Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - DuncanDoenitz

Pages: [1] 2 3 ... 18  Next >
1
I'll pick up your baton, mahogany.  (mahogany baton, geddit?)

I think there's 2 aspects to the awesome-ness of this.  First of all there's the technology; you take the biggest, heaviest rocket vehicle that ever existed and blast it off to the point of separation, at which time the pointy bit goes on to orbit.  The remaining 3/4 of this biggest-heaviest-rocket-that-ever-existed continues ballistically to the Karman Line.  You then adjust the trajectory to bring it back to the launch pad, relight the motors and have it literally hover until it's grabbed by the chopsticks. 

The second aspect is the pure spectacle.  Since we started recovering things from space in the 60's, there have only been 2 ways to do it, and both rely on aerodynamics:

One; you use unguided inherent vehicle-drag to decelerate to a (subsonic) point where a parachute becomes viable, then you allow it to simply fall to earth (Vostok, Soyuz, Mercury, Apollo etc). 

Two; you design a vehicle of such resiliance that aerodynamic surfaces will withstand the kinetic heating, and use lift/drag to make a controlled flight to an aeroplane-type touchdown (Shuttle, Buran, X-15, X-37 etc). 

In both these cases, the kinetic/potential energy of the orbital/sub-orbital vehicle is dissipated in a gradual and consistent manner from the time it encounters significant atmospheric drag.  Coincidentally, this is about the point at which it becomes catchable by the TV technology of the day, so the public becomes accustomed to space shots returning in a sedate and controlled manner.  What sets Starship apart is that the energy dissipated aerodynamically by the vehicle is consistent but minimal until the it is less than a mile from the Earth; at this point, well with sight and earshot of ground observers, it is still falling vertically, supersonic, going backwards, and impact seems inevitable.  Only at a height of 1000 metres do we get synchronous sonic boom, flame, thunder and violent deceleration. 

2
Just as an epilogue and summary, Tom said this at Reply#10;

"If you are sure that there is a category where sailing boats have sailed around it in a faster time then I would suggest finding it and then contacting Guinness World Records to inform them that they are incorrect about Lisa Blair holding the record for fastest circumnavigation by sailboat".

Well it turns out we don't need to e-mail Guinness (Tom's arbiter of choice on this subject); they already know.

https://www.guinnessworldrecords.com/world-records/527119-first-circumnavigation-of-antarctica-in-a-sailboat-south-of-the-60th-parallel

3
Interesting post Longtitube, and the best part is in the, almost throwaway, last paragraph. 

It's becoming clear that there are several categories for the "Record"; above and below certain latitudes, class of vessel, and single/multi crew.  Mariusz Koper's journey in Katharsis II is extraordinary.  Lets put it straight out there that this was a multicrew effort, so 24-hour watchkeeping was possible, but it was also a monohull.  Koper's record was performed entirely below 62degS, and achieved in 72 days, actually beating the single-handed monohull RTW record by 2 days. Not only that, but it was not even by the most direct sea-route.  Koper and his crew made a point of following the coast as closely as possible, even diverting south in order to sail on the Ross Sea, the most southerly navigable waters on Earth.  Reading some of his account is astonishing due to the presence of icebergs and floes which had to be avoided. 

You brought up the anomalous winds, but lets put that in context.  They can be strong, but also weak, and variable in direction.  Katharsis II actually encountered winds over 25 knots, but also less than 10.  Another standout, for anyone still under the impession it all blows one way, they anticipated "East winds, which are inconvenient for this route, could accompany us for about a third of the voyage".  And this was not from some commentator, but by the sailors that actually went there and experienced it. 

https://www.yachtingworld.com/voyages/sailing-antarctica-record-breaking-voyage-around-southern-continent-123341

There's lots of citations in the Wiki about the winds, describing them as "strongest on the planet" and so forth, which is not in doubt, but the only use of the term "anomalous" is by the Wiki itself.  And, of course, by Tom. 

4


She ventured a little off course in that instance, I suspect, but as I stated earlier, she was traveling with the wind.

Like I wrote, it is indeed bizarre you would provide a map that does not show an Ice Ring and only shows those eddys that are blowing to the W. She was probably caught up in one  of those.


I'm not sure why you keep bringing up the ice ring thing.  As per Tom's OP, the record is for circumnavigating Antarctica, which is clearly visible on the weather map which I posted, as well as Longtitube's route map from Lisa's website. 

