Search results

Currently, in many countries, aviation safety regulations allow piston engines exploitation above Time Between Overhaul (TBO) recommended by manufacturers. Upon fulfillment of certain requirements, which are already included in the manufacturers’ documentation, TBO extension is granted. National Aviation Authority has approved exploitation of piston engines to something like quasi on-condition maintenance, which has no technical proof behind. This leads to the conclusion that the current, simple way of the engine’s life extension is not the best solution for maintaining flight safety. Aircraft piston engines TBO extension requires changes in the current exploitation system.

The paper provides methodology for aircraft piston engines on-condition exploitation based on engine flight parameters (from cruise and takeoff) and engine oil particles analysis. The paper describes a method of diagnostic limits for certain engine parameters and elements in the oil assignation assuming that they come under rules of normal distribution.

It has been found that piston engines installed on maximum takeoff mass <5,700 kg class aircraft are the second biggest contributor as a source of aviation events, thereby having a significant impact on aviation safety. Engine flight parameters and elements content in the oil meet Gaussian rules.

Introduction of the engine on-condition exploitation into operation practices reduces the operator’s engine direct maintenance cost and increases technical knowledge of the employees and has a positive impact on flight safety.

It is the first scientific description in Poland, which proposes an empirically proved methodology of the aviation piston engines on-condition exploitation.

This study aims to contrastively investigate the effects of biodiesel and diesel on the power, economy and combustion characteristics of a compression ignition aviation piston engine for unmanned aerial vehicles.

Biodiesel used as alternative fuel will not be mixed with diesel during experimental study. Pure diesel fuel is used for the comparative test. Same fuel injection strategies, including pilot and main injection, are guaranteed for two fuels in same test points.

The engine-rated power of biodiesel is lower than diesel, which results in higher specific fuel combustion (SFC) and effective thermal efficiency (ETE). Biodiesel has the faster burning rate, shorter combustion duration. The crank angle of 50% mass fraction burned (CA50) is earlier than diesel. The ignition delay angle of biodiesel and diesel in the pilot injection stage is almost the same at high engine speed. As the speed and load decrease, the ignition delay angle of biodiesel in the pilot injection stage is smaller than diesel. At 100% high load conditions, the fuel-burning fraction of biodiesel in the pilot injection is the same as diesel. The peak heat release rate (HRR) of biodiesel is slightly lower than diesel. At 20% part load conditions, the fuel-burning fraction of biodiesel in the pilot injection stage is lower than diesel. Because of the combustion participation of unburned pilot injected fuel, the peak HRR of biodiesel in the main injection is equal to or even higher than diesel.

The application feasibility of alternative fuel and its effects on aviation engine power, economy and combustion characteristics will be evaluated according to the “drop-in“ requirements and on the low-cost premise without changing the aviation engine structure and parameters.

High reliability and high power-to-weight ratio are the technical difficulties in the development of aviation piston heavy fuel engines. This paper aims to provide a design evaluation method of the aero piston engine block, which can help R&D personnel quickly evaluate the performance of engine block, including effective bearing capacity and fatigue deformation, save a lot of experimental time and shorten the R&D cycle.

In this paper, structural efficiency is used to evaluate the reliability and durability of the engine block. Structural efficiency is a new evaluation method that lists its corresponding connotation according to different objects. In this paper, the function of the engine block in the engine is explained in detail, and three quantifiable connotations of the structural efficiency of the engine block are put forward. In the subsequent calculation, the calculation is carried out according to the three indexes, and the calculation results are used as the indexes to evaluate the performance of the engine block.

The structural efficiency evaluation method proposed in this paper can quickly and effectively evaluate the performance of the block from many aspects. Under the same boundary conditions, the two design schemes are simulated and analyzed, and the durability test is carried out. The analysis and experimental results show that Scheme 2 has good performance, which verifies the feasibility of the evaluation method.

This paper provides a method for rapid evaluation of engine block performance.

Europe has adopted Flight Path 2050 (FP 2050) challenge with an objective of 90 per cent of the travelers being able to reach door-to-door European destinations within 4 hours by 2050. The aim can be achieved by reliable, well-organized small aircraft transport (SAT). Analysis of the currently operating small aircraft operational reliability data will support the development of future aircraft designs as well as reliability and safety requirements necessary for commercial operations.

The paper provides results of a statistical analysis of small aircraft current operations based on the reported events contained in the Database named European Coordination Centre for Aviation Incident Reporting Systems database. It presents identified safety indicators and focuses particularly on those related to the aviation technology.

It has been found that certain airframe and powerplant systems have the biggest influence on flight safety.

Multidisciplinary analysis of the operational and aircraft components reliability data will help in a proper preparation of the SAT supporting facilities, a design process of new aircraft and improvements of the existing airframe and powerplant systems.

Presented results are valuable for further developments of the statistical tools facilitating new product introduction.

This paper aims to present the analysis of introduction of single engine turbo-prop aeroplane class in terms of certification specifications and flight crew licensing regulations.

Following the results of flight testing and additional performance and sizing calculations, the proposed class was placed among the existing aeroplane taxonomy in terms of performance, flight loads, mass penalty, fuel economy and several other factors. Concerning small air transport initiative, the new class was tried to be placed as a starting point in commercial pilot career.

