US3913245A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Propeller sound simulation
Assignee: CAE Link Corp
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Filing: 1974-04-19
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Granted: 1975-10-21
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Expires: 1994-04-19
Abstract
Abstract Apparatus for modulating the frequency of simulated sounds representative of the several propellers of a multi-engine propeller aircraft. Such modulation produces the characteristic slow undulating droning normally associated with propeller sounds from actual multi-engine aircraft as the aircraft engine servo system attempts to synchronize the speed of the several propellers. The continued varying frequency of the output sound occurs by randomly degrading the response of the electronic servo system which is used to control the simulated engine speed. This random degradation prevents a precise and rapid synchronization lock which if allowed to occur would prevent modulation of the output sound and consequently eliminate the characteristic droning.
Inventors
- 👤 Neil R Mccanney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:15
CPC Classifications
G; G09; G09B; G09B9/00; G09B9/02; G09B9/08; G09B9/22
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
254 words
An acoustic system for simulating sounds characteristic of the propellers of a multi-engine aircraft wherein the propeller sounds are modulated to produce the undulating droning sounds generated by the propellers as their speed is regulated during the continuous task of synchronizing the speed of all the propellers with a reference signal comprising: a plurality of simulated aircraft controls, each for providing a control signal representative of the setting of one of said aircraft controls; first combining means for combining one of said control signals with a phase error signal to produce an engine control signal; a plurality of signal generators connected to receive said engine control signal, and for producing a plurality of output signals, each output signal having a characteristic which varies according to changes in said engine control signal; selection means for receiving at least two of said output signals and for selecting one of said received output signals as a reference output signal; generating means for providing a pulse signal at substantially random intervals; second combining means for combining said reference output signal and said pulse signal to produce a synchronizing signal; phase detection means for comparing one of said output signals to said synchronizing signal to produce said phase error signal; and a sound generator responsive to said output signals for producing sounds characteristic of the propellers of a multiengine aircraft, said produced sounds varying in response to variations of said characteristic of said output signal to produce the undulated droning sound characteristic of the propellers of a multi-engine aircraft.
Claim 2
Dependent Claim
254 words
An acoustic system for simulating sounds characteristic of the propellers of a multi-engine aircraft wherein the propeller sounds are modulated to produce the undulating droning sounds generated by the propellers as their speed is regulated during the continuous task of synchronizing the speed of all the propellers with a reference signal comprising: a plurality of simulated aircraft controls, each for providing a control signal representative of the setting of one of said aircraft controls; first combining means for combining one of said control signals with a phase error signal to produce an engine control signal; a plurality of signal generators connected to receive said engine control signal, and for producing a plurality of output signals, each output signal having a characteristic which varies according to changes in said engine control signal; selection means for receiving at least two of said output signals and for selecting one of said received output signals as a reference output signal; generating means for providing a pulse signal at substantially random intervals; second combining means for combining said reference output signal and said pulse signal to produce a synchronizing signal; phase detection means for comparing one of said output signals to said synchronizing signal to produce said phase error signal; and a sound generator responsive to said output signals for producing sounds characteristic of the propellers of a multiengine aircraft, said produced sounds varying in response to variations of said characteristic of said output signal to produce the undulated droning sound characteristic of the propellers of a multi-engine aircraft.
Claim 3
Dependent Claim
50 words
The apparatus of claim 1 wherein at least one of said simulated aircraft controls is an aircraft throttle, and wherein the engine control signal provided by said first combining means varies in response to changes in said phase error signal and the control signal provided by said simulated aircraft throttle.
Claim 4
Dependent Claim
84 words
The apparatus of claim 1 and further comprising a trainee station having instruments and containing said simulated aircraft controls for providing a representation of the cockpit of an aircraft being simulated, said simulated aircraft controls including throttle means for providing one of said control signals which is representative of a variable throttle setting to said first combining means, and wherein said engine control signal provided by said first combining means varies in response to changes in said throttle setting and said phase error signal.
Claim 5
Dependent Claim
34 words
The apparatus of claim 1 wherein said reference output signal comprises a pulse train and said generating means provides said pulse signal at a rate determined by the magnitude of a variable input signal.
Claim 6
Dependent Claim
20 words
The apparatus of claim 4 wherein said generating means further comprises a sawtooth generator for generating said variable input signal.
Claim 7
Dependent Claim
27 words
The apparatus of claim 1 and further including enabling means for enabling said phase detector means to compare one of said output signals to said synchronization signal.
Claim 8
Independent Claim
179 words
A method for simulating the undulating drOning sounds generated by the propellers of a multi-engine aircraft as the propeller speed is regulated during the continuous task of synchronizing the speed of all of the propellers with a reference signal, comprising the steps of: generating a plurality of output signals, each of said output signals having a characteristic which is responsive to variations of an engine control signal; selecting one of said output signals as a reference output signal; providing a pulse signal at substantially random intervals; combining said reference output signal and said pulse signal to produce a synchronization signal; generating a phase error signal representative of the phase difference between one of said output signals and said synchronization signal; combining a signal representative of the setting of an aircraft control and said phase error signal to produce said engine control signal; and generating sounds characteristic of the propellers of a multi-engine aircraft, which sounds vary in accordance with variations of said characteristic of said output signal to produce the undulating droning sound characteristic of said propellers being synchronized.
Claim 9
Independent Claim
179 words
A method for simulating the undulating drOning sounds generated by the propellers of a multi-engine aircraft as the propeller speed is regulated during the continuous task of synchronizing the speed of all of the propellers with a reference signal, comprising the steps of: generating a plurality of output signals, each of said output signals having a characteristic which is responsive to variations of an engine control signal; selecting one of said output signals as a reference output signal; providing a pulse signal at substantially random intervals; combining said reference output signal and said pulse signal to produce a synchronization signal; generating a phase error signal representative of the phase difference between one of said output signals and said synchronization signal; combining a signal representative of the setting of an aircraft control and said phase error signal to produce said engine control signal; and generating sounds characteristic of the propellers of a multi-engine aircraft, which sounds vary in accordance with variations of said characteristic of said output signal to produce the undulating droning sound characteristic of said propellers being synchronized.
Claim 10
Dependent Claim
32 words
The method of claim 7 wherein said aircraft control is an aircraft throttle, and further comprising the step of varying said engine control signal in accordance with changes in said throttle setting.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |