Crosswind Component

[Doug G.]

Does anyone have a simple, do it in your head, way of calculating the crosswind ( and headwind?) component for a particular runway?

[Ian]

the rule of sixths

 

take the difference between your heading and the wind and round it off to the nearest 10 degrees

 

so, say it turn out at 20 degrees off, then the crosswind component of the windspeed will be 2/6 x actual windspeed

 

30 degrees is 3/6 or half!

 

If it is 60 degrees off then treat it as effectively all crosswind

 

Very easy to remember an calculate in your head.

[GravityKnight]

The 5-7-9 rule.

 

30 degree crosswind... multiply by 0.5

eg wind 30 degrees off runway heading at 20 kts x 0.5 = 10 kts

45 degree crosswind... multiply by 0.7

eg wind 45 degrees off runway heading at 20 kts x 0.7 = 14 kts

60 degree crosswind... multiply by 0.9

eg wind 60 degrees off runway heading at 20 kts x 0.9 = 18 kts

 

I was taught something similar

 

30 deg - half

50 deg - 3/4

70 deg - 90% or basically all

 

Which is easy to remember when you simplify it like this:

 

30 - 50

50 - 70

70 - 90

[S4Flier]

Doesn't anyone remember basic trig -- crosswind is simply the sine of angle between the runway and wind direction

[GravityKnight]

Doesn't anyone remember basic trig

 

Never made it that far

[FlyingMonkey]

Doesn't anyone remember basic trig -- crosswind is simply the sine of angle between the runway and wind direction

 

How are you getting a wind velocity from a wind direction and a runway direction? I'm pretty sure the wind speed has to be in the calculation somewhere...

[S4Flier]

 

 

How are you getting a wind velocity from a wind direction and a runway direction? I'm pretty sure the wind speed has to be in the calculation somewhere...

Perhaps I meant to say crosswind component.....

[FastEddieB]

Playing with WingXPro7 in bed last night, I came across this in "Utilities":

 

 

That's a screen shot from the same app on my iPhone.

 

Might be something similar in Foreflight and I'm sure there are sites that can do the calculation as well.

 

Doubt I'd ever use it in real life - over time I think I can pretty well intuit what the wind is going to do for any given crosswind, but it could still be handy and interesting to play with.

[Tom Baker]

The Dynon, at least my D100, doesn't figure crosswind component. It gives wind dirrection and speed based on the difference between ground track and speed compared to heading and airspeed. You can take the dirrection and speed compared to your runway heading and figure the crosswind component. I have never found the Dynon speed and dirrection to be very accurate.

[WmInce]

. . . "The Dynon Skyview calculates the xwind for you" . . .

 

Are you sure about that?

Where does the Dynon indicate crosswind component?

[FastEddieB]

That is a cool feature I've never seen before.

 

Thanks!

[Ed Cesnalis]

Ok, 14 posts on xwind component brings me to this question; What do you do with this number?

 

Personally the only thing I need to know about the wind before I approach and land is that I am not likely to land downwind or worse yet get a gust behind my wing when the wind is mostly in front of my wing.

 

I will not for instance leave without flying an approach just because my x-wind component exceeds a book or personal number instead I will see if I have enough rudder at the moment that I am on short final and or the moment that I am landing.

 

If I abandoned my approach because of what the AWOS reports I would have missed many opportunities to land at my home field.

 

I don't lower my upwind wing because of the wind sock or the reported winds I lower it to counter drift. When landing I make the sight picture correct and then I keep it correct and I leave the thinking, the numbers, the xwind component out of it. Headwind vs tailwind component is another matter.

 

The thing that occasionally keeps me from even flying the approach is wind shear in the pattern. If the shear is too much to even fly the pattern then I abort.

[Doug G.]

My home airport is towered and I often don't have the chance to see a wind sock. The Dynon tells me the crosswind, but it does not tell me what it will be on the ground. ATIS, or a request for a "wind check" will give me the info I need.

Knowing the crosswind component only gives me an idea what to expect during and after turning final. Does it change what I actually do? Probably not.

So far I have not faced the same issues as you deal with CT.

[coppercity]

The Dynons also need a little coordinated straight and level time to determine the wind component. Although they are a great situational awareness tool any side slip or turning can effect the calculation. I would advise using the ground based tools and your actual crab angle on short final as your guide to the real crosswind component, as these calculated wind indicators can suffer some errors in the traffic pattern due to the varied speeds, configuration changes (varied calibrated airspeeds), and of course changing headings.

[WmInce]

From the Dynon Skyview User Guide Dated, June 2013. (CTLSI equipped with dual 10inch displays)

 

Wind vector information is located just above the OAT display on the PFD. The

winds aloft arrow indicates the wind direction relative to your current direction of

flight. The wind strength, direction, and cross wind component are also textually

provided. If the cross wind component cannot be calculated the arrow will not appear.

 

The Dynon also calculates True Airspeed, Density Altitude, Ground Speed, Angle Of Attack (meter).

 

Thank you!

[coppercity]

The Dynon, at least my D100, doesn't figure crosswind component. It gives wind dirrection and speed based on the difference between ground track and speed compared to heading and airspeed. You can take the dirrection and speed compared to your runway heading and figure the crosswind component. I have never found the Dynon speed and dirrection to be very accurate.

 

The D100 will display the crosswind and headwind component on the HSI display assuming you have it connected to a GPS source.

[Anticept]

If your dynon wind indicator is not accurate, then your plane's pitot static system is out of calibration. There isn't anything you can do about the airspeed, but you can zero the reference pressure in the hangar and hope that fixes it.

[coppercity]

If your dynon wind indicator is not accurate, then your plane's pitot static system is out of calibration. There isn't anything you can do about the airspeed, but you can zero the reference pressure in the hangar and hope that fixes it.

 

Another item that really causes the wind calculation to be wrong is the magnetic calibration of the Dynon. A calibration of the magnetic data usually fixes this as well.

[Anticept]

Another item that really causes the wind calculation to be wrong is the magnetic calibration of the Dynon. A calibration of the magnetic data usually fixes this as well.

 

Aye that can do it. The process for mag cal is rather complicated compared to zero pressure calibration, so one should start there first. Wind readings will always be a couple kts off, but more than that, calibration should be considered.