CA2684526A1 - Helicopter settling protector and method of manufacturing same - Google Patents
Helicopter settling protector and method of manufacturing same Download PDFInfo
- Publication number
- CA2684526A1 CA2684526A1 CA 2684526 CA2684526A CA2684526A1 CA 2684526 A1 CA2684526 A1 CA 2684526A1 CA 2684526 CA2684526 CA 2684526 CA 2684526 A CA2684526 A CA 2684526A CA 2684526 A1 CA2684526 A1 CA 2684526A1
- Authority
- CA
- Canada
- Prior art keywords
- settling
- protector
- helicopter
- sheet
- mold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C25/00—Alighting gear
- B64C25/32—Alighting gear characterised by elements which contact the ground or similar surface
- B64C25/52—Skis or runners
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
- B29C51/10—Forming by pressure difference, e.g. vacuum
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2791/00—Shaping characteristics in general
- B29C2791/004—Shaping under special conditions
- B29C2791/006—Using vacuum
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2069/00—Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C25/00—Alighting gear
- B64C25/32—Alighting gear characterised by elements which contact the ground or similar surface
- B64C2025/325—Alighting gear characterised by elements which contact the ground or similar surface specially adapted for helicopters
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Aviation & Aerospace Engineering (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
Abstract
A helicopter settling protector and method of manufacturing same, the settling protector being made of a thermoformed polycarbonate resin thermoplastic.
Description
TITLE OF THE INVENTION
HELICOPTER SETTLING PROTECTOR AND METHOD OF MANUFACTURING SAME
FIELD OF THE INVENTION
The present invention relates to a helicopter settling protector and method of manufacturing same, and more particularly to a device for attachment to a helicopter skid to prevent settling of the helicopter when landing on soft terrain such as snow.
BACKGROUND OF THE INVENTION
Helicopters are extremely versatile aircraft. Because of their ability to hover, and take off and land vertically, they are employed for a very wide variety of missions. As such, they are occasionally required to land in soft terrain or deep snow, sometimes even sinking right up to the belly of the fuselage. This can potentially create a dangerous situation if the tail rotor of the aircraft becomes fouled, and could prevent the aircraft from being able to take off again. In order to mitigate this, operators have added "settling protectors". A settling protector is a device that increases the landing surface area of the helicopter, near or aft of the aircraft's center of gravity. The goal is not necessarily to support the entire aircraft, but to at least pivot the nose of the helicopter downward thus elevating the tail rotor away from the ground.
The settling protectors are attached to the rear end of the helicopter skids in order to increase the landing surface area of the helicopter. A settling protector kit, which includes a pair of settling protectors and related pieces for attachment to the helicopter skids, is typically in excess of 13.6 kgs or 30lbs. Adding this much weight to the landing gear of a helicopter can significantly alter the vibration characteristics of the aircraft, potentially setting off dangerous harmonics that did not exist prior to the installation of the kit. The method of installation of these kits is also typically quite complex and often involves permanent modification to the landing gear (such as drilling holes).
There are various styles of settling protectors currently on the market, manufactured by several different companies. These devices are made of Ultra High Molecular Weight (UHMW) plastic, metal or composite material which is machined using a computer numerical controlled (CNC) or conventional machine tool. An example of a settling protector according to the prior art is shown in Fig. 1, where the settling protector 2 has been machined out of a large piece of raw material by machine tool 4 to the desired shape for attachment to a helicopter skid.
While machined settling protectors are quite effective, the manufacturing lead time for the part is quite long. Also, the raw materials used to construct the settling protectors is quite expensive and when it is machined from a large block the majority of the raw material is machined away to reduce the weight. This is quite wasteful both from the standpoint of the raw material that goes to waste and the wasted money associated with the purchase of a large quantity of raw material that is simply wasted.
Thermoforming is a known manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. Thermoformed products are typically categorized as "thin-gauge" or "thick-gauge".
Examples of products manufactured through thin-gauge thermoforming include disposable cups, containers, lids, trays, blisters, clamshells, and other products for the food, medical, and general retail industries. Examples of products manufactured by thick-gauge thermoforming include vehicle door and dash panels, refrigerator liners, utility vehicle beds, and plastic pallets.
To date, thermoforming has not been used for the manufacture of settling protectors as the resulting product is too brittle and not suitable for its intended purpose.
Accordingly, it is an object of an embodiment of the present invention to provide a settling protector manufactured using a thermoforming process.
It is a further object of an embodiment of the present invention to provide a settling protector made of a cheaper, less costly material.
Other objects of the invention will be apparent from the description that follows.
