Method and apparatus for deicing a leading edge

• US 4,706,911 A
• Filed: 01/27/1986
• Issued: 11/17/1987
• Est. Priority Date: 01/27/1986
• Status: Expired due to Term

• Current Assignee: The B.F.Goodrich Company (Rtx Corporation)
• Original Assignee: The B.F.Goodrich Company (Rtx Corporation)
• Inventors: Putt, James C., Phillips, Ronald W. II, Briscoe, James A.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Corl, Rodney
• Application Number:
  US06/822,972
• Time in Patent Office: 659 Days
• Field of Search: 244/134 R, 244/134 A, 244/134 F
• US Class Current: 244/134.00A
• CPC Class Codes: B64D 15/16 by mechanical means

Abstract

An airfoil deicer and method for deicing an airfoil wherein the deicer has an outer skin having an elevated modulus of elasticity and a means for introducing a small deflection into the outer skin thereby creating substantial chord-wise tension in the outer skin, the deflection being induced in less than 0.250 seconds. In the method of deicing, the deflection is induced periodically and being completed within a time span of about 0.250 seconds to remove accumulations of ice as thin as 0.06 centimeters.

Claims

1. A method for deicing a substantially high modulus ice accreting surface upon which ice accumulates comprising the step of:

periodically activating beneath the ice accreting surface at least one inflatable member means of a size, position, and physical configuration such that activation of the inflatable member distorts the ice accreting surface placing chord-wise strain upon substantial portions of the ice accreting surface to an extent sufficient to produce periodic desirable distortion and chord-wise strain in the ice accreting surface sufficient to release accumulations of ice thereon;

activation being accomplished to the sufficient extent in not more than 0.250 seconds.

2. A method for deicing a high modulus, ice accreting leading edge surface upon which ice accumulates comprising the step of:

employing a fluid under pressure periodically inflating and deflating beneath the ice accreting surface at least one, flexible, substantially elastic, inflatable means of a size, position and configuration such that inflation of the inflatable means distorts the ice accreting surface placing chord-wise strain upon substantial portions of the ice accreting surface, inflation being accomplished to an extent sufficient to produce desirable distortion and chord-wise strain in the ice accreting surface sufficient to release accumulations of ice thereon and inflation being accomplished to the sufficient extent in not more than 0.250 seconds.

3. The method of claim 2, including the step of positively limiting the extent to which the surface is deformed and the extent of chord-wise strain imposed upon the outer surface.

4. The method of claim 2, inflation being accomplished in not more than 100 milliseconds.

5. A method for deicing a substantially high modulus ice accreting leading edge surface of an aircraft upon which ice accumulates, the surface being formed of a material having a Youngs modulus of at least 40,000 kPa comprising the step of:

periodically inflating and deflating beneath the surface at least one pneumatically inflatable tube of a size, position and configuration such that inflation of the tube distorts the surface placing chord-wise strain upon substantial portions of the surface and causing an elongation of the surface not greater than the ultimate elongation parameter of the material from which the surface is formed, to an extent sufficient to produce desirable distortion and chord-wise strain on the surface sufficient to release accumulations of ice thereon, the inflation being accomplished to the sufficient extent in not more than 0.250 seconds.

6. The method of claim 5, inflation being accomplished in not more than 100 milliseconds.

7. The method of claim 5, including the step of positively limiting the extent to which the surface is deformed and the extent of chord-wise strain imposed upon the outer surface.

8. Apparatus for deicing an ice accreting surface formed of a material having a substantially elevated modulus of elasticity and upon which ice accumulates comprising:

at least one inflation tube distorting means positioned thereunder of a size, position and physical configuration whereby activation of the inflation tube distoring means distorts to an extent necessary to effect deicing within 0.250 seconds the ice accreting surface by placing a chord-wise strain upon substantial portions of the ice accreting surface; and

activation means for triggering activation of the inflation tube to effectuate distortion of the outer surface.

