Fiberglass nosecone questions.

I found a nosecone online that I want to use with a project I'm starting ~ the air frame for the project is the 5.5" from LOC, and the nosecone is from another manuf that only spec's the shoulder as 5.5". It arrived today but the nosecone doesn't fit into the LOC tube, and there is no centering ring/cap at the bottom of the base (it's open).

Two questions:

1. Can I sand down the nosecone base to fit into the airframe tube? Standard sandpaper? Looking for the proper technique to do so with FG if there is such a thing. It's off by about 1/8 inch RADIUS total. Like I said it's a finished nosecone with a nice smooth finish.
2. What do you suggest for cementing/gluing a centering ring/nosecone into the base so I can attach the recovery system?

Thanks,
Frank

1/8" radius error, or 1/4" diameter, seems too much to readily deal with. For that much error, I'd likely chop the base off the nosecone down to where the diameter is a tiny bit larger than the airframe. Square it up carefully. Then I'd take an airframe coupler segment and sand a taper into one edge on the outside. Clean the inside of the nosecone, then rough it up, then epoxy in the coupler section. Make sure the nosecone base is square before doing this, and make sure to align the new nosecone shoulder straight! Then sand the outside edge of the nosecone to match the airframe tube.

For an attachment point, I like to take a 1" ring of coupler and notch out enough so that it can fit inside the nosecone shoulder. Make a solid bulkhead that can go in as well. Bulkhead goes in first, followed by the ring. Solidly epoxy both in place. Now that bulkhead is not coming out! Of course, you need to make provisions for eyebolt, and possibly foam filling the nosecone. I like filling the nosecone with expanding foam (2 part, not spray). It adds a little noseweight plus makes the nosecone much more survivable. If you think you might need some noseweight, then you might as well anchor it in with some foam before fitting the bulkhead and ring.

Gerald

UPDATE: I took the base to a belt sander and thinned out the gel-coat ~ seemed to do the trick.


It's actually 1/8" circumference, not radius sorry ~ it's close enough that it seem I may be able to sand down the gel-coat but is that something that can be done without affecting the integrity of the FB strength/structure?

I like the foam-fill idea, that'd help reduce impact cracks on minor bumps for sure.

Ok one more question. The nosecone is hallow and I am able to insert a 6 inch piece of cardboard tube into the base opening. It is a snug fit, so would standard 2 part epoxy be sufficient to bond the cardboard to the inner surface of the nosecone base?

I'm going to add a bulkhead and eyebolt.

Many fiberglass nosecones you need to add a coupler to the inner part of the bottom of the nosecone with your own bulkplate and eyebolt. High quality 2 part epoxy will work. sand the parts to be glued with 100 to 120ish grit use a forged eyebolt if the rocket is going to be over a couple pounds. What brand is the cone wildman/rocketry warehouse? Be sure to add weight to the cone now if you think you will need to move the CG forward

And a fiberglass coupler and bulkplate would be a nice choice for the shoulder if you want to use the cone in a all fiberglass kit in the future but not necessarily required.

Howhigh said:

Many fiberglass nosecones you need to add a coupler to the inner part of the bottom of the nosecone with your own bulkplate and eyebolt. High quality 2 part epoxy will work. sand the parts to be glued with 100 to 120ish grit use a forged eyebolt if the rocket is going to be over a couple pounds. What brand is the cone wildman/rocketry warehouse? Be sure to add weight to the cone now if you think you will need to move the CG forward

Click to expand...

Thanks for the info, I ended up going with a cardboard sleeve and used ABS Cement to join them together (before your reply was posted).

Yes, Rocketry Warehouse ~ they were the only ones that had a round 5.5" which is the look I wanted. It took a little "work" on the belt sander to get it to fit into the LOC Precision 5.38 ID / 5.5 OD airframe. Only took a bit of the gel coat off.

yeah I love rocketry warehouse they have a great selection of cones and fantastic prices on everything.

Yeah this was my first purchase with them and I'd recommend. Good pricing and quick shipping.