The altimeter compartment in the base of the nosecone

To save the additional weight and drag of a conventional payload section, a small lexan box was built to just fit the Jolly Logic Altimeter Two.  This was installed into a cutout of the Stonebreaker's nose cone and glued with CA.  (Which is quite brittle, if doing it again I would use hot glue and a rivet.  Gaps on the sides and a hole in the door allow for easy flow of air to prevent a pressure differential at the door that would cause altitude reading errors.

If the CA glue does eventually fail, I will still have the door riveted on to prevent the box from falling out of the nosecone.  I used a rivet because it is tight and prevents the plastic door from swinging open by itself (it takes considerable finger pressure to move it), and I can trust the rivet to not come loose like a nut and bolt would tend to do without special precautions.  The small aluminum rivet is also lighter than a typical steel nut and bolt, and every gram saved improves the rocket's altitude and speed performance.