cwerdna
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Re: Solar Impulse - Flying Around the World Powered Only by PV

Wed Jan 31, 2018 12:58 am

There's an ep of Nova airing on 1/31 on Solar Impulse. See http://www.pbs.org/wgbh/nova/tech/the-i ... light.html. My TiVo's set to record it.

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RegGuheert
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Re: Solar Impulse - Flying Around the World Powered Only by PV

Wed Jan 31, 2018 2:03 pm

cwerdna wrote:There's an ep of Nova airing on 1/31 on Solar Impulse. See http://www.pbs.org/wgbh/nova/tech/the-i ... light.html. My TiVo's set to record it.
Thanks! I have it scheduled also.
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GRA
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Re: Solar Impulse - Flying Around the World Powered Only by PV

Wed Jan 31, 2018 5:06 pm

Thanks for the reminder, as I'd been planning to watch it but forgot that it was today. I confess to being a bit conflicted - I want to watch even though I consider the whole thing a pointless exercise - while it's a personal achievement for the crew, the lack of any practical value for such a flight now or in the future turns me off, as it was presented at the time as if it had some. It was and remains a stunt with no practical potential, much as an around the world balloon flight or Lindbergh's NY-Paris flight.

If it has been presented solely as an adventure that was meaningless except as a personal test (ala' "Chasing Shackleton", or for that matter most (ant)artic exploration in the heroic age, and many other records) I wouldn't mind, and I hope that's the tack Nova takes.
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Re: Solar Impulse - Flying Around the World Powered Only by PV

Wed Jan 31, 2018 5:17 pm

Drones that can remain aloft for months definitely have practical applications.
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Re: Solar Impulse - Flying Around the World Powered Only by PV

Wed Jan 31, 2018 5:57 pm

LeftieBiker wrote:Drones that can remain aloft for months definitely have practical applications.

Absolutely:
GRA wrote:We already know what PV-battery planes are good for, HALE missions where speed is irrelevant.
See http://www.mynissanleaf.com/viewtopic.php?f=45&t=19346&start=10#p466269

for much else re the difference between practical value and stunt re. transatlantic flights.
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GetOffYourGas
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Re: Solar Impulse - Flying Around the World Powered Only by PV

Thu Feb 01, 2018 6:12 am

GRA wrote:
LeftieBiker wrote:Drones that can remain aloft for months definitely have practical applications.

Absolutely:
GRA wrote:We already know what PV-battery planes are good for, HALE missions where speed is irrelevant.
See http://www.mynissanleaf.com/viewtopic.php?f=45&t=19346&start=10#p466269

for much else re the difference between practical value and stunt re. transatlantic flights.


Are you implying that there is nothing they could learn which could be applied to unmanned electric aircraft? Because I suspect there is. Sure, we won't see this exact use case in real life, but it's far more engaging to follow a manned flight around the world than to simply watch a drone fly itself. This allows for sponsorship and the like, funding this extended test.
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Re: Solar Impulse - Flying Around the World Powered Only by PV

Thu Feb 01, 2018 8:54 am

I've just watched the NOVA special on the Solar Impulse and enjoyed it quite a bit. As is typical of NOVA shows: It has very high production quality and was very engaging. I particularly liked seeing all of the challenges involved with building and flying a machine which is so incredibly fragile as this one.

Here is one quote from Bertrand Piccard that I found memorable:
Bertrand Piccard at 8:18 wrote:It is so much more difficult to use these clean technologies in the air than to use them on the ground, so if it works in the air I really hope people will understand that they can replace all these old polluting old stuff by new clean technologies. What we can do in the air we can do on the ground. And this is our message.
Another good quote (and prediction) from Piccard while looking at old airliners in an aircraft graveyard:
Bertrand Piccard at 1:31:03 wrote:I'm not saying Solar Impulse will replace an airplane like that very soon. In ten years' time, we have airplanes flying electric with batteries, plugged in the grid before takeoff, and they will transport fifty people.
While I'm not sure how many years it will take, I believe his prediction is accurate. I doubt it will take as long as twenty years (from whenever he said that), but perhaps it will be a bit longer than ten. As always, time will tell.

I also really liked the videos of the propeller pod mounted on a minivan for testing (starting at 20:49 in the video) since that image is such a popular concept that is tossed about as a spoof of the next great idea for renewable energy. ;)

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Re: Solar Impulse - Flying Around the World Powered Only by PV

Thu Feb 01, 2018 6:41 pm

I watched it, and all through I just kept thinking, what a tremendous expenditure of human energy, brainpower and money for a meaningless stunt.

Re Nova, maybe I'm remembering things through rose-colored glasses, but some years back ISTM that Nova moved away from the science aspects and added more TV pizazz as PBS funding dried up - I can remember the first time they used a docudrama, thinking what the hell, is this the History Channel? I expect dumbed-down history from them.

