for the purposes of promoting an understanding of the principles of the invention , reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same . it will nevertheless be understood that no limitation of the scope of the invention is thereby intended , such alterations and further modifications in the illustrated device , and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates . referring to fig1 there is illustrated a gas turbine engine 20 that includes a compressor 21 , a combustor 22 , and a turbine 23 . the gas turbine engine 20 has been partially cut away to reveal a plurality of blades 24 coupled to a rotor assembly and a plurality of vanes . while the turbine 23 has been shown cut away to expose the blades 24 and vanes 25 , it is known to one of ordinary skill in the art that the compressor 21 also includes a plurality of blades and vanes . unless specified to the contrary , the term airfoil will be used herein to refer to blades and vanes . with reference to fig2 there is illustrated a blade 24 representative of the type used in a gas turbine engine 20 . airfoils in gas turbine engines are typically designed and constructed with internal cooling passages adapted to receive a cooling medium therein . typically , the cooling medium flows through a central cavity 19 within the airflow 24 and is discharged into a plurality of cooling cavities located within the airfoil 24 . in many airfoil designs contemplated herein , the cooling medium is discharged from the plurality of cooling cavities through a series of apertures 18 onto the surface of the airfoil . the present invention is not limited to the formation of cooling passages within a gas turbine engine blade , and is applicable to the formation of cavities within cast components , including but not limited to vanes , bladetracks , platforms and endwalls referring to fig3 there is illustrated a plan view of one embodiment of a ceramic core 30 of the present invention . the ceramic core 30 includes a base portion 31 having a plurality of holes 33 formed therethrough for the receipt of molten metal , and a plurality of upstanding members 32 coupled thereto . in one embodiment a substantially planar plate member defines the base portion 31 , and preferably the base portion 31 has a thickness of about 0 . 02 inches . further , in a preferred embodiment , the base portion 31 has an approximate width indicated by ‘ w ’ of about 0 . 25 inches , and an approximate length indicated by ‘ l ’ of about 0 . 50 inches . however , other geometric shapes and sizes are contemplated herein . the thickness of the base portion 31 being about 0 . 020 inches has been found to be small enough to minimize thermally induced stress in the cast component during the solidification of the molten metal . further , the number of holes 33 formed through the base portion 31 is preferably within the range of about 10 - 40 , and more preferably is about 20 . in one embodiment , the holes have a diameter of about 0 . 030 inches . however , other hole diameters and sizes are contemplated herein . in one embodiment a centerline ‘ z ’ of the plurality of upstanding members 32 is oriented perpendicular to the base portion 31 . in one embodiment the upstanding member is an elongated cylindrical member with a constant nominal diameter of about 0 . 020 inches . however , the selection of the diameter of the upstanding members 32 is a function of the desired fluid flow rate into the cooling cavity , and the diameter may be varied do to concerns associated with clogging of the fluid flow inlet apertures . in one embodiment the plurality of upstanding members are about 0 . 10 inches long . however , in alternate embodiments the upstanding members 32 : have alternative diameters , which may vary over the length of the member ; lengths , which can vary between different members on the same casting core ; cross sectional shapes , which can be round , oval , eliptical , and , are oriented at different angles with respect to the base portion . however , other geometric cross - sections and angles are contemplated herein . in one embodiment the plurality of upstanding members 32 are mechanically connected to the base portion 31 by a fusion process , such as but not limited to a laser processing operation or a torch melting operation . in another embodiment the casting core is formed by a gel casting process in which the core is subsequently sintered . further , in another embodiment , the core is an injection molded fused silica core . the number of upstanding members 32 is preferably within a range of about 7 - 8 , and more preferably is about 6 . in one embodiment , the ceramic casting core 30 is preferably formed of a fused silica material , having a density of about 36 . 2 × 10 3 lbs / cm 3 . alternate ceramic materials having different densities are contemplated herein . the material of the ceramic casting core is capable of being removed by leaching after the component has been is cast . with reference to fig5 there is illustrated a plurality of casting cores 30 positioned within an investment casting mold assembly 40 . the plurality of casting cores 30 are coupled to a series of inner casting cores 41 , 42 and 43 . the inner casting cores 41 , 42 and 43 in one embodiment are formed of silica . it is understood herein that the number and shape of the inner casting cores will be tailored to fit the design of the particular cast component , and the representative inner cores are not meant to limit the type , number and shape of the inner cores . surrounding the inner casting cores 41 , 42 and 43 is a wax layer 45 . wax layer 45 is preferably formed around the inner casting cores by injection . the plurality of casting cores 30 are positioned on the wax layer 45 and the plurality of upstanding members 32 pass through the wax layer 45 and contact the inner cores . a wax layer 46 is positioned on the outer surface 30 a of the casting core 30 . the assembly is then shelled with a ceramic system to form the outer ceramic casting mold shell 47 . the ceramic shell consists of primary layers for pattern detail , and backup layers for mechanical reinforcement . the layers comprise a slurry portion and a stucco portion . in one embodiment , the slurry portion is formed from a ceramic flour , water and a binder ; and the stucco portion includes a coarse ceramic sand which provides support to the slurry coat . the flour is preferably zircon , and the binder is preferably collidal silica . preferably the ceramic sand is an alumina material having varying particle sizes . with reference to fig6 there is illustrated an enlarged portion of the investment casting mold 40 . the upstanding members 32 are connected to the inner casting core 42 . in one embodiment an end 32 a of the upstanding member 32 is received within a pocket 42 a formed in the inner casting core 42 . in one form the end 32 a is held in place during the casting process by a frictional engagement between the outer surface of the upstanding member 32 and the wall of the pocket 42 a . in one embodiment , the size of the opening to the pocket is about twice the diameter of the end 32 a . in an alternate embodiment the end 32 a is held in place by a high temperature ceramic adhesive . the adhesive is preferably a ceramic adhesive that is removeable by leaching . one example of a ceramic adhesive is cermabond , sold by aremco of valley cottage , n . y . the number and shape of the casting cores 30 is configured to replicate the cooling scheme design within the cast component . the process of casting a component includes the acts of positioning the inner casting cores 41 , 42 and 43 in a predetermined relationship . surrounding the inner casting cores 41 , 42 and 43 with a wax layer 45 . orienting the individual casting cores 30 and passing the ends 32 a of the upstanding member 32 through the wax layer and into the pockets 42 a . in one form the adhesive is delivered by a syringe into the pockets 42 a . placing an additional layer of wax 47 over the outer surface 30 a of the ceramic casting cores . the subassembly is then shelled by a ceramic casting mold shelling system . the ceramic casting mold is now heated to remove the wax and molten metal is introduce into the cavity within the casting mold . as a person of ordinary skill in the art will readily appreciate the wax regions are now metal and the regions where the inner casting cores and ceramic cores were will be voids after the cores are removed . in a subsequent machining operation a series of discharge apertures are formed through the outer surface of the component . the discharge apertures , see fig2 for an example , connect with the inner - cooling cavity formed by the casting core 30 . one method of forming the discharge apertures is with an edm process . while the invention has been illustrated and described in detail in the drawings and foregoing description , the same is to be considered as illustrative and not restrictive in character , it being understood that the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protective .