대표
청구항
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1. A method of calculating a takeoff weight (EIW) of an aircraft (1) capable of hovering, characterized by comprising the steps of: recording at least one first and one second value (W(t1), W(t2), W(t3), . . . , W(ti), . . . , W(tn)) of a first quantity associated with the take-off weight of said aircraft at at least one first instant and second instant (t1, t2, t3, . . . , ti, . . . , tn), in which said aircraft (1) is in a stable hovering condition; andcalculating the takeoff weight (EIW) of said aircraft (1) on the basis of said first and second value...
1. A method of calculating a takeoff weight (EIW) of an aircraft (1) capable of hovering, characterized by comprising the steps of: recording at least one first and one second value (W(t1), W(t2), W(t3), . . . , W(ti), . . . , W(tn)) of a first quantity associated with the take-off weight of said aircraft at at least one first instant and second instant (t1, t2, t3, . . . , ti, . . . , tn), in which said aircraft (1) is in a stable hovering condition; andcalculating the takeoff weight (EIW) of said aircraft (1) on the basis of said first and second values (W(t1), W(t2), W(t3), . . . , W(ti), . . . , W(tn));said recording step comprising the steps of:recording a necessary hovering power (Power(t1), Power(t2), Power(t3), . . . , Power(ti), . . . , Power(tn)) at said first and second instant (t1, t2, . . . , ti, . . . , tn); andacquiring third values (PALT(t1), PALT(t2), . . . , PALT(ti), . . . , PALT(tn)) of a second quantity associated with a pressure at a flying height (h1, h2, . . . , h(i), . . . , h(n)) at said first and second instant (t1, t2, . . . , ti, . . . , tn);acquiring fourth values (TOUT(t1), TOUT(t2), . . . , TOUT(ti), . . . , TOUT(tn)) of a third quantity associated with a temperature at the flying height (h1, h2, . . . , h(i), . . . , h(n)) at said first and second instant (t1, t2, . . . , ti, . . . , tn);acquiring fifth values (n(t1), n(t2), . . . , n(ti), . . . , n(tn)) of a fourth quantity associated with a speed of an engine (6) of said aircraft (1) at said first and second instant (t1, t2. . . . , ti, . . . , tn);calculating, on the basis of said third, fourth and fifth values (PALT(t1), PALT(t2), . . . , PALT(ti), . . . , PALT(tn); TOUT(t1), TOUT(t2), . . . , TOUT(ti), . . . , TOUT(tn);n(t1), n(t2), . . . , n(ti), . . . , n(tn)), sixth values (σ(t1), σ(t2), . . . , σ(ti),. . . σ(tn)) of a fifth quantity associated with a relative density at the flying height (h1, h2, . . . , h(i), . . . , h(n)) at said first and second instant (t1, t2, . . . , ti, . . . , tn);using a hovering performance curve (100, 101, 102, 103) to calculate seventh and eight values of gross-weight (Weight(t1), Weight(t2), Weight(t3), . . . , Weight(ti), . . . , Weight(tn)) of said aircraft (1) at said first and second instant (t1, t2, . . . , ti, . . . , tn);said hovering performance curve (100, 101, 102, 103) showing the pattern of a first parameter, associated with said necessary hovering power (Power(t1), Power(t2), Power(t3), . . . , Power(ti), . . . , Power(tn)), as a function of a second parameter associated with said gross-weight (Weight(t1), Weight(t2), Weight(t3), . . . , Weight(ti), . . . , Weight(tn)) of said aircraft (1);said first parameter being: Power(ti)σ(ti)·n(ti)3where σ(ti) are said sixth values, andn(ti) are said fifth values;said second parameter being: Weight(ti)σ(ti)·n(ti)2;said recording step further comprising the steps of:correcting said seventh and eight values of gross weights (Weight(t1), Weight(t2), Weight(t3), . . . , Weight(ti), . . . , Weight (tn)) at said first and second instant (t1, t2, . . , ti, . . tn) with a first and a second correction values (C(t1), C(t2), C(t3), . . . , C(ti), . . . , C(tn)), according to the formula: W(ti)=Weight(ti)+C(ti);where W(t1), W(t2), . . W(ti), . . , W(tn) are said first and second value;said first and second correction values (C(t1), C(t2), C(t3), . . . , C(ti), . . . , C(tn)) comprising at least one first addend associated with fuel consumption of said aircraft up to said first instant and second instant (t1, t2, t3, . . . , ti, . . . , tn);said calculating step further comprising the step of calculating said takeoff weight (EIW) according to the equation: EIW=∑ti=1mW(ti)m+Δwhere Δis a safety value. 2. A method as claimed in claim 1, wherein said recording step comprises the substeps of: recording said first value (W(t1)) of said first quantity at a first height (h(t1)); andrecording said second value (W(t2)) of said first quantity at a second height (h(t2)) different from said first height (h(t1)). 3. A method as claimed in claim 1, further comprising the steps of: acquiring a number of flight parameters;identifying a stable horizontal flight condition of said aircraft (1) on the basis of said flight parameters; andexecuting said recording step if said aircraft (1) is in said stable horizontal flight condition. 