US4435695A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of predicting the approaching stall of an aircraft wing
Assignee: Marinvent Corp
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Filing: 1980-12-22
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Granted: 1984-03-06
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Expires: 2000-12-22
Abstract
Abstract A method of predicting the approaching stall of an aircraft wing which is dependent on an inherent characteristic of the airflow as the stall is approached. The method described uses a hot-wire probe which measures the turbulence of the airflow at a predetermined location on the top surface of the wing. When the turbulence exceeds a threshold, which threshold is dependent on the air-speed, a signal is produced which indicates that a stall is imminent. The method can be particularly applied to an artificial stall warning device fitted to a transport aircraft.
Inventors
- 👤 John M. Maris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:39
CPC Classifications
B; B64; B64D; B64D43/00; B64D43/02
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
88 words
A method of predicting the approaching stall of an aircraft wing, comprising: sensing air speed over the wing at a predetermined location spaced above the top surface of the wing to thereby produce input signals representative of air speed fluctuations at said location, said fluctuations being caused by air turbulence over the wing; using said input signals to produce a signal represensative of a ratio of the air speed fluctuations to an average air speed; and using said ratio signal to produce a signal indicative of imminent stalling.
Claim 2
Independent Claim
88 words
A method of predicting the approaching stall of an aircraft wing, comprising: sensing air speed over the wing at a predetermined location spaced above the top surface of the wing to thereby produce input signals representative of air speed fluctuations at said location, said fluctuations being caused by air turbulence over the wing; using said input signals to produce a signal represensative of a ratio of the air speed fluctuations to an average air speed; and using said ratio signal to produce a signal indicative of imminent stalling.
Claim 3
Dependent Claim
31 words
A method as claimed in claim 1, wherein said location is spaced from the leading edge of the wing by about 66% of the length of a chord of the wing.
Claim 4
Dependent Claim
30 words
A method as claimed in claim 1, wherein said location is at a height above the wing which is below 8% of the length of a chord of the wing.
Claim 5
Dependent Claim
32 words
A method as claimed in claim 1, wherein said location is at a height above the wing which is between 1% and 4% of the length of a chord of the wing.
Claim 6
Dependent Claim
46 words
A method as claimed in claim 1, wherein said signal indicative of immiment stalling is produced when the air turbulence exceeds an air speed dependent threshold, and said using said input signal includes continuously sensing a relationship of the measured air turbulence to said turbulence threshold.
Claim 7
Dependent Claim
17 words
A method as claimed in claim 1, wherein said sensing is performed using heated body probe means.
Claim 8
Dependent Claim
17 words
A method as claimed in claim 6, wherein said sensing is performed using a hot wire probe.
Claim 9
Independent Claim
96 words
A method of predicting the approaching stall of an aircraft wing, comprising: directly exposing airspeed sensing means to a free airstream over the wing at a predetermined location spaced above the top surface of the wing and above a boundary layer, to thereby produce input signals representative of airspeed fluctuations at said location, said fluctuations being caused by air turbulence over the wing; using said input signals to produce a signal representative of a ratio of the airspeed fluctuations to an average airspeed; and using said ratio signal to produce a signal indicative of imminent stalling.
Claim 10
Independent Claim
96 words
A method of predicting the approaching stall of an aircraft wing, comprising: directly exposing airspeed sensing means to a free airstream over the wing at a predetermined location spaced above the top surface of the wing and above a boundary layer, to thereby produce input signals representative of airspeed fluctuations at said location, said fluctuations being caused by air turbulence over the wing; using said input signals to produce a signal representative of a ratio of the airspeed fluctuations to an average airspeed; and using said ratio signal to produce a signal indicative of imminent stalling.
Claim 11
Dependent Claim
17 words
A method as claimed in claim 8, wherein said airspeed sensing means is heated body probe means.
Claim 12
Dependent Claim
31 words
A method as claimed in claim 8, wherein said location is spaced from the leading edge of the wing by about 66% of the length of a chord of the wing.
Claim 13
Dependent Claim
30 words
A method as claimed in claim 8, wherein said location is at a height above the wing which is below 8% of the length of a chord of the wing.
Claim 14
Dependent Claim
32 words
A method as claimed in claim 8, wherein said location is at a height above the wing which is between 1% and 4% of the length of a chord of the wing.
Claim 15
Dependent Claim
17 words
A method as claimed in claim 9, wherein said airspeed sensing means is a hot wire probe.
Claim 16
Dependent Claim
45 words
A method as claimed in claim 8, said signal indicative of imminent stalling is produced when the air turbulence exceeds an air speed dependent threshold, wherein said using said input signals includes continuously sensing a relationship of the measured air turbulence to said turbulence threshold.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-06 | 1987-09-05 | 1988-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-06 | 1991-09-05 | 1992-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-06 | 1995-09-05 | 1996-03-06 | $7700.00 | Window Closed / Lapsed |