Patent Description:
Test stands are used in testing facilities for testing and verifying performance of newly designed or recently overhauled aircraft engines in various operating conditions. For instance, tests can be performed to measure thrust generated by the aircraft engine, to simulate impact with foreign objects or to evaluate the effect of aircraft flight attitudes on some of the engine fluid systems (e.g. lubricant, coolant, fuel).

For instance, aircraft engines have lubrication systems for lubricating different components, such as bearings, gears, and so on. In use, an aircraft equipped with one or more engine(s) experiences movements along pitch, roll, and yaw axes. These movements alter an angle of the engine(s) with respect to a ground and may affect how the lubricant and/or other fluids flow within the engine(s). Attitude tests are thus conducted to evaluate whether the lubrication system operates as designed for the "Attitude Operational Envelope" in which a particular engine/aircraft combination is expected to operate.

Typically, a test stand, whether it is used for attitude testing or else, is a massive installation permanently implanted at a given site of an engine testing facility resulting in a test stand that is immobile. Noise issues are a significant concern for on-going outdoor tests in the area surrounding the testing facility. Engines tested on such a permanent and immobile test stand may generate an important level of noise. Since noise is classified as a "contaminant" in many jurisdictions, generating such noise above a given level may be prohibited. These limitations may impede the attitude tests and, thus, impede the implantation of test stands in certain environments.

A test stand for aircraft engine attitude testing is taught in patent document <CIT>. Said document discloses all technical features in the preamble of claim <NUM>.

In accordance with one aspect, there is provided a portable attitude test stand (PATS) for an aircraft engine in accordance with claim <NUM>.

In a further embodiment of any of the foregoing embodiments, the actuator includes two actuators each engaged to a respective one of the two carriages and to the support frame.

In a further embodiment of any of the foregoing embodiments, two shaft members are secured to the test cell, the two shaft members rollingly engaged to the two carriages, a step motor secured to one of the two carriages and in driving engagement with a corresponding one of the shaft members for rotating the test cell about the pitch axis of the aircraft engine.

In a further embodiment of any of the foregoing embodiments, the actuator includes two actuators, each of the two actuators including a first motor secured to a respective one of the two carriages and a threaded member in driving engagement with the first motor, the threaded member threadingly engaged to a threaded rod secured to the base and extending vertically away from the base, rotation of the threaded members by the first motors inducing translation of the threaded members and the two carriages relative to the vertical members of the frame.

In a further embodiment of any of the foregoing embodiments, the actuator includes two actuators, each of the two actuators including a first motor secured to the frame and a threaded rod in driving engagement with the first motor and extending vertically away from the base, the threaded rod threadingly engaged to a threaded member secured to a respective one of the two carriages, rotation of the threaded rods by the first motors inducing translation of the threaded members and of the two carriages relative to the vertical members of the frame.

In a further embodiment of any of the foregoing embodiments, the test cell includes a pitch frame and a roll cage rotatably received within the pitch frame, the roll cage sized to receive the aircraft engine, two shaft members secured to the pitch frame and protruding away therefrom, each of the two shaft members rollingly engaged to a respective one of the two carriages.

In a further embodiment of any of the foregoing embodiments, a first motor is secured to one of the two carriages and in driving engagement with one of the two shaft members for rotating the pitch frame about the pitch axis.

In a further embodiment of any of the foregoing embodiments, a second motor is secured to the pitch frame and in driving engagement with the roll cage for rotating the roll cage about the roll axis.

In a further embodiment of any of the foregoing embodiments, the test stand includes a pitch frame and a roll cage rotatably received within the pitch frame, the roll cage sized to receive the aircraft engine, the PATS including a cable management system having: a first annular wall secured to the roll cage and extending around the roll axis, a second annular wall secured to the pitch frame and extending around the first annular wall, and cables having first ends secured to the first annular wall and second ends secured to the second annular wall, the cables located between the first and second annular walls, lengths of the cables selected to allow rotation of the first annular wall relative to the second annular wall about the roll axis.

In a further embodiment of any of the foregoing embodiments, outriggers are secured to the support frame and lifting actuators secured to distal ends of the outriggers, the outriggers movable relative to the support frame between a retracted configuration and an extended configuration, a distance between the lifting actuators in a direction transverse to a direction of travel of the trailer is greater in the extended configuration than in the retracted configuration, in the extended configuration the lifting actuators operable to engage a ground to lift the support frame off the trailer.

In a further embodiment of any of the foregoing embodiments, the outriggers are pivotable relative to the support frame between the retracted configuration and the extended configuration.

In a further embodiment of any of the foregoing embodiments, the lifting actuators includes two pairs of lifting actuators, distances in the direction transverse to the direction of travel between the lifting actuators of each pairs of lifting actuators is at most a width of the trailer when the outriggers are in the retracted configuration.

In a further embodiment of any of the foregoing embodiments, dimensions of the support frame are selected to be contained within a footprint of a flatbed portion of the trailer.

In a further embodiment of any of the foregoing embodiments, the transport height extends from a ground to a most elevated point on the test cell, the transport height less than <NUM> feet (<NUM> metres) when the test cell is mounted on the trailer.

In a further embodiment of any of the foregoing embodiments, the test height is such that a clearance remains between the aircraft engine and a ground for a pitch angle of the aircraft engine varying from <NUM> to -<NUM> degrees, the pitch angle defined between a central axis of the aircraft engine and the ground.

In a further embodiment of any of the foregoing embodiments, a base of the support frame is defined by the trailer.

In another aspect, there is provided a method of preparing an aircraft engine for an attitude test in accordance with claim <NUM>.

In an embodiment of the foregoing embodiment, the increasing of the height includes unloading the PATS from the trailer before the increasing of the height.

In a further embodiment of any of the foregoing embodiments, the increasing of the height includes moving the test cell of the PATS relative to a support frame of the PATS with an actuator engaged to the support frame and the test cell.

