국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	COMPARISON OF X-31 FLIGHT AND GROUND-BASED YAWING MOMENT ASYMMETRIES AT HIGH ANGLES OF ATTACK
저자	Brent R. Cobleigh and Mark A. Croom
Keyword	Asymmetry; Water tunnel test; Wind tunnel test; X-31 aircraft; Yawing moment
URL	http://www.dfrc.nasa.gov/DTRS/2001/PDF/H-2455.pdf
보고서번호	NASA-TM-2001-210393
발행년도	2001
출처	NASA Dryden Flight Research Center
ABSTRACT	Significant yawing moment asymmetries were encountered during the high-angle-of-attack envelope expansion of the two X-31 aircraft. These asymmetries caused position saturations of the thrust-vectoring vanes and trailing-edge flaps during some stability-axis rolling maneuvers at high angles of attack. The two test aircraft had different asymmetry characteristics, and ship 2 has asymmetries that vary as a function of Reynolds number. Several aerodynamic modifications have been made to the X-31 forebody with the goal of minimizing the asymmetry. These modifications include adding transition strips on the forebody and noseboom, using two different length strakes, and increasing nose bluntness. Ultimately, a combination of forebody strakes, nose blunting, and noseboom transition strips reduced the yawing moment asymmetry enough to fully expand the high-angle-of-attack envelope. Analysis of the X-31 flight data is reviewed and compared to wind-tunnel and water-tunnel measurements. Several lessons learned are outlined regarding high-angle-of-attack configuration design and ground testing.