Cherokee-M Construction - Nosecone
July 12-13, 2003:
Large PML fiberglass nosecones come in three parts (at least this one did): a fairly flimsy phenolic coupler, the fiberglass tip, and a 1/2" plywood bulkhead with a U-bolt (not pictured):
This leaves two problems, reinforcing the coupler, and securing the coupler to the rest of the nosecone.
The solution kills two birds with one stone: laminate the inside of the coupler with fiberglass cloth, extending the cloth up into the main body of the nosecone to permantently join the two pieces. I chose to use fiberglass instead of carbon in case I want to install some sort of telemetry device into the nosecone at a later date.
It's kind of hard to vacuum-bag the inside of a coupler, but you can do a kind of inverse vacuum-bagging by sticking a baloon inside the coupler and inflating it. So you're using the pressure of the air inside the balloon to squeeze out the excess epoxy, instead of the pressure of the atmosphere against a vacuum.
As usual, my epoxy of choice is Aeropoxy (R2032 Resin and PH3660 hardener). For lamination, straight out of the can with no thickeners.
Fiberglass cloth:
Release film:
Breather cloth:
Inverse vacuum bagging:
Results before trimming:
Final results:
