High-Speed Flight in Aviation Essay Example

Introduction

Modern aeroplanes are designed to operate in transonic and supersonic speeds. According to Tewari, such aircraft manoeuvre and cruise at high supersonic and transonic speeds because they have a good cruising range and large turning rate of a jet-powered aircraft (140). Most aircraft with supersonic and transonic speeds have airframes designed for an efficient, fast flight and are expected to have their open-loop flutter in the transonic regime. Supersonic airplanes include fighter jets used in the military that cruise past the speed of sound and produces a thunderous shock wave in the air. Concorde and Tupolev Tu-144, used as civil airliners, were the pioneers in the supersonic aircraft industry but have since been retired. This paper is going to highlight high-speed flight such as supersonic and transonic flight and how it affects the aircraft.

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SUPERSONIC FLIGHT

Supersonic speeds affect the aircraft. When an aircraft flies this fast speed, it leads to superheating of up to 3,000oc, thus the faster the plane goes, the drag and lift increases which mandates a thinner fuselage, aerodynamic wings, and a high cruising altitude where the air is thin. Supersonic jets fly higher hence big engines are required to cram in enough air. This means that the aircraft will need a lot of fuel, which results in a relatively poor range. Due to the high speed of supersonic planes, the Concorde, for instance, was capable of transatlantic trips only, which gave indications that supersonic aircraft were not suitable for short routes. Supersonic planes required paths which take more than three hours thus were limited to overseas routes only.

The supersonic aircraft that were in the transport business charged exorbitant fares to different routes which led to a lot of competition. Despite this, the Concord, for example, ruled the airways for over 27 years and other airlines such as the British Airways made losses in the 1980s, but later Concorde could not compete with the British Airways which made profits over its lifetime. This competition affected the aircraft because it required constant servicing and maintenance because of its speed and regular flights on its different routes. Maintenance operations have a weighty effect on material ageing due to the degradation associated with airline servicing operations and maintenance. These include jetway interfaces, potable water servicing, and catering equipment. Also, servicing uses chemicals such as anti-icing, de-icing, cleaning, and paint stripper fluids which are harmful to the aircraft. Because of this, Airbus announced its plans of putting an end to servicing Concorde. This contributed to the fall of the Concorde as it ran out of business and was grounded.

Moreover, supersonic flight faces increase turbulence in the transonic regime, thus the drag also increases because of the amount of fuel used. According to Cha et al., supersonic speeds in aircraft leads to an increase in skin temperature because of aerodynamic heating derived by the effects of structure (6). Supersonic aircraft accelerates with a high speed thus the fuselage gets friction from the air. This makes the skin temperature of the aircraft to rise very quickly than the average temperature hence the distribution of temperature in the aircraft shifts sharply. In the Concord, for example, there was temperature variation in the fuselage skin with the nose cone, stabilizers, and the edges of the wings experiencing temperatures of up to 125oc, which is slightly above the boiling point of water. The anterior part of the fuselage skin had high temperatures of approximately 70c and reduced along the fuselage, with the aft of the aircraft experiencing 40c. The effects of skin overheating in supersonic aircraft include the increase in the length of the aircraft due to heating and the resultant expansion of the metals used in fuselage construction. Overheating also decreases the lift during take-off. Because of the increase in skin temperature, the concord required an on-board air conditioner that used water or air as a refrigerant to keep the cabin and interior cool.

A further problem that faced supersonic flight was the irregular changes in temperatures in the aircraft during the different phases of the flight. For example, changes in temperature were realized during acceleration to achieve the conditions for cruising and deceleration just before landing. This caused some parts of the plane to contract or expand more rapidly than others thus led to higher loads and stresses that acted on the structure of the plane. Significant stresses occur in supersonic flight as a result of thermal variations which is caused by the temperature differences in the structure of the aircraft. In the Concord, for instance, thermal stresses occurred resulting in thermal stresses and added to other stresses imposed on the aircraft. The management of the Concord had to look for ways to deal with these problems which included the use of an external paint used fot averting thermal expansion as well as the installation of sliding connections such as slotted lug attachments, diamond-shaped cutouts, and corrugated spar webs which eased internal stresses. These structural changes came with the financial implication that contributed to the grounding of the Concord.

