Accession Number : AD0772805

Title :   Pneumomechanical Critical Speed Control for Gas Turbine Engine Shafts.

Descriptive Note : Technical rept. 30 May 72-Sep 73,


Personal Author(s) : Cundiff,Richard A. ; Badgley,Robert H. ; Reddecliff,Jere M.

Report Date : NOV 1973

Pagination or Media Count : 115

Abstract : Initial evaluation of the use of gas-lubricated intershaft foil bearings to reduce inner spool vibration levels in small gas-turbine aircraft engines has been successfully concluded. A Hydresil intershaft foil bearing was applied to a power turbine shaft simulator operating on elastically-mounted ball bearings without support damping. A series of tests showed that the two-pad and three-pad Hydresil bearings are superior to the 360-degree bearing for the journal size and rotor speeds tested. Rotor balancing via the recently-developed MTI Multiplane-Multispeed Balancing Procedure was used to suppress the first (bending) shaft-bearing system critical speed and a pedestal resonance, and to leave a distinct vibration peak at the second (bending) critical speed. (Modified author abstract)

Descriptors :   *Gas turbines, *Shafts(Machine elements), *Gas bearings, Gases, Lubrication, Balance, High temperature, Dynamic tests

Subject Categories : Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE