I've flown my Big Daddy 6 times, three on D12-5's and three on E9-6's. All went well. I think I'm a little under the stated build weight and thus should be getting upwards of 900' AGL possibly more with the E9-6.
I've been reading about the concerns with the nosecone's angled shoulder allowing the ejection charge pressure to blow-by and not eject the parachute. This can only happen if the nose cone is pushed forward about 1 inch. I'm sure this has been mentioned somehwhere but I didn't find it, so I'll mention it here... It occurs to me that the pressure difference upon rocketing up to 900 ft could push out the nosecone. At 1000 ft AGL, the pressure difference vs. ground at sea level would be something like 14.7 psi - 14.16 psi = 0.54 psi. The area of the Big Daddy's Big nosecone is about 6.8 sq in. Thus for a "unvented" Big Daddy, the pressure force would be 0.54 * 6.8 = 3.67 lb. Without going through more calculations, it would seem quite possible that the nose cone could be pushed out all the way to the problematic angled shoulder where it would then vent pressure. If the ejection charge fired in that state... it would be less likely to eject the parachute properly, allowing the Big Daddy complete a ballistic lawn dart maneuver.
My Big Daddy's nosecone is relatively loose. It differs slightly from the nosecone on my Leviathan in that it has 6 evenly-spaced circumferential raised plastic lines around the nose cone shoulder section that run from the seat to the bottom. These raised "lines" are what make contact with my body tube inside diameter. I'd guess it is a near perfect slip fit.. very little friction and very little side-to-side play. I do not have a vent hole in my Big Daddy, but I think the slip fit nosecone along with those slightly raised lines give it the ability to equalize pressure somewhat as soon as the nosecone moves slightly from its seated position. I suspect I'm lucky that the stock nose cone fit the way that it did. I imagine that after launch the internal pressure does push out my nosecone as the rocket decelerates toward apogee, and when the nosecone comes off it's "seat", the internal pressure vents to the outside without the nosecone moving more than a fraction of an inch. Still, I plan to add a vent hole. The Big Daddy has a big diameter which in turn generates more pressure force with altitiude.
