Basic Information

Name

Xi-2

Launch date:

17 December, 2017

Rocket description

- 76.2/63.5mm aluminum airframe

- 4 fins, 2024 aluminum

- delrin conical nosecone

- 3 ft. ellipsoidal "Fruity Chutes" parachute

Payload

- Raven3 altimeter

- BRB900 GPS transmitter

- Smoke charge, activated by Raven 2 sec. post-apogee

- Timer for backup apogee separation

- Eggtimer Classic altimeter for backup apogee separation and main deploy

- SJ1000 Camcorder

Liftoff mass

2.977 kg.

Stability Margin (initial)

3.41

Flight objectives

Test on-board camcorder & improved tether

Motor details

Motor name

Impulser-X

Propellant

KNDX

Grain mass

382 grams

Nominal impulse

449 N-sec

Class

I

Additional information

-Higher strength tether and improved tether shock absorber.

-New aluminum parachute compartment piston

Weather conditions

Temperature

-9°C

Wind

SW 15-20 km/hr

Sky

Clear

Other

-

Ceiling

30k ft.

Launch Event Description

We used our sled to haul the supplies to the launch site. Following a checklist, setup of the rocket proceeded smoothly with no glitches. The BRB was activated first. After installing rocket on pad, Eggtimer was activated, followed by the Raven. Raven beeped eight times for voltage and gave positive indications for the 4 pyros. Backup Timer was then tested and confirmed to be operating nominally. For videotaping the flight, I used the hand-held camcorder (with scope tube).

After verifying the sky was clear, the countdown proceeded. Immediately after ignition switch was closed, motor ignited and rocket accelerated rapidly skyward, climbing straight and vertical. The Impulser-X motor burned for approximately 1.5 seconds. Rocket remained in sight during the entire ascent, thanks to the bright sun illuminating the rocket against the deep blue sky. A smoke cloud was seen to appear at apogee and the ‘pop’ sound heard a few seconds later The smoke tracking trail was then seen as rocket began tumbling downward.  After about half minute of decent, the parachute charge was seen to fire. No chute was seen and we lost sight of the rocket as it neared the ground. At this point it was about 1000 feet downrange.

We programmed the BRB GPS coordinates into the hand-held Garmin unit. Landing site was indicated as 0.3 miles away. As we approached the location of the downed rocket, it was apparent that the chute was not deployed. The two sections of the rocket landed some distance apart. Inspection revealed the tether connecting the piston to the AvBay had snapped, consequently, the chute was not pulled from the forward body.

Flight Analysis

Event:

Time (sec)

feet

metres

Apogee

13.2

2761

842

Separation

14.3

2746

837

Main deployment

41.9

728

222

Touchdown

51.3

-

-

Range

-

1266

386

Descent rates:

ft./sec.

m/sec.

Free-fall

80.2

24.4

Main parachute

-

-

Post-flight analysis and comments:

The Raven, Eggtimer and backup Timer all performed nominally. Peak altitude reported by Eggtimer closely matched Raven (2770 ft. versus 2761 ft.).  All pyros had fired.

There was some damage to the rocket due to the shallow depth of snow at the landing site, combined with frozen earth beneath. All four fins were loosened and some minor dents were present on the rocket body. The avionics had some minor damage, which was readily repairable.

The reason for the high tension load in the tether that caused it to snap was attributed to the large force required to pull the piston out of the rocket body. Although the close-fitting piston has a nearly frictionless sliding fit, lack of suitable venting of the parachute compartment resulted in a large suction force developing as the piston attempts to move. For the next flight, the six existing vent holes will be increased from 1/8 inch diameter to 3/8 inch. As well, dual (tandem) tethers will be used.

Good on-board video footage of the flight was obtained.