scholarly journals Ceramic Hybrid Bearings in Air-Cycle Machines

1996 ◽  
Vol 118 (1) ◽  
pp. 184-190 ◽  
Author(s):  
L. Burgmeier ◽  
M. Poursaba
Keyword(s):  
Air Force ◽  
Life Cycle Cost ◽  
Development Program ◽  
Flight Test ◽  
Rolling Contact ◽  
Test Program ◽  
High Speeds ◽  
Bearing Life ◽  
Near Term ◽  
Air Force Base

Extensive research in the field of ceramic rolling contact bearings has been conducted over the past several years. The results of this research indicate that silicon nitride may offer significant improvements in rolling fatigue life and a possible increase in operating temperature. AlliedSignal Aerospace Systems & Equipment (ASE) and the Air Force Item Management Engineering Branch at Tinker Air Force Base are conducting a development program under contract to ARPA to introduce ceramic hybrid bearings into existing F-15, F-111, and C-130 aircraft fleets in a near-term program involving retrofitting mature air-cycle machines with such bearings. The air-cycle machine (ACM) is a complex bearing application, operating at very high speeds (up to 100,000 rpm) and at high temperatures. In more severe military ACM applications, mean times between failures (MTBFs) of 2000 and 3000 hours are common. The fleet would see an immediate benefit from improved bearing life. This paper describes the analytical approach to evaluating and comparing ceramic to steel bearings, describes the laboratory test program to verify performance, and discusses the life-cycle cost improvement and the flight test program.

scholarly journals Ceramic Hybrid Bearings in Air-Cycle Machines

1994 ◽  
Author(s):  
Lyman Burgmeier ◽  
Matt Poursaba
Keyword(s):  
Air Force ◽  
Life Cycle Cost ◽  
Development Program ◽  
Flight Test ◽  
Rolling Contact ◽  
Test Program ◽  
High Speeds ◽  
Bearing Life ◽  
Near Term ◽  
Air Force Base

Extensive research in the field of ceramic rolling contact bearings has been conducted over the past several years. The results of this research indicate that silicon nitride may offer significant improvements in rolling fatigue life and a possible increase in operating temperature. AlliedSignal Aerospace Systems & Equipment (ASE) and the Air Force Item Management Engineering Branch at Tinker Air Force Base are conducting a development program under contract to ARPA to introduce ceramic hybrid bearings into existing F-15, F-111, and C-130 aircraft fleets in a near-term program involving retrofitting mature air-cycle machines with such bearings. The air-cycle machine (ACM) is a complex bearing application, operating at very high speeds (up to 100,000 rpm) and at high temperatures. In more severe military ACM applications, mean times between failures (MTBF’s) of 2000 and 3000 hours are common. The fleet would see an immediate benefit from improved bearing life. This paper describes the analytical approach to evaluating and comparing ceramic to steel bearings, describes the laboratory test program to verify performance, and discusses the life-cycle cost improvement and the flight test program.

F-16XL demonstrates new capabilities in flight test at Edwards Air Force Base

1988 ◽  
Vol 25 (3) ◽  
pp. 206-215 ◽  
Author(s):  
Patrick K. Talty ◽  
Donald J. Caughlin
Keyword(s):  
Air Force ◽  
Flight Test ◽  
Air Force Base

scholarly journals Problems and Solutions for Sand Environment Operation of Helicopter Gas Turbines

1968 ◽  
Author(s):  
G. C. Rapp ◽  
S. H. Rosenthal
Keyword(s):  
Gas Turbines ◽  
Field Experience ◽  
Development Program ◽  
Flight Test ◽  
Aerodynamic Design ◽  
Test Program ◽  
Turbine Engine ◽  
Engine Design ◽  
Problems And Solutions ◽  
Design Requirements

This paper is of two parts: a review of the experience of the T58 in an erosive environment, and a review of the design considerations, development testing and field experience in the T64 program relative to operation in a sand environment. Combat operation of various T58-powered helicopters showed erosion to be the major cause of engine premature removals. A description is given of problems encountered and of the design improvements and maintenance procedures implemented to minimize erosion effects. Field experience and redesign effort established general guidelines applicable to future turbine engine design and installations for helicopter and V/STOL aircraft. Mechanical and aerodynamic design requirements for sand environment operation are discussed as applicable to the T64, including the test experience obtained during the development program. Results are presented of the flight test program to evaluate the effectiveness of the inertial separator installed on the Sikorsky CH-53. Relative engine conditions are reviewed and compared to SEA field experience.

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