Patent US2553500A successfully refreshed from Google Patents.
Patent US4615497A successfully refreshed from Google Patents.
US4615497A
Expired / Lapsed
US
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Method and flutter brake for an aircraft
Assignee: Airbus Defence and Space GmbH
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Filing: 1986-01-21
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Granted: 1986-10-07
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Expires: 2006-01-21
Abstract
Abstract The invention relates to a method and an arrangement for the wings of a h speed aircraft, for increasing the flutter velocity. Aerodynamic auxiliary flaps or vortex generators are placed into an effective position in response to filtered sensor signals for causing a reduction in the local lift rise or for shifting the local neutral point toward the wing trailing edge to thereby provide an effective "flutter brake". The auxiliary flaps or vortex generators are activated only once when needed and stay in an activated effective position for a length of time sufficient for increasing the flutter velocity or speed and the activation takes place rapidly in about 200 to 400 milliseconds from the time the sensors pick up or provide a signal for such activation.
Inventors
- 👤 Hartwig Seeler
- 👤 Helmut Zimmermann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:58
CPC Classifications
B; B64; B64C; B64C13/00; B64C13/02; B64C13/16
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
157 words
A method for increasing the flutter velocity or speed of an aircraft comprising the following steps: (a) sensing a threshold signal anticipating an onset of an instability causable by flutter, (b) processing the sensed threshold signal for providing a control signal representing an anticipated onset of an instability causable by flutter, (c) automatically placing aerodynamic damping means (13, 14) in response to said control signal into a stationary operative position for modifying local lift increases at said onset of a flutter instability, (d) holding said aerodynamic damping means in said operative, stationary position for a length of time sufficient to reduce said flutter instability to a desired level by an increase in the flutter velocity, and (e) returning said aerodynamic damping means into an inoperative position when said sufficient time has elapsed and said flutter instability has been reduced to said desired level, whereby said aerodynamic damping means are not moved repeatedly for the same flutter situation.
Claim 2
Independent Claim
157 words
A method for increasing the flutter velocity or speed of an aircraft comprising the following steps: (a) sensing a threshold signal anticipating an onset of an instability causable by flutter, (b) processing the sensed threshold signal for providing a control signal representing an anticipated onset of an instability causable by flutter, (c) automatically placing aerodynamic damping means (13, 14) in response to said control signal into a stationary operative position for modifying local lift increases at said onset of a flutter instability, (d) holding said aerodynamic damping means in said operative, stationary position for a length of time sufficient to reduce said flutter instability to a desired level by an increase in the flutter velocity, and (e) returning said aerodynamic damping means into an inoperative position when said sufficient time has elapsed and said flutter instability has been reduced to said desired level, whereby said aerodynamic damping means are not moved repeatedly for the same flutter situation.
Claim 3
Dependent Claim
20 words
The method of claim 1, wherein said sensing involves sensing an aircraft speed at which said flutter caused instability begins.
Claim 4
Dependent Claim
19 words
The method of claim 2, wherein said sensing involves sensing a predetermined limit speed or a limit Mach number.
Claim 5
Dependent Claim
23 words
The method of claim 1, wherein said sensing involves sensing a predetermined vibration value of a vibration caused by the onset of flutter.
Claim 6
Dependent Claim
13 words
The method of claim 4, wherein said vibration value is a vibration amplitude.
Claim 7
Dependent Claim
13 words
The method of claim 4, wherein said vibration value is a vibration frequency.
Claim 8
Dependent Claim
41 words
The method of claim 1, comprising using as said aerodynamic damping means spoiler flaps (13) which are arranged symmetrically in each aircraft wing, said spoiler flaps being movable out of and back into the wing surface, especially the upper wing surface.
Claim 9
Dependent Claim
37 words
The method of claim 1, comprising using as said aerodynamic damping means vortex generators (14) arranged inside a wing alongside a wing leading edge, said vortex generators being movable out of and back into the wing surface.
Claim 10
Dependent Claim
21 words
The method of claim 1, wherein said step of automatically placing involves a time duration of about 200 to 400 milliseconds.
Claim 11
Dependent Claim
21 words
The method of claim 1, wherein said sufficient length of time is within the range of about 200 to 400 milliseconds.
Claim 12
Independent Claim
166 words
An apparatus for increasing the flutter velocity or speed of an aircraft, comprising sensing means for sensing a threshold signal anticipating an onset of an instability causable by flutter, signal processing means operatively connected to said sensing means for producing of the sensed threshold signal a control signal representing an anticipated onset of a flutter instability, aerodynamic damping means (13, 14), operating means operatively connected to said signal processing means and to said damping means (13, 14) for automatically placing said damping means (13, 14) in response to said control signal into a stationary operative position and for holding said damping means (13, 14) in said stationary operative position for a length of time sufficient to reduce said flutter instability to a desired level, and for returning said aerodynamic damping means into an inoperative position when said sufficient time has elapsed and said flutter instability has been reduced to said desired level, whereby said aerodynamic damping means are not moved repeatedly for the same flutter situation.
Claim 13
Independent Claim
166 words
An apparatus for increasing the flutter velocity or speed of an aircraft, comprising sensing means for sensing a threshold signal anticipating an onset of an instability causable by flutter, signal processing means operatively connected to said sensing means for producing of the sensed threshold signal a control signal representing an anticipated onset of a flutter instability, aerodynamic damping means (13, 14), operating means operatively connected to said signal processing means and to said damping means (13, 14) for automatically placing said damping means (13, 14) in response to said control signal into a stationary operative position and for holding said damping means (13, 14) in said stationary operative position for a length of time sufficient to reduce said flutter instability to a desired level, and for returning said aerodynamic damping means into an inoperative position when said sufficient time has elapsed and said flutter instability has been reduced to said desired level, whereby said aerodynamic damping means are not moved repeatedly for the same flutter situation.
Claim 14
Dependent Claim
25 words
The apparatus of claim 11, wherein said sensing means comprise speed sensing means for sensing an aircraft speed at which said flutter caused instability begins.
Claim 15
Dependent Claim
14 words
The apparatus of claim 11, wherein said sensing means comprise vibration value sensing means.
Claim 16
Dependent Claim
40 words
The apparatus of claim 11, wherein said aerodynamic damping means comprise spoiler flaps (13) which are arranged symmetrically in each aircraft wing, said spoiler flaps being movable out of and back into the wing surface, especially the upper wing surface.
Claim 17
Dependent Claim
36 words
The apparatus of claim 11, wherein said aerodynamic damping means comprise vortex generators (14) arranged inside a wing alongside a wing leading edge, said vortex generators being movable out of and back into the wing surface.
Claim 18
Dependent Claim
33 words
The apparatus of claim 13, wherein said operating means are automatically effective within a time duration of about 200 to 400 milliseconds for placing said damping means (13, 14) into an effective position.
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) | 1989-10-06 | 1990-04-07 | 1990-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-06 | 1994-04-07 | 1994-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-06 | 1998-04-07 | 1998-10-07 | $7700.00 | Window Closed / Lapsed |