Engine out control system for STOL aircraft

A method for automatically reconfiguring the control surfaces of an STOL aircraft having at least two engines when one of said engines is inoperative to the extent that such engine does not supply a desired level of thrust and said aircraft executes a STOL takeoff or landing maneuver, said engines being mounted on left and right wings of said aircraft with each of said engines supplying an exhaust stream to an associated extendable upper surface blown flap, each of said upper surface blown flaps extending spanwise along the trailing edge of the aircraft wing at a position aft of said associated engine, each of said upper surface blown flaps including slot means for opening at least one spanwise slot in said upper surface blown flap in response to a predetermined signal, said STOL aircraft also having at least two conventional slotted flaps, at least one of said conventional slotted flaps extending spanwise along the trailing edge of the aircraft wing at a position outboard of an upper surface blown flap, said method comprising the steps of:

• detecting that one of said engines is inoperative;
• automatically extending the upper surface blown flap located aft of said inoperative engine to an angle of extension which corresponds to the angle of extension of said conventional slotted flap located outboard of said upper surface blown flap being extended;
• supplying said predetermined control signal to open said spanwise slot in said upper surface blown flap located aft of said inoperative engine;
• automatically retracting each of said conventional slotted flaps located on the wing of said aircraft not including said inoperative engine, said conventional slotted flap being retracted to a position that at least partially counteracts the roll moment caused by said inoperative engine.

An automatic control system for improved short take off and landing performance of a STOL aircraft powered by at least two gas turbine engines wherein each outwardly extending wing of said STOL aircraft includes at least one flap that is extendable downwardly and rearwardly from the trailing edge of said wing to provide lift during take off and landing maneuvers and wherein each wing of said STOL aircraft includes at least one lift augmentation flap extendable downwardly and rearwardly from said trailing edge of said wing for receiving and redirecting at least a portion of the exhaust stream supplied by at least one of the gas turbine engines of said STOL aircraft, each of said lift augmentation flaps including at least one spanwise slot that is selectively openable and closable in response to a first predetermined control signal, said automatic control system activating said flaps and said lift augmentation flaps during short take off and landing maneuvers when one of said gas turbine engines supplying exhaust to one of said lift augmentation flaps is inoperative to the extent that said inoperative engine fails to provide a predetermined thrust level, said automatic control system comprising:

• thrust detection means for determining the thrust level being supplied by each of said gas turbine engines that supply an exhaust stream to one of said lift augmentation flaps, said thrust detection means including means for supplying a signal representative of the thrust levels of each of said gas turbine engines;
• means for supplying a first command signal when said STOL aircraft undertakes a short take off maneuver and for supplying a second command signal when STOL aircraft undertakes a short landing maneuver;
• and
• flight control means responsive to said signals representative of the thrust level being supplied by each of said gas turbine engines that supply an exhaust stream to one of said lift augmentation flaps and responsive to said first and second command signals representing that said STOL aircraft is undertaking a short take off and landing maneuver, said flight control means including comparison means for comparing each of said thrust representative signals with a predetermined threshold signal to determine when one of said gas turbine engines fails to provide said predetermined thrust level, said comparator means supplying an engine failure signal indicative of which one of said gas turbine engines is inoperative in that said inoperative engine is providing a thrust level less than said predetermined thrust level, said flight control means further including lift augmentation flap control means responsive to said engine failure signal and responsive to signals representative of the rearward and downward extension of said flaps and said lift augmentation flaps for supplying a signal to that particular lift augmentation flap normally supplied an exhaust stream by said inoperative gas turbine engine, said lift augmentation flap control means supplying a signal to deploy said particular lift augmentation flap to an extended position substantially corresponding to the extended position of each flap located on the same wing of said STOL aircraft as said particular lift augmentation flap, said lift augmentation flap control means including means for supplying said first predetermined control signal to open said spanwise slot of said particular lift augmentation flap normally supplied an exhaust stream by said inoperative gas turbine engine when said lift augmentation flap is extended downwardly and rearwardly by a predetermined amount, said flight control means further including flap retraction means responsive to said second command signal and said engine failure signal for supplying a flap retraction signal to partially retract each of said flaps other than said lift augmentation flaps that are located on said wing not including said particular lift augmentation flap that is normally supplied an exhaust stream by said inoperative engine, said flaps being retracted to at least partially alleviate roll moment caused by said inoperative engine failing to provide said predetermined thrust level.