4. A method as claimed in claim 3, wherein said number of flight parameters comprise a roll angle, pitch angle, vertical speed, radar-measured height, and true airspeed of said aircraft (1); said identifying step comprising the step of determining that, for at least a given time interval (Δt):said roll angle is below a respective threshold value;said pitch angle is below a respective threshold value;said vertical speed is below a respective threshold value;said radar-measured height is between respective threshold values; andsaid true airspeed is below a respective threshold value. 5. A method as claimed in claim 3, characterized by comprising the step of downloading the acquired said flight parameters to a ground-based station (19); and in that at least one of said identifying/recording/calculating steps is performed at said ground-based station (19). 6. A method as claimed in claim 1, wherein said first correction value (C(t1), C(t2), C(t3), . . . , C(ti), . . . , C(tn)) comprises a second addend entered by a user on said aircraft (1), and associated with a change in weight independent of said fuel consumption. 7. A method as claimed in claim 1, wherein said recording step comprises the step of generating a malfunction signal when the difference between said first and second value (W(ti), W(ti+1), . . . , ) recorded at consecutive respective said first and second instants (ti, ti+1) exceeds a further threshold value (Δ). 8. A software product loadable onto a control unit and designed, when executed, to implement the steps of a method as claimed in claim 1. 9. A system (10) for calculating a takeoff weight (EIW) of an aircraft (1) capable of hovering, the system being characterized by comprising: a recording stage (20) for recording at least one first and second value (W(t1), W(t2), W(t3), . . . , W(ti), . . . , W(tn)) of a quantity associated with takeoff weight of said aircraft at at least one first and second instant (t1, t2, t3, . . . , ti, . . . , tn) in which said aircraft (1) is in a stable hovering condition; anda calculating stage (25) for calculating the takeoff weight (EIW) of said aircraft (1) on the basis of said first and second values (W(t1), W(t2), W(t3), . . . , W(ti), . . . , W(tn));said recording stage (20) being designed to record a first and a second values of gross-weight (Weight(t1), Weight(t2), Weight(t3), . . . , Weight(ti), . . . , Weight (tn)), on the basis of:a necessary hovering power (Power(t1), Power(t2), Power(t3), . . . , Power(ti), . . . ,Power(tn)) at said first and second instant (t1, t2, . . . , ti, . . . , tn);third values (PALT(t1), PALT(t2), . . . , PALT(ti), . . . , PALT(tn)) of a second quantity associated with a pressure at a flying height (h1, h2, . . . , h(i), . . . , h(n)) at said first and second instant (t1, t2, . . . , ti, . . . , tn);fourth values (TOUT(t1), TOUT(t2), . . . , TOUT(ti), . . . , TOUT(tn)) of a third quantity associated with a temperature at the flying height (h1, h2, . . . , h(i), . . . , h(n)) at said first and second instant (t1, t2, . . . , ti, . . . , tn);fifth values (n(t1), n(t2), . . . , n(ti), . . . , n(tn)) of a fourth quantity associated with a speed of an engine (6) of said aircraft (1) at said first and second instant (t1, t2, . . . , ti, . . . , tn); anda number of performance curves (100, 101, 102, 103) showing the pattern of a first parameter, associated with said necessary hovering power (Power(t1), Power(t2), Power(t3), . . . , Power(ti), . . . , Power(tn)), as a function of a second parameter associated with said gross-weight (Weight(t1), Weight(t2), Weight(t3), . . . , Weight(ti), . . . , Weight (tn)) of said aircraft (1);said first parameter being: Power(ti)σ(ti)·n(ti)3where σ(ti) are sixth values, andn(ti) are said fifth values;said second parameter being: Weight(ti)σ(ti)·n(ti)2;said recording stage (20) being designed to correct said first and said second value of said gross-weight (Weight(t1), Weight(t2), Weight(t3), . . . , Weight(ti), . . . , Weight (tn)) at said first and second instant (t1, t2, . . . , ti, . . . tn), with a first and a second correction values (C(t1), C(t2), C(t3), . . . , C(ti), . . . , C(tn)), according to the formula: W(ti)=Weight(ti)+C(ti);first and second value;said first and second correction values (C(t1), C(t2), C(t3), . . . , C(ti), . . . , C(tn)) comprising at least one first addend associated with the fuel consumption of said aircraft up to said first instant and second instant (t1, t2, t3, . . . , ti, . . . , tn);said calculating stage (25) being designed to calculate said takeoff weight (EIW) according to the equation: EIW=∑ti=1mW(ti)m+Δwhere Δis a safety value. 10. A system as claimed in claim 9, further comprising an acquisition stage (30) for acquiring flight parameters of said aircraft (1); said calculating stage (25) being designed to also calculate the takeoff weight (EIW) on the basis of said flight parameters;said system further comprising a flight condition recognition stage (35) designed to determine, on the basis of the acquired flight parameters, whether or not said aircraft (1) is in stable horizontal flight. 11. A system as claimed in claims 9, wherein said calculating stage (25) and/or said recording stage (20) are/is ground-based.