<FIG> illustrates an aircraft engine, for instance, a gas turbine engine <NUM> of a type preferably provided for use in subsonic flight. The exemplified engine <NUM> is depicted in <FIG> as a turboprop having a propeller <NUM>. The engine <NUM> has, in serial flow communication, a compressor section <NUM> for pressurizing the air, a combustor <NUM> in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, and a turbine section <NUM> for extracting energy from the combustion gases. The engine <NUM> has a shaft <NUM> drivingly engaged to the propeller <NUM> via a reduction gear box <NUM>. The shaft <NUM> is rotatably supported by bearings <NUM>, which are contained within bearing housings <NUM>.

Referring to <FIG>, the engine <NUM> has a lubrication system <NUM> for providing lubricant to the bearings <NUM> and the reduction gear box <NUM>. The system <NUM> includes a tank <NUM> containing lubricant, a pump <NUM> hydraulically connected to the tank <NUM> and to the components in need of lubrication, which corresponds in the embodiment shown to the bearing housing(s) <NUM> and the reduction gearbox <NUM>, a scavenge pump <NUM> hydraulically connected to scavenge outlets of the components and used to flow scavenged lubricant back to the tank <NUM>, and a de-aerator <NUM> hydraulically connected to the scavenge outlets of the components and operable to extract lubricant from an air-lubricant mixture exiting the components via their scavenge outlets. The de-aerator <NUM> has an outlet hydraulically connected to the tank <NUM>. It will be appreciated that the lubrication system <NUM> may include other components, such as filters, not shown in <FIG>. The engine <NUM> may be equipped with any suitable lubrication system.

In use, the gas turbine engine <NUM> mounted to an aircraft is subjected to a plurality of movements about pitch, roll, and yaw axes P, R, Y. The lubrication system <NUM> is operable to inject the lubricant into the reduction gearbox <NUM> and the bearing housing(s) <NUM> and the lubricant flows by gravity within these components. Therefore, when the aircraft performs climb, descent, and roll manoeuvers, the flow of lubricant within these components may be affected.

Attitude tests are used to determine whether engine fluid systems, such as the engine lubrication system <NUM>, operate as designed for the "Attitude Operational Envelope" in which the aircraft and engine <NUM> are expected to operate. Current computational fluid dynamics tools may not properly simulate mixed flow (air/lubricant) and may be unable to predict where oil will flow in turboprop and/or turboshaft reduction gearboxes and accessory gearboxes. Attitude tests are carried out by physically rotating the running engine <NUM> around the pitch axis P and the roll axis R to simulate aircraft maneuvering. It is used to evaluate the effects of the aircraft flight attitudes on engine fluid systems, such as fuel, coolant and lubrication systems.

Known attitude test stands are typically permanent installations implanted at a given site of an engine testing facility resulting in test stands that are immobile and difficult to adapt to changing environmental requirements. Noise issues are a significant concern for on-going outdoor tests in the area surrounding the testing facilities. Engines tested on these test stands generate an important level of noise. Since noise is classified as a "contaminant" in many jurisdictions, generating such noise above a given level may be prohibited. These limitations may impede the attitude tests and, thus, impede the implantation of test stands in certain environment.

Referring now to <FIG>, a portable attitude test stand (PATS) system is shown at <NUM>. In the context of the present disclosure, "portable", means movable or transportable between different geographical locations, for instance, between different cities, regions, countries, and so on. As will be discussed below and in accordance with at least some embodiments, the system <NUM> is suitable for road transportation.

The PATS system <NUM> is a transportable attitude test stand transportable to any suitable geographical sites via public roads (e.g. highways) via standard flatbed transports. The PATS system <NUM> includes a portable attitude test stand (PATS) <NUM> sized to receive an engine to be tested and operable to move the engine about the pitch and roll axes P, R to simulate movements of the engine in flight. The PATS <NUM> is sized to be received on a trailer C. Said trailer C may then be hauled by a road vehicle (e.g., truck) for moving the PATS <NUM> between different geographical sites.

The illustrated embodiment of the PATS system <NUM> further includes an instrumentation container I used for containing instrumentations operatively connected to the engine to be tested, a water management system <NUM> for flowing water to and from the PATS <NUM>, and a lifting system <NUM> for lifting the PATS <NUM> off the trailer C. The instrumentation container I is separate from the PATS <NUM> and may be received on another trailer and hauled by another truck to the desired site for testing. The instrumentations container I is operatively connected to the tested engine for measuring data about the flow of lubricant within said engine. The PATS <NUM> is exemplified in <FIG> with a turboshaft engine 10a received in the PATS <NUM>, but may alternatively receive the turboprop engine <NUM> of <FIG>, a turbofan engine or any other types of aircraft engines.

The PATS <NUM> is shown in a test, or deployed, configuration in <FIG> and in a transport, or collapsed, configuration in <FIG>. The PATS <NUM> is shown in an intermediate configuration in <FIG>. The PATS <NUM>, in the transport configuration, is sized to be transportable by the trailer C. The trailer C may, for instance, be a lowboy trailer. The trailer C has wheels W at a rear end thereof and a traction pin TP at a front end thereof adapted to be attached to a motive vehicle, such as a truck (not shown). The trailer C has a flatbed portion B. The PATS <NUM> is sized to have a footprint matching the size of the flatbed portion B of the trailer C.

The PATS <NUM> has a transport height H1 in the transport configuration of <FIG> and a test height H2 in the test configuration of <FIG>. The transport and test heights H1, H2 are measured from a ground G to a most elevated point of the PATS <NUM>. The test height H2 is greater than the transport height H1. The transport height H1 is typically at most <NUM> feet (<NUM> metres), and preferably at most <NUM> feet (<NUM> metres). The transport height H1 is measured when the PATS <NUM> is on the trailer C. Such a height constraint in the transport configuration is selected to allow the PATS <NUM> mounted on the trailer C to pass under overpasses when moving between the different geographical sites. As will be discussed below, the test height is selected to provide sufficient clearance between the engine being tested and the ground G when moving the engine about the pivot axis P (<FIG>).

