{"copyright":{"thirdPartyPermissionsProduced":false,"disclosedToPublic":false,"containsIndication":false,"publisherPermissionOrRightsToDistribute":false,"belongsToUsGov":false,"determinationType":"PUBLIC_USE_PERMITTED","thirdPartyContentCondition":"NOT_SET","belongsToContractor":false,"disclosedInvention":false,"submissionId":20180005467,"containsThirdPartyMaterial":false,"belongsToPublisher":false,"id":"cb301e7770a04ce5983726c4fd2819e6","belongsToAuthors":false},"subjectCategories":["Aircraft Propulsion And Power"],"keywords":["Gear","Windage","Drag"],"exportControl":{"isExportControl":"NO","eccnNumber":"","submissionId":20180005467,"ear":"NO","id":"8b100d5bac15455485cae160c2b1b997","itar":"NO"},"distributionDate":"2019-07-12T00:00:00.0000000+00:00","otherReportNumbers":["GRC-E-DAA-TN56393","Report Number: GRC-E-DAA-TN56393"],"fundingNumbers":[{"number":"WBS 664817.02.03.02.02","submissionId":20180005467,"id":"4740579553eb4d289cd7baaca1c293dd","type":"WBS"},{"number":"NNC15BA02B","submissionId":20180005467,"id":"fca531eda62b4e76a85225d8ec86a1b2","type":"CONTRACT_GRANT"}],"title":"The Jetting Phenomena in Meshed Spur Gears","stiType":"PRESENTATION","distribution":"PUBLIC","submittedDate":"2018-09-24T11:13:26.8600000+00:00","authorAffiliations":[{"sequence":0,"submissionId":20180005467,"meta":{"author":{"name":"Delgado, I. R."},"organization":{"name":"NASA Glenn Research Center","location":"Cleveland, OH, United States"}},"id":"15b4fc9352f8403fa5ce8b176b4318fa"},{"sequence":1,"submissionId":20180005467,"meta":{"author":{"name":"Hurrell, M. J."},"organization":{"name":"HX5 Sierra, LLC","location":"Cleveland, OH, United States"}},"id":"09ed4263104243e697e304e6833d25bf"}],"stiTypeDetails":"Presentation","technicalReviewType":"TECHNICAL_REVIEW_TYPE_NONE","modified":"2025-08-31T18:39:21.7150190+00:00","id":20180005467,"legacyMeta":{"__type":"LegacyMetaIndex, StrivesApi.ServiceModel","accessionNumber":""},"created":"2018-09-24T11:13:26.8600000+00:00","center":{"code":"GRC","name":"Glenn Research Center","id":"19eeb25fa404421d9eaa5f876e853e3c"},"onlyAbstract":false,"sensitiveInformation":2,"abstract":"Rotorcraft gearbox transmissions are required to efficiently transfer power from the turbine engine to the main and tail rotor blades. Losses in transmission efficiency impact mission payload and aircraft range. These systems are expected to deliver high power with high gear pitch line velocities. More recently, shrouding has been employed to reduce windage power losses associated with the high gear rotational speeds. However, recent experimental results from tests conducted by the authors show the negative impact of close clearance shrouds on windage power loss, particularly at the meshed region where flow is ejected, or jetted, from the collapsing tooth spaces. A literature review was conducted to gain further insight into the phenomenon of gear mesh jetting and strategies to mitigate and control the associated losses. An analysis was conducted on windage losses in the mesh region. Test results are given for a modified shroud configuration. Finally, a discussion on observed trends follows with suggestions on future research.","isLessonsLearned":false,"disseminated":"DOCUMENT_AND_METADATA","meetings":[{"country":"United States","submissionId":20180005467,"endDate":"2018-05-17T00:00:00.0000000+00:00","sponsors":[{"organizationId":"0d95c07968f44f50a9754c6dec8c0969","meta":{"organization":{"name":"Vertical Flight Society","location":"Fairfax, VA, United States"}},"meetingId":"c5367ab414834260bae16d2a8316a51a","id":"fbab52153db141a79c2deb7c31f22c7c"}],"name":"Annual Forum & Technology Display of the Vertical Flight Society","location":"Phoenix, AZ","id":"c5367ab414834260bae16d2a8316a51a","startDate":"2018-05-14T00:00:00.0000000+00:00"}],"publications":[{"submissionId":20180005467,"id":"2bf72e3c8a924388b1524541f7d011f3","publicationDate":"2018-05-14T00:00:00.0000000+00:00"}],"status":"CURATED","related":[{"disseminated":"DOCUMENT_AND_METADATA","id":20180003334,"type":"SEE_ALSO","title":"The Jetting Phenomena in Meshed Spur Gears","stiType":"CONFERENCE_PAPER","distribution":"PUBLIC","status":"CURATED"},{"disseminated":"DOCUMENT_AND_METADATA","id":20180006519,"type":"SEE_ALSO","title":"Jetting Phenomenon in Meshed Spur Gears","stiType":"TECHNICAL_MEMORANDUM","distribution":"PUBLIC","status":"CURATED"},{"disseminated":"DOCUMENT_AND_METADATA","id":20180006519,"type":"SEE_ALSO","title":"Jetting Phenomenon in Meshed Spur Gears","stiType":"TECHNICAL_MEMORANDUM","distribution":"PUBLIC","status":"CURATED"},{"disseminated":"DOCUMENT_AND_METADATA","id":20180003334,"type":"SEE_ALSO","title":"The Jetting Phenomena in Meshed Spur Gears","stiType":"CONFERENCE_PAPER","distribution":"PUBLIC","status":"CURATED"}],"downloads":[{"draft":false,"mimetype":"application/pdf","name":"20180005467.pdf","type":"STI","links":{"original":"/api/citations/20180005467/downloads/20180005467.pdf","pdf":"/api/citations/20180005467/downloads/20180005467.pdf","fulltext":"/api/citations/20180005467/downloads/20180005467.txt"}}],"downloadsAvailable":true,"index":"submissions-2026-04-23-04-53"}