On Wednesday, July 24, 2013 7:40:07 AM UTC-7, GC wrote:
On 24/07/2013 23:10, brayera wrote:



This video presents final glide of his Discus 2a wing to wing with



Arcus flying at 200km/h. As you can see at this speed performance



of 20m span glider is no better than 15m Discus 2a.





course not. the drag penalty for the extra span kills you at high

speeds. when they slow down the arcus will walk away.



When they slow down a Libelle would walk away from both of them. But

that's evading the issue. 200ks (108 kts) is hardly high speed in a

modern glider. When DOES the Arcus earn its keep?



GC

Increasing wing span is the solution to induced drag. At high speeds, Cl is low therefore Ci is low therefore wingspan is no longer the solution. We are not breaking new ground here, this is 100 year old information. However against the Libelle, my money is on the Arcus at any speed.