In the embodiment shown, the PATS <NUM> is sized to accommodate gas turbine engines generating a maximum thrust of <NUM> lbs (<NUM> N) or less. The size of an attitude test stand able to accommodate gas turbine engines generating a maximum thrust of more than <NUM> lbs (<NUM> N) of thrust may be too big for road transportation. In other words, the dimensions of the attitude test stand able to accommodate engines of <NUM> lbs (<NUM> N) or more of thrust may be too big to circulate on public roads and under overpasses when moving between the different geographical sites.

By being transportable, the PATS <NUM> allows the testing of engines in any suitable locations, away from municipalities where regulations prevent or limit noise emissions. Testing sites usually start billing as soon as testing facilities are on sites. Therefore, rapidity in deploying the PATS <NUM> from its transport configuration to its testing configuration is a key to minimize costs involved in the testing. Many components of the PATS <NUM> aim to facilitate the deployment and the storage of the PATS <NUM> and are described herein below.

Referring to <FIG>, the PATS <NUM> includes a support frame <NUM>, right and left carriages <NUM>, <NUM>', actuators <NUM> connected to the support frame <NUM> and to the carriages <NUM>, <NUM>' and operable to lower and raise the test cell TC relative to the support frame <NUM>, a pitch frame <NUM> supported by the support frame <NUM>, a roll cage <NUM> rotatably received within the pitch frame <NUM>, and a cable management system <NUM>. As will be described below, the right and left carriages <NUM>, <NUM>' support the pitch frame <NUM> and are movable relative to the support frame <NUM> in a vertical direction to elevate the pitch frame <NUM> from the ground G thanks to the actuators <NUM>. The support frame <NUM>, in the embodiment shown, is able to lift itself from the trailer C such that testing is carried out with the support frame <NUM> laying on the ground G and not on the trailer C.

The PATS <NUM> is shown in the test configuration in <FIG> and in the transport configuration in <FIG>. As will be discussed below, the PATS <NUM> is able to move itself from the transport configuration to the test configuration and vice versa. The actuators <NUM> are connected to the carriages <NUM>, <NUM>' and to the support frame <NUM> to move the pitch frame <NUM> and the roll cage <NUM> relative to the support frame <NUM> between the transport and test configurations. A height H of the engine <NUM>, 10a to be tested is greater in the test configuration than in the transport configuration. The height H of the engine <NUM>, 10a is increased to avoid an exhaust of the engine <NUM>, 10a from being too close to the ground G for safety purposes. Also, the height H of the engine <NUM>, 10a is increased to allow for sufficient amplitude of movements of the engine <NUM>, 10a about the pitch axis P. More specifically, the test height H2 is such that the height H of the gas turbine engine <NUM>, 10a is sufficient to allow a pitch angle of the gas turbine engine <NUM>, <NUM> to vary by <NUM> to -<NUM> degrees. The pitch angle is defined between the central axis of the gas turbine engine <NUM>, 10a and the ground G. If the engine <NUM>, 10a were not elevated sufficiently from the ground G, the engine <NUM>, 10a may become in contact with the ground G at certain pitch angles. The PATS <NUM> allows for decreasing the height H of the pitch frame <NUM> and the roll cage <NUM> in the transport configuration such that the trailer C having the PATS <NUM> mounted thereto is below a height threshold allowing it to roll on public roads and to pass underneath overpasses. As aforementioned, this height threshold is <NUM> feet (<NUM> metres), in some cases <NUM> feet (<NUM> metres). Decreasing the height may also decrease a drag force exerted on the PATS <NUM> by ambient air when the PATS <NUM> is transported from one site to another.

Referring now to <FIG>, the support frame <NUM> is the base of the PATS <NUM> as it supports the weight of the pitch frame <NUM>, the roll cage <NUM>, and the engine <NUM>, 10a secured within the roll cage <NUM>. The frame <NUM> includes a base <NUM> including two longitudinal frame members 62a extending along a longitudinal axis L, which corresponds to a direction of travel DT (<FIG>) of the trailer C (<FIG>) and two transversal frame members 62b extending along a transversal axis T being transverse to the longitudinal axis L and transverse to the direction of travel DT. In the illustrated embodiment, each of the two transversal frame members 62b extends from one of the two longitudinal frame members 62a to the other. The support frame <NUM> includes four vertical frame members <NUM> extending along a vertical axis V normal to both of the longitudinal and transverse axes L, T and from corners of the base <NUM>.

In the embodiment shown, a width W2 of the support frame <NUM> in a direction transverse to the direction of travel DT of the trailer C (<FIG>) is at most a width W1 (<FIG>) of the trailer C. In some embodiments, the width W1 of the trailer C is <NUM> inches (<NUM> metres). Having the width W2 of the support frame <NUM> being at most that of the trailer C may contribute in facilitating transportation of the PATS <NUM> since the support frame <NUM> does not protrude beyond the trailer C.

Referring to <FIG>, a top view of a portion of the support frame <NUM> shows that the vertical frame members <NUM> defines cavities 64a sized to slidably receive a respective one of the left and right carriages <NUM>, <NUM>'. Each vertical frame members <NUM> defines a groove, or track 64b for receiving portions of the carriages <NUM>, <NUM>' and for guiding movements of the carriages. As shown in <FIG>, the support frame <NUM> further includes four threaded rods <NUM> each extending along the vertical axis V and being secured to a respective one of the four vertical frame members <NUM>.

