The Effect of Surface Irregularities on Wing Drag. IV - Manufacturing Irregularities
- Robinson, Russell G.
- February 1938.
- Physical Description:
- 1 electronic document
- Restrictions on Access:
- Unclassified, Unlimited, Publicly available. and Free-to-read Unrestricted online access
- Tests were made in the NACA 8-foot high speed wind tunnel of a metal-covered, riveted, 'service' wing of average workmanship to determine the aerodynamic effects of the manufacturing irregularities incident to shop fabrication. The wing was of 5-foot chord and of NACA 23012 section and was tested in the low-lift range at speeds from 90 to 450 miles per hour corresponding to Reynolds numbers from 4,000,000 to 18,000,000. At a cruising condition the drag of the service wing was 46% higher than the drag of a smooth airfoil, whereas the drag of an accurately constructed airfoil having the same arrangement of 3/32-inch brazier-head rivets and lap joints showed a 29% increase. The difference, or 17% of the smooth-wing drag, is apparently the drag caused by the manufacturing irregularities: sheet waviness, departures from true profile, and imperfect laps. the service wing, for one condition at least, showed a drag increase due to compressibility at a lower air speed than did the more accurate airfoil.
- NASA Technical Reports Server (NTRS) Collection.
- Document ID: 20090015310. and NACA-SR-79.
- No Copyright.
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