Of course the prevailing wind is westerly, just as it is in the equivalent latitudes of the northern hemisphere, but you seem to write off the "eddies" as insignificant ("she ventured a little off course .... she was probably caught up in one of those").  Just as in the northern hemisphere, they are weather systems, several hundred kilometers across, circulating around areas of high and low pressure. 

5

I looked at your map. The only winds not traveling in the same easterly direction are those eddys forming close to land she wasn't sailing in those areas.

It is bizarre to provide your source as some kind of counter.


A source for her route? 

You realise of course that this is a live map, not instantaneous indications of the wind at the time she was in each area.  At the latitudes between 45S and Antarctica the general trend is westerly (ie blowing towards the east), but there are significant times when the wind varies considerably, from all points of the compass.  Do you think that those times and "eddies" don't count?  To claim that "winds on the inside of the ice ring always travel the same way" is complete fantasy. 

But don't take my word; this from her blog Day 79:

"Hi All,
 
 Last night I finally managed to get to bed by around 3am and by 4am the winds had started to veer from the SW to the W before shifting to the NW and build in strength.  I needed to put a gybe in, but I decided to wait until first light to make it a little easier
". 

You'll know of course that a gybe is a similar manouver to a tack, but performed before the wind, so more hazardous. 

6
"...something that is not the Ice Ring and where the boat would not sail anyway ...".

Well this is bizarre.  Southern extent of the world's oceans, but not the Ice Ring?  And "not where she would sail"; did you scroll around?  The Earth's entire oceans are on the page, and I believe she sailed on an Earth-ocean. 

7
I don't think we need to start writing letters to the editor yet, but we can perhaps clarify something, and put a bit of meat on the bone.

Yes, the record for global circumnavigation is 41 days, but as Longtitube suggested earlier, that was in a multihull vessel.  The record for a single-handed monohull is actually 74 days (Armel le Cleach, 2016-17 Vendee Globe).  Still faster than Lisa, but 41 days/74 days illustrates the variables involved.  (Bit of a stretch to suggest that we are claiming it's a "bad boat" btw).  And go back to 2001, same race, the record stood at 93 days.  I guess the moral is (like all things), keep plugging away, get a faster boat, the records fall. 

https://en.wikipedia.org/wiki/Around_the_world_sailing_record#

Speaking of which, of course, a Round-the-World record is really the Blue Riband event; boats and sponsors are tripping over themselves to break records and pick up the kudos.  On thre other hand, refer back to the Sail-World article in the OP and we find that Lisa is actually only the 3rd person to ever perform the Antarctic journey.  Not bad, for a tree-hugger. 


8

Winds on the inside of the ice ring always travel the same way.


That is simply incorrect. 
 
https://www.windy.com/?-74.235,-66.562,3 

9
Same Antarctic-lady, Lisa Blair, also holds the record for circumnavigating Australia in the same boat.   

At 58 days, this was 17 days longer than the global circumnavigation record, proving almost beyond doubt that Australia is bigger than the Earth. Even more curious; Australia is entirely in the southern hemisphere, where the spooky anomalous winds blow. 

If Lisa's average speed for the Australia-gig (5.69 knots) were extrapolated onto the Antarctic expedition, that would give a distance of 11,000 nautical miles to travel around the ice-wall. 

I'm sure other correspondents on here can advise further about tacking, gibeing, spinakers, and so forth.   

10
Philosophy, Religion & Society / Re: US Presidential Election 2024
« on: September 21, 2024, 08:31:08 AM »
You can take my car when you prise my cold, dead corpse out of it. 

11
Philosophy, Religion & Society / Re: Trump
« on: July 14, 2024, 12:00:12 PM »
Damn it, just a little better aim and we'd have had great news.

Not even close.  Missed his brain by around 3 feet.

12
Flat Earth Theory / Re: Northern lights and the sun and radiation
« on: July 01, 2024, 07:31:44 AM »
If you jump out of a plane, going skydiving, why do you not need to immediately pull your parachute? You can wait, because the force at which you’re being pulled down to the surface gets stronger the closer you are. So when you jump from 20,000 ft. The force pulling you back down isn’t as strong as it will be at 10,000 ft.  Thank you.
Don't know where you get this.  FE, Earth accelerating up at constant 1g; RE, skydiver accelerating down at 1g.  Only thing that changes with altitude is an increase in drag due to increased air density, which mitigates against further acceleration, and which I don't think FE dispute. 

I'm a roundy, btw. 

13
Flat Earth Community / Re: The Final Experiment
« on: May 17, 2024, 10:14:16 PM »
It's on the internet, and you suspect its a scam?  Have you no faith in human kindness? 

