What is the benefits of making fins of water rockets by using old CDs?

Question

ok, I want to save money, so I use that Cds to make fins for the rockets...

Answer 1

Almost no benefits because awkward shape of bottle puts a lot of air turbulance around location of fins and flight is so short with constant changes of "fuel" mass.

Have you tried cutting old CD's, not easy.

Answer 2

The benefits are availability and cost.  Most have lots of old AOL CDs lying around that were sent in the mail over and over and over again.  From an aerodynamics viewpoint - it's a water rocket - it's an aerodynamic nightmare from the start, so performance isn't really an issue in my opinion.