Aircraft Sideslip vs Airspeed (notional) 16 14 Sideslip (Deg) Advanced, highly-maneuverable aircraft are expected to make increasing demands on initial off-axis conditions with which ejection systems must contend. A notional representation of current aircraft sideslip capabilities is shown in Figure 9. 1 . 2 10 As aircraft become more agile using 8 advanced flight control systems and thrust 6 4 will become more of a concern. Experience with aircraft such as the F-16 and F-22 that 2 have a relatively large canopy profile and xial length has already highlighted a number 200 300 700 of structural concerns. In these aircraft, the Airspeed (KEAS) lateral moment on the canopy during Jettison in sideslip conditions can cause extremely Figure 9. 1 Airspeed vs Sideslip Angle for Notional Aircraft high loads in the aft hinge areas.
In a typical design, failures in this area can result in an unguided canopy Jettison and potential for impacts with the pilot. Escape system designs with a canopy-attached seat initiation lanyard must also contend with adverse lanyard pull angles and the possibility of the lanyard itself failing. Further, ost of the current ejection seats were not designed or tested to any off-axis requirements. The US Air Force has only recently added off-axis testing capabilities with the introduction of the Multi Axis Sled for Ejections (MASE) in the late 1980’s.
This asset can be utilized in sled tests for vehicle yaw angles up to 20 degrees. 9. 2 CURRENT US ESCAPE SYSTEM CAPABILITY The primary ejection seat currently in USAF service is the Advanced Concept Ejection Seat (ACES II) designed by the Douglas Aircraft Company (Figure 9. 2). Based on pre-1970 technology, the ACES II has been in use since 1978, with over 8000 units nstalled in fixed-wing tactical and strategic aircraft. The ACES II represents third- generation ejection seat technology.
It represents technology that supercedes first generation, or catapult only, as a propulsive force and 122 Figure 9. 2 ACES II Ejection seat second generation, which includes rocket motors to improve low-altitude and low- speed performance. Third-generation seats are characterized by the ability to sense speed and altitude and adjust timing for parachute opening. While the ACES II major injury or fatality) have occurred over 500 KEAS, and none over 600 KEAS. It is uspected that the actual safe ejection envelope has a much lower top-end speed.
The envelopes of ejection seats with poor directional stability and little or no windblast protection are limited by their ability to prevent ejectionrelated injuries rather than their ability to withstand the aerodynamic and inertial loads imposed during emergency escape. Ejection seat statistics clearly show an increased potential for major injury and fatality at speeds over 425 KEAS. Navy experience with the Martin-Baker Mk-7 seat is similar. During the Vietnam War, many US aircrew ejected near the pper limits of their aircraft flight envelope and incurred severe or fatal injuries due to high aerodynamic forces.
Inheritance and Polymorphism
Inheritance and Polymorphism.
Create a class Product which models customer’s purchased products. This class has:
– two private instance variables name (String) and unitPrice (double).
– A constructor to initialize the instance variables through parameters.
– A default constructor to initialize name to “unkown”, and unitPrice to 0. Use this(…)
– A method getPrice that returns the unitPrice.
– A getName method that returns the name.
– A toString method to return the name of the product followed by @ symbol, then the unitPrice.
Create two subclasses WeighedProduct and CountedProduct. WeighedProduct has an additional instance variable weight (double) in Kg while CountedProduct has an additional variable quantity (int) both private.
– Write an appropriate constructor for each of the classes making use of the constructor of the superclass.
– Override getPrice method that returns the price of the Product based on its unit price and weight (WeighedProduct), or quantity (CountedProduct). Make use of getPrice of the superclass
– Override also toString method for each class making use of the toString method of the superclass in defining those of the subclasses.
– toString should return something that can be printed on the receipt. For example
o Apple Fuji @ 5.00 1.5Kg 7.5 AED (in case of WeighedProduct class)
o Notebook Al-Bayan @ 6.5 10 units 65 AED (in case of CountedProduct class)
Write an application class with main method where you create an ArrayList<Product > object. Create several objects from the two subclasses and add them to the array list. Display the contents of the array list, one item per line. For each item, the display should contain Product name, unit price, weight (in Kgs) or quantity, and amount. You may use the toString method. The last line should show the total amount of all items purchased.
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