SUMMARY OF THE INVENTION
HELICOPTER SETTLING PROTECTOR AND METHOD OF MANUFACTURING SAME
FIELD OF THE INVENTION
The present invention relates to a helicopter settling protector and method of manufacturing same, and more particularly to a device for attachment to a helicopter skid to prevent settling of the helicopter when landing on soft terrain such as snow.
BACKGROUND OF THE INVENTION
Helicopters are extremely versatile aircraft. Because of their ability to hover, and take off and land vertically, they are employed for a very wide variety of missions. As such, they are occasionally required to land in soft terrain or deep snow, sometimes even sinking right up to the belly of the fuselage. This can potentially create a dangerous situation if the tail rotor of the aircraft becomes fouled, and could prevent the aircraft from being able to take off again. In order to mitigate this, operators have added "settling protectors". A settling protector is a device that increases the landing surface area of the helicopter, near or aft of the aircraft's center of gravity. The goal is not necessarily to support the entire aircraft, but to at least pivot the nose of the helicopter downward thus elevating the tail rotor away from the ground.
The settling protectors are attached to the rear end of the helicopter skids in order to increase the landing surface area of the helicopter. A settling protector kit, which includes a pair of settling protectors and related pieces for attachment to the helicopter skids, is typically in excess of 13.6 kgs or 30lbs. Adding this much weight to the landing gear of a helicopter can significantly alter the vibration characteristics of the aircraft, potentially setting off dangerous harmonics that did not exist prior to the installation of the kit. The method of installation of these kits is also typically quite complex and often involves permanent modification to the landing gear (such as drilling holes).
There are various styles of settling protectors currently on the market, manufactured by several different companies. These devices are made of Ultra High Molecular Weight (UHMW) plastic, metal or composite material which is machined using a computer numerical controlled (CNC) or conventional machine tool. An example of a settling protector according to the prior art is shown in Fig. 1, where the settling protector 2 has been machined out of a large piece of raw material by machine tool 4 to the desired shape for attachment to a helicopter skid.
While machined settling protectors are quite effective, the manufacturing lead time for the part is quite long. Also, the raw materials used to construct the settling protectors is quite expensive and when it is machined from a large block the majority of the raw material is machined away to reduce the weight. This is quite wasteful both from the standpoint of the raw material that goes to waste and the wasted money associated with the purchase of a large quantity of raw material that is simply wasted.
Thermoforming is a known manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. Thermoformed products are typically categorized as "thin-gauge" or "thick-gauge".
Examples of products manufactured through thin-gauge thermoforming include disposable cups, containers, lids, trays, blisters, clamshells, and other products for the food, medical, and general retail industries. Examples of products manufactured by thick-gauge thermoforming include vehicle door and dash panels, refrigerator liners, utility vehicle beds, and plastic pallets.
To date, thermoforming has not been used for the manufacture of settling protectors as the resulting product is too brittle and not suitable for its intended purpose.
Accordingly, it is an object of an embodiment of the present invention to provide a settling protector manufactured using a thermoforming process.
It is a further object of an embodiment of the present invention to provide a settling protector made of a cheaper, less costly material.
Other objects of the invention will be apparent from the description that follows.
SUMMARY OF THE INVENTION
The invention consists of a settling protector manufactured using a thermoforming process.
The settling protector is manufactured of a polycarbonate resin thermoplastic.
The foregoing was intended as a broad summary only and of only some of the aspects of the invention. It was not intended to define the limits or requirements of the invention. Other aspects of the invention will be appreciated by reference to the detailed description of the preferred embodiment and to the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings and wherein:
Fig. 1 is a perspective view of a machined settling protector according to the prior art;
Fig. 2 is a helicopter equipped with a settling protector according to the present invention;
Fig. 3a is an exploded perspective view from the top of a sheet of material and a mold to which it will be molded;
Fig. 3b is an exploded perspective view from the bottom of the sheet of material and the mold shown in Fig. 3a;
Fig. 4 is a perspective view showing the sheet of material being molded to the mold of Figs. 3a and 3b with a portion of the material cut away to reveal the mold;
Fig. 5 is a pair of perspective views, one from the top and one from the bottom, of the molded sheet of material shown in Fig. 4 being trimmed of excess material; and Fig. 6 is a perspective view of a settling protector according to the invention DESCRIPTION OF THE PREFERRED EMBODIMENTS
A settling protector 50 is shown in Fig. 2 attached to a helicopter skid 52 of a helicopter 54.
The settling protector 50 is formed of a polycarbonate resin thermoplastic which is shaped by thermoforming as described in more detail below.
The process for forming the settling protector 50 will now be described with reference to Figs.
