May 20th, was the first launch day of the 2016 season. Instead of all Dutch rocket organizations having their own separate launch days at the OTCVust, this time it was a combined launch campaign from the DARE, NAVRO, NERO & T-Minus with 12 rockets and 1 static motor test. We successfully flew the Intimidator 5 for the fifth time on a KNSU 2% RIO reload, with a “talky” GPS tracker by LD as a payload. Furthermore LD static tested an AP/AN/HTPB reload in the KILO 4G motor hardware.
I had no plans flying the Intimidator 5 at OTCVust this year but since the new launch rail trailer had to be end-to-end tested we opted to fly it anyway. This launch would be a good opportunity to test the launch rail before heading to Poland by the end of this year. The continuous drizzle throughout the morning and a SE wind made for uncomfortable launching conditions especially while waiting. Launch rail was set at 45° azimuth / parallel to the road and with an 80° elevation to cancel out the rocket would weathercock over the crowd. Launch window of the I5 was around 11:00 and after a bit of misunderstanding / communication with launch control it was launched shortly after that.
The nose cone payload for this flight consisted out of a 100mW BigRedBee Beeline GPS, a 1W “talky” GPS tracker by LD and a 50mW radio beacon by LD as well in case of a last resort. The whole payload was bench tested without any problems and the night before tested in the rocket and all worked successfully. On the launch day the rocket was inserted in the rail. The pull pin removed but after 6min the Beeline GPS still wasn’t sending APRS packages / messages. Initially we though it didn’t have a lock (the Beeline GPS doesn’t send packages / messages when it doesn’t have a GPS lock) so we decided to launch anyway since the “talky”GPS was transmitting fine. However this Beeline GPS also stopped sending packages last launch (where it was happily sending messages right up to the moment the rocket was launched). It is time to send in the Beeline GPS for repairs and use it as a back up or retire it. After the launch and upon downloading the flash memory and much to our surprise, the BRB Beeline GPS did get a perfect GPS lock. With 10 satellites during the entire flight it provide a nice 3D flight profile in Google Earth. According to the Beeline GPS maximum altitude was 2322m and launched from 52m from sea level. Note: this particular Beeline GPS had encountered a flight anomaly during the CHIRON I launch where a 60” Iris fruity chute deployed and shredded at Mach 1+ and subsequently had a rough landing, nose cone only, under the shredded chute where free flying 9V batteries in the compartment damaged some of the SMD components. Note: this particular Beeline GPS had encountered a flight anomaly during the CHIRON I launch where a 60” Iris fruity chute deployed and shredded at Mach 1+ and subsequently had a rough landing, nose cone only, under the shredded chute where free flying 9V batteries in the compartment damaged some of the SMD components.
KILO 6G motor
For the potential use as a booster motor in a 2-stage configuration I’m looking for maximum thrust out of the KILO 6G hardware. With the previous KNSU PG reload the thrust was a bit disappointing. For this reload all known tricks in the book were used. KNSU as a fast(er) burning candy propellant and RIO (red iron oxide) as an additive to increase burn rate a bit. Grains came out nicely with an average ideal density of KNSU of 99,+% likely due to the fine RIO filling up any voids between the KN and SU.
The KILO 6G motor featured a re-designed nozzle after the st. st. nozzle with graphite insert showed cracks at the throat. Likely caused by the poor nozzle design we had to work with in the first place due to the st. st. blank we had
- Flight I: Hybrid aluminium nozzle with graphite insert – failed as the aluminium melted
- Flight II: Stainless steel nozzle – heavily corroded at the convergent and nozzle
- Flight III: Stainless steel nozzle blank from flight II with graphite insert – to be checked
- Flight IV: Stainless steel nozzle blank from flight II with graphite insert
- Flight V: Aluminium nozzle with graphite insert and RTV layer – worked as a charm, no aluminium erosion, no cracks and only convergent and nozzle have an “sand blasted” appearance.
Key figures Intimidator 5 – flight V – 20-05-2016:
- Apogee: 2167m
- Maximum velocity: 227m/s; 817km/h
- Maximum acceleration: 12 G’s
- Rocket mass: 23,6kg
- Experimental KNSU 2%RIO in the well-proven KILO6G hardware
- Total impulse: 5660 Ns
- Burn time: 3,4 seconds
- Favg: 1890 N
- Fmax: 2620 N
- Isp: 125 s
- Destination: M1890 – 11%