WindSock

[Guest danda]

I have noticed here at Holbrook that the windsock doesn't always give a true indercation of the direction of the wind and I was wondering weather buildings effect the windsock as its has hangers on 3 sides?

 

Don

 

 

[PaulN]

Hi Don,

 

We have a sock at each end of the 2120m runway here at Cooma and it's not unusual, in fact more usual, to see them indicating differently.

 

The wind will always be affected by terrain and man made obstacles. The degree and resultant effects will change with the dominant air flow (wind direction).

 

As air is fluid, we can liken it to water flowing in a stream. Place an object (rock, stick, whatever) into a part that appears to be flowing smoothly in the down stream direction and you will see the direction of flow alter, at least in the vicinity of the object. Make the object bigger and the effect will be greater and more widespread. Place a number of objects in random spots and the flow is all over the place while still generally heading downstream. Added to this is the eddy effect around some objects causing the flow to momentarily head upstream as it swirls around like a mild whirlpool.

 

Also worth considering is the drag effect that the ground surface has on air flow. Say the lower level atmospheric wind is flowing north to south (northerly). Close to the ground the drag effect of the surface, even a substantially flat and smoothe surface, will cause a directional variation of the wind, say NNE or NNW, and sometimes more acute directional changes.

 

Hope this helps,

 

Paul

 

 

[Guest David C]

The two wind socks at Lord Howe Island Airport often point in different directions due to terrain shielding , and they are placed only 800M distant from each other ..

 

 

[Guest Fred Bear]

At The Oaks one points North and the other South...often...just ask Dave C!

 

 

[Guest danda]

I thank you all for your help I find it a little confusing if you have a windsock at each end of the runway and they both give you a diffrent wind direction how can you best judge what direction you need to land from?

 

I was also wondered if by moving the windsock to open ground closer to the intersection of the two runways where it would be in open country would we expect a more accurate indercation of the wind direction?

 

Don

 

 

[Guest David C]

At The Oaks one points North and the other South...often...just ask Dave C!

No worries in the Bantam ...... Just land across the runway !!

 

Dave C

 

 

[Ultralights]

Hoxton park is the same, the norther sock will be in calm air, yet the southern (more accurate) will be in gale force winds.

 

 

[Guest Fred Bear]

Maybe a half way point in between Don? As Dave suggests, across the runway in the Bantam mate Without taking the pee pee out of anyone, look at which sock is giving the strongest indication whilst you are overflying (with the traffic you have heard previous) and judge by the ARFOR and that should give you a good indication. Buildings/trees etc will give you a strange reading so look for the one where there are the least obstructions. Hope this helps.