The first 4 grains were cast today. Each grain weighs approximately 3 kgs. In total 8 of these grains are needed for the CHIRON2 solid rocket motor.

Fig. 1. Four grains in the compression molds

The CHIRON2 rocket requires custom made casting tubes. As the kraft paper tubes of the CHIRON1 rocket may have caused the engine failure, a more solid approach was taken.

120*114 (OD/ID) aluminium tubes were reduced to approximately 117.5*114. To assure proper bonding of the sorbitol propellant, a single layer of thick kraft paper was glued into the aluminium tube.

Fig. 1. Aluminium tubes with the inner layer glued in.

6g black powder

https://youtu.be/x3lzKKul-WA

The Talkie GPS transponder has been updated to transmit both APRS and spoken GPS locations. Altitude is measured using a barometric pressure sensor. This also allows for monitoring altitude at high speed where the GPS may not stay locked.

Below a static test using DireWolf to decode the APRS signal.

https://youtu.be/FaQ07trv9aU

To facillitate high altitude flights, the brown-out capacitor on the timer was sealed into an aluminium container. Board design in Sparkdesign, board fabrication OSH park, USA.

The engine on the XOZ-XL got extended from a six grain to a massive 12 grain configuration. In addition there is room for a starter grain, which makes this an ideal rocket for slow burning propellants like the recently developed AN-AP composite fuel.

The Talky GPS tracker was tested for the first time in the Intimidator 5 rocket that flew to 2200m.

https://youtu.be/-okTvmzEXAA

A first test of the AN-AP dual oxidator propellant test in a 4 grain 90mm motor.

https://youtu.be/qT845LK23N8