3 through 6. As shown in Figs. 3a and 3b, a mold 10 is provided with the raised imprint 16 of the desired settling protector shape. A plurality of raised ribs 13 and sunken recessed elements 14 are provided about the surface of the mold. A vacuum conduit 12 extends out the bottom of the mold 10 for connection with a vacuum. The sunken recessed elements 14 are connected in fluid communication with the vacuum conduit 12 by way of passageways within the mold.
Additional openings and passageways or channels can be formed throughout the mold to provide added suction when thermoforming as discussed below.
In order to commence the thermoforming process, a sheet 18 of raw material is clamped horizontally in a frame as known in the art (a portion of a representative frame referred to by reference numeral 17). The sheet 18 is heated in an oven until it begins to sag under its own weight, preferably at a temperature of about 150 degrees Celsius (approximately 300 degrees Fahrenheit), although this can vary depending on the atmospheric conditions of the day. The best temperature for use on a given day can be determined through a test run with visual confirmation of suitable softening of the sheet 18.
Once the sheet 18 has been sufficiently softened in the oven, the frame 17 and sheet 18 are removed and positioned for molding. This involves indexing the heated sheet 18 into a form station in position relative to mold 10. The mold 10 is raised into the softened plastic sheet 18 (or vice versa) and a vacuum (not shown) attached to vacuum conduit 12 is engaged, removing any trapped air between the mold 10 and sheet 18 and essentially sucking the sheet 18 down against the surface of the mold 10 as shown in Fig. 4. The sheet 18 is then allowed to cool and harden. Once the material has hardened, the vacuum is turned off, the sheet 18 is lifted or otherwise disconnected from the mold (for example, by way of a reverse blast of air from the vacuum) and the frame 17 is removed from the sheet 18.
The settling protector is manufactured of a polycarbonate resin thermoplastic.
The foregoing was intended as a broad summary only and of only some of the aspects of the invention. It was not intended to define the limits or requirements of the invention. Other aspects of the invention will be appreciated by reference to the detailed description of the preferred embodiment and to the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings and wherein:
Fig. 1 is a perspective view of a machined settling protector according to the prior art;
Fig. 2 is a helicopter equipped with a settling protector according to the present invention;
Fig. 3a is an exploded perspective view from the top of a sheet of material and a mold to which it will be molded;
Fig. 3b is an exploded perspective view from the bottom of the sheet of material and the mold shown in Fig. 3a;
Fig. 4 is a perspective view showing the sheet of material being molded to the mold of Figs. 3a and 3b with a portion of the material cut away to reveal the mold;
Fig. 5 is a pair of perspective views, one from the top and one from the bottom, of the molded sheet of material shown in Fig. 4 being trimmed of excess material; and Fig. 6 is a perspective view of a settling protector according to the invention DESCRIPTION OF THE PREFERRED EMBODIMENTS
A settling protector 50 is shown in Fig. 2 attached to a helicopter skid 52 of a helicopter 54.
The settling protector 50 is formed of a polycarbonate resin thermoplastic which is shaped by thermoforming as described in more detail below.
The process for forming the settling protector 50 will now be described with reference to Figs.
3 through 6. As shown in Figs. 3a and 3b, a mold 10 is provided with the raised imprint 16 of the desired settling protector shape. A plurality of raised ribs 13 and sunken recessed elements 14 are provided about the surface of the mold. A vacuum conduit 12 extends out the bottom of the mold 10 for connection with a vacuum. The sunken recessed elements 14 are connected in fluid communication with the vacuum conduit 12 by way of passageways within the mold.
Additional openings and passageways or channels can be formed throughout the mold to provide added suction when thermoforming as discussed below.
In order to commence the thermoforming process, a sheet 18 of raw material is clamped horizontally in a frame as known in the art (a portion of a representative frame referred to by reference numeral 17). The sheet 18 is heated in an oven until it begins to sag under its own weight, preferably at a temperature of about 150 degrees Celsius (approximately 300 degrees Fahrenheit), although this can vary depending on the atmospheric conditions of the day. The best temperature for use on a given day can be determined through a test run with visual confirmation of suitable softening of the sheet 18.
Once the sheet 18 has been sufficiently softened in the oven, the frame 17 and sheet 18 are removed and positioned for molding. This involves indexing the heated sheet 18 into a form station in position relative to mold 10. The mold 10 is raised into the softened plastic sheet 18 (or vice versa) and a vacuum (not shown) attached to vacuum conduit 12 is engaged, removing any trapped air between the mold 10 and sheet 18 and essentially sucking the sheet 18 down against the surface of the mold 10 as shown in Fig. 4. The sheet 18 is then allowed to cool and harden. Once the material has hardened, the vacuum is turned off, the sheet 18 is lifted or otherwise disconnected from the mold (for example, by way of a reverse blast of air from the vacuum) and the frame 17 is removed from the sheet 18.