9. The apparatus of claim 8, distortion being accomplished to the desired extent in not more than 100 milliseconds.

10. Apparatus for deicing an ice accreting leading edge surface formed of a material having a substantially elevated modulus of elasticity upon which ice accumulates comprising:

at least one tubular inflatable means beneath the ice accreting surface of a size, position and configuration such that inflation of the inflatable means distorts the ice accreting surface and places a chord-wise strain upon substantial portions of the ice accreting surface;

means for inflating the tubular inflatable means in not more than 0.250 seconds employing a fluid under pressure to extent sufficient to produce a desirable distortion and chord-wise strain in the ice accreting surface sufficient to release accumulations of ice thereon; and

means for deflating the tubular inflatable means.

11. The apparatus of claim 10, the fluid under pressure being a gaseous fluid.

12. The apparatus of claim 11, including a positive limitation means for limiting the extent to which the surface is deformed and the extent of chord-wise strain imposed upon the outer surface.

13. The apparatus of claim 11, the inflation means inflating the tubular inflatable means in not more than 100 milliseconds.

14. An apparatus for deicing an ice accreting leading edge surface formed of a material characterized by a modulus of elasticity of at least in excess of about 40,000 kPa comprising:

at least one inflatable tubular member therebeneath of a size, position, and configuration such that inflation of the tubular member distorts the ice accreting surface layer and places a chord-wise strain upon substantial portions of the ice accreting surface layer;

means employing a fluid under pressure for inflating the inflatable member in not more than 0.250 seconds to an extent sufficient to produce a desirable distortion and chord-wise strain in the ice accreting surface layer sufficient to release accumulated ice thereon;

means for deflating the inflatable tubular member; and

control means for assuring against inflating the inflatable tubular member to an extent in excess of that necessary for providing desirable deformation and chord-wise strain in the ice accreting surface layer.

15. The apparatus of claim 14, wherein the control means includes a source of gaseous fluid under substantial pressure, and further including means for accumulating a particular volume of the fluid under substantial pressure, and wherein the inflation means includes a means for releasing the accumulation into tubular member in not more than 0.250 seconds from initiation of release until completion thereof.

16. The apparatus of claim 15, the accumulating means being a chamber of a size such that when filled with the fluid under substantial pressure and discharged into the tubular member, a desired inflation pressure obtains in the tubular member sufficient to produce the desired distortion and chord-wise strain in the our surface layer.

17. The apparatus of claim 15, the inflation means being a solenoid operated pilot valve.

18. The apparatus of claim 15, the inflation means including an ejector configured to draw a vacuum on the tubular member.

19. A leading edge pneumatic deicer comprising:

an outer surface formed by at least one ply of a material having a modulus of elasticity of at least an excess of about 40,000 kPa;

a pair of intermediate plies therebeneath, the intermediate plies being fabric coated on one surface with a rubberizing compound, the intermediate plies being fastened one to the other at trailing edges thereof in a manner whereby the uncoated surfaces are in opposition defining an interstitial space therebetween and establishing an upper intermediate ply and a lower intermediate ply;

the upper intermediate ply being bonded to the outer surface ply;

an inflatable tubular pneumatic member formed of a fabric coated on one surface with a rubberizing compound and configured to form a tube wherein the uncoated surface defines an interior wall of the tube, the tube being bonded to the lower intermediate ply;

a bonding ply bonded to the lower intermediate ply and the tubular member and formed of a material bondable to a substrate upon which the deicer is to be employed;

at least one passageway configured for establishing air communication with the tubular member;

at least one passageway configured to establish air communication with the interstitial space;

an accumulator configured to confine a quantity of air under substantial pressure suitable for inflating the tubular member to a desired extent;

a pilot valve in communication with the accumulator and with the tubular member passageway configured for conducting air from the accumulator to the tubular member employing the tubular member passageway;

a source of vacuum in communication with at least one of the passageways for evacuating at least one of the tubular member and the interstitial space; and

a source of gas under substantial pressure.

20. The apparatus of claim 19, the source of gas under substantial pressure being a intensifier comprising a pair of piston surfaces, one piston surface having a relatively small surface area and the other piston surface having a relatively large surface area, a passageway for introducing a supply of low pressure gas to a chamber associated with smaller piston surface, a shuttle poppet, a means for indexing the shuttle poppet, at least one passageway, in part carried by the shuttle poppet, configured to evacuate gas from a cavity associated with the larger piston surface, an inlet means for introducing a supply of low pressure gas to the cavity associated with the larger piston surface, and an outlet configured for removing high pressure compressed gas from the cavity associated with the smaller piston surface.