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-   -   Where a Twotter goes even ... (https://www.pprune.org/canada/580491-where-twotter-goes-even.html)

ExXB 17th June 2016 12:02

Where a Twotter goes even ...
 
Hercules fear to tread ....

https://www.washingtonpost.com/news/...evening&wpmm=1

Flight aware track of one of the two ...

Jhieminga 17th June 2016 12:12

Impressive! But I notice that the aircraft does not seem to have moved a lot over the past day... duty time limitations perhaps? Or have they moved too far South for them to be tracked?

akaSylvia 17th June 2016 15:03

They are showing as in Costa Rica so definitely not too far south. I don't see why Flight Aware wouldn't be able to track them to Rothera. Only one will continue from there and the NSF's site says the earliest it could arrive is the 19th. I wonder if they are waiting for better weather, although it would seem worthwhile to head down to Chile first?

albatross 17th June 2016 16:12

I think the KBA crews know how to do this flight in the safest, quickest way!

Loose rivets 17th June 2016 21:06

I've just spent a tough but enjoyable hour three layers deep in articles on the science. Again, I'll mention Smoot's book, 'Wrinkles in time'. As a page turner, it beats Geoffrey Archer.


Back to this link.



. . . powerful,” Kovac told me.

This is a man who has devoted his professional life to South Pole astronomy, making 24 trips there, each as arduous as you can imagine (fly to New Zealand, then to the McMurdo station on the Antarctica coast, then to the South Pole). In his early 20s, he overwintered at the South Pole, spending 14 months straight at the bottom of the world. In the early 1990s, South Pole astronomer was a much more rugged affair with primitive equipment and a lot of exposure to the elements. He showed me a photograph in which, dressed almost like an astronaut, he’s climbing onto a telescope with a giant tank of liquid helium on his back. This kind of astronomy requires very cold instruments, which is why he has spent two decades lugging liquid helium to the South Pole. As he puts it, the South Pole just isn’t cold enough by itself.

It’s safe to say that if Kovac and his colleagues can’t detect the signal of cosmic inflation, it won’t be for lack of trying.

Just lots and lots of gutsy people doing science these days.

The Banjo 17th June 2016 21:19

How do they manage the low fuel temps? A bit hard for a Twotter to descend to a lower level and increase mach number!

Phileas Fogg 18th June 2016 03:02


Between February and October, only one type of craft can fly to, land at and take off again from the South Pole: the tiny Twin Otter.
Ahem,

I'd bet a beer that a DHC7 could do it and with some 2.5 times the payload of a DHC6

pattern_is_full 18th June 2016 03:19


How do they manage the low fuel temps? A bit hard for a Twotter to descend to a lower level and increase mach number!
Apparently the fuel is preheated before loading - one reason for choosing the Twotter over the Hercules, 2500 lbs to heat instead of 60000.

The Twotter can carry a cabin auxiliary tank, which of course is not exposed to the cold until needed. (but I presume Herky-Birds have that option also).

They'll need the reserve tank just for the outbound leg, so there must be refueling capacity at the Polar base - and that fuel can be preheated also before the return.

Lazerdog 18th June 2016 05:46

The DHC-6 is an impressive aircraft in many ways. A friend ferried one back from a remote field in Alaska years ago which required a single engine take-off. Not sure many twins would be capable of that but with that large vertical tail and keeping it light, it was apparently quite easy.

troppo 18th June 2016 05:55

I don't get it...
Winter flights to NZ's Scott Base in Antarctica under way | Stuff.co.nz

ion_berkley 18th June 2016 06:21


I don't get it...
Winter flights to NZ's Scott Base in Antarctica under way | Stuff.co.nz
Scott Base is right next to the US base at McMurdo. Its a Costal location, likely with relatively warmer weather than the South Pole base.

Ant T 18th June 2016 07:58


I'd bet a beer that a DHC7 could do it and with some 2.5 times the payload of a DHC6
I think not.........

South Pole is 9,300ft above sea level, and does not have a runway - the only aircraft that operate into there are Twin Otters on skis, and Air National Guard LC-130 (ski-fitted Hercules). The LC130s operate off over 10,000ft of groomed snow (that is maintained through the short summer operating season). The Twin Otter obviously needs much less skiway.
As far as I know, the LC-130 has a minimum temperature for take-off and landing of -50C (hydraulic system limitation?). Twin Otter, with simpler systems, has been operated down to -60C. (Would have to dig out my books to check the official limit).
Year round average surface temperature at South Pole is -49C, and can get into the minus 80s. At this time of year, the average temperature is between -55 and -62C. The operating window for routine operation of the LC 130s to Pole is early November to late February. (Today looks like a warmish day there for the time of year, -51C, 1600m in blowing snow)

The flight from Rothera (British base at 67S on the Antarctic Peninsula) to Pole is about 1300nm, approximately 10 hours in a ski-fitted Twotter. Ferry tanks in the back, PNR approximately half way, nowhere else possible to land. Almost the whole route in complete darkness, including the landing on a skiway with no proper lighting. Although there have now been 3 landings at Pole during the winter, two were early or late when there was still a bit of light in the sky. I believe only one was in total darkness - this one is going to be pretty close to mid-winter.


(2500 hrs ski Twin Otter inc 5 landings at South Pole, 2000 hrs DHC7)

OPENDOOR 18th June 2016 10:53

Any news on when they will depart Costa Rica?

AC560 18th June 2016 12:56


Originally Posted by Lazerdog (Post 9412183)
The DHC-6 is an impressive aircraft in many ways. A friend ferried one back from a remote field in Alaska years ago which required a single engine take-off. Not sure many twins would be capable of that but with that large vertical tail and keeping it light, it was apparently quite easy.

AC560 can ;-)

golfyankeesierra 18th June 2016 23:49

Ant T, Hats off to you and those other bush pilots!

Roo 19th June 2016 00:36

Yes hats off. Damned impressive.

....there have now been 3 landings at Pole during the winter, two were early or late when there was still a bit of light in the sky. I believe only one was in total darkness - this one is going to be pretty close to mid-winter.
Would seem (Very sensibly) this mid winter flight may be getting timed so as not to occur in the dark. Coordinated with a full moon that last for weeks!
https://blogs.crikey.com.au/planetal...not-done-dark/

The Ancient Geek 19th June 2016 00:50

Another nice thing about the Twotter is its performance at the other end of the limits, if a donkey quits when is is very hot and high - no worries, it still has some climb left.
Marvellous machine with very few vices other than the noisiest office in the business.

Phileas Fogg 19th June 2016 01:07

Had a Twotter one day en-route PLH/LHR with a full load, one engine disintegrated resulting in a "Mayday" and a dirty dive in to RAF Odiham.

compressor stall 19th June 2016 03:40

Roo,

I'd pay scant attention to Sandilands' articles. He purports to be an Antarctic aviation expert journalist because he went there as a passenger in a herc some 37 years ago. He might know more than the standard journo, but that does not an expert make.

Many of his articles are riddled with factual errors (including the one you linked above) and big noting to suit some agenda I cannot understand.

Car RAMROD 19th June 2016 04:45


How do they manage the low fuel temps? A bit hard for a Twotter to descend to a lower level and increase mach number!
Fuel tanks are in the belly, not the wings. Unpressurised cabin. I'm guessing there might be a way to keep the ferry tanks warm enough via normal bleed air heating of the cabin and in turn keep the main tank fuel warm, either through circulating the fuel or ducting warm air around it?

No experience with Twotter winter ops myself, but one or two hours on type in a former life. Great machine.
Anyone with proper winter experience on the Twotter around who can share info?


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