Launch Report: Cygnus Probe Ship With Body Tube Extension

Date: 2024-05-30

Background

• This is the 3^rd launch of the Cygnus Probe Ship. This version has the longer body tube. The previous launches were both unstable.

On Site Preparations

• For wadding I used a Nomex recovery bag.
• For a parachute I used a 18” Nylon chute.
• This launch will use a F52-5C Composite motor. This is Aerotech’s “Classic” propellant which is nearly clear during launch.
• The supplied Aerotech igniter was used.
• The rocket was slid onto the 5/16" launch rod and the controller wires were attached to the igniter leads.

Launch

• Wind was out of the East and was about 4 mph at the most.
• John stated the sky was clear - launch site was clear and did the countdown: 5-4-3-2-1. Teresa pushed the button on the launch controller.
• The motor ignited and the rocket leaped off the pad. It flew stable upward but then went unstable heading toward the East. The chute deployed and the rocket ground hit 270 feet from the launch horse.

Condition of rocket after the flight

• The rocket was uninjured and flight ready.

Conclusions

• The Rocketry Forum member Andy, sr205347d, speculated that the outriggers and legs, being round, were the cause of the instability. I feel this last test with the extended body tube shows that Andy is indeed correct. While the extended body tube helped, the rocket is clearly still unstable.
• A string swing test was performed and the rocket passed that test.

What I learned

• Post flight discussions on The Rocketry Forum have lead me to add some "Sails" to the outriggers that will induce roll stabilization. We'll fly this one again.