Basic Information
Name	Xi-25
Launch date:	14 August 2021
Rocket description	- 76.2/63.5mm aluminum airframe - 4 fins, 2024 aluminum - 3D printed conical PLA nosecone - 3 ft. ellipsoidal "Fruity Chutes" parachute
Payload	- Raven3 altimeter (primary role) - Eggtimer Classic altimeter for backup apogee separation and backup main deploy - BREO-N flight computer (2^nd backup, apogee only) - BRB900 GPS transmitter - Lift-off activated smoke tracker with Legendary formulation - SQ11 micro-camcorder, aft-facing
Liftoff mass	2.930 kg.
Stability Margin (minimum)	2.71
Flight objectives	- Flight test of experimental APM-E.2 motor (38mm) powered by five BATES grain segments of AXP-AP2.4 propellant: AP 67.8% Epoxy 25% (NuLustre) Iron powder 7% (atomized) Lamblack 0.2%

Motor details
Motor name	APM-E.2
Propellant	AXP-AP2.4 (APCP)
Grain mass	298 grams
Nominal impulse	505 N-sec. (delivered)
Class	I

Additional information

- APM-E.2 motor had been successfully static fired 31 July 2021.

- Measured thrust & chamber pressure graph.

Weather conditions
Temperature	31°C (88°F)
Wind	WSW 20 km/hr gusting to 25 km/hr
Sky	Clear with bright sun
Other	Relative humidity 21%
Ceiling	unlimited

Launch Event Description

Following our checklist, we proceeded to set up the rocket. Setup went well with no glitches. The BRB transmitter and receiver were activated and verified that a good GPS signal was obtained. The BREO was activated and verified to be functioning, followed by the EggTimer unit and Raven. Raven beeped out codes indicating nine volts battery power and two active pyros. The SQ11 camcorder was then powered up and installed in the rocket. The lift-off activated smoke charge was then powered.

For videotaping the flight, I used my Sony HDR-CX240 Handycam fitted with scope tube.

After verifying the sky was clear, the countdown proceeded. At the zero mark, the ignition button was pressed, the igniter fired immediately, and the rocket lifted off about a ½ second later. After departing the launch rod, the rocket weathercocked noticably into the wind. A black smoke trail formed as the rocket climbed skyward. The motor burned for about two seconds. After burnout, the rocket flight path was clearly seen by the grey smoke trail emitted by the lift-off activated smoke charge. The smoke trail continued as the rocket reached apogee. A smoke cloud appeared as the apogee pyro charge fired, followed by a second smoke cloud a few seconds later as the backup pyro fired. The smoke trail continued to be emitted for an unexpected duration, and finally burnt out approximately 30 seconds after launch. The rocket was seen tumbling earthward, its presence clearly indicated by the sun glinting off the rocket’s chrome bands. The parachute pyro charge was seen to fire and the parachute immediately blossomed. Drifting with the wind, the rocket landed about a half-minute later around 1000 feet from where we were standing.

We programmed the GPS coordinates into the handheld Garmin unit. Indicated distance to touchdown site was 0.18 miles (300m.). Arriving at the touchdown site, all the rocket components were seen to be present. The rocket appeared to be in pristine condition. Raven beeped out an apogee of 2690 feet. A quick check indicated that all pyro charges had fired.

Flight Analysis
Event:	Time (sec)	feet	metres
Apogee *	13.5	2850	869
Separation *	14.4	2846	867
Main deployment	40	787	240
Touchdown	66	-	-
Range	-	725	221
Descent rates:	ft./sec.	m/sec.
Free-fall	79.4	24.2
Main parachute	26.6	8.1

* Corrected for non-standard base temperature

Post-flight analysis and comments:

Post-flight examination of the rocket and data indicated that the operation of the Raven and EggTimer was fully nominal. The BREO stopped recording at the 40 second mark, coinciding with chute deployment. The rotary off/on switch is suspect, as it seemed to have a less positive “click” when it was turned on. The Raven, EggTimer and BREO each gave apogee readings within 0.7%. The BRB GPS indicated apogee was 2457 feet. The reason why the GPS reading was 8% lower than the barometric readings is not presently understood (there was no data dropout).

Examination of the flight computer data, and post-inspection of the rocket motor, showed that the APM-E.2 motor had a fully nominal burn with the acceleration data closely matching the static test thrust curve.

The lift-off activated smoke tracker functioned, however, only one of the two igniters functioned. As such, the smoke grain was ignited at a single end, resulting in half the smoke being produced for double the duration. The smoke trail during initial ascent, when the rocket was traveling at high velocity, was noticeably less dense and made initial tracking the rocket more challenging. The reason for the failed igniter is likely due to having lead wires that were a bit too short and during installtion, the leads had to be tugged.

The on-board SQ11 micro-camcorder functioned well. Once again the sound recording was compromised beginning at liftoff. It now appears likely that the high noise intensity adversely affected the microphone.

Raven data:

Barometric and axial acceleration data Xi-25\Xi-25_Raven_basic.jpg

Acceleration curve, boost phase Xi-25\Xi-25_Raven_accel.jpg

Eggtimer data:

Altitude versus flight time Xi-25\Xi-25_ET.gif

BREO data: Xi-25\Xi-25_BREO.gif

BRB GPS data:

Plot of flight path over terrain Xi-25\Xi-25_BRB_track.jpg

Miscellaneous photos:

APM-E.2 rocket motor Xi-25\APM-E.2_motor.JPG

AXP-AP2.4 propellant grain segments Xi-25\E.2_grains.JPG

Launch photos: