Nose cone weight

Well, I finally got to work on my L1 cert model - and it is almost finished. I'm building a 3" diameter tube fin model and plan to fly it on an H128W. According to Rocsim, I need 5 ounces of weight in the nose cone for good stability. I have two ounces in tip already (epoxy and shot added one ounce at a time to avoid curing heat problems). But now I am concerned that having all the weight in the forward tip of the nose might cause problems (drag sep). The nose cone is an 11" long blow molded cone. I plan to drill two holes and make a loop of kevlar cord to attach the shock cord to the nose so I will not use the molded loop at all.

My question is: should I put the rest of the weight in the forward tip, or should I put the rest near the shoulder? I know that will move the CG back a bit but it should be OK - just not sure how to get the shot slurry in and at the aft end of the nose (the hole is about 3/4" in diameter.

Suggestions?

Leave the weight in the tip. With a proper NC/BT fit, the NC won't go anywhere (until it is supposed to). I have a Madcow Phoenix with ~8 oz noseweight, and I've never had a problem in 15 flights.

David

I would think location inside the nose cone would be a non issue when it comes to drag separation.

The distribution of mass won't change the total effective energy present in the nose cone. For you to make a meaningful change, you would want to mass anchored to the body tube. But such would then likely effect the recovery system's ability to be pulled out. It could be done, but typically isn't.

Looking around, you will find many people have quite a bit of mass in their nose cone and fly fine.


Kirk

Use shear pins. Depending on the rocket 2 or 3 2x56 nylon screws through the body tube and nose cone.


Mark Koelsch
Sent from my iPhone using Rocketry Forum

When you prep for flight. Get everything loaded (motor, recovery etc).

Pick the rocket up by the nose and give it a shake or two - as if trying to get it to separate... if it does come apart, add some masking tape to the shoulder for a tighter fit. Ask for help from a more experienced flyer if you need to.

With the proper fit you will not need to worry about drag separation on your 3" rocket powered by an H123.

No need for shear pins or anything exotic at this size/power level regardless of nose weight placement.

Good Luck!