I'm truly shocked by your cynicism, Pete.  Shocked. 

14
Flat Earth Community / Re: The Final Experiment
« on: May 17, 2024, 03:22:32 PM »
Dunno about this, AATW.  Yes, the ultimate experiment in theory, but the website makes Jeran look like George Lucas by comparison; no pages at all except a bunch of You-Tube links.  If this thing gets as far as the equator I'll eat my tinfoil hat. 

15
Flat Earth Investigations / Re: What is the true map of the earth?
« on: May 15, 2024, 08:21:43 PM »
A80; I think you'll find 35 on-schedule return flights is 70 instances.  Why, what have you got? 

(And, as you apparently failed to notice, Tom just (once again) reiterated previous apocrypha without actually referencing any single jetsteam-related cancellation). 


16
Flat Earth Investigations / Re: What is the true map of the earth?
« on: May 14, 2024, 01:40:03 PM »
Tom,

Maggie Teneva.  I think you misunderstand; I wasn't implying satire or humour with regard to Maggie, I was just making the point that the article was about making air-journeys more enjoyable, and its relevance to flight cancellations was a single line in the summary implying that cancellations were frequent, but without any evidence or analysis. 

Continental Airlines.  The article is 12 years old, and refers to Boeing 757s.  Almost no-one uses 757s for transatlantic travel these days and, unless I am missing your point, it confirms my assertion that jetstreams impede, rather than assist, westbound travel. 

"ETOPS stops".  There is no such thing.  ETOPS refers purely to the aircraft's range from a suitable diversion airport at cruising speed on a single engine. 

East-to-west winds.  You earlier drew a distinction between "jetstreams" and "winds"; I am throwing it back at you.  Your graphic, and the Wikipedia article from which it is drawn, is about wind; specifically trade-winds.  The whole point of trade winds is that they assist sailing ships, which generally operate at sea level.  They are part of a Hadley Cell, in which the high altitude component flows away from the equator and the low altitude element towards the equator, forming the trade wind.  I reiterate that jetstreams are almost exclusively a west-to-east phenomenon. 

Cancelled/rescheduled flights.  I would refer you again to the LATAM Santiago/Melbourne service as an example.  Three months of scheduled flights, 3 times per week, only one flight cancelled.  Of the remainder, every flight left Santiago on the day planned, most within an hour of the scheduled departure time.  Not replanned.  Not rescheduled.  Not removed. 

17
Flat Earth Investigations / Re: What is the true map of the earth?
« on: May 13, 2024, 08:23:31 PM »

They don't. Flights are canceled all the time, especially long haul flights. See this quote by travel writer Maggie Teneva:

“Long-haul flights are often associated with long layovers and delays or cancellations.”

If there are unexpected changes to the jet stream or winds mid-flight, a non-stop flight might even stop for fuel:

“ Dozens of Continental Airlines flights to the East Coast from Europe have been forced to make unexpected stops in Canada and elsewhere to take on fuel after running into unusually strong headwinds over the Atlantic Ocean.

The stops, which have caused delays and inconvenience for thousands of passengers in recent weeks, are partly the result of a decision by United Continental Holdings Inc., the world's largest airline, to use smaller jets on a growing number of long, trans-Atlantic routes. ”

Per ETOPS, plane flight routes are required to be in vicinity of airports or landing strips for unexpected stops like that. Even long haul flights over oceans need the capability to make detour routes to islands with landing strips in case something like the above happens. The US Military is even known to maintain landing strips on certain uninhabited islands in remote locations for ETOPS purposes.



The quote from Maggie teneva (who she?) is simply a throwaway line at the end of an article about entertaining your kids on longhaul. 

The "stopping for fuel" link doesn't go anywhere. 

The Continental Airlines example is undated, has no reference, and (if true) sounds like poor planning by  the airline in not using aircraft with apprpriate capacity/range.   

ETOPS is not a restriction; it is a relaxation of previously existing routes that require aircraft to route within 1-hour flying time of a suitable diversion airfield.  In the case of the Airbus A350, this can now be extended to 5hrs 30min at single engine cruise speed (frightening but true), meaning that only Antarctica is off limits (unless, of course, one of the ice-runways is the destination). 

The USAF, being outwith ICAO regulations, is not limited by ETOPS.  The United States maintains "landing strips on certain uninhabited islands in remote locations" for military operational, security and diplomatic purposes. 

