Effect of Engine Integration on a 4.6%-Scale Flying-V Subsonic Transport

The installation and interference effects of an engine and nacelle to a 4.6%-scale half model of a Flying-V subsonic transport airplane are presented. Wind tunnel tests are performed at 20m/s in an open jet facility while balance measurements are taken to record lift, drag and pitching moment. The results show significant interference effects between the wing and engine. Interference drag is observed over the full range of angles of attack above 5 ^◦, with a maximum of 60 drag counts (16.5% of isolated-wing drag) at an angle-of-attack of 10 ^◦ . At incidence angles lower than 5 ^◦, the interference effect during engine operation reduces the drag by approximately 20 counts. At high thrust settings and incidence angles between −5 ^◦ and 12.5 ^◦ the interference effects amplify the lift coefficient. The pitching moment coefficient shows a similar interference effect as the lift coefficient, showing a strong correlation between the two coefficients. The interference effects of thrust and nacelle on lift and pitching moment are of the same order of magnitude as the effect of superpositioning the contributions of the isolated engine and the wing. They can therefore not be neglected. However, further research is needed to study the interaction effects on the local pressure distribution as this could not be derived from the measurements presented in this study.