I can remember watching the Nova episodes on the Gossamer Albatross and Condor, and at least in my memory they were a lot more focused on the science. I thought this episode had at least 15-20 minutes of filler that added nothing to the show beyond providing local color. The attempted justifications to try and provide some larger context (We're popularizing sustainable energy and energy efficiency!) struck me as as at least a decade too late - If this flight had started in 2005 instead of 2015 that might have been valid, but RE and energy efficiency were both widespread and well known by the time this came about. Maybe the only lasting impact this flight might have beyond the personal achievement is if some of the kids who saw the a/c or watched the show are inspired to get into engineering themselves.

quote="GetOffYourGas"]Are you implying that there is nothing they could learn which could be applied to unmanned electric aircraft? Because I suspect there is. Sure, we won't see this exact use case in real life, but it's far more engaging to follow a manned flight around the world than to simply watch a drone fly itself. This allows for sponsorship and the like, funding this extended test.

I'm saying that there is nothing in this flight that couldn't have been learned by flying unmanned HALE a/c which are already performing the exact sorts of missions for which they are suited. The only thing this flight told us is that massive increases in the power densities of PV cells and the energy densities of batteries will be required before this becomes a viable form of transportation, and anybody could have told us that without ever flying an a/c. At least the Spirit of St. Louis was designed for several G while fully loaded, so it could handle some degree of rough weather. I believe the only thing this flight showed was how to get sponsorship to achieve a personal goal, but that's hardly new - adventure explorers have been doing that for more than a century, although in the past they generally had the good taste not to plaster their sponsor's logos all over their clothing and equipment, but just mentioned them in the book or film credits. If you watched the show, you know that the decision to take off for Hawaii was made against the unanimous advice of the engineers, who said it wasn't worth the risk. That the pilot decided to do so anyway shows that this was about personal goals and not disappointing sponsors rather than gathering technical information, not that there was ever much doubt about that.

Sometimes daredevil stunts are important for their PR value, even if there's no technical justification. For example the Daily Mail's prize to fly across the English Channel was offered in the full expectation that it would be won by Wilbur Wright, who had been amazing Europe by his flight demonstrations in France in 1908-09. He declined to try it, saying that it proved nothing in a technical sense as he'd already flown distances considerably greater than what was required. He was correct, but the PR value of Bleriot's flight (England is no longer an Island!) would have been more than worth it to someone who was trying to sell a/c to European militaries. The Wrights were technically astute, but had no sense of PR. The transatlantic crossings of 1927 did make the public air-minded in a sort of "let's see the Circus" way, but didn't do anything for technical development.

Actually, there was one technical aspect that this flight confirmed:
TomT wrote:
RegGuheert wrote:It seems that during the successful 5-day flight from Nagoya, Japan, to Oahu, Hawaii, the batteries overheated and will need to all be replaced before the RTW trip can continue. As a result, the Solar Impulse 2 will remain in Hawaii until next Spring.

According to this article, the cooling system was insufficient to keep the batteries cool in the high temperatures they experienced during the daily ascent they made to get above the cloud cover to permit the photovoltaic panels to receive the most energy from the Sun.

Must have been designed by Nissan! :lol:

The show mentioned that the reason the batteries overheated was that they had too much insulation for the cold at high altitudes, and no way to vent excess heat during the climb at low altitudes. The solution was to add pilot-operated vents to the batteries to allow this excess temperature to be removed, which sounds rather like proving that a current battery pack which must operate in a variety of conditions should have a Thermal Management System! :D
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Re: Solar Impulse - Flying Around the World Powered Only by PV

Fri Feb 02, 2018 8:49 am

GRA wrote:I watched it, and all through I just kept thinking, what a tremendous expenditure of human energy, brainpower and money for a meaningless stunt.
I don't agree with what was portrayed as perhaps the "main meaning" of this adventure, but I hardly see it as "a meaningless stunt".
GRA wrote:The attempted justifications to try and provide some larger context (We're popularizing sustainable energy and energy efficiency!) struck me as as at least a decade too late - If this flight had started in 2005 instead of 2015 that might have been valid, but RE and energy efficiency were both widespread and well known by the time this came about.
Bertrand Piccard conceived of this flight in 1999. No doubt he fully intended to complete this flight in, or before, 2005. I'm pretty sure he did not expect it would take 16 years and countless millions of Euros before the around-the-world flight could be started.

My family and I went to see the Solar Impulse several years back. That Solar Impulse plane that we saw at the Udvar-Hazy Museum was not this one which flew around the world, it was a prototype. In other words, that one was not quite able to achieve the final objective.

