This report contains the results of low-speed tunnel tests of longitudinal stability on a modified Sea Venom Mk. 21 fitted with blowing over the flaps. At each flap angle, a range of values of the sectional momentum coefficient was tested. As a typical example, the increase in trimmed CL at constant incidence resulting from blowing at flaps 60 deg was about 0-45, the increase in CLmax being somewhat smaller. The equivalent reduction in approach speed of 10 to 15 kt predicted from the tunnel results was later achieved in flight. The tunnel results suggested a beneficial reduction in minimum-drag speed due to blowing, particularly at large flap angles. Trim changes were large, amounting to about 8 deg on the all-movable tail at flaps 60 deg.nA comparison is made between estimated and measured effects of blowing. It is shown that, whilst the lift and pitching-moment increments resulting from flap blowing can be estimated fairly closely, the drag increments at large flap angles are much larger than would be expected.
展开▼