Aircraft often divert from route for reasons of security, medical or technical emergency, but beyond the apocryphal stements you have made, I challenge you to identify a single recent occurance made purely for a splash and dash.  Any commercial aircraft diverting from its planned route purely for a fuel stop would find its captain and dispatcher having a series of one-way conversations with management. 

And yes, jetstreams are a perpetual phenomenon, but no they are not alway at the extreme stengthsyou suggest, and almost without excdeption are a west-to-east direction.  Apart from local eddies there is absolutely no, general, assistance, anywhere on Earth, to westbound travel. 

Your statement "Flights are canceled all the time, especially long haul flights" is simply untrue.  For example, I've just looked at data on FR24 for LATAM's Santiago-Melbourne service LA804/805; run with a Boeing 787 Dreamliner.  The service operates 3 times a week in each direction and between 15 Feb and today, 12 weeks, 36 planned return trips; one cancellation.  And the flight times:

Santiago-Melbourne; quickest 12.55 (16 Feb), longest 14.45 (1 March). 
Melbourne-Santiago; quickest 11.38 (12 March), longest 12.35 (23 March). 


Action80;  You haven't said when your flight was, or whether it was over land or sea, but its not unusual.  Over land there is normally good radar coverage and separation is normally monitered by ATC controllers.  Oceanic; aircraft are cleared to fly a route between specific waypoints, but the principal separation is made by altitude.  Separation used to be 1000feet but for the last 20 years or so this was reduced to just 500feet, with a strict regime of altimeter-inspections and aircrew compliance.  At about a mile, a 500foot difference would probably be indistinguishable. 

18
Flat Earth Investigations / Re: What is the true map of the earth?
« on: May 12, 2024, 09:09:48 PM »
You're talking about the jetstreams as being a constant phenomenon.  They aren't, they are variable, in location, direction and velocity.  Like I said, its just a wind.  If its above 60 kts, as you say, they term it a jetstream, but its still just a wind. 

And you are absolutely correct that favourable jetstreams (like other winds) are exploited for the purpose of speed and economy, but if the jetstream is absent, or unfavourable, the flights still occur.  Just look at the post-Covid-resurrected Qantas/LAN services between Chile and Australasia; they take place on schedule every time, eastbound and westbound.  They can't be that anomalous can they? 

Now try Googling Air France flight AF174 on 8 May.  (Or here's a link);

https://www.flightradar24.com/data/flights/af174?utm_campaign=website&utm_medium=email&utm_source=sendgrid.com#351eba3d

Airbus A350 F-HUVC departed Paris CDG as AF174 for Mexico City but developed a problem over Newfoundland and returned to CDG.  Flight tracking data shows that the return leg was performed almost completely along the same route and at a similar altitude as the outbound leg.  Pretty dumb with a 300mph wind wasn't it, or maybe the airline actually knew the windspeed? 



19
Flat Earth Investigations / Re: What is the true map of the earth?
« on: May 02, 2024, 07:27:17 PM »
I showed you the calculation at Reply#2.  Average the groundspeeds of 2 aircraft flying in opposite directions at a similar airspeed in a similar airspace; for each aircraft the difference from the average is the headwind/tailwind speed component. 

20
Flat Earth Investigations / Re: What is the true map of the earth?
« on: May 02, 2024, 06:55:21 PM »


Those numbers are around the plane's cruise speed. But the plane should not be traveling at a speed around its cruising speed, since we know that on long haul flights planes across the oceans planes use jet streams to reach their location. It would be traveling the plane's cruising speed + jet stream.

Jetstreams even enable supersonic flight for commercial aircraft.

On the flight trackers there have been some interesting anomalies. Jeran shows at the 1h32m mark of the following video about the flight between Auckland and Santiago that True Airspeed can be seen to far exceed ground speed. Over the course of the flight the True Airspeed is either "N/A" or shows quite fast speeds.

https://www.youtube.com/watch?v=GKKHY72x3ZU




A jetstream is just a wind, and I accounted for it in my calculation.  A look at any jetstream map will show that they are predominently westerly in the southern hemisphere, which corresponds with my previous statement and, if it is assisting the eastbound flight will it not be hindering the westbound which is occuring simultaneously and at similar latitudes? 

We've also done Jeran's thing before.  Simultaneous to the "supersonic" speeds is a series of altitude changes which an F-16 would struggle with.  Its just a batch of missing data on aircraft position; when it recovers the position data it integrates the delta-position over time to determine speed.   

Pages: [1] 2 3 ... 18  Next >