Transonic Wind-Tunnel Testing of a Slotted, Natural-Laminar-Flow Wing at Full-Scale Conditions

Transonic Wind-Tunnel Testing of a Slotted, Natural-Laminar-Flow Wing at Full-Scale Conditions | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Transonic Wind-Tunnel Testing of a Slotted, Natural-Laminar-Flow Wing at Full-Scale Conditions James Coder This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6389577/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Mar, 2026 Read the published version in CEAS Aeronautical Journal → Version 1 posted You are reading this latest preprint version Abstract A semi-span wing based on the slotted, natural-laminar-flow (SNLF) airfoil concept was experimentally tested in the NASA Ames Unitary Plan Wind Tunnel 11-ft transonic test section to validate the viability of SNLF for commercial transport applications. The model is based on the S207, SNLF airfoil, which was designed using requirements derived from a transonic, truss-braced wing (TTBW) aircraft. The wind-tunnel model itself is a constant-chord, constant-sweep to emphasize the airfoil aerodynamics. Three rows of pressure orifices are present, and distributed between the fore and aft elements. Total force and moment measurements were collected using a floor balance. Transition locations were measured using IR thermography, facilitated by the model being coated with a low-emissivity black paint finished to a roughness below 20 microinches. The capabilities of the wind tunnel allowed for testing at Reynolds and Mach numbers exceeding those expected for the reference TTBW aircraft, which is notable for ground testing. It was found that the model achieved extensive runs of laminar flow around its design point, validating the concept at flight-relevant conditions. Low-speed testing with the aft element deflected like a Fowler flap showed significant increases in maximum lift compared to the cruise configuration. Altogether, the data confirm the viability of SNLF for commercial transport applications. Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 10 Mar, 2026 Read the published version in CEAS Aeronautical Journal → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6389577","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":443653217,"identity":"9c57e790-16a4-4a37-b80b-6cb57192ea37","order_by":0,"name":"James Coder","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAArElEQVRIiWNgGAWjYBACxgYGBgkGBhsIj4cELWkkaAEBoJbDJGhhbj988MbHPefz5GckMD5420aMw3rSki1nPLtdbHAjgdlwLlFaZvCYSfMcuJ24QSKBTZqXaC1/DpxLnD8jgf038VoYDhxIbLiRwMZMnBaQX3oOJBcbnHnYLDnnHBFaDEEh9uOAXZ58e/LBD2/KiNHSAKETILFKDJBngGsZBaNgFIyCUYADAAATWzd0j0UZxQAAAABJRU5ErkJggg==","orcid":"","institution":"Pennsylvania State University","correspondingAuthor":true,"prefix":"","firstName":"James","middleName":"","lastName":"Coder","suffix":""}],"badges":[],"createdAt":"2025-04-07 03:08:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6389577/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6389577/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s13272-026-00956-0","type":"published","date":"2026-03-10T16:00:28+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":104740833,"identity":"c0b1a954-f67e-4766-b63a-f2afdc6936e6","added_by":"auto","created_at":"2026-03-16 16:19:16","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3798702,"visible":true,"origin":"","legend":"","description":"","filename":"SNLFAmesCoder.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6389577/v1_covered_12fbacd7-d149-4e2c-bf23-d5e7e5948103.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Transonic Wind-Tunnel Testing of a Slotted, Natural-Laminar-Flow Wing at Full-Scale Conditions","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-6389577/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6389577/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"A semi-span wing based on the slotted, natural-laminar-flow (SNLF) airfoil concept was experimentally tested in the NASA Ames Unitary Plan Wind Tunnel 11-ft transonic test section to validate the viability of SNLF for commercial transport applications. The model is based on the S207, SNLF airfoil, which was designed using requirements derived from a transonic, truss-braced wing (TTBW) aircraft. The wind-tunnel model itself is a constant-chord, constant-sweep to emphasize the airfoil aerodynamics. Three rows of pressure orifices are present, and distributed between the fore and aft elements. Total force and moment measurements were collected using a floor balance. Transition locations were measured using IR thermography, facilitated by the model being coated with a low-emissivity black paint finished to a roughness below 20 microinches. The capabilities of the wind tunnel allowed for testing at Reynolds and Mach numbers exceeding those expected for the reference TTBW aircraft, which is notable for ground testing. It was found that the model achieved extensive runs of laminar flow around its design point, validating the concept at flight-relevant conditions. Low-speed testing with the aft element deflected like a Fowler flap showed significant increases in maximum lift compared to the cruise configuration. Altogether, the data confirm the viability of SNLF for commercial transport applications.","manuscriptTitle":"Transonic Wind-Tunnel Testing of a Slotted, Natural-Laminar-Flow Wing at Full-Scale Conditions","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-05 22:00:30","doi":"10.21203/rs.3.rs-6389577/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"06a9764f-6aab-4385-aea9-56dd09b78677","owner":[],"postedDate":"August 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-16T16:16:44+00:00","versionOfRecord":{"articleIdentity":"rs-6389577","link":"https://doi.org/10.1007/s13272-026-00956-0","journal":{"identity":"ceas-aeronautical-journal","isVorOnly":false,"title":"CEAS Aeronautical Journal"},"publishedOn":"2026-03-10 16:00:28","publishedOnDateReadable":"March 10th, 2026"},"versionCreatedAt":"2025-08-05 22:00:30","video":"","vorDoi":"10.1007/s13272-026-00956-0","vorDoiUrl":"https://doi.org/10.1007/s13272-026-00956-0","workflowStages":[]},"version":"v1","identity":"rs-6389577","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6389577","identity":"rs-6389577","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}