Referring to <FIG>, the support frame <NUM> slidably supports the pitch frame <NUM> and the roll cage <NUM> via the two carriages <NUM>, <NUM>', one being shown in <FIG>. The carriage <NUM> includes a main frame <NUM> and a pitch frame supporting member <NUM> pivotably mounted to the main frame <NUM> for rotation about pivot axis P1. The carriage <NUM> includes a plurality of bearings <NUM> (eight in the illustrated example), four on each opposite sides of the carriage <NUM>. Any suitable types of bearings can be used. For instance, it is contemplated to use combination bearings. The two carriages <NUM>, <NUM>' are slidably received within the cavities 64a (<FIG>) defined between the vertical frame members <NUM> of the support frame <NUM>. The bearings <NUM> are received within the grooves, or tracks, 64b of the vertical frame members <NUM> to provide a sliding engagement between the main frames <NUM> and the vertical frame members <NUM> of the support frame <NUM> to allow the carriages <NUM>, <NUM>' to move up and down along the vertical axis V.

As shown more clearly on <FIG>, the two actuators <NUM> of the two carriages <NUM>, <NUM>' are ball screw actuators. Each of the two actuators <NUM> includes a motor <NUM> (e.g., an electric motor), two gearboxes <NUM>, two threaded members 77a, a shaft <NUM>, and two threaded rods <NUM> (<FIG>).

The motors <NUM> and gearboxes <NUM> are secured to the main frames <NUM>. Each of the motors <NUM> is in driving engagement with two of the gearboxes <NUM>. In the embodiment shown, the two gearboxes <NUM> of each of the carriages <NUM>, <NUM>' are drivingly engaged to one another via the shaft <NUM>. Each of the two gearboxes <NUM> is disposed on a respective one of opposite sides of the main frame <NUM> and secured thereto. Each of the gearboxes <NUM> is in driving engagement with a threaded member 77a. Each of the threaded members 77a is threadingly engaged to a respective one of the four threaded rods <NUM>. In use, operation of the motors <NUM> creates rotational inputs transmitted to the four threaded members 77a via the four gearboxes <NUM> and shafts <NUM>. As the threaded members 77a rotate about the threaded rods <NUM>, the carriages <NUM> move up and down along the vertical axis V.

It is contemplated that that each of the four gearboxes <NUM> may be coupled to a respective one of four motors <NUM>. It will be appreciated that any suitable actuators operable to move the carriages <NUM> relative to the vertical frame members <NUM> of the support frame <NUM>, such as hydraulic actuators connected to the carriages <NUM>, <NUM>' and the support frame <NUM>, may be used without departing from the scope of the present disclosure. Any suitable number of actuator(s) may be used to lift the pitch frame <NUM> and roll cage <NUM> relative to the support frame <NUM>. In some cases, only one actuator may be used. Actuators should in the present disclosure be construed as any system operable to change a height of the test cell TC relative to the ground G.

Still referring to <FIG>, each of the two pitch frame supporting members <NUM> is pivotably secured to a respective one of the two main frames <NUM> via two shaft portions 74a rotatably received within two bearings <NUM>. The two bearings <NUM> are secured to the main frames <NUM>. Pivotal movements of the pitch frame supporting members <NUM> relative to the main frames <NUM> about the pivot axes P1 may cater to flexion of shaft members <NUM>, <NUM> that secure the pitch frame <NUM> to the carriers <NUM>, <NUM>'. Such a flexion may occur because of the weight of the engine <NUM>, 10a and/or because of a misalignment between the two carriages <NUM>, <NUM>' when raising or lowering the test cell.

Referring to <FIG>, one of the two carriages <NUM> is able to induce rotation of the pitch frame <NUM> to rotate the engine <NUM>, 10a about the pitch axis P (<FIG>). To this end, the carriage <NUM> has a step motor <NUM> drivingly engaged to a first gear 74c. The first gear 74c is meshed with a second gear 74d. As will be explained herein below, the second gear 74d is secured to the pitch frame <NUM> such that the step motor <NUM> transmits a rotational input to the second gear 74d to rotate the pitch frame <NUM> about the pitch axis P of the engine. In the present embodiment, the first and second gears 74c, 74d are received within a gear housing 74e. The gear housing 74e is secured within the pitch frame supporting member <NUM>. As shown in <FIG>, the pitch frame supporting member <NUM> defines an aperture 74f sized to receive either one of the shaft members <NUM>, <NUM>.

It will be appreciated that, in the present embodiment, only one of the two carriages <NUM>, <NUM>' is equipped with a step motor <NUM>. Alternatively, each of the two carriages <NUM>, <NUM>' may be equipped with a step motor <NUM>. The carriage <NUM> equipped with the step motor <NUM> is referred as the motorized carriage <NUM>.

Referring now to <FIG>, a test cell TC of the PATS <NUM> is shown in an exploded view and includes the pitch frame <NUM> and the roll cage <NUM>. The roll cage <NUM> is rotatably received within the pitch frame <NUM> and is rotatable relative to the pitch frame <NUM> about the roll axis R (<FIG>) of the engine <NUM>, 10a. An extension <NUM> is secured to the roll cage <NUM> when a dynamo <NUM> (<FIG>) is required, for instance, when the engine tested is the turboshaft engine 10a. More detail about the dynamo <NUM> are presented below.

The pitch frame <NUM> includes a main frame <NUM>, a first shaft member <NUM> and a second shaft member <NUM>. The first and second shaft members <NUM>, <NUM> are secured to and extend from the main frame <NUM> in a direction away from one another. As shown in <FIG>, the shaft members <NUM>, <NUM> are coaxial. Each of the first and second shaft members <NUM>, <NUM> is rotatably secured within a respective one of the apertures 74f (<FIG>) of the pitch frame supporting members <NUM> of the carriages <NUM>, <NUM>'. In the embodiment shown, the first shaft member <NUM> is secured to the second gear 74d of the motorized carrier <NUM>. It will be appreciated that bearings are provided between the carriages <NUM> and the first and second shaft members <NUM>, <NUM> to assist rotation of the pitch frame <NUM> relative to the carriages <NUM>.

