Economical UAV Design of Drones
When natural calamity may take place, it often disturbs the smooth functioning of phone and internet services over the affected locations. Drones tend to provide assistance in situation like these. Autonomous aircraft tends to provide some sort of assistance to these areas by means of providing communications payload offering short-term telecommunication coverage to those in need.
But these types of unpiloted aerial vehicles – Drones tend to be expensive and could be useful in the air for a couple of days as in the case with most of the autonomous surveillance vehicles run by the U.S. Air Force. Provision of sufficient and insistent reporting would need a relay of numerous aircraft landing as well as refuelling all the time.
Moreover operational cost of thousands of dollars per hour for each vehicle would also be essential. But now a team of MIT engineers have developed a much economical drones design which tends to hover for longer period of time in providing a wide range of communication assistance. The researchers have planned, constructed and verified a drones alike to a thin glider with a 24-foot wingspan which can carry 10 to 20 pounds of communication equipment flying at an altitude of 15,000 feet.
Drones Controlled by 5-Horsepower Gasoline Engine
With just under 150 pounds in weight, the vehicle is controlled by a 5-horsepower gasoline engine which according to the researchers has the potential of keeping itself aloft for over five days which is longer than any gasoline-powered autonomous aircrafts, remaining in flight. Its results will be presented by the team at the American Institute of Aeronautics and Astronautics Conference in Denver, Colorado.
The team is headed by R. John Hansman, the T. Wilson Professor of Aeronautics and Astronautics; and Warren Hoburg, the Boeing Assistant Professor of Aeronautics and Astronautics. Hansman together with Hoburg are the co-instructors for Beaver Works project for MIT, student research collaboration between MIT and the MIT Lincoln Laboratory.
As a part of a Beaver Works capstone project, they had worked with MIT students in designing a long-duration Drones, usually a two-or three semester course enabling MIT students to design a vehicle meeting definite mission specification and to build and test their design.
The U.S. Air Force, in the spring of 2016 had approached the Beaver Works collaboration with the intention of designing a long-duration drones powered by solar energy. At that point of time it was assumed that an aircraft fuelling by the sun would probably remain in flight indefinitely.
Solar-Powered High Altitude Aircraft – Continuous Internet Access Rural/Remote
Others comprising of Google had experimented this concept, designing solar-powered, high altitude aircraft in delivering continuous internet access to rural as well as remote areas of Africa. However when the team had reconsidered the idea and had analysed the issue from various engineering point of view, they realised that solar power for long-duration emergency reply was not the solution.
A solar drones vehicle would probably be operational during summer but in winter, especially if one is far away from the equator and the nights seem longer with not much sunlight during the day, it would be difficult. Then the issue of being loaded with more batteries would come up which would give rise to additional weight and make the plane bigger.
Hansman informed that for the mission of disaster relief this would only be a solution to disaster which tend to take place in summer at low latitude. After showing the problem utilising GPkit which is a software tool created by Hoburg enabling engineers in determining the optimal design decisions or dimensions for a vehicle with certain constraints or mission need, the researcher arrived at their conclusions.
Technique of Hoburg Drones
This system is not exceptional among preliminary aircraft design tools but different from these tools, that take into consideration the various constraints, the technique of Hoburg enables the team to consider about 200 constraints as well as physical models at the same time and fits them together in creating an ideal aircraft design. Hansman commented saying that this gives us all the information needed to draw up the airplane.
Moreover it also states that for every one of these hundreds of parameters, if one of them is changed, how much would that influence the performance of the drone plane? If one changes the engine a little, it will make a great difference and if the wingspan is changed, would it display an effect? After defining through their software valuations that a solar-powered drones would not be practical for at least long duration usage in any area of the world, the team implemented the same modelling for a gasoline powered aircraft.
Eventually they came up with a design which had been expected to remain in flight for longer than five days at an altitude of 15,000 feet in up to 94th percentile winds at any latitude. A prototype UAV was built by the team in the fall of 2016 after the dimensions determined by the students utilising the software tool of Hoburg.
Special Contemplations
In order to maintain the vehicle lightweight, they utilised materials like carbon fibre for the wings and fuselage. Kevlar was used for the tail and nosecone which accommodates the payload. The UAV had been designed by the researchers to be taken apart easily and stored in a FedEx box which could be shipped to any disaster area and reassembled rapidly.
In spring the prototype was refined and a launch system was developed by the students, in the fashion of a simple metal frame to fit on a classic car roof rack. The UAV is placed atop the frame as a driver fast-tracked the launch vehicle up to rotation speed, the optimal take-off speed of the drone. At that point of time, the remote pilot tends to angle the UAV headed for the sky mechanically releasing a clasp and permitting the drones to launch.
The UAV took off effectively in its preliminary tests and landed safely. According to Hoburg there are special contemplations which need to be made for testing the vehicle over numerous days like having sufficient people in monitoring the aircraft over a long period of time. Hoburg had stated that there are few aspects to flying for five straight days and that they are quite confident that they have the right fuel burn rate and right engine where they could fly it for five days.