The paper points the potential market for single engine turbopropeller aeroplanes and lists today obstacles in wider introduction. Therefore, remarks about required change of regulations and requirements for design process, as well as for crew licensing, are underlined.

The results of the study would be helpful in preliminary design of a new low-power turboprop aeroplane, as well as during tailoring the certification specifications.

The approach presented in this paper is a detailed extension of an original idea presented by author for the first time during Clean Sky/small air transport workshop.

The purpose of this paper is to compare the combustion characteristics, including the combustion pressure, heat release rate (HRR), coefficient of variation (COV) of indicated mean effective pressure (IMEP), flame development period and combustion duration, of aviation kerosene fuel, namely, rocket propellant 3 (RP-3), and gasoline on a two-stoke spark ignition engine.

This paper is an experimental investigation using a bench test to reflect the combustion performance of two-stroke spark ignition unmanned aerial vehicle (UAV) engine on gasoline and RP-3 fuel.

Under low load conditions, the combustion performance and HRR of burning RP-3 fuel were shown to be worse than those of gasoline. Under high load conditions, the average IMEP and the COV of IMEP of burning RP-3 fuel were close to those of gasoline. The difference in the flame development period between gasoline and RP-3 fuel was similar.

Gasoline fuel has a low flash point, high-saturated vapour pressure and relatively high volatility and is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. Adopting a low volatility single RP-3 fuel of covering all vehicles and equipment to minimize the number of different devices with the use of a various fuels and improve the application safeties.

Most two-stroke spark ignition UAV engines continue to combust gasoline. A kerosene-based fuel operation can be applied to achieve a single-fuel policy.

The purpose of this paper is to investigate the knock combustion characteristics, including the combustion pressure, heat release rate (HRR) and knock intensity of aviation kerosene fuel, that is, Rocket Propellant 3 (RP-3), on a port-injected two-stoke spark ignition (SI) engine.

Experimental investigation using a bench test and the statistical analysis of data to reflect the knock combustion characteristics of the two-stroke SI unmanned aerial vehicle (UAV) engine on RP-3 kerosene fuel.

Under the full load condition of 4,000 rpm, at the ignition timing of 25 degree of crank angle (°CA) before top dead centre (BTDC), the knock combustion is sensitive to the thinner mixture; therefore, the knock begins to occur when the excess air ratio is larger than 1.0. When the excess air ratio is set as 1.2, the knock obviously appears with the highest knock intensity. At the excess air ratio of 1.2, better engine performance is obtained at the ignition timing range of 20-30 °CA BTDC. However, the ignition timing at 30° CA BTDC significantly increases the peak combustion pressure and knock intensity with the advancing heat release process.

Gasoline has a low flash point, a high-saturated vapour pressure and relatively high volatility, and it is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. The authors adopt a low-volatility single RP-3 kerosene fuel for all vehicles and equipment to minimise the number of different devices using various fuels and improve the military application safety.

Most two-stroke SI UAV engines for military applications burn gasoline. A kerosene-based fuel for stable engine operation can be achieved because the knock combustion can be effectively suppressed through the combined adjustment of the fuel amount and spark timing.

The purpose of this paper is to investigate power performance, economy and hydrocarbons (HC)/carbon monoxide (CO) emissions of diesel fuel on a two-stoke direct injection (DI) spark ignition (SI) engine.

Experimental study was carried out on a two-stroke SI diesel-fuelled engine with air-assisted direct injection, whose power performance and HC/CO emissions characteristics under low-load conditions were analysed according to the effects of ignition energy, ignition advance angle (IAA), injection timing angle and excess-air-ratio.

The results indicate that, for the throttle position of 10%, a large IAA with adequate ignition energy effectively increases the power and decrease the HC emission. The optimal injection timing angle for power and fuel consumption is 60° crank angle (CA) before top dead centre (BTDC). Lean mixture improves the power performance with the HC/CO emissions greatly reduced. At the throttle position of 20%, the optimal IAA is 30°CA BTDC. The adequate ignition energy slightly improves the power output and greatly decreases HC/CO emissions. Advancing the injection timing improves the power and fuel consumption but should not exceed the exhaust port closing timing in case of scavenging losses. Burning stoichiometric mixture achieves maximum power, whereas burning lean mixture obviously reduces the fuel consumption and the HC/CO emissions.

Gasoline has a low flash point, a high-saturated vapour pressure and relatively high volatility, and it is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. The authors adopt a low volatility diesel fuel for all vehicles and equipment to minimise the number of different devices using various fuels and improve the potential military application safety.

Under low-load conditions, the two stroke port-injected SI engine performance of burning heavy fuels including diesel or kerosene was shown to be worse than those of gasoline. The authors have tried to use the DI method to improve the performance of the diesel-fuelled engine in starting and low-load conditions.

Hypertac Ltd have developed an impressive 2100‐way backplane which they regard as a significant development in high density connectors.

The first wing to be manufactured by British Aerospace for its new Airbus A340 made its public debut recently at the company's Airbus Division in Broughton, near Chester.