Effects of Propellers and of Vibration on the Extent of Laminar Flow on the N.A.C.A. 27-212 Airfoil
Abstract
The effects of propellers and of vibration on the extent of laminar flow on the N.A.C.A. 27-212 airfoil were investigated in the N.A.C.A. 8-foot high-speed tunnel by testing the airfoil in conjunction with a tractor and a pusher propeller and with a mechanical vibrator. The Reynolds numbers of the investigation ranged from 3,500,000 to 7,600,000 for the propeller tests and to 10,300,000 for the vibration tests. The results show that neither the pusher propeller nor vibration with amplitudes up to 0.094 inch and with a frequency of 1,650 cycles per minute had any consequential effect on the extent of laminar flow but that the tractor propeller had a very pronounced effect. The tractor propeller caused transition to move from approximately midchord to a position near the leading edge; the accompanying increase in drag probably exceeded 100 percent for the N.A.C.A. 27-212 airfoil. The corresponding drag increase for the N.A.C.A. 0012 airfoil would be approximately 25 percent because this airfoil normally has a less extensive laminar boundary layer.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1939
- Accession Number
- ADB807260
Entities
People
- M. E. Gaydos
- M. J. Hood
Organizations
- National Advisory Committee for Aeronautics