Originally Posted by mikeyd

I was always under the impression, this was done, to get the Saturn V to market, as Estes did not have the D13-3 ready yet, but it was planned. I even thought the earliest Saturn V kits did not include the "D engine Adapter". But this is all just from memory, so I have no proof, or first hand knowledge. By the time I got my original K-36, the D13's were available, but even now I still like to fly it on 3 C6-3's occasionally. First available in the 1969 catalog.
http://www.ninfinger.org/rockets/no...a/69est024.html, only lists C6-3 for engines.