Air Command
Water Rockets

L1ght Shadow - Build Log - Part 2

This build log represents our attempt to build an L1 rocket that can fly on both 38mm motors and water.

The log is in chronological order so to see the most recent post you need to Jump To The Bottom. You may need to refresh this page to see any latest updates.

CAUTION: If you are going to attempt to build rockets such as these, please exercise extreme care when testing and flying them. This rocket uses very high pressures that can potentially cause severe injury to yourself and those around you. Always double check your equipment and review safety procedures before every test and flight. See more information on Safety Guidelines.

Build Log

22 August 2016 - The electronics tube was cut to a length of 7.5cm. We ended up using a part of the original MMT tube as it provided more clearance for the servo motor and the shock cord mounting point. We also cut out two PVC rings that will hold the electronics package inside the payload bay tube. Those were then glued together with PVC cement.

23 August 2016 - Lots of odd little jobs today, cutting out centering rings for the payload bay, as well as PVC rings for the coupler. We finally installed the StratoLogger software and hooked it up to the StratoLogger and got the two talking after installing the drivers. We glued first of the centering rings to the electronics package tube and also glued the PVC reinforcing rings in place. The nosecone bulkhead was also cut out from plywood and shaped to neatly fit inside the nosecone coupler.

We also tested the StratoLogger with the Servo Timer. We had contacted Perfectflite earlier to ask how we can connect up to the trigger of the Servo Timer II as the StratoLogger continuously does a continuity check on the drogue ejection charge channel which would have continuously triggered the timer rather than only at apogee. They were very prompt with their reply and an easy fix. All we had to do was to put a 220 Ohm resistor across the output which would allow the StratoLogger to pass it's continuity check but would produce a voltage low enough that it wouldn't trigger the timer. This setup worked perfectly and we were able to activate the servo when using the test application for the StratoLogger.

24 August 2016

Today we mounted the servo motor into the central tube using 4x M3 bolts. We also modified a standard servo horn for the correct shape to hold the parachute in.

We also made the components for the parachute bracket today. These were made from a piece of carbon fiber flat bar 12x2 mm and a short length of Carbon fiber 6mm round bar. Counter sinking the holes was a bit of a pain in the flat bar as the tools just didn't want to cut, it was like they had graphite lubricant on them :)

We also chose the parachute today that the rocket was going to use so that we would keep the descent rate to around 5m/s. We ended up choosing the blue and yellow umbrella chute we've been using on Polaron G2. This was larger than the one used on Dark Shadow,

25 August 2016

We glued the fiberglass ring to nosecone coupler with 24 hour epoxy. This ring will be the thrust ring that supports the nosecone assembly during acceleration.

We also bought some spray putty that will be used to fill in the surface of the rocket for a smoother finish. The StratoLogger software was installed onto the little laptop as that is what we are going to be using at the launch site. We wired it up to make sure we can download the data at the launch site. We have also decided on the batteries for the electronics. We are going to use two separate power supplies. Each supply is made out of two 100mAh 25C Lipo batteries. We wanted the altimeter to have its own clean supply and the servo timer also its own as it is going to be driving a larger servo motor.
We also wired up the electronics that we will fly aboard one of the rockets to see if it all works properly before flying it in the actual rocket.

And finally we glued the parachute bracket together with epoxy.