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April 13, 1987

AERONAUTICAL ENGINEERING

Douglas Plans UHB-Powered MD-91X As Successor to Turbofan Transports

TECHNICAL SURVEY: ULTRAHIGH BYPASS RATIO ENGINES

Airframe Manufacturers Near Landmark UHB Decisions

AVIONICS

British Scientists Reveal Signai Format Of Soviet Navsat

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AERONAUTICAL ENGINEERING

Douglas Plans UHB-Powered MD-91X As Successor to Turbofan Transports

Long Beach, Calif.—The McDonnell Douglas MD-91X derivative transport design features a number of significant changes—including a new, larger, all-composite horizontal stabilizer—from the MD-87 it is based on in order to replace conventional turbofans with unshrouded ultrahigh bypass engines (UHBs).

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TECHNICAL SURVEY: ULTRAHIGH BYPASS RATIO ENGINES

Airframe Manufacturers Near Landmark UHB Decisions

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AVIONICS

British Scientists Reveal Signai Format Of Soviet Navsat

Washington—Analysis by British scientists of signals from the USSR’s new Global Navigation Satellite System (Glonass) reveals some notable differences from the U. S. Navstar global positioning system despite many similarities.

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ULTRAHIGH BYPASS RATIO ENGINES

Rolls Skeptical About Early Propfan Service Introduction

Derby, England—Rolls-Royce has begun a technology demonstrator program aimed at producing an economically viable propfan propulsion system within 10 years, but the company sees propfans as restricted in the thrust range in which they will compete with shrouded fans and unlikely to be ready for airline service, even within a limited thrust range, until at least the mid-1990s.
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ULTRAHIGH BYPASS RATIO ENGINES

No. 2 UDF Engine Prototype Will Fly On MD-80 by June

Evendale, Ohio—General Electric Co. has completed flight tests of its Unducted Fan ultrahigh bypass proof-of-concept engine on a Boeing 727-100, and has started assembly of a second prototype engine, scheduled to fly on a McDonnell Douglas MD-80 transport before June.
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AIR TRANSPORT

Airbus Defines New A340 To Use CFM56 Turbo fans

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ULTRAHIGH BYPASS RATIO ENGINES

Lockheed, NASA Will Begin Propfan Test Assessment Flights

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AIR TRANSPORT

New Tax Laws Increase Cost Of Leasing, Buying Aircraft

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ULTRAHIGH BYPASS RATIO ENGINES

Airframe Makers Face Challenge Of Characterizing Propfan Noise

Los Angeles—Dealing with the high noise levels generated by unshrouded contrarotating propfans is a major design effort for airframe manufacturers. The challenge is to have acceptable sonic fatigue life and a quiet cabin without a large weight penalty.
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PROCUREMENT REFORM

GAO Warns of Potential Risks In Major New Weapons Programs

April 61987 April 201987