what will it do?
My final project will be a drone, not an ordenary one more a specialized one. The main difference between my drone and the ones out there is, it's hybrid system based on a modular spaceframe structure that can be scaled to different pourposes. So it has to fly, in a small scale setup as good as in a bigger setup. If that task is achieved than the second ability comes in - thanks to the support of the helium filled vessel it should reach an higher airtime. The successful combination of this abilities will make the difference to the established multicopter.
The specifications for my final project are:
a spaceframe structure
expandable with a helium vessel
The main thought was to "marry" a multicopter (drone) with an Airship (Heliumvessel) in a manner that looked cool and functional. As I am a designer by profession it is always a naturally automatism that my work has to "look" good in different meanings. So instead of taking a standard drone frame and mounting just a ballon filled with helium to it - I sat down and made my mind up how to design a new hybridcopter that meet my needs.
So I ended with a so called spaceframe structure - depending on the material that is used it can be not only lighter than comparable objects also it can be stronger or stiffer than those.
who's done what beforehand?
I did some research to find out if something similar is done before. I found some reports about airships and airship technology but nothing close to my idea. I could be mistake as a "Blimp", that is actually somehow a modern way of an airship. And my design can can be easily mistaken as a blimp but in comparision to that my concept will be flying even without the helium vessel. And than I found by accident a short viedoclip from the research division of FESTO Tools, a german manufacturer of high quality professional tools. They made a vessel filled with Helium and a ringstructure with a couple of rotors to control the ballon-drone. But because of its design, a 1 cubicmeter big sphere it can only be used indoors. Outdoors it would become uncontrollable because of the wind load.
To minimize the wind load - that can be an issue - i decided to use a shape of an elipsoid. It gives me by a certain size enough volume so that the impetus of the helium will have an effect to my drone.
what materials and components will be required?
Because of the specification above only materials that are light but stiff will be processed. The wooden parts are made of 4mm plywood sheets processed with a laser cutter. For the first model pultruded carbon tubes with 3mm diameter, this can be changed in later models. For the joints PLA and/or ABS is used regarding on the application field.
where will they come from?
● Carbon fibre tubes 1000 x 3/1mm, ca. 6g 50pcs a € 1,56 € 78,-
● Superglue, gelbased 20g € 6,99
● Superglue, liquid 7g € 4,49
● Stainless steel nuts, washers & Screws M3 € 2,-
● The cost for the ABS /PLA are difficult to calculate at the moment
● Mylar film 10m x 0.52m €1,80/m €18,-
● Motors & Props € 64,-
The Transmitter and the receiver I didn't buy because we had some in the FabLab so these cost are not in the list, but just to be complete just in case the cost for the set will be another € 70 - 100.
what parts and systems will be made? /
what processes will be used?
The connectors called joints are made by 3D printer, while the first series were produced on a Projet 3500HDmax with an amazing surface quality, they fail by stability durability means. The were breaking under load. So the use of FDM printers will be the standard process at the moment. Some cover surfaces will be produced as composite layered elements, holder for the electronics are cut with a laser. The segements for the helium vessel will be cut by the laser cutter and welded together with a hot seal tool. The flight controller is made baased on the SATSHAkit Flightcontroller by Daniele Ingrassia, modified for the dedicated use in this project. Also the power distribution board. both will be milled on a Roland MDX 40 Milling machine. The joints for the first models are stuck together with gelbased superglue, with gapfilling abilities.
what tasks need to be completed?
While I learned a lot during the making and setting up the multicopter I am not satisfied with the to day results. The tests showed that it can fly but the main structure needs a redesign to fullfil the stability tasks. While parts of the design/structure will be just implemented as is other sections need some enforcements. ALso I will rethink the use of soem lasercut parts and maybe switch to composite made elements. Some test in this direction have to be done to make a decision. Since I had some difficulties processing the mylar film this is also a important task on the list that needs further investigation. More tests have to be done with the infill settings at the 3D printers to optimise the weight.
what questions need to be answered?
Besides the difficulties with the vessel there questions about the flight system more precisely the accelerometer. It seems that this was an issue that has to be clarified. And finally the dimensions/combinations motor + rotor need some calculations too.