Another effect of supersonic flight on a plane is the ground ambient exposure for both military and commercial aircraft. When aircraft are exposed to ultra-violet radiation, extreme humidity, harsh desert conditions, and temperature ranging between 60C to 30C, the structural materials and coating are quickly degraded and the harmful effect of flight exposure conditions are exasperated. These damaging events, both in flight and on the ground, pose a threat to sensitive components and polymeric composite through lighting strike and hail impact.

TRANSONIC FLIGHT

Transonic airplanes frequently operate switching between modes of flights such as landing, descending, cruise, climb, and takeoff. In these flight conditions, fundamental changes are realized in the free-stream approaching the wings. In a transonic flight, especially aerospace or military applications, the performance of the airfoil is altered because of the presence of unsteady and nonlinear effects of the airflow stream. Shockwave interactions, development of turbulent boundary layers, and boundary layer transition are also affected by supersonic flight. Lutsenko et al. argue that these problems alter the skin drag force distribution and pressure over the surface of the foil thus the pilot may face challenges in controlling the drag and lift force of the blades or wings (1).

The speed of the transonic flight affects aircraft because it develops a severe instability caused by shock waves that glide through the air quickly like the speed of sound. Shock waves accumulate in the front of an aircraft to form a considerable shock wave when it moves at a very high rate. The plane must glide through this shock wave and faces instability as a result of fast movement in the parts of the wing. When this happens, unequal and severe stress is created on the rotor blade, which is a trigger for dangerous accidents.

OTHER EFFECTS OF TRANSONIC AND SUPERSONIC FLIGHTS

Transonic and supersonic flights have harmful effects both in the air and ground. For instance, the environment has been affected by the flights as they have big engines which burn a lot of fuel thus emit greenhouse gases to the atmosphere which leads to global warming. If supersonic commercial flights are revived, it will worsen the environment because air travel is already a problem for the environment. Also, sonic booms are destructive since they can cause the shaking of items off shelves, breaking glass, and physical damages. For instance, in 1966, a fighter aircraft created a boom which displaced substantial qualities of rocks which crashed archaeological sites in the Canyon de Chelly National Monument. Covello, Menkes, and Mumpower note that booms in some countries have led to cattle stampedes, the collapse of roofs, death among factory workers, and cracking walls and doors (74).

CONCLUSION

Transonic and supersonic flights have changed the face of commercial and military transport. Despite their high speed and reduced travel time, the aircraft are affected by the speed which is close to the speed of the sound. For instance, high temperatures causes friction between the skin of the fast moving plane and the air outside resulting in kinetic heating. This leads to the thermal expansion of some parts of the plane. The conditions outside the aircraft such as high humidity and extreme desert conditions structurally degrade the materials and coating used in the manufacture of the aircraft. Exposing the plane to ultra-violet radiation and temperature ranging between 60C to 30C can easily degrade its structural materials and coating. Similarly, transonic aircraft develop shock waves which make the plane unstable hence accidents become inevitable. Despite these effects, both transonic and supersonic aircraft are the future of military and civil aviation because the travel times have been greatly reduced.

Works Cited

Cha, Jong Hyun, et al. "Variation of Supersonic Aircraft Skin Temperature under Different Mach number and Structure." Journal of the Korea Institute of Military Science and Technology 17.4 (2014): 463-470.

Covello, Vincent T., Joshua Menkes, and J. L. Mumpower, eds. Risk Evaluation and Management. Vol. 1. Springer Science & Business Media, 2012. Print.

Lutsenko, I., et al. "Effect of Free-Stream Turbulence Intensity on Transonic Airfoil with Shock Wave." IOP Conference Series: Materials Science and Engineering. Vol. 234. No. 1. IOP Publishing, 2017.

Scott, Jeff. "Concorde History III." Aerospaceweb, 24 October 2004, http://www.aerospaceweb.org/question/planes/q0199a.shtml

Tewari, Ashish. Adaptive Aeroservoelastic Control. John Wiley & Sons, 2016. Print.