Control effectiveness tests at transonic speeds on an EC.1250 section with 0.25 chord concave control

Abstract

Control effectiveness tests, using the ground-launched rocket-boosted model technique, have been made on rectangular wings of aspect ratio 4, EC.1250 section, and fitted with a 25 per cent chord concave control flap. Tests were done from M=0.73 to M=1.5, and at R=3.5 x10power6 and 7x10power6 at M=1. There is a sudden and large reversal in control effectiveness at M=0.9, but the measured effectiveness below M=0.8 and above M= 1.1 is in good agreement with theory. These tests confirm and extend to higher Reynolds numbers and Mach numbers previous tunnel tests on the same section, which are reported in R. & M. 2436.