A few notes

• All-axis control of aircraft in ultra deep stall - Patent Shows that the aircraft is stable in deep stall, that deep stall rapidly reach (<1sec) from many flying conditions and that the airplane is controllable in pitch (elevator), in yaw (using the rudder... but I assume you need some forward velocity or propwash to achieve that) and somewhat controllable in drop rate (control the pitch to orient the thrust) and in the forward direction.
• Flight at Supernormal Attitudes
  • Used a 1/4-scale flying model of a two-place, general aviation aircraft similar to the Piper PA-38 TOMAHAWK for wind tunnel experiments.
  • Repeatable, precise approaches were made with spot landings at the pilot's feet ...
  • The horizontal tail was clearly capable of providing stability and control for angles of attack to at least 63 degrees and most likely to about 70 degrees for the reference moment center at 0.25C
  • In summary, the static lateral-directional data show that the configuration is stable and that there is control available for maneuvering. At angles of attack approaching 90 degrees, these control moments are not of the magnitude or direction normally experienced in unstalled flight but could be used for orienting the airplane in the desired direction with modified piloting techniques
  • With T/W of 0.25, they estimate that a full scale model would be able of descent rate of 0 at alpha = 15 degrees and 4300 ft/min at alpha = 60 degrees (corresponding to a flight path of -15 to -62 degrees from horizontal).
• Nasa Schweizer 1-36 Deep Stall Research:
  • Schweizer 1-36 in Flight - Deep Stall Research Study
  • Flight Characteristics of a Manned, Low-Speed, Controlled Deep Stall Vehicle Shows that it is possible to attain and stabilize a pitch angle from 30 to 72 degrees but that poor lateral stability (control of bank angle and sideslip) was present at angle of attack above 60 degrees. They identified the control derivative of the airplane.
  • Flight Characteristics of a Modified Schweizer SGS 1-36 Sailplane at Low and Very High Angles of Attack Detailed analysis of trim, longitudinal and lateral stability. Stabilized flight at very high angle of attack yielded handling qualities that were acceptable to gently maneuver the airplane
  • A Parametric Study of Factors Influencing the Deep-Stall Pitch-Up Characteristics of T-Tail Transport Aircraft
• System Identification of Post Stall Aerodynamics for UAV Perching Physically-inspired basis functions which have enabled system identification of a nonlinear aerodynamics model along perching trajectories (from Tedrake's group).
• Aerovironment's Raven
  • Raven landing, More landing
  • Catching a Raven, More catching
• Skylark UAV deep stall
• American Krestel puts its wings in a V shape to create a stable dive (at least the one around the Stanford Dish):
  • Raptor_Hunting
  • Info on the Kestrels
  • More info on the Kestrels
• "Dethermalize" - RC Groups
• What is a "deep stall" landing? - RC Groups
• Deep stall on wikipedia
• Design of a skydiving glider
• Skyboard
• Type synthesis and kinematics of a modular variable geometry truss mechanism for aircraft wing morphing

-- AlexisLD - 23 Aug 2010