Possibilities of Cost Reduction with All-Wing Aircraft

1965 ◽  
Vol 69 (659) ◽  
pp. 744-749 ◽  
Author(s):  
C. H. Lee
Keyword(s):  
Cost Reduction ◽  
Design Problem ◽  
Short Range ◽  
Operating Cost ◽  
Design Features ◽  
General Survey ◽  
General Argument ◽  
Sequence Of Events ◽  
Range Transport ◽  
Direct Operating Cost

The aim of this paper is to show how design improvements may lead to a reduction in direct operating cost, pence per passenger mile. In all the comparisons made it is assumed that equal standards of equipment, accommodation, powerplant efficiency, and so forth, apply and that equal skill and standards apply in manufacturing; differences therefore are due to design features. The paper is in two main sections:(1) A Satellite's eye-view of the whole design problem of the cheap short-range transport aeroplane.(2) A more detailed description of two specific examples which illustrate the conclusions drawn from the general survey.The first part is historically fiction but technically fact; the second part (despite the temptation to interchange the above two nouns and adjectives) is, I claim, fact both historically and technically.I have departed from the historical sequence of events for the first part because we have now realised that it is possible to present in a comprehensive general argument the rather confused mass of data, ideas, techniques, inspirations and false trails that, in the course of time, led us to an enthusiasm for the all-wing Aerobus.

Application of the Geared Turbofan With Constant Volume Combustor on Short-Range Aircraft: A Feasibility Study

2009 ◽  
Author(s):  
Fernando Colmenares Quintero ◽  
Rob Brink ◽  
Stephen Ogaji ◽  
Pericles Pilidis ◽  
Juan Carlos Colmenares Quintero ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Short Range ◽  
Operating Cost ◽  
Constant Volume ◽  
Superior Performance ◽  
Wave Rotor ◽  
Environmental Aspects ◽  
Direct Operating Cost ◽  
Combustion Technology ◽  
Further Development

Recently a considerable effort was made to understand the gas- and thermodynamics of wave rotor combustion technology. Pressure-gain combustors potentially have superior performance over conventional combustors due to their unsteady flow behaviour. Wave rotor combustion provides semi-constant volume combustion and could be integrated in the steady-flow gas turbine. However, a feasibility study to assess the economical and environmental aspects of this concept has not been conducted for short-range missions. Preliminary Multidisciplinary Design Framework was developed to assess novel and radical engine cycles. The tool comprises modules to evaluate noise, emissions and environmental impact. Uncertainty can be accounted for with Monte Carlo simulation. The geared turbofan with constant volume combustor is simulated and benchmarked against a baseline geared turbofan engine. Results indicate that the former complies with CAEP/6 and FAR Part 36 regulations for noise and emissions. Furthermore, acquisition cost of the engine is higher, but engine direct operating cost decreases by 25.2%. The technology requires further development to meet future noise and emissions requirements.

scholarly journals Enabling the potential of hybrid electric propulsion through lean-burn-combustion turbofans

2021 ◽  
Vol 5 ◽  
pp. 164-176
Author(s):  
Stavros Vouros ◽  
Mavroudis Kavvalos ◽  
Smruti Sahoo ◽  
Konstantinos Kyprianidis
Keyword(s):  
Electric Propulsion ◽  
Direct Injection ◽  
Operating Cost ◽  
Pollutant Emissions ◽  
Civil Aviation ◽  
Lean Burn ◽  
Lean Direct Injection ◽  
Direct Operating Cost ◽  
Hybrid Electric ◽  
The Impact

Hybrid-electric propulsion has emerged as a promising technology to mitigate the adverse environmental impact of civil aviation. Boosting conventional gas turbines with electric power improves mission performance and operability. In this work the impact of electrification on pollutant emissions and direct operating cost of geared turbofan configurations is evaluated for an 150-passenger aircraft. A baseline two-and-a-half-shaft geared turbofan, representative of year 2035 entry-into-service technology, is employed. Parallel hybridization is implemented through coupling a battery-powered electric motor to the engine low-speed shaft. A multi-disciplinary design space exploration framework is employed comprising modelling methods for multi-point engine design, aircraft sizing, performance and pollutant emissions, mission and economic analysis. A probabilistic approach is developed considering uncertainties in the evaluation of direct operating cost. Sensitivities to electrical power system technology levels, as well as fuel price and emissions taxation are quantified at different time-frames. The benefits of lean direct injection are explored along short-, medium-, and long-range missions, demonstrating 32% NO<italic><sub>x</sub></italic> savings compared to traditional rich-burn, quick-mix, lean-burn technologies in short-range operations. The impact of electrification on the enhancement of lean direct injection benefits is investigated. For hybrid-electric powerplants, the take-off-to-cruise turbine entry temperature ratio is 2.5% lower than the baseline, extending the corresponding NO<italic><sub>x</sub></italic> reductions to the level of 46% in short-range missions. This work sheds light on the environmental and economic potential and limitations of a hybrid-electric propulsion concept towards a greener and sustainable civil aviation.

The Relative Commercial and Operational Properties of Short-Range Transport Aeroplanes Powered by Turbine and Reciprocating Engines

1957 ◽  
Vol 61 (560) ◽  
pp. 560-563
Author(s):  
C. F. Toms
Keyword(s):  
Short Range ◽  
The Other ◽  
Operating Costs ◽  
Relative Earning ◽  
Range Transport ◽  
Reciprocating Engines

There have recently appeared a number of papers and notes bearing on the merits of turbo-prop vis-a-vis turbo-jet transport aeroplanes, mostly exhibiting specific favour towards one type or the other, but disagreeing among themselves and all based upon investigations which, it is contended here, are incomplete.The basis used has invariably been a comparison of the relative direct operating costs per unit of weight (i.e. per passenger or per ton) per mile, and the relative earning capacities have not been considered. This, it is believed, is a serious omission which can only lead to a distorted assessment and erroneous conclusions.The author has been associated with a thorough-going investigation into the relative merits of twin-engined turbo-prop, turbo-jet, and reciproeating-engined aeroplanes, all designed on a strictly comparable basis to do, as far as the performance of suitable available engines would allow, the same job in terms of capacity payload and associated operational stage length, take-off and landing performance and one-engine-inoperative climb performance in given atmospheric and altitude conditions.

Next Generation Turboprop Gearboxes

1982 ◽  
Author(s):  
W. L. McIntire ◽  
D. A. Wagner
Keyword(s):  
Operating Cost ◽  
Past Experience ◽  
Reduction Ratio ◽  
Next Generation ◽  
Propulsion Systems ◽  
Aircraft Systems ◽  
General Arrangement ◽  
Significant Interest ◽  
Direct Operating Cost ◽  
New Generation

A new generation of fuel-efficient turboprop propulsion systems is under consideration now that fuel is a significant portion of the direct operating cost of aircraft. Systems in the 5000- to 15,000-hp (3730- to 11,185-kW) range that use conventional propellers or the new propfan are being studied. Reduction gearing for this next generation of turboprops is of significant interest due to new requirements for cruise speed life, and reliability. Detroit Diesel Allison’s past experience with the T56 family of turboprop reduction gearboxes is recounted. Probable requirements of the next generation of reduction gearboxes are discussed since new requirements for gearboxes combined with past experience should determine the profile of the next generation of gearboxes. A discussion of gearbox general arrangement and its impact on airframe installation is included, along with comments on reduction ratio, gear arrangement, accessory drives, reliability goals, and probable technology needs.

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