I built the Hydra-7 this spring. I chose to leave the center engine plus one of the outer engines open for ejection. I painted most of the parts before building which was a good choice. First launch was on 7x Quest C-6-5 (photo of liftoff below). beatiful lift off. near apogee you could hear 7 distinct "pops" - but there was no separation / no chute. Kit lawndarted in so fast you could hear the whistle as it dove deep into - the swamp (see picture). Intrepid RSO Mark Bundick volunteered to wade into the swamp (without realizing that it was going to be 2+ feet deep) to retreive my rocket.
Upon inspection, it was clear that all 7 engines fired and that both of the engines used for ejection were still in the rocket - the back end of the rocket was all that could be recovered - so no real explanation. The "fit" of the nose section prior to launch felt perfect....
So, I did what anyone would... I rebuilt it... and renamed it the "Swamp Bunny 7". The new rocket was nearly identical, but I added 6" of length to move the CG further a bit more than the original. I also made extra sure that the holes near the half-nose-cone-section were fully plugged as I thought this might have been the problem.
Second launch, same launch site 2 months later.... 7x Quest C-6-5 engines.
EXACTLY SAME RESULT - except that this time I missed the swamp and lawn darted onto mother earth. As you might expect, singificantly more damage hitting earth versus the "forgiving" swamp.
Maybe someday I'll re-build it once again, but for now I'm working on other things to keep my mind off the Hydra....
By the way, the Q2G2 ignighters are THE BEST - I've 7/7 on the Hydra twice. (4/4 5 times, 3/3 2 times and 2/2 10 times on other rockets this summer) See the picture for the Q2G2's after the Hydra launch....
-Kerry