Basic Information

Name

Xi-4

Launch date:

19 February, 2018

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 Video camera

Liftoff mass

3.026 kg.

Stability Margin (initial)

3.30

Flight objectives

Test video camera with improved (compared to Zeta) aft-facing mirror

 

Motor details

Motor name

Impulser-X

Propellant

KNDX

Grain mass

385 grams

Nominal impulse

453 N-sec

Class

I

 

Additional information

-Larger first-surface mirror (19mm x 27mm) mounted at 45 degrees for aft-facing view. Zeta mirror was 15mm x 21mm.

 

Weather conditions

Temperature

-17°C

Wind

N 5 km/hr

Sky

Variable clouds, light overcast

Other

R.H. 50%

Ceiling

14k ft.

 

Launch Event Description

As usual for winter launches, 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 4 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 in a stable manner. Rocket disappeared from sight shortly after burnout. The lack of sun and the white cloud layer made for difficulty trying to spot the rocket. After about 15 seconds we heard the ‘pop’ sound of the apogee pyro charge. No smoke cloud or smoke tracking trail could be seen against the whitish cloud cover.  After about half minute of decent, the parachute charge was heard to fire and we immediately spotted the parachute which was fully blossomed. The rocket at this point was about 500 feet downrange. The rocket drifted gently downward, and landed in a snow-covered field.

 

We programmed the BRB GPS coordinates into the hand-held Garmin unit. Landing site was indicated as 531 feet away. When we arrived at the location of the downed rocket, we found the rocket to be in perfect condition.  The Raven beeped out a peak altitude of 2944 feet.

 

Flight Analysis

Event:

Time (sec)

feet

metres

Apogee

13.0

2944

897

Separation

14.0

2926

892

Main deployment

44.8

496

151

Touchdown

62.9

-

-

Range

-

1925

587

Descent rates:

ft./sec.

m/sec.

 

Free-fall

83.1

25.3

 

Main parachute

24.7

7.53

 

                                  

Post-flight analysis and comments:

The Raven and Eggtimer performed nominally. Peak altitude reported by Eggtimer closely matched Raven (2979 ft. versus 2944 ft.).  The Backup Timer pyro had not fired. Post-flight examination indicated a fault with the arming switch circuit. This will be investigated and rectified prior to next flight.

 

Examination of the Raven/Eggtimer data indicated an anomaly with chute deployment. The Raven main pyro charge fired at 720 feet AGL as expected, but separation of the AvBay compartment did not occur. When the Eggtimer (backup) main charge fired at 496 feet AGL, separation was successful and parachute was deployed. This anomaly is attributed to the cold ambient temperature (-17C. at ground level) combined with minimally sized pyro charge (1.2 grams C.P.). For future cold-weather flights, the main pyro charge will be upsized.

 

No on-board video camera footage of the flight was obtained. Recording ceased 9 minutes after power-up on the pad. This anomaly is attributed to a combination of the cold ambient temperature combined with incomplete pre-flight charging of the camera Li-ion battery. For future cold-weather flights, a chemical hand-warmer will be used to keep the camera compartment from over-chilling.

 

Raven baro and accelerometer graph:                                                

Barometric and axial acceleration data                                                 Xi-4\Xi-4_Raven_Basic.jpg

 

Photos:

BRB transmitter with insulation shroud                                                  Xi-4\DSCF5257a.JPG

                                                                                                                        Xi-4\DSCF5258a.JPG

Rocket for Flight Xi-4                                                                                  Xi-4\Dscn0131a.jpg

Ignition…Liftoff…                                                                                         Xi-4\2018-02-26_12-07-22.jpg

Ascent                                                                                                            Xi-4\2018-02-26_12-07-38.jpg

                                                                                                                        Xi-4\2018-02-26_12-07-56.jpg

Descending                                                                                                   Xi-4\2018-02-26_12-08-44.jpg

                                                                                                                        Xi-4\2018-02-26_12-09-05.jpg

                                                                                                                        Xi-4\2018-02-26_12-09-42.jpg

                                                                                                                        Xi-4\2018-02-26_12-10-03.jpg

                                                                                                                        Xi-4\2018-02-26_12-10-39.jpg                                                                                                                       

Rocket at touchdown site                                                                         Xi-4\DSCN0136.JPG

                                                                                                                        Xi-4\DSCN0141.JPG

Forward section                                                                                           Xi-4\DSCN0139.JPG

Aft section                                                                                                    Xi-4\DSCN0140.JPG

AvBay                                                                                                             Xi-4\DSCN0138.JPG

 

Video:                                                                                                           

Flight Xi-4 (Youtube)                                                                                                                        https://www.youtube.com/watch?v=SdI-ENKXqmE