Rajul,

Retro pattern is basically what pattern was from the 60's and 70's right up thru the introduction of the present day "turnaround" pattern. The "OLD" pattern was basically one manouver on each pass. One upwind and one downwind... and you could turn around anyway you felt like and then do the next manouver. This means you are covering a MUCH larger flight line than the present day airplanes. Speed was king at that time and nobody cared (and most people really loved) the sound of the piped .60's turning 14K Plus. I believe turnaround came into being mainly due to the massive noise problems that were rearing their heads in Europe. Turnaround pattern has a smaller noise footprint, plus the planes must fly much slower to complete all the aerobatics within the "BOX". For comparison, check out the Senior Pattern Association web sight
http://www.seniorpattern.com/ and then compare that to the NSRCA website www.nsrca.org/. It will give you an insight into two very different styles of flying and aircraft. While both are concerned w/precision aerobatics, they accomplish this in very different ways. I fly planes in both and enjoyed it a LOT !! Hope this info helps...

Dan Hines
Carolina Custom Aircraft