the end result, which is hard for anyone to say with much certainty at this point even with a thorough analysis because nether business has reached scale yet.
From the picture in the article I'm not sure what else to call it other than "full size". Wiki claims it has a ~90 foot wingspan^[1]. Wiki also claims it has an 11 lb payload capacity, so one imagines a practical version of this concept would need to be be substantially larger in order to carry a useful telecom payload.
(A Starlink satellite is a couch-sized slab weighing over 500 lbs, and one can only assume how much of that is telecom equipment, but it's probably a lot more than 11 lbs. So it seems plausible that you'd need on the order of 10 aircraft of this size, or a single much larger and much more expensive aircraft, to equal the throughput of a single Starlink satellite. None of that sounds cheap.)
Being a UAS doesn't necessarily make it cheaper, either. The MQ-1 Predator, a borderline obsolete ~1500 lb airframe pushed by a ~100 hp air-cooled Rotax, seems to cost governments on the order of 10 million dollars to procure. I'm sure there's a lot of pork in there, but it seems far from obvious that relatively exotic UASs like this one can be procured and pressed into production use for, say, two orders of magnitude less than that.
> This is fairly obvious and uninteresting, what is interesting is cost per GB/user/km2, in other words the end result, which is hard for anyone to say with much certainty at this point even with a thorough analysis because nether business has reached scale yet.
Starlink is already a service you can buy and use, subject to whatever "beta" rollout scheme they're using. They still have a long way to go to realize their scale ambitions, but I think their economics are far more settled than other schemes (like this one).
I do agree that cost per user is the interesting number here, but--as above--it seems far from obvious that this UAS scheme can even be competitive with Starlink, let alone cheaper in any reasonable sense.
It's sort of in between a stationary cell tower and LEO satellite constellation.
But then you have to worry about them failing and hitting those population centers, whereas satellites deorbit slowly and usually burn up completely.
https://www.brookings.edu/techstream/loitering-munitions-pre...
1: https://www.engineering.com/story/how-the-worlds-first-solid...
https://www.amprius.com/2019/10/airbus-partners-with-amprius...
https://www.gizchina.com/2015/04/27/bluboo-x550-will-feature...
They've made some improvements since, but the exact parameters haven't been disclosed.
This military-industrial style of English always sounds very odd and is ubiquitous with these companies. Is it because they’re selling to Military buyers?
https://www.aviationpros.com/engines-components/aircraft-air...
https://en.wikipedia.org/wiki/Airbus_Zephyr
I can imagine you'd want to take advantage of gravity to a certain extent, but it seems a bit tricky to estimate how much. Presumably there's a particular altitude at which the aircraft's overall efficiency is at a maximum. Deviating from this altitude allows you to store a bit of extra energy (which means you can get away with a smaller battery) but you don't want to deviate too far, or you'll lose more energy to various inefficiencies than you're saving. And you probably need to keep some electrical reserve power anyway, in order to be able to actively navigate away from unfavorable winds.
Pretty interesting thought, tape a few hundred micro SD cards to it and you've got some impressive bandwidth.
It looks like solar-powered zeppelins are a thing, although with the brief googling I did it looks like nothing really exists just yet.
If the aircraft needs to stay in one place maybe that would be less efficient though, since it would be harder to fight winds.
https://www.washingtonpost.com/news/powerpost/wp/2016/04/23/...
What sort of power requirements would this bring? I assume that it would be more sophisticated than just dumping RF energy indiscriminately across a huge area.
When a bank teller says "The robbers drove away in a blue car," the police want the ability to roll back the tape and find all the blue cars that left the bank in the past hour and see where they are now.
Cessna 172 flown for 64 days, 22 hours, 19 minutes and 5 seconds.
https://www.aopa.org/news-and-media/all-news/2008/march/pilo...
> A Ford truck, donated by Cashman Auto in Las Vegas, was outfitted with a fuel pump, tank, and other paraphernalia required to support the aircraft in flight. When fuel was required, a rendezvous would be arranged on a stretch of straight road in the desert near Blythe, California. An electric winch lowered a hook, the fuel pump hose was picked up, and Timm or Cook inserted it into the belly tank. It took a little more than three minutes to fill the belly tank.
> The total fuel capacity of the airplane was 142 gallons. Plans called for refueling twice daily. Sometimes weather or the inevitable glitches upset the schedule, and a new rendezvous was worked out by radio. This activity was repeated more than 128 times.
The whole article is worth a read; it was quite the hairy sounding endeavour. Two months in a C-172 would kill me, I'm quite certain.
Haven't read it to find the answer to your question yet, but bless the Internet Archive
ROLF!!!
"From December 4, 1958, to February 7, 1959, Robert Timm and John Cook set the world record for (refueled) flight endurance in a used Cessna 172, registration number N9172B. They took off from McCarran Airfield in Las Vegas, Nevada, and landed back at McCarran Airfield after 64 days, 22 hours, 19 minutes and 5 seconds in flight. The flight was part of a fund-raising effort for the Damon Runyon Cancer Fund.[14][15]"
Presumably there's a number, I just doubt it's tens of days, so isn't it interesting that it was achieved?
From an engineering stand point, performance of components or materials are always assumed to be much worse than actual and the forces / conditions they are subject to overestimated, with further factors of safety applied on top. This is how it should be. It also means properly designed things will carry on working better than you expect (on average).
It’s not interesting (to me) from a technological stand point compared to the solar UAV because flying up and down the same road with a truck refuelling you is not useful, and if others (e.g. Military, NASA) could be bothered to do it - they would probably do a better job relatively easily.
To me - It’s the same as building the worlds longest domino trail. You could beat the previous record by 1 million dominos which is neat but.. what have you proven, and why does it matter ?
Fair enough, I didn't know about that, I'd have been as interested to hear about either of them first, and like you not so much the other second. (And I doubt the commenter that shared it meant it as 'wow look 64 compared to 50' either.)
This also ignores all the unexpected issues that pop up in aviation. My only experience with Cessna 172s are rentals which are treated like crap - those planes need something looked at like every 50 hours.
Same idea could work with solar powered aircraft.
I really hope Airbus and others are able to make this concept work. It would be nice to have an in-between option between UAS and satellite.
The hardware for this purpose doesn't require a heavy aircraft, I suppose.
Sources: I work in a big agtech company with satellite imagery. PS: We should connect.
It would be like if someone developed a cheap, non-invasive technology that could detect cancer extremely early, and then you complained because they hadn't cured cancer instead.
If this is the case, shame they don't just admit this up front
Depending on altitude, that would require an awfully fast aircraft.
A solar-powered aircraft has completed an 18-day test flight offering hope it could be used to create internet access for billions of unconnected people around the world...The test flight touched down in Arizona on September 13.
https://www.thenationalnews.com/world/the-americas/2021/10/1...
Phoenix has about 12.5 hours of daylight on Sept 13th. (compared to ~14.5 hours on June 21st, ~10 hours on Dec 21st.