• SD7003-PT (Fig. 12.118)
• SD7003-PT repeated (Fig. 12.119)
The SD7003 was designed to have a very long and gradual upper-surface bubble ramp. In fact, it may be considered to span the entire upper surface. The resulting effect is particularly apparent in the overall smoothness of the polar which shows no trace of high drag due to a laminar separation bubble. However this does not mean there is no bubble. Rather, the bubble losses are small. At Rn’s of 60k and 100k, the drag is especially low when compared with all the other airfoils tested.
The polars shown in Fig. 12.119 axe from a second series of runs to provide a measure of the overall repeatability. Other than a few small discrepancies, the agreement is quite good and typical of repeated runs (see the E387A-PT).
• SD7003-PT u. s.t. xjc = 60%,/i/c = .I7%,iv/c = 1.0% (Fig. 12.120)
• SD7003-PT u. s.t. xjc = 70%,h/c = .17%,w/c = 1.0% (Fig. 12.121)
• SD7003-PT u. s. bumps xjc = 50%, type A (Fig. 12.122)
• SD7003-PT u. s. bumps xjc = 60%, type A (Fig. 12.123)
• SD7003-PT u. s. bumps xjc — 70%, type A (Fig. 12.124)
Several attempts were made to reduce the drag through the use of trips, but they either increased the drag or had no eifect. One is tempted to ask whether this means that the SD7003 is optimized for ramps such that no further improvements can be made. It seems unlikely, but it is an interesting question nonetheless. (See Section 5.3.)
Also see: SD8000, RG15, S3021, MILEY Digitizer plot: Figs. 10.44-10.49 Polar plot: Figs. 12.118-12.124 Lift plot: Fig. 12.125
Thickness: 8.51% Camber: 1.46%