The roll cage <NUM> is rotatably received within an opening <NUM> of the pitch frame <NUM>. The roll cage <NUM> includes two annular members 90a secured to one another by ribs 90b. The roll cage <NUM> has a gear <NUM> secured to one of the two annular members 90a. The gear <NUM> of the roll cage <NUM> is engageable by another gear drivingly engaged by a motor <NUM> (<FIG>) secured to the pitch frame <NUM>. Actuation of the motor <NUM> induces rotation of the roll cage <NUM> about a rotation axis A and relative to the pitch frame <NUM> to rotate the gas turbine engine <NUM>, 10a about the roll axis R (<FIG>). It will be appreciated that any other suitable means used to rotate the roll cage <NUM> relative to the pitch frame <NUM> are contemplated without departing from the scope of the present disclosure.

Still referring to <FIG>, the main frame <NUM> of the pitch frame <NUM> includes longitudinal, longitudinal, transversal, and vertical members 81a, 81b, 81c. A number and disposition of which may be varied from what is being illustrated in <FIG>. The main frame <NUM> includes two floor sections 81d secured to the longitudinal and transversal members <NUM>, 81b to support a user working on the gas turbine engine <NUM>, 10a for setting up said engine in preparation of the attitude test.

The extension <NUM> includes two rails 94a and a web <NUM> secured to the two rails 94a. As will be described below, the extension <NUM> is used as an interface between the gas turbine engine to be tested and the roll cage <NUM>. The extension <NUM> may be omitted if the engine tested is a turbofan or a turboprop. The extension <NUM> is securable to the ribs 90b and/or the annular members 90a of the roll cage <NUM>.

Referring now to <FIG>, the dynamo <NUM> is drivingly engaged to an output shaft of the turboshaft 10a to simulate a rotatable load. In other words, the dynamo <NUM> exerts a rotational resistance on the turboshaft engine 10a. The dynamo <NUM> is hydraulically connected to a water source S (<FIG>) as will be explained herein below. The dynamo <NUM> uses water to create the rotational resistance to the turboshaft engine 10a. It will be appreciated that if the engine tested in the PATS <NUM> is the gas turbine engine <NUM> of <FIG>, which is a turboprop engine, the propeller <NUM> is drivingly engaged to the shaft <NUM> of the engine <NUM> and no dynamo is required since the propeller <NUM> will generate the rotatable load. A turbofan may also be tested using the PATS <NUM> and the fan acts as the rotatable load.

In the embodiment shown, the gas turbine engine 10a and the dynamo <NUM> are supported on a mounting structure <NUM>. The mounting structure <NUM> has two transversal members 96a longitudinally spaced apart from one another and secured to one another by longitudinal members 96b. Combination bearings 96c are secured to the transversal members 96a. According to the illustrated embodiment, two combination bearings 96c are secured on each of the two transversal members 96a. The combination bearings 96c are rollingly engageable to the two rails 94a (<FIG>) of the extension <NUM> (<FIG>) to allow the mounting structure <NUM> and the engine 10a secured thereto to move relative to the roll cage <NUM>. This movement may be used to allow the user to setup different connections to the engine 10a for testing purposes. Any suitable means of fastening the engine 10a to the roll cage <NUM> are contemplated without departing from the scope of the present disclosure.

Referring now to <FIG>, during the attitude test, the engine <NUM>, 10a mounted on the PATS <NUM> is hooked up to the instrumentation container <NUM> via cables C1, C2. However, the engine <NUM>, 10a is moving along its pitch and roll axes P, R (<FIG>) and the connections between the engines <NUM>, 10a and the instrumentation container <NUM> has to be maintained during the attitude test. To this end, the PATS <NUM> is equipped with a cable management system <NUM> that allows the cables C1, C2 to follow movements of the engine <NUM>, 10a. Some elements of the PATS <NUM> have been removed for illustration purposes to better illustrate the cable management system <NUM>.

In the embodiment shown, the cables C1, C2 include a first set of cables C1 used to follow pitch movements of the engine <NUM>, 10a and a second set of cables C2 used to follow roll movements of the engine <NUM>, 10a.

The first set of cables C1 is partially wrapped around the first shaft member <NUM>, which is secured to the pitch frame <NUM>. A length of the cables of the first set C1 is selected to allow rotation of the pitch frame <NUM> along a direction denoted by arrow D1 without having the cables C pulling on their connectors C3. More specifically, the cables of the first set C1 extends from the first shaft member <NUM> downwardly up to a location below the connectors C3 and extend therefrom upwardly to the connectors C3. This excess in length is such that rotation of the first shaft member <NUM>, and thus pitching of the engine <NUM>, 10a, will pull on the cables of the first set C1 up to a point where there is no more excess length and without pulling on the connectors C3.

Similarly, rotating the pitch frame <NUM> along a direction denoted by arrow D2 and opposite the direction D1 will increase the excess length of the cables of the first set C1. To avoid the cables of the first set C1 from rubbing against the ground G, a cable support <NUM> is provided and secured to the support frame <NUM> (<FIG>) of the PATS <NUM>. The cable support <NUM> receives the cables of the first set C1 when the pitch frame <NUM> is rotated along the direction D2 opposite the direction D1.

Still referring to <FIG>, the cables of the second set C2 are connected at one extremity to the cables of the first C1 and are secured to the roll cage <NUM> at their opposite extremities. The cables of the second set C2 are partially wrapped around a roll <NUM>, which is movably received within a cable cage <NUM> secured on top of the pitch frame <NUM>. Ropes <NUM> are secured at one of their ends to the roll <NUM> and at their opposite ends to the roll cage <NUM>. In such a case, rotation of the roll cage <NUM> along direction D3 will pull on the cables of the second set C2 and causes the roll <NUM> to slide along direction D4 thereby increasing an effective length of the cables of the second set C2. Similarly, rotation of the roll cage <NUM> along direction D5 opposite direction D3 will cause the roll cage <NUM> to pull on the ropes <NUM> thereby pulling on the roll <NUM> to move said roll <NUM> in a direction D6 opposite the direction D4. The cable management system <NUM> may, thus, allow the cables C1, C2 to follow any movements of the engine <NUM>, 10a about the pitch and roll axes P, R (<FIG>).

Referring now to <FIG>, the water management system <NUM> is described in more detail. The water management system <NUM> includes water lines <NUM>. The water lines <NUM> are removed from <FIG> for illustration purposes. The water lines <NUM> hydraulically connect the dynamo <NUM> (<FIG>) to the water source S. The dynamo <NUM> uses water to provide rotational resistance to the turboshaft engine 10a. In use, the water within the dynamo <NUM> becomes hot and may require cooling. The water lines <NUM> are used to bring water to the dynamo <NUM> and to drain heated water from the dynamo <NUM>.

During testing, the turboshaft engine 10a moves with the pitch frame <NUM> and roll cage <NUM>. To allow the water lines <NUM> to follow movements of the dynamo <NUM> and of the turboshaft 10a, the water management system <NUM> uses a railing system <NUM> to ease movements of the water lines <NUM>.

Referring more particularly to <FIG>, the railing system <NUM> includes two bogies <NUM> slidably mounted on rails <NUM>, which are secured to the ground. A bottom panel <NUM> is disposed between the rails <NUM> to prevent the water lines <NUM> from rubbing against the ground. When the gas turbine engine 10a moves it may push or pull on the water lines <NUM>. To cater to those movements, the bogies <NUM> slide along the rails <NUM> to follow the movements of the engine 10a. The bogies <NUM> include bracket 113a for securing the water lines <NUM> on the bogies <NUM>.

Referring more particularly to <FIG>, the rails <NUM> and brackets 113a are removed for illustration purposes. The bogies <NUM> each includes four bearings 113b, namely, two bearings on each sides. The bearings 113b are slidingly received within grooves 114a of the rails <NUM>.

Referring now to <FIG>, the lifting system <NUM> of the PATS <NUM> has a retracted configuration (shown in <FIG> and <FIG>) and an extended configuration shown in <FIG>. The lifting system <NUM> is operable to lift the PATS <NUM> off the trailer C as illustrated in <FIG>. Once the PATS <NUM> is elevated from the trailer C, the trailer C may be moved relative to the PATS <NUM> to remove the trailer C from underneath of the PATS <NUM>. Once the trailer C is removed, the lifting system <NUM> lowers the PATS <NUM> until the base <NUM> (<FIG>) of the support frame <NUM> (<FIG>) is laid on the ground G. The lifting system <NUM> may be stowed back in the retracted configuration during the attitude test, or may remain in the extended configuration for added stability.

Referring more particularly to <FIG>, the lifting system <NUM> includes two outriggers <NUM>, namely a front outrigger and a rear outrigger longitudinally offset from the front outrigger about the longitudinal axis L. According to the illustrated embodiment, the front and the rear outriggers <NUM> are identical to one another.

The outriggers <NUM> are secured to the support frame <NUM>. In the embodiment shown, each of the outriggers <NUM> is secured to two of the vertical frame members <NUM>. One of the two outriggers <NUM> is shown in <FIG> shows the outrigger of <FIG> with some parts removed for illustration purposes.

The outrigger <NUM> includes a housing <NUM> secured to the support frame <NUM> via two transversally spaced apart brackets <NUM>. The housing <NUM> slidably receives two slidable members <NUM>. Each of the two slidable members <NUM> is secured to a respective one of two actuators <NUM>. In the depicted embodiment, the actuators <NUM> are hydraulic actuators but any suitable actuators may be used. As known, the two actuators <NUM> include first sections 125a secured to the slidable members <NUM> and second sections 125b slidably received within the first sections 125a. Lengths of the actuators <NUM> along the vertical axis V are variable by sliding the first sections 125a relative to the second sections 125b. In other words, the actuators <NUM> are extensible in a vertical direction relative to the vertical axis V to elevate the support frame <NUM> off the ground. In the present case, the actuators <NUM> are hydraulic actuators.

The outrigger <NUM> is shown in <FIG> in the retracted configuration suitable for transportation of the PATS <NUM>. When it is required to lift the support frame <NUM> off the ground, the two sliding members <NUM> are moved away from one another within the housing <NUM> and along the transversal axis T such that the two actuators <NUM> of each of the two outriggers <NUM> extend away from one another along the transversal axis T. Any suitable means may be used to move the two sliding members <NUM> relative to the housing <NUM> of the outriggers <NUM>. For instance, a rack and pinion gear arrangement may be used with a motor drivingly engaged to the pinion gear.

The outriggers <NUM>, in the retracted configuration depicted in <FIG>, have a transversal distance D between the two actuators <NUM> that is smaller than that in the extended configuration depicted in <FIG>. Moreover, the transversal distance D in the extended configuration of <FIG> is greater than a width W1 (<FIG>) of the trailer C along the transversal axis T to allow the actuators <NUM> to be operated without being impeded by the trailer C. Moreover, in the retracted configuration, the transversal distance D between the actuators <NUM> is such that the actuators <NUM> do not protrude beyond the flatbed portion B of the trailer C for ease of transportation. This can be appreciated by looking at <FIG> that shows that the four actuators <NUM> are contained within the width W1 of the trailer C. In other words, in the transport configuration, the PATS <NUM> is contained within a footprint of the flatbed portion B of the trailer C. This may ensure that a width of the PATS <NUM> does not protrude beyond the width W1 of the trailer C for ease of transportation on public roads.

The outriggers <NUM> are moved from their retracted configuration illustrated in <FIG> to their extended configuration shown in <FIG> when it is required to remove the PATS <NUM> from the trailer C. The actuators <NUM> are actuated to lift the support frame <NUM> off the bed portion B of the trailer C until the support frame <NUM> is sufficiently high to clear the trailer C. At which point, the trailer C is rolled away from underneath the support frame <NUM> and the actuators <NUM> may be operated to decrease the height of the support frame <NUM> until the support frame <NUM> is laid on the ground G.

