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Manufacturing Tolerances for Natural Laminar Flow Airframe Surfaces
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Abstract
In recent years, natural laminar flow (NLF) has been proven to be achievable on modern smooth airframe surfaces over a range of cruise flight conditions representative of most current business and commuter aircraft. Published waviness and boundary-layer transition measurements on several modern metal and composite airframes have demonstrated the fact that achievable surface waviness is readily compatible with laminar flow requirements. Currently, the principle challenge to the manufacture of NLF-compatible surfaces is two-dimensional roughness in the form of steps and gaps at structural joints. This paper presents results of recent NASA investigations on manufacturing tolerances for NLF surfaces, including results of a flight experiment. Based on recent research, recommendations are given for conservative manufacturing tolerances for waviness and shaped steps.
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Holmes, B., Obara, C., Martin, G., and Domack, C., "Manufacturing Tolerances for Natural Laminar Flow Airframe Surfaces," SAE Technical Paper 850863, 1985, https://doi.org/10.4271/850863.Also In
References
- Holmes, B.J. Obara, C.J. Yip, L.P. “Natural Laminar Flow FLight Experiments on Modern Airplane Surfaces,” NASA TP 2256 1984
- Fage, A. “The Smallest Size of Spanwise Surface Corrugation Which Affects Boundary Layer Transition on an Airfoil,” Brit. A.R.C. 1943
- Carmichael, B.H. Whites, R.C. Pfenninger, W. “Low Drag Boundary Layer Suction Experiments in Flight on the Wing Glove of an F-94A Airplane,” Northrup Aircraft Inc. Rep. No. NAI-57-1163 (BLC-101) 1957
- Carmichael, B.H. “Surface Waviness Criteria for Swept and Unswept Laminar Suction Wings,” Norair Rep. No. NOR-59-438 (BLC-123) 1959
- Carmichael, B.H. Pfenninger, W. “Surface Imperfection Experiments on a Swept Laminar Suction Wing,” Norair Rep. No. NOR-59″ 454 (BLC-124) 1959
- Obara, C.J. Holmes, B.J. “Flight Measured Laminar Boundary-Layer Transition Phenomena Including Stability Theory Analysis,” NASA TP 2417 1985
- Schlichting, H. Boundary Layer Theory McGraw-Hill 7th 1979
- Spence, D.A. Randall, D.G. “The Influence of Surface Waves on the Stability of a Laminar Boundary Layer With Uniform Suction,” A.R.C. C.P. No. 161 (15.916), T.N. No. AERO 2241 1953
- Holmes, B.J. “Progress in Natural Laminar Flow Research,” AIAA Paper 84-2222 1984
- Stall, C.G. Pfenninger, W. “Present Status of Production Aircraft Surface Waviness at Norair Norair Rep. No. NOR-59-444 (BLC-126) 1959
- Anon “Final Report on LFC Aircraft Design Data Laminar Flow Control Demonstration Program,” Northrop Corp. June 1967