My conclusion from all of this is that this flight was not really possible before 2015. It's clear from what was portrayed in the NOVA documentary that it was barely achievable as it was. I believe that this type of "first" is important because when we look back on history, we can say with some confidence that such a feat was likely NOT possible using the technology which existed up until approximately that point in time.
GRA wrote:If you watched the show, you know that the decision to take off for Hawaii was made against the unanimous advice of the engineers, who said it wasn't worth the risk.
I did watch the show and that is NOT what happened. What ACTUALLY happened is Pierre took off for Hawaii with the full blessing of the engineering team. After some time, he reported a malfunction with the system which monitors the autopilot and alerts the pilot if it determines his attention is needed. This malfunction threatened to (and proved to) put additional stress on a pilot who was already attempting to extend a human endurance record by a large margin (over 5 days of continuous flying versus 3 days). The engineers, who have responsibility for the safety of both the pilot and the aircraft, felt that this added additional risk was not warranted and they recommended that Pierre turn around and return to Japan before he reached the limit of an abort. Pierre and Bertrand overrode their recommendation and decided to push on to Hawaii. This created a significant amount of friction within the team and Bertrand fully expected some of them to quit even if they reached Hawaii safely. NOVA did an admirable job of capturing this very human drama.

Your characterization of this decision is:
GRA wrote:That the pilot decided to do so anyway shows that this was about personal goals and not disappointing sponsors rather than gathering technical information, not that there was ever much doubt about that.
You went on to imply that this had become a "daredevil stunt". I have to agree with you that achieving the goal of flying this plane around the world was very much at the forefront of the decision to push on, but while it was originally a personal goal of only Bertrand Piccard, it had also become a corporate goal of ALL of the people involved in the effort as well as of the financial sponsors and many other supporters.

What you failed to point out were the following very pertinent facts:
- Pierre had previously aborted this flight after taking off due to adverse weather conditions, resulting in the plane being in Japan instead of China.
- The flight had been aborted again on the runway while trying to take off from Japan, again based on weather.
- As a result of these two aborts, the window was rapidly closing on successfully achieving this five-plus-day flight to Hawaii. The main reasons for this were 1) the Summer solstice had passed and thus the available solar energy for the flight was being reduced each day. There was very little energy margin, even right at the solstice, 2) The typhoon season was quickly approaching, which not only threatened to prevent the flight, but could actually destroy the blow-up hangar and the plane itself, and 3) The team was starting to suffer from severe fatigue from the waiting and the three periods of intense preparation (and worrying) for this most-difficult flight which they had just gone through.
- Bertrand felt that if this flight was aborted, the entire mission would fail.

So did they make the wrong decision? Hindsight tells us that the flight to Hawaii was a success. Pierre was certainly more harassed by the autopilot monitor than he should have been, but he did an amazing job piloting the plane and pulled through to achieve an incredible world-record feat of endurance. The batteries failed during that flight and the rest of the mission had to be pushed back until 2016, but that design issue was already baked in and was not part of the go/no go decision. And, yes, the engineers were pissed off that their recommendation had been overruled by "two managers". In the end, however, none of them quit.

I have to say I feel that Bertrand and Pierre made the correct decision. Note that those two people who made that decision were the person whose life was on the line and the person whose personal reputation was most on the line. They personally had the most to lose in case of a failure. Ultimately, the entire team would have been MUCH more upset had they aborted and had the entire mission been scrubbed.

As far as collecting data goes, the data which was yet to be collected was the data which could ONLY be gathered on this leg of the mission. They needed to find out if the plane could store enough potential and battery energy to make it through the night over the Pacific, and to do this over and over again each day for five days. They also needed to find out if Pierre could manage to fly the plane for five days. The ONLY way to collect that data was to actually DO it. It turned out that Pierre WAS able to succeed even with an additional hurdle put in his way. OTOH, it also turned out that the thermal design of the batteries was insufficient for the purpose.

Ultimately, it was bad enough that this around-the-world series of flights stretched into a second year. In my mind, that was a bit of a failure. But had they balked at attempting that longest leg in 2015, the effort possibly would have either dissolved at that point or the adventure would have stretched into the third year, with no improvement in the possibility of success, but a greatly increased probability of failure due to a loss of funding.

I appreciated that NOVA did an excellent job of showing how challenging this task really was. I appreciate this documentary in the same way that I appreciate the HBO documentary series "From the Earth to the Moon" that brought that same kind of information to light about the Mercury, Gemini, and Apollo missions. Ultimately, there are a LOT more challenges in such an undertaking than you can appreciate by just watching it unfold on TV or on the internet. The difference with the NOVA documentary is that they recorded the events as they happened, so likely it was more accurate than the HBO dramatizations.
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cwerdna
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Re: Solar Impulse - Flying Around the World Powered Only by PV

Sun Feb 04, 2018 1:29 am

I finally finished the Nova ep. It was very good. I didn't realize they had such big challenges of needing to find a window of clear weather each time as well as issues of not enough hours of sunlight.

I do wish they did focus a bit more on what was inside the cockpit, about the toilet, food and the pilots' routine beyond the 20 minute cat naps (which seems nutty).

I forgot to mention that on the night I saw Solar Impulse 2 land at Moffett Field (well, we were on a road outside the base), I happened to bump into surfingslovak there. Was very strange that we'd both be there on the same road to watch the landing. Neither of us knew the other would be there.

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