Referring now to Fig. 5, an abrasive wheel 20 or the like is used to trim the excess materials from the settling protector 50. This includes trimming the excess material corresponding to the recesses 14 so as to form openings 22, which act to minimize suction between the settling protector and the surface upon which it is placed. A plurality of mounting holes 24 are drilled into the settling protector for connecting it to the helicopter landing gear skidtube using steel band clamps.
As shown in Fig. 6, the settling protector 50 corresponds to the shape of the mold 10, with a raised perimeter 21, a plurality of raised arcuate ribs 23, a plurality of openings 22. A
longitudinal depression corresponds to the skid tube of a helicopter for mounting thereto by way mounting holes 24. A pair of longitudinally extending ribs are visible along either side of the depression. The raised perimeter 21, raised arcuate ribs 23 and longitudinally extending ribs provide the required structural rigidity so that the settling protector is able to withstand the forces applied when a helicopter lands on a soft surface and the wear and tear associated the same. The shape and layout of the ribbing optimizes the stiffness of the settling protector 50 without making it too stiff, with some flexibility necessary in order to allow it to bend and flex uniformly across the protector 50, thus reducing the stress concentrations.
It will be appreciated by those skilled in the art that the preferred and alternative embodiments have been described in some detail but that certain modifications may be practiced without departing from the principles of the invention.
As shown in Fig. 6, the settling protector 50 corresponds to the shape of the mold 10, with a raised perimeter 21, a plurality of raised arcuate ribs 23, a plurality of openings 22. A
longitudinal depression corresponds to the skid tube of a helicopter for mounting thereto by way mounting holes 24. A pair of longitudinally extending ribs are visible along either side of the depression. The raised perimeter 21, raised arcuate ribs 23 and longitudinally extending ribs provide the required structural rigidity so that the settling protector is able to withstand the forces applied when a helicopter lands on a soft surface and the wear and tear associated the same. The shape and layout of the ribbing optimizes the stiffness of the settling protector 50 without making it too stiff, with some flexibility necessary in order to allow it to bend and flex uniformly across the protector 50, thus reducing the stress concentrations.
It will be appreciated by those skilled in the art that the preferred and alternative embodiments have been described in some detail but that certain modifications may be practiced without departing from the principles of the invention.
Claims
1. A settling protector comprising a sheet of polycarbonate resin thermoplastic thermoformed on a mold.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2684526 CA2684526A1 (en) | 2009-11-05 | 2009-11-05 | Helicopter settling protector and method of manufacturing same |
| PCT/CA2010/001723 WO2011054084A1 (en) | 2009-11-05 | 2010-11-05 | Helicopter settling protector and method of manufacturing same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2684526 CA2684526A1 (en) | 2009-11-05 | 2009-11-05 | Helicopter settling protector and method of manufacturing same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2684526A1 true CA2684526A1 (en) | 2011-05-05 |
Family
ID=43969511
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2684526 Abandoned CA2684526A1 (en) | 2009-11-05 | 2009-11-05 | Helicopter settling protector and method of manufacturing same |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2684526A1 (en) |
| WO (1) | WO2011054084A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3135702B1 (en) * | 2022-05-19 | 2024-04-12 | Airbus Helicopters | Skid landing gear fitted with anti-sinking skids |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2372081A1 (en) * | 1976-11-24 | 1978-06-23 | Aerospatiale | SKATE LANDING TRAIN FOR AIRCRAFT |
| FR2541931A1 (en) * | 1983-03-04 | 1984-09-07 | Saurer Diederichs Sa | Mould for forming thermoplastic materials |
| US4544116A (en) * | 1983-11-14 | 1985-10-01 | Shwayder Warren M | Helicopter landing skid shoe pad |
| FR2750394B1 (en) * | 1996-06-28 | 1998-09-04 | Fb Ind | HELICOPTER SKATE |
| RU2295446C2 (en) * | 2004-03-24 | 2007-03-20 | Институт механики и машиностроения Казанского научного центра Российской академии наук | Method of manufacture of the ribbed sheaths of the positive curvature |
-
2009
- 2009-11-05 CA CA 2684526 patent/CA2684526A1/en not_active Abandoned
-
2010
- 2010-11-05 WO PCT/CA2010/001723 patent/WO2011054084A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO2011054084A1 (en) | 2011-05-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |