Did you know that the white and orange strips on windsocks are not for decoration, they actually indicate relative wind speeds

Windsocks are conical textile tubes that are often installed at airports and at chemical plants where there is risk of gaseous leakage. They are sometimes also located alongside highways at windy locations. Wind socks indicate wind direction. However, many windsocks also provide an indication of relative wind speed, as shown below.

The most popular design of windsock includes alternating white and orange bands. The windsocks are calibrated to reach full erection at a particular wind velocity. At half that speed, the first half of the windsock should be erect and the second half should droop sorrowfully. At one third, the speed it will be one third, and so on.

Patentyogi_wind speeds

Patents reveal 5 most interesting designs of wind socks:

1. US 2617298 A – Miniature combination wind sock and anemometer

This device includes a wind sock and an anemometer. The direction of the Wind is indicated by the opening of the wind sock swinging into the wind and the velocity of the wind is indicated by the speed of rotation of the anemometer.

PatentYogi_US2617298

2. US 4730488 A – Windsock with wind speed indicators

This windsock includes a multiplicity of spaced chevrons for enhancing the detection of wind direction. The chevrons are spaced from one another by such distances that each chevron represents the addition of 4 or 5 knots to the prevailing windvelocity. Accordingly, if 4 chevrons are visible from above, the prevailing windspeed is 4 to 5 knots greater than if only 3 chevrons are visible from above.

PatentYogi_US4730488

3. EP2327991A1 – Windsock assembly

This windsock includes alternating white and orange bands. A light source directs light into the interior of the windsock. This makes the windsock visible at night and may help airport staff working at night.

Image credit: IMT
Image credit: IMT

PatentYogi_EP2327991

 

4. US 5319967 A – Wind speed indicator

This wind speed indicating device includes multiple panels of flexible fabric are attached to a pole. Each panel is heavier than the one above it, thus requiring a higher wind necessary to unfurl it or extend it horizontally. Each panel has markings on its side to indicate the wind speed required to effectuate its unfurling. The three panels indicate speeds of 8 mile per hour breeze, 16 mile per hour breeze and 24 mile per hour breeze.

PatentYogi__1PatentYogi_US 5319967

 

5. US 5117690 A – Wind speed and wind direction indicator

This wind speed and direction indicator includes a pole having a vertical scale of wind speed indicia for visually reading wind speed at a distance from the pole. A swivel head is mounted at the top of the pole for rotation to different compass directions. A rigid arm pendulum is pivotally coupled to the swivel head for pivotal motion of the pendulum to different angles with respect to the support pole. A wind drag structure such as a wind sock is coupled to the free end of the rigid arm pendulum for angular positioning in response to varying wind speed. A sliding collar is mounted on the support pole for sliding motion up and down over the scale of wind speed indicia.  A line is coupled between the free end of the rigid arm and the sliding collar for sliding motion of the collar over the scale of wind speed indicia in response to varying wind speed.

Combined image of all these 5 variations:

PatentYogi_Indicate relative wind speeds