Month: March 2014

Guardian 54 Construction Continuing

I’ve been working hard on Guardian 54.

I did all 3 sets of Fillets using Cotronics Duralco 4525. This stuff is very expensive, but I was lucky to have some “donated” to me by a friend who was no longer using it.

Duralco 4525 is useful because of its very high tensile strength (10.8 ksi) and it’s very high heat distortion temperature of around 500F. For this high performance rocket, I decided to bond the fins with the best epoxy that I can get in small quantities.

I used a 5/8″ wooden dowel to shape the fillets. I also terminated the fillets at the length of the bevel of the fin.


After pulling the tape, the fillets looked great!


Here is the fully assembled rocket so far – Parachute and Electronics bay are included as they are completed too.


You can see that I also coated the nose cone with Cotronics Epoxy. Three layers have been applied, with minor sanding between coats. I now need to sand it to smooth, but this epoxy is extremely difficult to sand. IMG_0807

The rocket can be seen here in a Solidworks 3D model that I made. The model includes every component that will actually fly in the rocket. Note the parachute (yellow ellipsoid with a gray band around it) and it’s line cutter, as well as the BigRedBee GPS transceiver for GPS altitude verification and tracking, and finally the Raven Altimeter Bay. It’s a pretty tight fit in that nose cone! Hopefully everything will fit in there in reality just like my model.


This model also includes the internals of the motor such as the nozzle and forward bulkhead, and the propellant grains.



Next up is the tip to tip reinforcement. I will be doing two layers of bidirectional plain weave, vacuum bagged.