Conversion principle-angle of attack to airspeed

Claim 2

In an aircraft control circuitry of the type including the development of an error signal based on the discrepancy between a computed reference angle of attack and a sensor-measured angle of attack, said error signal being utilized in control circuitry to control the airspeed of the craft as a predetermined function of the stall speed of the craft for a particular angle of attack as defined by said reference angle of attack input parameter; means for selectively modifying said predetermined stall speed function by incremental linear airspeed input increments, said latter means comprising computer means for converting said linear incremental airspeed increments to equivalent angle of attack increments, means for combining said equivalent angle of attack increments with said reference angle of attack signal to formulate an angle of attack command signal, and means for comparing said angle of attack command signal with said measured angle of attack input parameter to develop said error signal.

Claim 3

Control means as defined in claim 1 wherein said means for modifying comprises signal-generating means supplying a first signal proportional to a selected one of said incremental linear airspeed input increments, means for developing a second signal proportional to the measured angle attack of the aircraft, means for developing a third signal proportional to the angle of attack corresponding to zero lift for said aircraft, means for developing a fourth signal proportional to the airspeed of said aircraft, and signal-computing means receiving said first, second, third, and fourth signals as inputs thereto and computing therefrom an output signal proportional to an incremental angle of attack command parameter equivalent to the selected one of said incremental airspeed input increments.

Claim 4

Control system as defined in claim 2 wherein said signal-computing means develops incremental angle of attack output signal in response to a selected one of said first input signals thereto and existing ones of said second, third and fourth input signals thereto in accordance with the expression where Alpha is the measured angle of attack, Alpha 0 is the angle of attack corresponding to zero lift, Ve is the aircraft airspeed, and Delta Ve is the incremental airspeed input parameter, whereby said incremental airspeed input parameters modify the control system to effect an aircraft airspeed corresponding to said predetermined function of aircraft stall speed plus a selected one of said incremental airspeed input parameters Delta Ve.

Claim 5

A control system as defined in claim 3 including means for computing each of said reference angle of attack and incremental angle of attack parameters as functions of aircraft flap setting.

Claim 6

A control system as defined in claim 4 wherein said computing means comprises signal-summing means receiving said experienced airspeed signal and said incremental airspeed signal as respective inputs thereto and providing an output proportional to the sum thereof, signal-dividing means receiving said experienced airspeed signal and the output from said signal-summing means as respective inputs thereto and developing an output proportional to the ratio thereof, squaring amplifier means receiving the output from said signal-dividing means, and producing an output signal proportional to the square of the output from said signal-dividing means, operational amplifier means receiving the output from said signal-squaring means and including a predetermined feedback from the output to the input thereof to produce an output signal proportional to the output of said signal-squaring means less unity, further signal Development means receiving first and second input signals respectively proportional to the experienced angle of attack of said aircraft and a predetermined angle of attack input parameter corresponding to zero lift wherein, said further signal development means comprising signal-mixing means receiving said first and second input signals and developing an output signal proportional to the difference therebetween, and further signal-multiplying means receiving the output from said last-named mixing means and the output of said operational amplifier means and producing an output signal comprising said incremental angle of attack signal.

Claim 7

A signal conversion means for converting an input signal proportional to a desired incremental aircraft airspeed to an output signal proportional to a corresponding incremental change in aircraft angle of attack, comprising signal-summing means receiving said experienced airspeed signal and said incremental airspeed signal as respective inputs thereto and providing an output proportional to the sum thereof, signal-dividing means receiving said experienced airspeed signal and the output from said signal-summing means as respective inputs thereto and developing an output proportional to the ratio thereof, squaring amplifier means receiving the output from said signal-dividing means and producing an output signal proportional to the square of the output from said signal-dividing means, operational amplifier means receiving the output from said signal-squaring means and including a predetermined feedback from the output to the input thereof to produce an output signal proportional to the output of said signal-squaring means less unity, further signal development means receiving first and second input signals respectively proportional to the experienced angle of attack of said aircraft and a predetermined angle of attack input parameter corresponding to zero lift wherein, said further signal development means comprising signal-mixing means receiving said first and second input signals and developing an output signal proportional to the difference therebetween, and further signal-multiplying means receiving the output from said last-named mixing means and the output of said operational amplifier means and producing an incremental angle of attack output signal equivalent to said incremental airspeed input signal.

Claim 8

A signal conversion means for converting an input signal proportional to a desired incremental aircraft airspeed to an output signal proportional to a corresponding incremental change in aircraft angle of attack, comprising signal-summing means receiving said experienced airspeed signal and said incremental airspeed signal as respective inputs thereto and providing an output proportional to the sum thereof, signal-dividing means receiving said experienced airspeed signal and the output from said signal-summing means as respective inputs thereto and developing an output proportional to the ratio thereof, squaring amplifier means receiving the output from said signal-dividing means and producing an output signal proportional to the square of the output from said signal-dividing means, operational amplifier means receiving the output from said signal-squaring means and including a predetermined feedback from the output to the input thereof to produce an output signal proportional to the output of said signal-squaring means less unity, further signal development means receiving first and second input signals respectively proportional to the experienced angle of attack of said aircraft and a predetermined angle of attack input parameter corresponding to zero lift wherein, said further signal development means comprising signal-mixing means receiving said first and second input signals and developing an output signal proportional to the difference therebetween, and further signal-multiplying means receiving the output from said last-named mixing means and the output of said operational amplifier means and producing an incremental angle of attack output signal equivalent to said incremental airspeed input signal.