Latest Update: 1st May 2021 - Day 213 - Drop Away Rail Buttons

Day 213 - Drop Away Rail Buttons

Date: 24th April 2021
Location: Whalan Reserve, Australia
Conditions: Calm, sunny
Members: JK, PK, GK

Drop Away Rail Buttons

Notes:

The STL files of the buttons presented in the video are available for download here: Rail Button STL Files

Here is a diagram of the bracket the button fits on. The dimensions are approximate.

Flight Day report

Today we wanted to get out into the field and test out the new drop away rail buttons on actual flights. The weather was almost perfect with mostly clear skies and virtually no wind. The night before we had 3D printed a whole bunch of different rail buttons so that we could film them being put into different rails.

The first flight of the day was our Axion rocket fitted with a couple of the new buttons. We only pressurised it to 110psi as we weren't going after particular altitude, we were just interested in seeing how the rail buttons would perform and also where they would land. The flight looked normal, and the rocket had good recovery. The buttons had landed very close to the pad.

For the second flight we set up "Waterless" our LOC Weasel rocket and put in quite an old E15-7. This was a little dodgy on two fronts, the E15 is a little under powered for this rocket, and the 7 second delay was a bit too long, we really needed a 4 second delay. But it was the only E motor we had. When we tried to ignite it, the igniter fired but did not light the engine. So we decided to buy the lowest power F motor that Sam from Altius Gold had at the launch site. We wanted the lowest power because we did not want to exceed the launch site ceiling. So the brand new E20-4 went in and this time, it fired first go. Although the rocket probably went close to 1000 feet, because there was no wind, it didn't drift too far down range. This rocket has a small parachute anyway. The flight was nice and straight with good recovery right around apogee.

The buttons on this flight were designed for a guide rod which was set up by the club. We again found the rail buttons within a couple of meters of the pad. Overall this was a successful test.

We launched the Axion rocket for a second time. Again the flight was very similar to the first, and the rocket recovered safely. The buttons also worked well, although one dropped off a second later than the first and landed perhaps 10m away from the pad.

New GoPro Hero9

This month we also bought a new GoPro9 for filming various events. Our previous version was the Hero 3, so we've skipped quite a few generations. The new GoPro has lots of cool features, but the best one is the screen on the back so that you know exactly what's in frame, and the fact it has Full HD at 240fps. The video above has a few shots from the new GoPro. We hope to put it to good use over the coming weeks.

Flight Details

Launch Details
1
Rocket   Axion
Pressure   110psi
Nozzle   9 mm
Water   1500mL + foam
Flight Computer   ST II - 5 seconds
Payload   HDCam 808 #16
Altitude / Time   ?
Notes   Testing drop away rail buttons. Beautiful straight flight, nice and quiet. Parachute deployed soon after apogee. 
2
Rocket   Waterless
Motor   F20-4
Payload   None
Altitude / Time   ?' / ? seconds
Notes   Good burn and nice altitude. Parachute deployed around apogee. Rocket landed safely. First rail button test
3
Rocket   Axion
Pressure   110psi
Nozzle   9 mm
Water   1500mL + foam
Flight Computer   ST II - 5 seconds
Payload   HDCam 808 #16
Altitude / Time   ?
Notes   Testing drop away rail buttons. Good straight flight, nice and quiet. Parachute deployed soon after apogee.