I'm not real sure of the point of going to all the trouble of scale detail on a Gemini-Titan and then using a 3-motor cluster.
I will say, it did fly pretty straight for a finless GT design with no "invisible fins."
I would also say I wouldn't want to be in the general vicinity of a rocket made substantially out of metal (including metal nose cones) coming down with no recovery system after a boost on 3 E's.
It occurred to me when he showed the shot of the post-impact rocket leaning up against the back of the van -- if the wind had carried that thing in the right direction, it probably would have punched right through the roof of the van, if not the floorboards as well.
There are reasons rockets are supposed to have recovery systems. If not to get the rocket you poured hours of work into back in something resembling the condition it took off in, at least to avoid ballistic projectiles auguring in at several hundred mph.
To address the question: the rocket motors have ejection charges usually sufficient to detach the nose section from the airframe.
Usually the nose and airframe are connected together by a fabric cord and a plastic or fabric parachute packed inside to recover the whole package (or at least to prevent uncontrolled ballistic impact).
While the workmanship on the large models doesn't look bad, I can only suggest it might have been an idea to work your way up with a couple smaller starter-kit type rockets to learn the basic nuts-and-bolts of how model rockets are generally supposed to work then graduate up to the bigger stuff. I don't mean to be nasty but this is stuff most of us learned when we were 8 years old the day we built our first rocket kits.
Plus you have probably already been told this many many many many times but these rockets you have built, while they look OK as far as workmanship, paint job, etc etc etc, violate just about every conceivable safety code related to model rocketry and also high-power rocketry as well as probably several state or local laws and ordinances, and model rocketeers are getting tired of having to contend with hassles of new regulations imposed when stuff like this goes wrong and drills through somebody's back yard or something, so it really might not be a bad idea to spend a couple more hours building these things the way they're supposed to be built.
