Voting Result: 2.14649097403
Overview for MUPA (Modular Universal Payload Aircraft)
Critical deliveries drone may break or malfunction during repeated missions.
A drone like this, should be easily serviceable by non-expert personnel. It's replacement parts should be cheaply and quickly acquired and if it needs to be transported, it should fit in an average car trunk.
This system was designed on the above principals and with its simplicity and efficiency it will get the job done anytime.
Explanation of design details
The landing gear is composited by four spring supported legs inside the aircraft's structure. This enables the aircraft to land on rough surfaces and also confirm that it has actually landed with incorporated sensors.
All components (FCC, Comm Systems, Power Modules, etc.) live inside the fuselage which is weather proofed. All external wiring lives inside the tubes. and wings.
Servo actuators and motors are water resistant and there are no other exposed electronics which can be damaged by nature.
All surfaces are covered with smooth, aerodynamic materials which also function as water obstructors.
The biplane design was selected in the premise of using shorter wing spans (and having smaller footprint). That helps a lot with the transportability of the aircraft and the general aircraft handling.
Having this smaller footprint, permits the handler to easily store the aircraft without disassembling it and also to easily transport it on foot.
The wings, tail and payload/battery compartment of the aircraft can be removed resulting in a 4-part assembly that easily fits in a big pelican type case.
Motor mounts can also be removed for easy maintenance but there is no need to remove them for other reasons as for transportation purposes as the footprint is already small.
One of the key aspects of this system, is the payload compartment.
It can get inserted both ways. Inserting it from bellow makes the system able to be offloaded automatically. Inserting it from above, makes the system optimal for payload extraction by humans.
The payload compartment is completely removable and can contain the system's batteries. The end user removes the box, gets the useful payload. From there, if the aircraft needs more power for the next mission, the end user can easily provide it by charging or replacing the box. He does not have to mess with small cables and wonder if the battery placement is correct.
For the battery, the following configuration was selected:
Kokam 3200SHD (20C); 12 series x 5 parallel cells; 3200mAh @ 3.7V; 0.008 Ohms/cell.
This configuration strikes a very nice ballance of power/weight for the MUPA aircraft and allows it to cruize with speeds up to 80 km/h.
Ease of handling
This kind of modular design, enables tool-less, quick and reliable assembly and disassembly workflows without being intimidating to the inexperienced user. Any electrical connections are thoughtfully and securely positioned inside the tube joints so the user would not need to deal with the wiring of the fuselage to replace a motor. All the modular connections need no tools as they are achieved by using a tube-in-tube design in conjunction with spigots and clips.
Other connections require a single Allen screwdriver.
That design is also optimal for sensor payloads. The battery capacity can be adjusted according to the system's needs and big specialised sensor units can be used.
The materials used, are 22mm carbon fibre tubes for the structure, the main fuselage is made of fibreglass composite and the wings are made of foam.
That results in a total weight around 19.2 kg (with 3kg payload) which is under the airport baggage restrictions.
Fail Safe components
For the vertical flight, the X8 configuration was chosen so there would be no problems in the case of an engine loss.
For the same reasons, there are two forward flight motors. In case of a total failure scenario, the aircraft employs a flight termination parachute and launcher powered by a discrete battery.
Safety and mostly human safety is a main concern and big factor in MUPA’s design process. In every take-off, the aircraft alerts the surrounding crowd of its presence by sound. Forward flight motors only work on safe altitude, so there is no danger for someone to get injured by the forward flight pusher motors.
From the moment the aircraft touches the ground, the motors power down and get into the unarmed state. When they stop spinning, they lock automatically.
The shroud around the motors prevents them from bumping onto other objects and also prevent accidents in low altitude flight without adding too much weight.
The same is true for the front flight motors. They are inside the frame which makes them difficult to reach and they engage only in safe altitudes.