NASA-TP-2256
Natural laminar flow experiments on modern airplane surfaces
Year: 1984
Abstract: Flight and wind-tunnel natural laminar flow experiments have been conducted on various lifting and nonlifting surfaces of several airplanes at unit Reynolds numbers between 0.63 x 10 to the 6th power/ft and 3.08 x 10 to the 6th power/ft, at Mach numbers from 0.1 to 0.7, and at lifting surface leading-edge sweep angles from 0 deg to 63 deg. The airplanes tested were selected to provide relatively stiff skin conditions, free from significant roughness and waviness, on smooth modern production-type airframes. The observed transition locations typically occurred downstream of the measured or calculated pressure peak locations for the test conditions involved. No discernible effects on transition due to surface waviness were observed on any of the surfaces tested. None of the measured heights of surface waviness exceeded the empirically predicted allowable surface waviness. Experimental results consistent with spanwise contamination criteria were observed. Large changes in flight-measured performance and stability and control resulted from loss of laminar flow by forced transition. Rain effects on the laminar boundary layer caused stick-fixed nose-down pitch-trim changes in two of the airplanes tested. No effect on transition was observed for flight through low-altitude liquid-phase clouds. These observations indicate the importance of fixed-transition tests as a standard flight testing procedure for modern smooth airframes.
Subject: AIRFRAMES
Show full item record
contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
date accessioned | 2017-09-04T15:52:28Z | |
date available | 2017-09-04T15:52:28Z | |
date copyright | 01/01/1984 | |
date issued | 1984 | |
identifier other | QNBBFEAAAAAAAAAA.pdf | |
identifier uri | http://yse.yabesh.ir/std/handle/yse/55784 | |
description abstract | Flight and wind-tunnel natural laminar flow experiments have been conducted on various lifting and nonlifting surfaces of several airplanes at unit Reynolds numbers between 0.63 x 10 to the 6th power/ft and 3.08 x 10 to the 6th power/ft, at Mach numbers from 0.1 to 0.7, and at lifting surface leading-edge sweep angles from 0 deg to 63 deg. The airplanes tested were selected to provide relatively stiff skin conditions, free from significant roughness and waviness, on smooth modern production-type airframes. The observed transition locations typically occurred downstream of the measured or calculated pressure peak locations for the test conditions involved. No discernible effects on transition due to surface waviness were observed on any of the surfaces tested. None of the measured heights of surface waviness exceeded the empirically predicted allowable surface waviness. Experimental results consistent with spanwise contamination criteria were observed. Large changes in flight-measured performance and stability and control resulted from loss of laminar flow by forced transition. Rain effects on the laminar boundary layer caused stick-fixed nose-down pitch-trim changes in two of the airplanes tested. No effect on transition was observed for flight through low-altitude liquid-phase clouds. These observations indicate the importance of fixed-transition tests as a standard flight testing procedure for modern smooth airframes. | |
language | English | |
title | NASA-TP-2256 | num |
title | Natural laminar flow experiments on modern airplane surfaces | en |
type | standard | |
page | 145 | |
status | Active | |
tree | NASA - National Aeronautics and Space Administration (NASA):;1984 | |
contenttype | fulltext | |
subject keywords | AIRFRAMES | |
subject keywords | CONTAMINATION | |
subject keywords | DETECTION | |
subject keywords | FLIGHT TESTS | |
subject keywords | FLOW VISUALIZATION | |
subject keywords | GENERAL AVIATION AIRCRAFT | |
subject keywords | LAMINAR BOUNDARY LAYER | |
subject keywords | LAMINAR FLOW | |
subject keywords | LIFTING BODIES | |
subject keywords | REYNOLDS NUMBER | |
subject keywords | STABILITY | |
subject keywords | VELOCITY DISTRIBUTION | |
subject keywords | WIND TUNNEL TESTS |