Referring now to <FIG>, another embodiment of a portable attitude test stand is shown at <NUM>. For the sake of conciseness, only elements that differ from the test stand <NUM> of <FIG> are described herein below.

The pitch frame <NUM> of this second embodiment of the PATS <NUM> has two shaft portions, as for the pitch frame <NUM> of <FIG>. However, the two shaft portions of the pitch frame <NUM> are of the same length instead of being of different length.

In the embodiment shown, the lifting system <NUM> includes four pivotable outriggers <NUM> each pivotably mounted to a respective one of the four vertical frame members <NUM> of the support frame <NUM>. The four pivotable outriggers <NUM> are pivotable about respective pivot axes PA each being parallel to the vertical axis V. The pivotable outriggers <NUM> are pivotable between an extended configuration shown in <FIG> and a retracted configuration shown in <FIG>. In the retracted configuration, the pivotable outriggers <NUM> lay parallel and adjacent to the longitudinal frame members 62a of the support frame <NUM>.

Any suitable means used to pivot the pivotable outriggers <NUM> are contemplated without departing from the scope of the present disclosure. For instance, the pivotable outriggers <NUM> may be manually moved by a user. Stoppers <NUM> (<FIG>) are used to limit rotation of the outriggers <NUM> when said outriggers <NUM> define an angle of about <NUM> degrees with the longitudinal frame members 62a of the support frame <NUM>. Locking pins may be engage the stoppers <NUM> to lock the pivotable outriggers <NUM> into their extended configuration.

Referring to <FIG>, the cable management system <NUM> includes an inner annular wall <NUM> and an outer annular wall <NUM>. The inner annular wall <NUM> is secured to the roll cage <NUM> for rotation therewith upon movements of the engine <NUM> about the roll axis R (<FIG>). The outer wall <NUM> is secured to the pitch frame <NUM> and extends around the inner wall <NUM>. The roll cage <NUM> is rotatable relative to the outer wall <NUM> of the cable management system <NUM>. Cables C4 are secured at first ends to the inner wall <NUM> and at their opposite second ends to the outer wall <NUM>. An excess length of cable is contained between the inner and outer walls <NUM>, <NUM> such that, in use, when the roll cage <NUM> rotates, the first ends of the cables C4 are movable relative to the second ends to follow movements of the roll cage <NUM>. In the embodiment shown, the lengths of the cables C4 contained between the inner and outer walls <NUM>, <NUM> are such that the first ends of the cables C4 may be located diametrically opposed to their second ends to allow the engine <NUM> to rotate by <NUM> degrees.

The cable management system <NUM> further includes cables C5, C6 on opposite sides of the pitch frame <NUM> each being partially wrapped around shaft members of the pitch frame <NUM>. This system allows the cables C5, C6 to follow pitching movements of the pitch frame <NUM> as explained above with reference to <FIG>.

As shown more particularly on <FIG>, a cable guide <NUM> is secured to the pitch frame <NUM> and is used for supporting cables (not shown) connecting the cables C6 to the cables C4.

Referring more particularly to <FIG>, the cable management system <NUM> further includes a front inner annular wall <NUM> and a front outer annular wall <NUM>. The front inner annular wall <NUM> is secured to the roll cage <NUM> for rotation therewith upon movements of the engine <NUM> about the roll axis R (<FIG>). The front outer annular wall <NUM> is secured to the pitch frame <NUM>. As explained above, cables C7 (<FIG>) has a first end secured to the front inner annular wall <NUM> and a second end secured to the front outer annular wall <NUM>. An excess length of cable is contained between the two front annular walls <NUM>, <NUM> to allow movements of the roll cage <NUM> relative to the pitch frame <NUM>. The cable located between the front annular walls <NUM>, <NUM> may be connected to the cables C6 that are wrapped around one of the two shaft portions of the pitch frame <NUM>. In the embodiment shown, the cables C4 and C5 are used for connecting measuring instruments whereas the cables C6 and the cables C7 contained between the front annular walls <NUM>, <NUM> are used for power. Separating the instrument cables C4, C5 and the power cables C6, C7 may avoid exposing the instrument cables C4, C5 to a magnetic field generated by the power cables C6, C7. This may avoid faulty measurements.

Referring more particularly to <FIG>, the PATS <NUM> includes two carriages <NUM> and two actuators <NUM> used to carry the pitch frame <NUM> and roll cage <NUM> up and down along the vertical frame members <NUM> of the support frame <NUM>.

In the embodiment shown, each of the two actuators <NUM> includes a threaded rod <NUM> disposed between two corresponding ones of the four vertical frame members <NUM> of the support frame <NUM>, a motor <NUM> (e.g., electric motor) secured to the support frame <NUM>, on top of the vertical frame members <NUM> in the embodiment shown, a gearbox <NUM> drivingly engaged to the motor <NUM> and secured to the support frame <NUM>, and a threaded member <NUM> threadingly engaged to the threaded rod <NUM> and connected to the carrier <NUM>. In the present embodiment, the threaded rods are pivotable about respective central axes CA.

Each of the two motors <NUM> is in driving engagement with a respective one of the two threaded rods <NUM> via the gearboxes <NUM>. Upon actuation, the motors <NUM> transmit rotational inputs to the threaded rods <NUM> that are threadingly engaged with the threaded members <NUM>. Rotation of the threaded rods <NUM> induces translation of the threaded members <NUM> and of the carriages <NUM> along the central axes CA of the threaded rods <NUM> to change a height of the pitch frame <NUM>, roll cage <NUM>, and engine <NUM> secured within the roll cage <NUM> as discussed herein above. The motors <NUM>, the threaded rods <NUM>, and the threaded members <NUM> act as actuators to lift the test cell. Any other suitable actuators may be used without departing from the scope of the present disclosure.