An automatic flight control system for a STOL aircraft having first and second wings extending outwardly from a fuselage wherein first and second gas turbine engines are respectively mounted to supply rearwardly flowing exhaust effluent along predetermined regions of the upper surface of said first and second wings and wherein first and second upper surface blown flaps are respectively mounted along the trailing edge of said first and second wings, said first and second upper surface blown flaps being respectively mounted to receive at least a portion of the exhaust effluent from said first and second gas turbine engines that flows along said predetermined regions of said wing upper surfaces, said first and second upper surface blown flaps being respectively positionable in response to first and second command signals to extend said first and second upper surface blown flaps downwardly annd rearwardly for redirecting said received exhaust effluent to selectively provide both forwardly and upwardly directed thrust components, said first and second upper surface blown flaps each including at least one spanwise slot responsive to a slot control signal to operate from a closed position to an open position wherein ambient air flows through said slots to provide lift, said first and second wings each including slotted flaps mounted along the trailing edge of said first and second wings at a location other than those predetermined regions of said wing that receive exhaust effluent from said first and second gas turbine engines, each of said slotted flaps being operable in response to a flap control signal to extend downwardly and rearwardly for lift control during take off and landing maneuvers of said STOL aircraft, said slotted flaps of said first and second wings further being respectively operable in response to first and second differential flap control signals to selectively extend said slotted flaps of said first wing and selectively extend said slotted flaps of said second wing, said automatic flight control system for positionally controlling each of said slotted flaps and said first and second upper surface blown flaps during short take off and landing maneuvers in which one of said gas turbine engines fails to provide a predetermined thrust level, said automatic flight control system comprising:

• first and second pressure sensors, said first pressure sensor being mounted within said first gas turbine engine to supply a first pressure signal representative of the thrust being produced by said first engine, said second pressure sensor being mounted within said second gas turbine engine to supply a second pressure signal representative of the thrust being produced by said second gas turbine engine;
• a flap position selector including means for supplying said flap control signal to position each of said slotted flaps in a predetermined downwardly and rearwardly extending position when said STOL aircraft undertakes a take off and landing maneuver, said flap position selector further including means for supplying a first predetermined signal to indicate said STOL aircraft is engaged in a short take off maneuver and for supplying a second predetermined signal to indicate said STOL aircraft is engaged in a short landing maneuver;
• and
• a flight control unit for supplying said first and second differential flap control signals for positionally controlling said slotted flaps of said first and second wings and said first and second command signals for positioning said first and second upper surface blown flaps, said flight control unit including comparator means for comparing each of said first and second pressure signals with a predetermined threshold signal representative of a predetermined thrust level to supply a first engine failure signal when the thrust supplied by said first gas turbine engine is less than said predetermined thrust level and to supply a second engine failure signal when said thrust level supplied by said second gas turbine engine is less than said predetermined thrust level, said flight control unit including means for supplying said first command signal to extend said first upper surface blown flap downwardly and rearwardly to said predetermined extended position of the slotted flap of said first wing when said flap position selector supplies either of said first and second predetermined signals and said comparator means supplies said first engine failure signal and means for supplying said second command signal to extend said second upper surface blown flap downwardly and rearwardly to said predetermined extended position of the slotted flap of said second wing when said flap position selector supplies either of said first and second predetermined signals and said comparator means supplies said second engine failure signal, said flight control unit further including means for supplying said first differential flap control signal to partially retract said slotted flap of said first wing when said second engine failure signal is supplied and means for supplying said second differential flap control signal to partially retract said slotted flap of said second wing when said first engine failure signal is supplied, said flight control unit further including means for supplying said slot control signal to open each of said spanwise slots in said first upper surface blown flap when said first engine failure signal is supplied and said first upper surface blown flap is extended beyond a predetermined extension position, and means for supplying said slot control signal to open each of said spanwise slots in said second upper surface blown flap when said second engine failure signal is supplied and said second upper surface blown flap is extended beyond a predetermined extension position.