This print is for mounting an electronic altimeter/tracker in the nosecone of a high powered rocket. The rocket airframe is 3" in diameter. The base of the nosecone is necessary for recovery harness attachment and is mounted to the nosecone itself with screws to a bonded internal ring. The altimeter/tracker mount must be small enough to pass through this ring and allow for full extension of the antenna tuned for the 70cm Ham band.
The altimeter used in this case is Altus/Metrum, The red button at the base of the mount is a push on / push off switch. The switch is inserted in a cutout specifically crafted for it. The altimeter is attached with screws into brass inserts in the ABS print (obtained from McMaster-Carr). Below the altimeter is a bay for a 1200mAH battery which is sufficient to keep the tracking function working and transmitting coordinates for over 12 hours. The antenna is taped to a 5/16" dowel inserted into the end of the mount.
The bay should be printed laying on the print bed as shown, not standing on end, so that the weaker extrusion lines are not on the cross section of the print. This gives maximum strength during violent launch and chute deployment.
This was used in a recent launch at BALLS 2016 and provided excellent tracking of the rocket through launch and descent. The rocket was recovered nearly 8 miles away and we continued receiving transmissions throughout the recovery.
This print is the second iteration of the design providing better strength for the antenna dowel mount as it broke off during flight, probably at drogue chute ejection which saw a very large impulse due to a likely excess black powder ejection charge.
the original design was printed standing on end, which did not provide enough lateral strength between layers such that the antenna mount broke free. The design is now strengthened, but I would recommend printing it horizontally with 45 degree supports underneath for much better lateral shear strength.