As shown in <FIG>, each of the carriages <NUM> has a step motor <NUM> secured thereto. As described above with reference to <FIG>, the step motors <NUM> are used to rotate the pitch frame <NUM> about the pitch axis P (<FIG>) of the engine <NUM>.

In the embodiment shown, each of the vertical frame members <NUM> has a rail 164a secured thereto. The two carriages <NUM> have pulleys <NUM> rotatably mounted thereto. The pulleys <NUM> are rollingly engaged to the rails 164a of the vertical frame members <NUM> to allow smooth upward and downward motions of the carriages <NUM> relative to the support frame <NUM>.

Still referring to <FIG>, the PATS <NUM> includes an air conduit AC connectable to an air starter (not shown) of the gas turbine engine <NUM> and to a source of compressed air. The air conduit AC is therefore used for starting the gas turbine engine <NUM> for carrying the attitude test.

As shown in <FIG>, the PATS <NUM> includes two actuated locking pins <NUM> secured on top of the vertical frame members <NUM> The locking pins <NUM> may be actuated upon the PATS <NUM> in its test configuration to lock the carriages <NUM> relative to the vertical frame members <NUM> of the support frame <NUM> for safety purposes.

Referring now to <FIG>, another embodiment of a PATS is shown at <NUM>. The PATS <NUM> includes the test cell TC secured to the support frame <NUM> via two carriages <NUM>. The support frame <NUM> includes a base <NUM> mountable on the flat bed portion B of the trailer C and two vertical members <NUM> protruding from the base <NUM>. Each of the two carriages <NUM> defines an opening slidably receiving a respective one of the two vertical members <NUM> of the support frame <NUM>. Any suitable actuators may be used to engage the vertical frame members <NUM> to the carriages <NUM> to move the test cell TC between the transport and test heights. Rack and pinion gears may for instance be used.

The disclosed PATS <NUM>, <NUM>, <NUM> may improve ergonomics by allowing operators to work at ground level, as well as, year round testing in more favorable climates. The PATS <NUM>, <NUM>, <NUM> may be deployable on suitable airport properties. The PATS <NUM>, <NUM>, <NUM> may be capable to test gas turbine engines of any kind (e.g., turbofan, turboshaft, turboprop, auxiliary power unit).

The disclosed PATS <NUM>, <NUM>, <NUM> may secure, maintain and enhance attitude testing capabilities. Full engine testing, improved ergonomics, engine access and handling, simultaneous pitch and roll motion and year round operation may be possible with the disclosed PATS <NUM>, <NUM>, <NUM>. The disclosed PATS <NUM>, <NUM>, <NUM>, by being movable, may address the risks associated with the non-movable facilities noise emissions, environment health and safety issues, and equipment obsolescence.

The PATS <NUM>, <NUM>, <NUM> may remain assembled for transport. The PATS <NUM>, <NUM>, <NUM> may offer ease of mobility to transport to different sites within North America. Cranes and/or heavy lifting equipment are not required to setup the PATS <NUM>, <NUM>, <NUM>.

It will be appreciated that the PATS <NUM>, <NUM> may be secured to the trailer C and may remain on the trailer C during the attitude test. In some cases, when the PATS <NUM>, <NUM> remain on the trailer C during testing, actuators, such as hydraulic actuators, may extend laterally from the trailer to lift the trailer C, and the PATS <NUM>, <NUM> off the ground during testing for increased stability.

For preparing the aircraft engine <NUM> for the attitude test, the trailer C and the portable attitude test stand (PATS) <NUM>, <NUM>, <NUM> mounted on the trailer C are transported from a first site to a second site. The test cell TC of the PATS <NUM>, <NUM>, <NUM> has a transport height during the transporting. At the second site, the height of the test cell TC of the PATS <NUM>, <NUM>, <NUM> is increased from the transport height to the test height greater than the transport height. The test height is selected to allow pitch movements of the aircraft engine <NUM>, 10a.

Claim 1:
A portable attitude test stand (PATS) (<NUM>; <NUM>; <NUM>) for an aircraft engine (<NUM>; 10a), comprising:
a support frame (<NUM>; <NUM>; <NUM>) mountable on a trailer (C) of a road vehicle;
a test cell (TC) supported by the support frame (<NUM>; <NUM>; <NUM>) and sized to receive the aircraft engine (<NUM>; 10a), the test cell (TC) operable to rotate the aircraft engine (<NUM>; 10a) about a pitch axis (P) and a roll axis (R) of the aircraft engine (<NUM>; 10a); characterised in that it further comprises
an actuator (<NUM>; <NUM>) operatively connected to the test cell (TC) and to the support frame (<NUM>; <NUM>; <NUM>), the actuator (<NUM>; <NUM>) operable to lower and raise the test cell (TC) relative to the support frame (<NUM>; <NUM>; <NUM>) between a transport configuration in which the test cell (TC) has a transport height (H1) and a test configuration in which the test cell (TC) has a test height (H2), the test height (H2) being greater than the transport height (H1), wherein
the support frame (<NUM>; <NUM>; <NUM>) includes a base (<NUM>; <NUM>) and vertical members (<NUM>; <NUM>; <NUM>) protruding from the base (<NUM>; <NUM>), two carriages (<NUM>, <NUM>'; <NUM>; <NUM>) movably engaged to the vertical members (<NUM>; <NUM>; <NUM>) of the support frame (<NUM>; <NUM>; <NUM>), the test cell (TC) supported by the support frame (<NUM>; <NUM>; <NUM>) via the carriages (<NUM>, <NUM>'; <NUM>; <NUM>), the carriages (<NUM>, <NUM>'; <NUM>; <NUM>) movable relative to the vertical members (<NUM>; <NUM>; <NUM>) to vary the height of the test cell (TC) between the test height (H2) and the transport height (H1).