Invictus Flight 1 - Final Anomaly Report and All Flight 2 Design Changes

The launch pad on Invictus Flight 1 was originally intended to be used for rockets in the size class of BAR, with a maximum of a single F15-0 motor. However, due to the time crunch involved in this first flight with only a 4 month total time from first parts arriving to liftoff, we could not upgrade the flame diverter in the pad. This led to the ablation of the diverter. To the left is a photo showing the damage. This photo was a key indicator of the left F15 igniting prior to the right F15 on the first stage. This caused stage 1 problems which we will get into later. The desynchronized motor ignition is very obvious when looking at the ablation caused by either motor. The left motor had more time to damage the diverter.

Additionally, other launch pad systems weren't sufficient, such as the launch rod. The launch rod was inserted into a hole in the pad for this flight, but the hole that was initially used before the emergency repair that had to happen prior to flight was not deep enough. This caused the rocket to fall over before flight, which heavily damaged the stage 2 and stage 3 mounts before flight commenced. To the left is a photo taken after repairs. A new hole was drilled into the pad for the launch rod to sit in. Additionally, the "repaired" (we'll get into that later) stage 2 is sitting next to the pad, with the undamaged stage 1 on top of the pad.

Stage 1's mount performed admirably in this flight despite being cracked. It supported the thrust of both engines even after the crack formed. This crack only formed because the two motors were not lit at the exact same time, which is not a fault of the mount, but a fault of using two motors. In this post-flight photo on the left, an angle is visible in the motors used on the flight, which was caused by the crack. This angle caused the powerslide after liftoff, which damaged the launch rod, but did not significantly affect the flight. The launch rod will be replaced ahead of the next flight with the new launch pad due to this.

Stage 2's mount did not perform well with this flight. Prior to flight, it was cracked once, then the motor broke off prior to flight due to the launch rod issues mentioned in the launch pad section. It was then hastily repaired improperly because there was no way it would have held the force anyway. During flight, the motor lit on the mount and then promptly broke off, flying a few hundred feet away. Due to the holes that were mistakenly not sealed before flight in the mount (these are necessary for a proper 3d print of this design) the ejection charge gasses from stage 1 also lit stage 3 at the same time. You can see the second stage motor breaking away in the photo on the left, as the plume is angled. On the forward end of the second stage, the ejection charges from stage 1 are visible.

Stage 3's mount was similar to stage 2's mount. It was not damaged during the two times the entire rocket fell over, but was damaged when the stage 3 tube fell over after being left in wind unclamped for paint to dry. This nearly completely destroyed the mount, and practically it did. This caused the third stage to perform as if it was not even there, with the entire stage 3 mount severing right at the moment of ignition. Here is a photo of the mount taken after flight.

Design Changes:

- Stage count reduced from 3 to 2.

- Stage 1 powered by a new motor (G80-13T).

- Stage 1 fin junction height increased from 1 inch to 2 inches.

- Stage 2 fin shape completely overhauled.

- Fin material is now balsa.

- Engine mounts will be completely redesigned and 3D printed in steel.

- Flight computer/housing added to plans.

- Stage 2 will air light with flight computer.

- NC and FC housing will be joined together.

- Tube couplers will be redesigned due to being too large and too long on Flight 1.

- New launch pad design.