Stability

From Inventing aviation
(Redirected from Equilibrium)
Jump to navigation Jump to search

One definition of stability in regard to aircraft is:

The quality of an aircraft in flight which causes it to return to a condition of equilibrium when meeting a disturbance.[1]

There were efforts to make aircraft more stable in the air, and so this is a technological category for patents and publications.

Lawrence Hargrave made a useful finding that box kites were more stable than flat kites in the wind, and this led to the development of biplanes.

Some inventors focused on designing self-correcting systems, in which a tilt in one direction would predictably cause a compensatory corrective force.

Maxim, 1909, Artificial and Natural Flight, p. 92:

A ship at sea has only to be steered in a horizontal direction; the water in which it is floated assures its stability in a vertical direction; but when a flying machine is once launched in the air, it has to be steered in two directions—that is, the vertical and the horizontal. Moreover, it is constantly encountering air currents that are moving with a much higher velocity than any water currents that have ever to be encountered. It is, therefore, evident that, as far as vertical steering is concerned, it should be automatic.

(He recommends the gyroscope as the only acceptable means for accomplishing this type of stability.)

Stability versus control

Stability is closely related to the issue of how the pilot can control the aircraft (navigation or piloting), as the pilot may be able to accomplish through directed control the object of restoring the aircraft to a stable course. According to aviation historian Charles Harvard Gibbs-Smith, the European engineers of the first decade in the twentieth century were wedded to the "inherent stability" model, while the Wright Brothers had chosen to develop control systems.[2]

Crouch, 1981, p. 36, writes on the same subject:

Most experimenters chose simply to ignore the possibility of active pilot control in roll. Following the lead of French experimenter Alphonse Pénaud, they sought to perfect a mechanism that would guarantee absolute inherent lateral stability. This would mean that a flaying machine would proceed on a straight and level course, with the pilot intervening only when changing direction or altitude. Thus, a simple mechanism such as building dihedral into the wings, which would provide some measure of stability in roll, was substituted for an active control system. The rudder alone would be used to swing the aircraft around in a slow, flat turn, perhaps assisted by some device that could increase air resistance on the pivoting wing.

A number of factors explain this emphasis on automatic stability. Many students of the atmosphere were so convinced that upper-air gusts and currents shifted so rapidly as to defeat human reflexes. They believed that a mechanism that could "sense" these changes and automatically maintain the craft on an even keel was required. [...]

Just as important, however, is the fact that few experimenters really sought to develop a finished aircraft, complete with adequate controls. Most felt that the first task was to demonstrate a simple straight-line flight with a man on board. Once this had been accomplished, they argued, full attention could be given to control.

Automatic stability of the Airplane

Throughout our data we find specifically “automatic airplane stability”, achieved by way of several fairly distinct and quantifiable modalities. Though it is highly unlikely that any innovation oriented towards stability would be designed to involve undue burden on the aviator, we may want to subcategorize this further.

We have extensive publications on issues of automatic stability, on false claims thereto, on "dangers" thereof, on relations between "automatic" and other.

Patent FR-1912-455480 is a case of interest emphasizing innovations in control which are applicable whether "automatic" or "optional".

In contrast, at least semantically, Patent FR-1911-434663, along with its addition, gives us an example of stability which is not only "automatic" but "required", or "imperative".

Patent FR-1910-424474 and its addition give us an instance in which automatic airplane stability, achieved via control wind resistance, is conjointly manifest with speed regulation, or "cruise control".

Patent US-1908-927605 has the properties of automatic stability and also allows for direct adjustment by the pilot.

Distinct and fundamental principles upon which stability is based, automatically or otherwise

Over time, drawing from received patent data, we notice 3-4 semi-distinct principles through which airplane stability achieved. These all corresponding tech areas. Any perusal of pendulum or gyroscope results, for instance, will show a prevalence of stability and-or the clearly related equilibrium.

Particular cases

Patent reports

This wiki has 5 patents in category "Stability". Other techtypes related to Stability: AT 63b, Ballast, Ballonet, Carène, CH 96g, CPC B64C17/00, CPC B64C17/02, CPC B64C17/06, CPC B64C5/00, CPC B64C5/02, CPC B64D27/023, CPC F42B10/06, CPC F42B10/12, CPC F42B10/26, CPC F42B10/30, Cybernetics, Empennage, Fighter airplane, Keel, Pratt truss, Quille, Springs, Tail fin, USPC 244/177, USPC 244/179, USPC 244/3.1, USPC 244/3.12, USPC 244/3.21, USPC 244/3.23, USPC 244/3.24, USPC 244/3.26, USPC 244/3.27, USPC 244/3.28, USPC 244/3.29, USPC 244/3.3, USPC 244/76, USPC 244/80, USPC 244/91, USPC 244/92, USPC 244/93, Winglets

Patents in category Stability

Publications referring to Stability

Techtype and related matters of categorization

Enclosing categories Simple tech terms
Subcategories Gyroscope, Pendulum, Aileron, Keel, Automatic stability
Keywords CPC B64C17/00, USPC 244/91, Airfoil
Start year
End year


References

  1. ↑ Aircraft Year Book, 1919, "Nomenclature for Aeronautics", Compiled from Report No. 9 of the National Advisory Committee for Aeronautics, pp. 366–371.
  2. ↑ Gibbs-Smith, Aviation, 1970, pp. 111–112.
Retrieved from "http://econterms.net/aero/index.php?title=Stability&oldid=294971"