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Airfoil performance data were collected using a three-component
force and moment balance. The balance was new to the wind-tunnel
facility and balance testing methods were verified. Elimination
of 3-dimensional effects in the balance drag data was not fully
realized. Balance lift and moment, along with drag calculated
from the wake momentum loss, was suitable for airfoil performance
testing. Performance data were collected on the S809 airfoil, and
were found to be in good agreement to past studies. An
investigation of the performance loss the S809 airfoil due to
initial (early stage) leading-edge ice accretions has been
conducted. Initial ice accretions were simulated by applying grit
roughness to the airfoil leading edge. For the icing/roughness
limits tested, an increase in grit size produced greater airfoil
performance losses up to a maximum limit around k/c = 0.0009.
Further increases in grit size beyond k/c = 0.0009, resulted in
reduced performance loss. Current data suggested grit density
played an important role on the airfoil flowfield and performance.
Lift curve slope decreased 10%, maximum lift decreased 12%, and
minimum drag coefficient increased approximately 173% or 140 drag
counts, for the maximum icing limits tested. In general,
trailing-edge separation appeared at much earlier angles of attack
(both positive and negative) with simulated ice on the airfoil
leading edge.
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