This invention relates generally to gas turbine engines and more particularly, to valve assemblies used to regulate fluid flow for a gas turbine engine. 
Gas turbine engines typically include an engine casing that extends circumferentially around a compressor, and a turbine including a rotor assembly and a stator assembly.  Within at least some known engines, a plurality of ducting and valves coupled to an exterior surface of the casing are used to channel fluid flow from one area of the engine for use within another area of the engine.  For example, such ducting and valves may form a portion of an environmental control system (ECS). 
At least some known valve assemblies are used to control fluid flow that is at a high temperature and/or high pressure.  Such valve assemblies include a substantially cylindrical valve body that is coupled between adjacent sections of ducting.  The valve body includes a valve sealing mechanism that is selectively positionable to control fluid flow through the valve.  More specifically, at least some known valves includes a piston/cylinder arrangement that is positioned external to the valve body and is coupled to the valve sealing mechanism to provide the motive force necessary to selectively position the valve sealing mechanism. 
Because the piston/cylinder arrangement is offset from the main valve body, a center of gravity of the valve assembly is typically displaced a distance from a centerline axis of the valve body.  Such an eccentric center of gravity may induce bending stresses into the valve assembly, adjoining tubing, and supporting brackets during engine operation.  Depending on the application, the physical size and weight of the piston/cylinder arrangement may also present difficulties during the duct routing phase of the engine design. 
In one aspect, a method for operating a gas turbine engine is provided.  The method comprises directing fluid flow from a source into an inlet of a valve, channeling the fluid flow entering an inlet portion of the valve towards an outlet portion of the valve such that a direction of the fluid flow is changed within the inlet portion, and controlling the amount of fluid flow entering the outlet portion of the valve by selectively positioning a valve disk coupled within the inlet portion of the valve by a valve disk axle.  The method also comprises channeling the fluid flow from the inlet portion of the valve through the outlet portion of the valve and into a fluid supply pipe, wherein the valve outlet portion has a substantially right cylindrical shape such that a direction of fluid entering the body outlet portion remains substantially constant therethrough. 
In another aspect of the invention, a valve for use with a gas turbine engine is provided.  The valve comprises a valve body including a valve inlet portion and an outlet portion.  The inlet portion extends from an inlet to the body outlet portion.  The body outlet portion forms a substantially right cylinder that extends from the inlet portion to a valve outlet, such that a direction of fluid flowing within the body outlet portion remains substantially unchanged between the body inlet portion and the valve outlet.  The inlet portion includes a valve disk and at least one bend formed between the body outlet portion and the valve inlet such that a direction of fluid entering the valve body through the valve inlet is changed prior to entering the body outlet portion.  The valve disk is pivotally coupled within the inlet portion for controlling fluid flow through the valve. 
In a further aspect, a gas turbine engine is provided.  The engine includes a fluid supply pipe a valve configured to regulate an amount of fluid flow entering the fluid supply pipe.  The valve includes a valve body comprising an inlet, an outlet, an inlet portion, and an outlet portion.  The inlet portion extends between the inlet and the outlet.  The outlet portion extends between the inlet portion and the outlet.  The outlet portion has a substantially right cylindrical shape such that a direction of fluid entering the body outlet portion remains substantially constant therethrough.  The inlet portion includes a valve disk and at least one bend formed between the inlet and the body outlet portion, such that a direction of fluid flowing through the body inlet portion is changed prior to entering the outlet portion.  The valve disk is used to control fluid flow through the valve into the fluid supply pipe.