Thursday, 21 March 2013

Payload - Part Two

We've been making some real progress with the payload this week - if you missed our first post detailing how we constructed our polystyrene box you can see it here.

We've made a video which we hope will explain things further.  Be sure to read below for more information and pictures.

The majority of the work has been organising the layout of the components within the payload and making compartments inside the box to offer them extra protection and insulation. Basically we need everything to fit nice and snug! Here come the photos:
Drilling a hole for the camera lens with a hole cutter.
The hole. 
We tested a few options based on recommendations by other HABers for cutting out this aperture, such as using metal cookie cutters or just cutting it freehand. This method however gave us the cleanest finish. The cookie cutter method proved particularly tricky as our polystyrene has a closed cell structure. This is the property that makes it waterproof in case it lands in the world's deepest muddy puddle or the English Channel etc. It is therefore very dense and resilient to cookie cutter pressure!
A spot of hoovering.
Freehand trimming was easiest with a fine hacksaw blade.
Layer 1 - the base of the payload.

The first layer of polystyrene shown left is actually one layer of our 1" polystyrene sitting on top of the base of our payload box. Here we have the GoPro resting on top and facing outwards with a square cut into the side wall. The backup tracker is slightly sunken down into the polystyrene level and a space for the digital camera has been completely cut out so it can face down and the lens can extend out through the circle cut out of our payload base.
A quick weigh of the payload.
It was essential for us to check our payload mass as we added our internal compartments - the polystyrene can add a surprising amount of weight and we didn't want to go overboard and let the weight creep up. It doesn't matter how well organised and pretty it looks - it's got to get off the ground after all! Luckily it was all under control so we set about making Layer 2.
Layer 2 in the making.

Our tracker and battery pack in position.
The space on the right is to secure the GoPro in position.
The hole in the middle is for the aerial.
The tracker's nice and snug.
Layer 2 in situ.
With all of our components housed and layers completed, we decided our payload box had approximately 2" of excess height. When we originally designed the box, we opted for a cube mainly for ease/it seemed pretty logical, and well you have to start somewhere don't you? Now in hindsight this extra polystyrene was an unnecessary weight so we trimmed it off.
Things get a little nervy as we measure
what's about to get the chop.
The moment of truth. With an upturned dust bin lid acting as a polystyrene dust receptacle. Resourceful.

Bye bye extra weight.
Our new low profile design being sanded.

Time to make it a hat.
Our double layer lid being glued together.

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