Flight porosity and effect on performance

Flight porosity - how readily air passes through the flight or skirt of a shuttlecock, is all important. Feathers act as an almost complete baffle. They do this with help of a few 100 million years of evolution culminating in a rigid stiff but flexible structure which weighs almost nothing and can self repair. However they not meant to be hit at 250kph with a carbon fibre racket. Nylon shuttles are made with a lattice in order to be moulded and give a resilient product. This makes a perforated flight which gives less air resistance than a feather flight.  This has a number of affects on the feel and performance compared with feathers but most significantly it makes standard nylon shuttles less controllable around the net. In a net shot a shuttle is pushed backwards and the level of resistance to the air determines the speed of turn over or 'righting' and  the height of the bounce off the racket. Standard nylon shuttles therefore 'ping' higher and are more difficult to keep tight to the net. This is why feather users say that nylon shuttles are not controllable and nylon users say that feathers feel 'heavy' - in affect,  in backwards mode, they are as they trap more air.
The unique two part construction of the Bird2 design facilitates a much denser lattice pattern which forms a much more feather-like baffle so that the height off the racket in net shots is similar to that of feathers. The Bird3 design, due to reach the market in a few months, carries this feature on further and matches a feather performance.