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Planning Transport Systems
Published in Milan Janić, Transport Systems, 2017
As will be seen, over the past 50 years, the payload capacity of cargo commercial aircraft has increased ten-fold, starting from milestones like introducing the aircraft DC-6B in the year 1954, then B707-320C, B747-200F, -400F, and -8F, and finally A380F with a payload capacity greater than 150 ton in the year 2010. These exclusively cargo versions of aircraft have better matched the specific needs of air cargo transportation; in particular, the largest is the Antonov 225 aircraft, a derivative of the Antonov 124 cargo aircraft, with a payload capacity of 250 ton. However, only a single unit has been built so far and is hence not represented on the trend line.
Effect of bleed air on performance of small turbojet engine used in unmanned aerial vehicle
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
By virtue of the working principle, gas turbine engines have been employed for different purposes such as electrical generation by generator, power production for miscellaneous pumps used on it, and thrust for propelling the aircraft. If gas turbine systems are used on the ground, these are named cogeneration systems due to producing both heat and electric energy. For air vehicle applications, these produce thrust for fixed wings or power for rotating helicopter blades. Gas turbine engines are categorized into four subsystems such as turbojet utilized unmanned aero vehicles, turbofan employed on mainly passenger aircraft, turboshaft for helicopter and turboprop used on mainly cargo aircraft. Figure 1 indicates turbojet engine with one spool, which links air compressor to turbine unit. This engine consists of air inlet, air compressor, combustion chamber, turbine and exhaust unit. It could be kept in mind that the present engine bears similar specifications with TRI 60–5 version (Forecast, 2010). Moreover, Table 1 presents engine-specific parameters for sea level and baseline. As can be seen, net thrust of STE is 4370 N whereas its air mass flow entering from air inlet is 6.63 kg/s. However, at 10 km of altitude, net thrust of STE is computed as 1420 N while air mass flow is measured 2.42 kg/s. As mentioned above, bleed air ratio taken from compressor changes between 1% and 8%. The values of other specifications could be provided from Table 1.
Investigating the green performance limits of a cargo aircraft engine during flight: a thermo-environmental evaluation
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Yasin Şöhret, Selcuk Ekici, Ali Dinc
In the current paper, a three-spool turboprop engine of a cargo aircraft, commonly in service with military units, is evaluated. The maximum range of the aircraft is between 3300 and 8700 km (depending on the payload), whereas it can fly up to a speed corresponding to 0.72 Mach. Additionally, the payload capacity of the aircraft is limited to 37 tones. Wingspan, overall length, and overall height values of the aircraft are 42.357 m, 45.091 m, and 14.675 m, respectively. The aircraft is also powered by four turboprop engines. A three-spool axial flow turboprop engine consists of a propeller reduction gearbox, a five-stage axial-flow intermediate pressure compressor, a six-stage axial-flow high pressure compressor, an annular combustion chamber, a single stage axial-flow high pressure turbine, a single stage axial-flow intermediate pressure turbine, a three-stage axial-flow low pressure turbine, an accessory gearbox and a FADEC (EASA 2013, 2019).
Analyzing manufacturer and the insurance-based risk mitigation policy with equipment service contracting
Published in Enterprise Information Systems, 2018
Xuwei Qin, Zhong-Zhong Jiang, W.H. Ip, Ying Sheng, C.H. Wu
Proposition 1 shows that the distinct retirement ages are possible, depending especially on the value of , and the cost ratio . The parameter reflects an inherent feature of equipment at the failure rate and the complexity of repairs. The ratio is mostly determined by the cost tradeoff between replacement and repair. The more the downtime target decreases, the more the performance requirement of the customer restricts. One important insight from this proposition is that the type of equipment determines its retirement age. Aviation engines GE90 is one of the classical capital-intensive equipment with very high replacement cost, relatively low repair cost as well as strict performance requirement, since new composite materials and manufacturing technology are used extensively to improve the reliability, such as carbon fiber, 3D printing and so on. Aviation engine obviously accords with the second scenario. Its retirement age is determined by the customer’s performance requirement and repair effort, as showed in . This finding provides a reasonable explanation of recent aviation practices where many outdated engines for airliner have extended their retirement age due to new repair technology improving the failure process and repair time or transferred to cargo aircraft because of the lower performance requirement. On other hands, general lathe becomes one of common equipment with low-price and relatively high repair cost. General lathe obviously belongs to the first scenario. Its retirement age is mostly determined by the cost ratio and repair efforts. Since the manufacturing technology enhances and the labor cost of repair service is increasing, aging lathe recently accelerates to be replaced. In other words, the retirement age of general lathe becomes short. Therefore, the equipment type has a determinant impact in the retirement age decision.