Preliminary airfoil testing experience in the NDA cryogenic wind tunnel

A small two-dimensional high-speed cryogenic wind tunnel was constructed at the Japanese National Defense Academy (NDA) in 1985. The authors describe the present status of the NDA cryogenic wind tunnel and give some preliminary airfoil testing results and experience. Two airfoil models, a NACA 0012 and a R4 airfoil model, were constructed. The R4 test results were compared with those of NASA TM-85739. They were in good agreement in the negative angle of attack range. However, the present R4 model has an extremely small aspect ratio of 0.5 and a high section thickness to tunnel height ratio of about 0.1. Therefore, the present results might be more influenced by the tunnel walls than those of NASA