I believe you are going to have to ignore this leading theory. EVERY Pro Series Kit has this exact same type of nose cone including the 4" diameter Mega Der Red Max. My non scientific theory would be modelers for some reason like to have their nose cones not come off easily so they apply tape to the shoulder of the nose cone to increase the friction, or maybe it's just to tight a fit to begin with and they never took the time to sand te shoulder down for a loose enough fit. I for one prefer my nose cones to fall off when the rocket is pointed nose down. I've NEVER had a nose cone come off because of drag separation that some people clam will happen. Maybe you need more friction for high power models that obtain extreme altitudes but for anything Estes related even with uprated motors I don't see the need. Estes has sold Tens of Thousands of our new ARF line which have nose cones with very loose fits. I've actually flown close to two thousand of them with around 500+ two stage flights with our D booster and I never saw one of the loose nose cones come off. So my advice would be to loosen up your nose cone fit.
John Boren
Obviously you have way more experience than any of us, and I'm sure you know very well what you are talking about with regards to Estes kits and how best to set them up for flight. But I don't agree that Estes models NEVER drag separate. I'm pretty sure I had it happen on my Trajector about a month ago. The nose cone very clearly came off right after burnout, and the parachute deployed while the rocket was traveling upward very quickly. Everyone agreed that we saw an ejection charge several seconds later. Of course, it's really hard to say for sure what happened --- maybe the ejection charge went of early and we didn't see the smoke until later. But I had flown the rocket with the nosecone much looser than I usually do, so the next flight I added some tape, and the flight was perfect on the second motor in the same pack as the first. Drag separation is probably not an issue with a fat rocket like the Big Daddy, but on a skinny rocket with high-drag features like the Trajector, it might be.
I had 3 lawn darts with the Big Daddy, and one parawad, and I'm pretty sure I know what happened with all of them except that last fatal one. The parawad was on an early flight, and I think I just did not get enough wadding/dog barf in there. After that, I bought my first nylon chute and nomex blanket. These were both bulkier than the plastic chute, and the nomex was definitely too big. It was too much for the space available, and it jammed in too tight. That's what caused the first lawn dart. The second lawn dart was caused by an E9-6 motor, which was just too little thrust and too long of a delay --- the rocket arced over and hit the ground before the ejection charge went off. The last lawn dart was unexplained. It was a night launch, so we could not really see what was going on with the rocket, but the nosecone definitely did not come off, and it drilled in ballistic. The motor was an E12-4, so plenty of thrust and a short delay, and should have been a good flight. Anyway, I'd chalk most of my Big Daddy crashes up to user errors, but the tight fit of the recovery bay make it a challenge. Even if the sloped nosecone shoulder is not the root cause of failed deployments, cutting it off and replacing it with a bulkhead and eyebolt is not a bad user modification, just for the fact it makes more room to work with for wadding and a more loosely packed chute.