Air Command
Water Rockets

Latest Update:13th May 2018 - Day 197 - Dark Shadow II - New Personal Record

Day 197 - Dark Shadow II - 2,016 feet!

Date: 5th May 2018
Location: Mullaley, Australia
Conditions: Clear, wind 0-10km, 25C
Members: Paul K, John K, PK and GK

Dark Shadow II

This week we travelled to Mullaley to attempt to get over the 2,000 foot mark with Dark Shadow. We also wanted to fly Light Shadow on water again as it has had only one previous water flight. And lastly we wanted to do some hydro tests of test pressure chambers for the horizon project. The results of the pressure chamber tests are covered in the Horizon build log.

The weather conditions throughout the day were near perfect with absolutely blue skies, very little wind and comfortable temperatures.

Dark Shadow II was set up again as with previous launches and filled with 1.8L of water. The timer delay was set to 11 seconds. We brought the pressure up slowly to 740psi (51 bar) and launched. The rocket went up beautifully and deployed the parachute right at apogee. It drifted down to a gentle landing a few hundred meters away. On reviewing the slow motion pad video the guide rail still touched the rocket a little during launch, but not as much this time as we had a larger block of wood under it. You could also see the rocket flex a little during launch.

The Z-log altimeter gave a max altitude reading of 2,006 feet (611m) and the AltimeterOne gave a reading of 2,027 feet (618m). With the values in close agreement with each other it gives us confidence that the values are correct and so we just average their readings and then use that as our final altitude of 2,016 feet (614m).

Here is a plot of the data from the z-Log altimeter.

From this we can derive the velocity data. The top speed was 430 feet/s or 471km/h.

Here are some photos from the day.

L1ght Shadow

We decided to fly Light Shadow again since it needed a bit of airing out and so we increased the pressure slightly to 260psi since we really don't know what the upper limit is. Setup and prep ran smoothly and the rocket was loaded up on the pad.

The rocket took off well and the Stratologger deployed the parachute right at apogee. With the lower speeds (compared to pyro) there was no zipper this time and the rocket landed well without incident. The AltimeterOne gave a reading of 624 feet and the Stratologger gave us a max altitude of 615 feet for an overall average value of 619 feet.

Here is a plot of the altitude and velocity data from the Stratologger:

 

Other Rockets and Tests

We also flew a couple of Paul's rockets, the Pod 2 with a C6-0 booster stage and Flygon on a D12-5. Both rockets flew and recovered successfully. The Pod 2 booster sustained slight damage, probably on landing where the motor mount came loose. This can be easily fixed.

All in all it was a great day for flying rockets, and we managed to get a new personal altitude record with it as well. The one take away from this weekend was the strength of the pressure chamber tests for the Horizon project and the potential implications this has for Dark Shadow's upper strength limit. Stay tuned!

Here are some more photos from the launch day that we took: NSWRA Photo Gallery

Flight Details

Launch Details
1
Rocket   Dark Shadow II
Pressure   740psi
Nozzle   15.5mm
Water   1800mL
Flight Computer   ST II - 11 seconds
Payload   zLog Mod6, HD cam #16 V3, AltimeterOne,  STII
Altitude / Time   2016 feet ( 614 m ) / 92 seconds
(2006' - Zlog altimeter, 2027' AltimeterOne)
Notes   Good fast launch. Very straight vertical flight. Good deploy and good landing.
2
Rocket   Pod 2
Motor   C6-0 (Estes) to C6-5 (SCR)
Payload   None
Altitude / Time   ?' / ? seconds
Notes   Good launch, and good recovery. Booster motor mount broken on impact
3
Rocket   Flygon
Motor   D12-5
Payload   None
Altitude / Time   ?' / ? seconds
Notes   Good launch, and good recovery. 
4
Rocket   Light Shadow
Pressure   260psi
Nozzle   15.5mm + launch tube
Water   2800mL
Flight Computer   StratoLogger CF & ST II - 0 seconds
Payload   HD Cam 16 V3, AltimeterOne
Altitude / Time   619 feet / 54 s
(AltimeterOne: 624', Stratologger: 615')
Notes   Good straight flight. Parachute deployed at apogee. Good landing.