Posts Tagged ‘average wind speed’


1. Design a Monster Duck

November 7, 2013

Dutch conceptual artist Florentijn Hofman has entertained millions around the world with his Monster Rubber Ducks.

pic 1 duck Rubber-Duck-Florentijin-Hofman-21-537x357

Different sized ducks have appeared in Amsterdam, Lommel (Belgium), Osaka, Sydney, Sao Paulo, Hong Kong and Pittsburgh.

pic 2 duck

Each duck is constructed using 3D and Computer computer generated models.

More here. 

pic 3 Hofman duck construction

pic 4 rubber duck beak

The Duck that appeared in Darling Harbour, Sydney in 2013 measured approx 15 m x 15 m.

It was FIVE STORIES high.

The largest duck, which appeared in Saint Nazaire, France measured approx 25 m high or 82 ft and weighed almost 600kg or 1300 lbs.

This mega duck is over 8 stories high!!!!!

BUT how does an artist stop the wind picking up an 8 story duck and dumping it on your head?

He – Florentijn is a he – does his maths.

Here is a simple wind load formula for stormy conditions.

F = Kv2A

F  = Wind Force (Newton)

K = Coefficient of Exposure = 0.5 (Engineers use standard tables for K)

v = Wind velocity = 72 kph = 20 m/sec

A = area of X-section exposed to the wind

Pic 5

Now, we’re going to be tricky. A 1 kg weight (eg. a litre of milk) exerts a force of 9.8 N or 1 kgf = 9.8 N on your hand. If we divide the above formulae by 10 we end up with a unit we know …. kgf.

F = Kv2A/10   kgf

pic 7


If the wind force is 9,560 kgf in a storm it can easily pick up a 600kg duck. In fact, if you do the calcs, it is only in a normal wind ( 20 kph or 5 m/sec) that the duck would stay put (F = 597 kgf).


If that duck is not tethered to a building or pontoon it could take off and it could easily take out a school!!!!!

pic 8