Positive Stop For Circulation-Control Slot

Rounded shoulder on bushing ensures repeatable stop position. Improved stop mechanism allows airflow slot on circulation-control airfoil to be limited to precise width. Shoulder bushing installed in duct so shoulder rests on inside surface of duct. Bolt slides in bushing in duct wall between more open and less open positions. No relative motion or wear between bolt and slot panel. Prevents bushing from being dislodged by stop forces and provides stiffer stopping surface than sleeve bushing bonded in duct wall.