So, how to attach a bulky container to a drone. Its probably going to be thrown around the sky in certain situations so it will have to be a strong connection, it will also have to be a quick release so that the turnaround time on the loading can be short and the drone can whizz into the war zone drop the load and scarper in double quick time. I am intending BUDD to be multi role so it will have to be universal to all the proposed loadouts. To complicate matters for me, I want it to actually work in some way because if I have time at the end of the build I want to construct some said loadouts.
For real world inspiration, I looked toward the CH54 Skycrane but came up with a blank, magnificent aircraft, but it is really a big skyhook and its payloads are mainly carried by hook, wire winches or bolted to the structure, so no quick release here. Most other helicopter lifting operations revolve around a hook, the Chinook offered a quick release solution but it was still a hook and the payload swings about under the aircraft like a huge pendulum.
Inspiration finally came from the cranes that pick up the shipping containers at container ports, they have a hydraulic grab that attaches at the four corner posts of the container. On the drone, this morphed into two clamps made of a continuous length of angle that attach to a reinforced edge along the top of the container.
The opening mechanism was the next hurdle, I devised all sorts of systems in my head some impractical, others would work but would be difficult to model in 1/72 scale. In the end, I opted for brute force and simplicity, three hydraulic rams that would hold the container tight in flight and release it very quickly when on the ground.
So, to the construction, quite simple in the end. Empty biro tubes became the Hydraulic Rams with plastic rod forming the push/pull rods, the clamp is constructed of plastic angle with connecting plates glued on. This construction was then glued to the end of the rod leaving the rod to slide in an out of the biro tube. I will be first to admit it’s a bit stiff in operation and a tad over scale, But It Works !!!
20171201_201904 by
Robomog, on Flickr
Here we see the biro rams in place these are stuck with gel superglue, this is my CA of choice it doesn’t run everywhere and has a little bit of grip that aids positioning parts also if you put down a generous blob it rides up the sides of the part and improves the quality of the fixing. It does need to be left 24 hours to fully cure however. The rams are covered by a protective plate which also strengthens the assembly.
20171201_201921 by
Robomog, on Flickr
The top of the cargo pod has received its reinforcement and the clamps constructed. It was at this point I realised that I had made a boo-boo in the construction. With 20-20 hindsight, I should have assembled the clamps and rams on the cargo pod first then attached them to the drone. But I had already glued down the rams. Doh! A frustrating night entailed carefully attaching the clamp to the rods.
20171203_200743 by
Robomog, on Flickr
20171203_200806 by
Robomog, on Flickr
Got there in the end.
………Clamp closed
20171203_201013 by
Robomog, on Flickr
……..Clamp open
20171203_201030 by
Robomog, on Flickr
And a picture of the finished assembly YAY!
Coming next the Turbofans or the landing gear or the tail assembly or the Command module assembly. Who knows? I'm working on all four in relays.
Update soon……….
Mog
