FGM | Windsocks

Fiberglass Moulding Coffs Harbour Pty Ltd. PO Box 1177, Coffs Harbour, NSW, 2450, Australia.
Factory
 34 Hawke Drive, Woolgoolga, NSW, 2456, Australia
Phone
: 02 6654 0325  Fax: 02 6654 0725
Mobile 0427 733 012


Windsocks were originally developed during the First World War for aeroplanes with tail wheels.  These aeroplanes had to land and take off directly into wind.  These airfields were all over landing strips (i.e. there wasn't a runway as such, the airfields were large flat areas and the pilot landed in whatever direction he needed to).  Later when nose wheel aircraft were developed sealed runways were developed.  Although it was advisable still to land and take off into wind these aeroplanes were not as susceptible to cross winds.

While still having an obviously important application in aviation, windsocks have become important in many industries where wind direction is important, such as agricultural spraying, power stations, factories as well as helipads.

Because windsocks were developed in England before metric conversion the calibrated windsock size is 12ft long with 36 throat tapering to 10.  This calibration enables windsocks have a further application other than just signifying wind direction, they can give a reasonably accurate indication of wind speed.  This can be judged by the angle of the windsock as per the drawings below.

Wind strength is measured by a scale known as the Beaufort Scale.  Named after Admiral Sir Francis Beaufort who developed the scale for sailors.  The scale is shown below.

 

Force

Description

Appearance of the Sea

Visual Indications on Land

KM/H

Windsock

0

Calm

Like a Mirror

Smoke rises vertically

0

 

1

Very Light

Ripples

Smoke drifts.  Wind sock will not be affected.

1-5

 

Light Breeze

Wavelets crest but do not break.

Wind discernable on skin. Wind sock will indicate direction & speed.

6-11

 

3

Gentle Breeze

Large wavelets which begin to break, occasional white caps

Leaves and twigs are moved

12-19

4

Moderate Breeze

Small waves becoming longer, frequent white caps

Wind raises dust and loose paper.  Small branches move

20-29

 

5

Fresh Breeze

Moderate waves, many white caps, some spray

Small trees sway, waves appear in lakes and dams

30-39

 

6

Strong Breeze

Some large waves, extensive white foam crests, some spray

Large branches moving

40-50

 

7

Near Gale

Sea heaped up, white foam from breaking waves blowing in streaks

Whole trees in motion, walking becoming difficult

51-61

 

8

Gale

Moderately high and long waves. Crests break into spindrift, blowing foam into streaks

Twigs break off trees, walking difficult

62-74

 

9

Strong Gale

High waves, wave crests tumble and roll over.  Visibility lowered by spray

Roofing in danger of blowing off.

75-87

 

10

Storm

Very high waves with overhanging crests.  Poor visibility

Trees uprooted, structural damage

88-101

 

11

Violent Storm

Exceptionally high waves, Sea completely covered with white patches of foam.

Widespread damage

102-117

 

12

Hurricane / Cyclone / Typhoon

Air filled with foam and spray

Widespread damage

>119

 

   


Windsocks, Pegs & Poles    Placement of Windsocks

 


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