US4908619A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aircraft stall warning system
Assignee: Boeing Co
•
Filing: 1984-11-13
•
Granted: 1990-03-13
•
Expires: 2004-11-13
Abstract
Abstract A stall warning "stick shaker" reference level signal is produced as a function of both flap position and total aircraft thrust. More specifically, a correction term Δα is combined with a standard stick shaker reference level signal which is scheduled as a function of aircraft flap position. The Δα signal is scheduled as a function of the total aircraft gross thrust coefficient. The resultant reference level signal produces advance stall warnings that are essentially invariant with engine power level.
Inventors
- 👤 Paul F. Bala
- 👤 Edgars A. Kupcis
- 👤 William B. Fisher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:20
CPC Classifications
G; G05; G05D; G05D1/00; G05D1/04; G05D1/06; G05D1/0607; B; B64; B64D; B64D43/00; B64D43/02
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
60 words
Apparatus for producing an aircraft stall warning signal comprising: a means for producing a signal a representative of aircraft angle of attack; Δα means for producing a signal Δα which is predeterminedly related to engine thrust level; and comparator means for comparing said a and said Δαsignals and producing a stall warning signal in response to a predetermined relationship therebetween.
Claim 2
Dependent Claim
60 words
Apparatus for producing an aircraft stall warning signal comprising: a means for producing a signal a representative of aircraft angle of attack; Δα means for producing a signal Δα which is predeterminedly related to engine thrust level; and comparator means for comparing said a and said Δαsignals and producing a stall warning signal in response to a predetermined relationship therebetween.
Claim 3
Dependent Claim
44 words
The apparatus of claim 1 wherein said Δα means comprises: C T .sbsb.G means for producing a signal C T .sbsb.G representative of aircraft gross thrust coefficient; and means for producing said Δα signal as a predetermined function of said C T .sbsb.G signal.
Claim 4
Dependent Claim
86 words
The apparatus of claim 2 wherein said C T .sbsb.G means further comprises: T G means for producing a signal representative of aircraft gross thrust; s means for producing a signal s representative of aircraft wing area; means for dividing said T G signal by said signal s to produce a signal T G/s ; q means for producing a signal q representative of aircraft dynamic pressure; and means for dividing said T G/s signal by said signal q to produce said signal C T .sbsb.G.
Claim 5
Dependent Claim
80 words
The apparatus of claim 3 wherein said q means further comprises: V CAS means for producing a signal V CAS representative of aircraft calibrated airspeed; squarer means for squaring said V CAS signal to produce a signal V 2 CAS ; means for producing a signal k representative of a conversion constant between said signal V 2 CAS and aircraft dynamic pressure; and means for dividing said V 2 CAS signal by said signal k to produce said signal q.
Claim 6
Dependent Claim
58 words
The apparatus of claim 1 further comprising: means for detecting a reduction in thrust of said aircraft below a predetermined level and producing a predetermined thrust detector signal in response thereto; and means responsive to a produced thrust detector signal for inhibiting said signal Δα from affecting the production of said stall warning signal by said comparator signal.
Claim 7
Dependent Claim
72 words
The apparatus of claim 1 further comprising: control surface detector means for producing a control surface detector signal responsive to an aircraft condition of asymmetrical control surface deployment; means for producing a predetermined worst case stall warning signal α wc in response to a produced control surface detector signal; and selector means for providing said comparator means for comparison with said signal a the higher of said Δα and α wc signals.
Claim 8
Dependent Claim
77 words
The apparatus of claim 6 further comprising: α LIMIT means for producing a signal α LIMIT representative of a limit value aircraft angle of attack as a function of flap deployment; and means for predeterminedly summing said α LIMIT signal with the higher of said Δα and α WC signals provided by said selector means so that a resultant signal produced by said summing means is provided to said comparator means, for comparison with said signal α.
Claim 9
Dependent Claim
54 words
The apparatus of claim 1 further comprising: means for producing a signal V CAS .sbsb.MIN representative of a predetermined minimum allowed aircraft calibrated airspeed; means for producing a signal V CAS representative of aircraft calibrated airspeed; and means for producing said stall warning signal responsive to the condition V CAS .sbsb.MIN >V CAS .
Claim 10
Dependent Claim
21 words
The apparatus of claim 8 wherein said signal V CAS .sbsb.MIN is produced as a predetermined function of aircraft flap position.
References Cited (Backward Citations)
US3839699A
Cited
US3686936A
Cited
US4093158A
Cited
US4027839A
Cited
US4230290A
Cited
US4235104A
Cited
US4347572A
Cited
US4467429A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-12 | 1993-09-11 | 1994-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-12 | 1997-09-11 | 1998-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-12 | 2001-09-11 | 2002-03-13 | $7700.00 | Window Closed / Lapsed |