{"id":56,"date":"2023-07-15T06:13:29","date_gmt":"2023-07-15T06:13:29","guid":{"rendered":"https:\/\/libraryresources.nse.org.ng\/engineeringwithcountry\/chapter\/aeronautics\/"},"modified":"2026-03-16T13:46:13","modified_gmt":"2026-03-16T13:46:13","slug":"aeronautics","status":"publish","type":"chapter","link":"https:\/\/libraryresources.nse.org.ng\/engineeringwithcountry\/chapter\/aeronautics\/","title":{"raw":"Aeronautics","rendered":"Aeronautics"},"content":{"raw":"
\n\nThe ability of science to understand and manipulate the world is exemplified in our engineering. All civilisations have developed technology to suit the world they live in and to assist them to live a life they value. The technology that First Nations Australians developed not only had their own features unique to the culture, they also embraced principles that were valued by western cultures, such as aerodynamics and flight.\n\n<\/div>\n \n
\n\nDavid Unaipon has been recognised on Australia\u2019s $50 note since 1995. \u202fHe lodged 19 provisional patents during his life which he could not afford to fully patent, including shearing blades that converted a curved motion into the straight line movement which is the basis of modern mechanical shears. He wrote prolifically, and conceptualised the helicopter two decades before it became a reality. Three elements were regularly referred to in the press during his life: his sheep shearing innovations, his basic design for a helicopter based on the motion of the \u00a0boomerang, and his interest in the then entirely theoretical field of laser light. In a 1914 account Unaipon gave to the\u202f Daily Herald\u202f he suggests:\n\n<\/div>\n
\n\n\u201cAn aeroplane can be manufactured that will rise straight into the air from the ground by application of the boomerang principle. The boomerang is shaped to rise in the air according to the velocity with which it is propelled, and so can an aeroplane\u201d (Unaipon,\u202fDaily Herald\u202f1914).<\/span>\n\n<\/div>\n
\n\nA functioning helicopter did not appear until 1936, however the concept produced by Unaipon has been shown to work by students' projects at various institutions including Deakin University. The boomerang is an aerofoil design which provides the lift to enable it to fly long distances. By pairing two boomerangs and combining with motorised energy to rotate the blades, Unaipon provided the basic design of the rotor now used in helicopters.\n\n<\/div>\nThe principle of aerofoils is important for lift in large aircraft and can provide direct lift when rotated rapidly in a circle. For more analysis of the flight path of a returning boomerang see this paper by Nicholas Landell-Mills (2019) on How boomerangs fly according to Newtonian mechanics.<\/a><\/span>\n\nOn the boomerang, the aerofoil design is created by the carver who whittles the wood into the uneven profile that creates the pressure difference around the blade. The amount to remove from the faces and the amount to bend the blades come from good judgement of how to affect the flight. The carver is a person skilled in the design and balance of a boomerang, however nowadays they are often carved by programs from plywood or moulded in plastic.\n\n \n\n[caption id=\"attachment_55\" align=\"alignright\" width=\"350\"]\"Flight Figure 1 Flight Path Depends on Angle of Attack provided by author[\/caption]\n\nThe second aspect of the flight is the curvature of the path, which is created by the gyroscopic procession. The uneven lift between the two arms of the blade tries to tip the boomerang over, but just like leaning a moving bike over makes it turn in an arc. When the boomerang spins the tipping force between the blades is at an angle to its flight plane. This curves the boomerang's flight.\n\nThe angle of attack on a boomerang is the angle between the incoming airflow and the plane surface of the boomerang. The angle of attack affects the boomerang's lift and stability. It also affects the angle of curvature of the flight path. The greater the angle of attack will:\n
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