{"id":599,"date":"2009-10-21T12:57:27","date_gmt":"2009-10-21T10:57:27","guid":{"rendered":"http:\/\/www.verticallimits.nl\/?page_id=599"},"modified":"2015-02-18T18:09:38","modified_gmt":"2015-02-18T16:09:38","slug":"deca-2-stage-54mm-minimum-diameter-2-stage-rocket","status":"publish","type":"page","link":"https:\/\/www.verticallimits.nl\/?page_id=599","title":{"rendered":"DECA V – Two-Stage"},"content":{"rendered":"

\"\"<\/span><\/a>Rocket outline<\/span><\/span><\/h3>\n

Rocket \u2013 Two stage rocket<\/span><\/p>\n

Motors \u2013 DECA 8 grain KNDX & Cesaroni 54mm J1055 Vmax – 2G<\/span><\/p>\n

Booster \u2013 Newly\u00a0constructed similar to the DECA IV fin can method\u00a0–\u00a0 with enlarged fins to allow for a high static stability margin upon lift off.<\/span><\/p>\n

Separation – By ignition of the second stage.<\/span><\/p>\n

Recovery Sustainer – Design as per DECA IV.<\/span><\/p>\n

Recovery Booster – motor delay set at 7s.<\/span><\/p>\n

Payload \u2013 IMU, I-AM and\u00a0Beeline GPS tracker into nosecone and\u00a0#11 HD camera looking down<\/span><\/p>\n

Documentation \u2013 Full NERO RSDS, parachute simulation sheet, SolidRocketMotor file\u00a0& RockSim file.<\/span><\/p>\n

Diameter: 58mm<\/span><\/p>\n

Length: 2446mm<\/span><\/p>\n

Weight fully loaded as-built: 6476gr of which was 1153gr propellant<\/span><\/p>\n

Cd derrived from flight data: xxx<\/span><\/p>\n

Motor: DECA 8 grain KNDX. Total impuls & Isp from flight data: xxxNs. Isp xxx,xs<\/span><\/p>\n

Goals<\/span><\/h3>\n
    \n
  • Fly in a two\u00a0stage configuration to\u00a0\u00b1 3,4km.<\/span><\/li>\n
  • Use head end ignition on the DECA 8 grain KNDX motor<\/span><\/li>\n
  • Separate sustainer from booster\u00a0by sustainer motor ignition.<\/span><\/li>\n
  • Use a Cesaroni\u00a0 54mm 3G casing with spacer on a Cesaroni J1055 Vmax reload (2G)\u00a0and use the motor delay to recovery the booster.<\/span><\/li>\n<\/ul>\n

    Flight 1 DECA V two stage – Friday 26.04.2013<\/span><\/h3>\n

    \u00a0On Friday 26.04.2013<\/strong>\u00a0we woke up and the fog was hard to miss from our hotel window. Temperatures plummeted from comfortable 16-18\u00b0 C to 7-9\u00b0 Celsius with a 4-7m\/s wind blowing from the North. On top of that it never stopped drizzling throughout\u00a0the day and the rain ranged from\u00a0a drizzle to a hefty shower. The weather reminded us\u00a0of an unfavorable launch in 2004. Clouds were estimated to be at 200m. With only a few active flyers on the NERO side\u00a0we had some trouble with erecting the tower to the rather unusual 20\u00b0 azimuth. Lessons learned: set up the launch rail on Thursday and focus on flying rockets on Friday.<\/p>\n

    DECA V<\/strong> – By that time a fellow\u00a0NERO rocketeer\u00a0LD decided not to risk his 3+km rocket and did not fly. Quite understandable when seeing the extensive\u00a0Arduino payload in the nosecone. The same risks could be opted\u00a0about the DECA V two stage with a simulated apogee of 3,4km. However with a Beeline GPS in the nose cone and a GSM GPS tracker attached to the shock cord and no experimental launch day scheduled within the coming moths I decided to fly the two stage rocket anyway. Eventough only the first 200m could be witnessed. Rocket prep was easy, the\u00a0GPS trackers were confirmed to function\u00a0and within the hour the DECA V was sitting in the launch rail. One problem popped up which would later be the cause of flight anomaly. Because of the rain the plastic nosecone became wet. Normally the payload module is activated though the nosecone end after which the nosecone is put on and secured by aluminium tape. This had worked flawless during the last 4 launchs however this time the tape holding the nosecone to the airframe would not stick due to the rain. A quick fix was deemed to be found when the aluminium tape was exchanged for duct tape. After the launch area was cleared\u00a0the recovery and sustainer ignition electronics were powered on & armed (quite a tense moment with the sustainer motor being a mere 30cm away). But the reliable RDAS Tiny functioned just fine. Secondly the Cesaroni igniter was inserted into the J-1055 Vmax and the DECA V two stage was ready for launch at 12:45.<\/p>\n

    After a\u00a0quick count down the\u00a0Cesaroni Vmax\u00a0hauled the two stage rocket quickly out of the rail into a straight and stable ascent, quickly disappearing into the clouds. The seconds were counted down and\u00a0right on que (considering the\u00a03s coast delay and 2 additional seconds for distance to be covered at the speed of sound) the sustainer came up to full\u00a0pressure. With a muffled sound and absolutely no visual confirmation\u00a0the sustainer was thought to be on its way to 3,4km. However, only seconds into the flight we stopped receiving the Beeline GPS coordinates (later the cause was tracked to the nosecone separating from the airframe and taking\u00a0along the antenna and\u00a0half of the Beeline GPS) and about a minute into the flight the rocket was spotted under parachute at an unlikely angle from the launch rail. This made recovery of the sustainer easy but straight away stopwatches were checked as the rocket landed way too soon. But nobody knew what happened because of the clouds. Landing location of the sustainer as sent by the GSM GPS: 52.395768 005.922133. While writing this report the booster is still misplaced and\u00a0has yet to be found. Recovery of the booster should have been\u00a0simple trusting on the Cesaroni motor ejection set at 7-8s with\u00a0the recovery harness\u00a0consisting of Kevlar and the parachute wrapped in a Kevlar burrito. Nobody saw it landing.<\/p>\n

    Onboard video of the DECA V two stage flight also\u00a0capturing the booster separation by sustainer ignition:\u00a0<\/p>\n