In "Quad Cargo", we determined that the Alias had 2.5oz – or just under 71 grams* – of cargo capacity. Now it was time to build a frame that we will use to attach what the Alias would need to lift.
Our first attempt was to lay some hollow cardboard tubes across the arms of the copter.
Next, we planned to attached those two tubes together with wooden dowel. I marked the tubes where the dowel would go…
…and then measured out the doweling.
I drilled holes in the tubing for the dowel to pass through.
I glued the pieces together, and and then verified there would be enough clearance for them between the arms and the rotor blades.
There was, but only barely. I was a little concerned about the effect the frame would have on the Alias’ flight characteristics. The frame’s components weighed a little more than 21 grams, but I didn’t know how much the rotor’s thrust would be compromised having the doweling and tubing positioned so close.
So, instead of putting the frame on top of the arms, I moved it to below the arms.
I zip-tied the four corners down…
…and we were ready for our first test flight.
The Alias appeared to respond well. It still felt like we had good control over it.
That is, until I got a little too wild on the stick, and crashed it. The Alias was fine. The new frame, however, was not.
The crash illuminated a fatal flaw in our design. The holes drilled through the cardboard for the dowel weakened them too far to be useful. We would undoubtedly crash several more times even before we go to the "tough" parts, so we needed something more resilient.
Back to the drawing board.
* Dealing with the weights in grams is easier than dealing with fractions of ounces, so from here on out, all of our measurements will be in metric.