Everything you need to know about windsocks | Hacker News Reader

Everything you need to know about windsocks

hollandaviation.nl

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Title in HN context gave me a flashback to the 90s: Everything you need to know about Winsocks [1] (windows sockets)

1: https://en.wikipedia.org/wiki/Winsock

Beej's guide still gets updated! I remember it from the early 2000s.

https://beej.us/guide/bgnet/html/

Me too. I thought this post is related to Windows network programming.

I thought the same thing.

I finally realized that “winsocks” name is a clever pun.

It didn’t help that the original logo was an orange and white windsock...

90's? On desktop world this is pretty much still in use due to Windows being king on desktop. And if you master Winsock you can still rack in the big bucks even if you ignore everything else.

By doing what exactly?

Why not use a wrapper API like ASIO?

Why not just use the API? :)

Advantages:

* Using a wrapper lets you use the same API on different platforms. This is not just for programs that are expected to compile and run on multiple platforms (although that is the main reason); it's also for developers who are expected to write programs for multiple platforms.

* This potentially allows for a cleaner API, because the native OS one has to be careful about backwards compatibility, whereas wrapper APIs can be more carefree about it, at least initially. In the most extreme case, you can use a totally new library with a freshly-designed API. At this point ASIO has stabilised, but you can see it's substantially different from WinSock (albeit it has the same fundamental concepts, of course).

* The underlying OS API generally has to be purely C-based, whereas a wrapper can make use of langauge features, such as C++ features in the case of ASIO. It is sometimes debatable whether it's a benefit to make use of C++ language features! But at least some people would consider it to be.

Disadvantages:

* As discussed above, job security!

I also immediately thought of winsock.

This is the first time I felt that the title "Everything you need to know about..." actually was correct. I learned something and the text contained everything I ever might ever need to know about windsocks.

> A metal basket (or so called swivel frame) is placed on top of the mast, which can rotate 180 degrees horizontally.

Is there some reading of this that makes sense with the figure being 180° instead of 360°?

Even 360 degrees would be incorrect. That's how you would describe a construction that allows to do one full rotation and then stop. For example, tarsiers or owls can rotate their heads about 360 degrees.

But a windsock needs to be able to rotate over and over and over without bound. That's distinctly different from 360 degrees.

> owls can rotate their heads about 360 degrees

No, some of them can rotate their heads > 200 degrees in either direction. This gives them a full 360 field of view but they cannot rotate their vertebrae all the way round.

That gives them total rotation angle of slightly over 360 degrees.

For a mechanical example, consider a common rc servo. They are specced as 180 degree, but from their normal center they can only rotate 90 degrees in either direction. Doesn't matter, they are still capable of 180 degrees of revolution.

So, your parent comment was correct, owls can rotate their heads through 1 full revolution. If they could rotate their heads one revolution either direction, then they could rotate their heads 720 degrees.

15 minutes on a web search and I can't figure it out either. Any flight experts here?

https://www.skybrary.aero/index.php/Windsock

"Windsocks must rotate freely around a vertical shaft"

10 seconds google for "windsock rotation". Second result right after the original article here on HN. And arguably more informative

Yes thanks, it makes sense the posted article has an error in that regard and the link you posted is indeed more informative! Though on my search I learned that they probably originated in China or Japan, made of paper, to celebrate the birth of a child.

If you want to dive deeper, here's way more than you ever wanted to know about windsocks:

https://www.faa.gov/documentLibrary/media/Advisory_Circular/...

An easier way to "read" a windsock: count the bars until the windsock "breaks" / folds down, as per: https://patentyogi.com/wp-content/uploads/2016/03/Patentyogi...

Exactly that is mentioned in the article.

To be fair, the article mentions reading via which elements are 'full', and I mention by the 'crease point'.

When I started parachuting, I struggled to quickly read windsocks, because the definition of 'full' can be somewhat ambiguous (Is it mostly / somewhat / completely inflated, what if it's full now but wasn't three seconds ago..)

I'd found: See where it 'breaks' provided a much better point of reference.

Perhaps this will help others that shared my confusion :)

An infographic like this would have made that part of the article much more clear!

"A metal basket (or so called swivel frame) is placed on top of the mast, which can rotate 180 degrees horizontally. "

180 degrees ? Isn't that 360 degrees ?

No. Both are incorrect. It needs to be able to rotate freely, more than just one full turn (360 deg)

Another use: skydivers rely on wind socks as well to land against the wind

They also throw wind drift indicators out of the plane before commencing the jump run

Wind drift indicators are more to determine the winds at altitude vs on the ground. We drop them right over the landing zone and watch where they land. Then, adjust the jump run, exit point, and pattern accordingly. So, not necessarily determining the direction of landing, because winds can be different on the ground and at altitude.

My wife, who used to work in an airport tower, gave me this tip about reading windsocks: Imagine a tiny aircraft coming out of the mouth of the windsock---that's the direction a real aircraft will use to take off and land.

But you might be off by up to 89 degrees. Depends how many runways you have :)

Argh. Why are knots still used? I imagine it's the same reason the USA can't go metric

Well, a nautical mile is defined relative to a fundamental constant -- the circumference of the earth at the equator. This is objectively useful when at sea, and so I, for one, prefer it to either statute miles or kilometers.

Here in Norway, people tend to talk about wind speed in meters per second. Happily, a knot is very close to a half a meter per second, so I'm not as lost as I'd be otherwise.

There is good video about "Imperial VS. Metric" posted by 'Real Engineering' two month ago.[0]

> USA can't go metric

SpaceX already use[1] metric:

> Despite NASA's non-compulsory policy, commercial space manufacturer SpaceX currently designs its systems (e.g. Dragon and Falcon 9) using metric units.

According F9 v1.0 Users Guide it seems like SpaceX mixed SI (preferred) and US units on same vehicle.[2]

FTR, On May 1st, 2016 Elon Musk said[3] next:

> Historical precedent. Mars vehicle will be metric.

And its proved in Starship Users Guide v1.0, posted by SpaceX on March 2020.[4]

[0] https://www.youtube.com/watch?v=hid7EJkwDNk

[1] https://en.wikipedia.org/wiki/Metrication_opposition#Governm...

[2] https://old.reddit.com/r/spacex/comments/1urk4k

[3] https://twitter.com/elonmusk/status/726878573001216000

[4] https://www.spacex.com/media/starship_users_guide_v1.pdf

Most windsocks I see are solid orange, without stripes. I guess pilots “eyeball” where the bend is?

Pilots don't really care about where the bend is because it only shows up to 15 knots and it becomes mostly relevant for limitations at higher speeds. Most relevant visually is the general direction, changes in direction and whether it's half inflated or full, that's enough precision from a glance.

The strength and gusts are also reported by the tower, they'll say something like "Wind 270 at 15 gusting 25, runway 23 cleared to land" which means the wind is coming from 270 degrees (West), at 15 knots with gusts up to 25. Then you have a general idea of the crosswind on the runway being about 12kt gusting just under 20ish from the right. Accurate enough to figure out whether a limit needs to be calculated.

You see the striped ones in Europe and the solid orange ones in the U.S.

It's not a precision instrument. Windsocks wear out fairly quickly. It' gives you the direction fairly accurately, and the speed say +- 5 knots, which is adequate to choose a runway and have a good initial guess of how to correct for a crosswind. Once you've started your takeoff/approach, you make corrections based on the observed behavior of the plane, e.g. on final approach, if you drift a little to the right of centerline, you correct a little to the left.

Didn't realize there was anything I needed to know about windsocks. Interesting, thanks!

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