Telescoping tail assemblies for use on aircraft

A propulsion assembly for an aircraft, the propulsion assembly having a fore-aft length, the propulsion assembly comprising:

• a nacelle having forward and aft ends;
• a rotor assembly coupled to the forward end of the nacelle;
• and
• a telescoping tail assembly at the aft end of the nacelle, the telescoping tail assembly comprising:
• a housing extending in an aftward direction;
• a tailboom slidable along the housing into a plurality of positions including an extended position and a retracted position;
• one or more control surfaces coupled to the tailboom;
• and
• a retainer interposed between the housing and the tailboom, the retainer having a disengaged position in which the tailboom is slidable between the plurality of positions and an engaged position in which the tailboom is locked into the extended position, the retainer including a base, a flap rotatably coupled to the base via a forward pivot joint and an aft pin spring interposed between the base and the flap configured to bias the flap into the engaged position;
• wherein, the tailboom increases the fore-aft length of the propulsion assembly in the extended position and decreases the fore-aft length of the propulsion assembly in the retracted position;
• and
• wherein, the retainer is configured to move from the disengaged position to the engaged position in response to the tailboom sliding aft of the retainer.

An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation, the aircraft comprising:

• an airframe;
• and
• a thrust array attached to the airframe, the thrust array including a plurality of propulsion assemblies each having a fore-aft length, each propulsion assembly comprising:
• a nacelle having forward and aft ends;
• a rotor assembly coupled to the forward end of the nacelle;
• and
• a telescoping tail assembly at the aft end of the nacelle, the telescoping tail assembly comprising:
• a housing extending in an aftward direction;
• a tailboom slidable along the housing into a plurality of positions including an extended position and a retracted position;
• one or more control surfaces coupled to the tailboom;
• and
• a retainer interposed between the housing and the tailboom, the retainer having a disengaged position in which the tailboom is slidable between the plurality of positions and an engaged position in which the tailboom is locked into the extended position, the retainer including a base, a flap rotatably coupled to the base via a forward pivot joint and an aft pin spring interposed between the base and the flap configured to bias the flap into the engaged position;
• wherein, the tailbooms increase the fore-aft lengths of the propulsion assemblies in the extended position and decrease the fore-aft lengths of the propulsion assemblies in the retracted position;
• and
• wherein, the retainer is configured to move from the disengaged position to the engaged position in response to the tailboom sliding aft of the retainer.