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.

UAS Pilot Assessments of Display and Alerting for the Airborne Collision Avoidance System XU

2020 ◽  
Vol 64 (1) ◽  
pp. 159-163
Author(s):  
Casey L. Smith ◽  
R. Conrad Rorie ◽  
Kevin J. Monk ◽  
Jillian Keeler ◽  
Garrett G. Sadler
Keyword(s):  
Collision Avoidance ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Next Generation ◽  
National Airspace System ◽  
Aircraft Systems ◽  
Collision Avoidance System ◽  
Further Development ◽  
Initial Iteration ◽  
Integrated Display

Unmanned aircraft systems (UAS) must comply with specific standards to operate in the National Airspace System (NAS). Among the requirements are the detect and avoid (DAA) capabilities, which include display, alerting, and guidance specifications. Previous studies have queried pilots for their subjective feedback of these display elements on earlier systems; the present study sought pilot evaluations with an initial iteration of the unmanned variant of a Next Generation Airborne Collision Avoidance System (ACAS XU). Sixteen participants piloted simulated aircraft with both standalone and integrated DAA displays. Their opinions were gathered using post-block and post-simulation questionnaires as well as guided debriefs. The data showed pilots had better understanding and comfort with the system when using an integrated display. Pilots also rated ACAS XU alerting and guidance as generally acceptable and effective. Implications for further development of ACAS XU and DAA displays are discussed.

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 next generation of spacecraft orbit control propulsion systems

1979 ◽  
Author(s):  
R. SACKHEIM ◽  
D. FRITZ ◽  
H. MACKLIS
Keyword(s):  
Next Generation ◽  
Propulsion Systems ◽  
Orbit Control ◽  
Spacecraft Orbit

CMCs - Critical Weight Reduction for Next-Generation Propulsion Systems

2012 ◽  
pp. 103-113
Author(s):  
M.C.L. Patterson ◽  
C. Leslie ◽  
L.L. Fehrenbacher
Keyword(s):  
Weight Reduction ◽  
Next Generation ◽  
Propulsion Systems ◽  
Critical Weight

The Next Generation of Internet Portals

2011 ◽  
pp. 89-100
Author(s):  
Ali Jafari
Keyword(s):  
Artificial Intelligence ◽  
World Wide Web ◽  
World Wide ◽  
Next Generation ◽  
The World ◽  
Internet Portals ◽  
New Generation

Today’s portals bring together existing technologies in useful, innovative ways, but they don’t scratch the surface of what is possible. The constant build-up of information and resources on the World Wide Web demands a smarter more advanced portal technology that offers dynamic, personalized, customized, and intelligent services. This chapter discusses next-generation portals and the requirement that they come to know their users and understand their individual interests and preferences. It describes a new generation of portals that have a level of autonomy, making informed, logical decisions and performing useful tasks on behalf of their members. The chapter highlights the role of artificial intelligence in framing the next generation of portal technology and in developing their capabilities for learning about their users.

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.

Future Aero-Engines’ Optimisation for Minimal Operating Costs

2008 ◽  
Author(s):  
Fernando Colmenares ◽  
Daniele Pascovici ◽  
Stephen Ogaji ◽  
Pericles Pilidis ◽  
Alexander Garci´a ◽  
...  
Keyword(s):  
Public Awareness ◽  
Operating Cost ◽  
Design Tool ◽  
Commercial Aircraft ◽  
Commercial Aviation ◽  
Passenger Traffic ◽  
Direct Operating Cost ◽  
Promising Solution ◽  
Aero Engines ◽  
Bypass Ratio

While aircraft environmental performance has been important since the beginnings of commercial aviation, continuously increasing passenger traffic and a rise in public awareness have made aircraft noise and emissions two of the most pressing issues hampering commercial aviation growth today. The focus of this study is to determine the feasibility of vey-high bypass ratio, geared and contra-rotating aero engines (see figures 2–4) for short range commercial aircraft in terms of economics and environment. This involves optimising the engines’ design point to minimise the direct operating cost and evaluating the economic and environmental impact. The results present a great potential benefit of the geared turbofan compared to high BPR one (baseline) to reduce DOC; however this may involve NOx penalties, that is an increase of 11.6% in comparison to the baseline. The CRTF engine seems to be, at least according to the simulations, a very promising solution in terms of environmental and economical performance. This is one on the series of work that would be carried out using the design tool proposed. Further work on the assessment of more radical turbofans at different economical and environmental scenarios would be published when completed.

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