Detailed Action
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 11/20/2025 has been entered on 12/30/2025.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 16 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claim 16, because the aerodynamic turning surface that is not disposed between the first secondary fan and the second secondary fan claimed in claim 1 is interpreted as at least one of a stator vane and an additional secondary fan in light of the specification, it is unclear whether claim 16 means i) the aerodynamic turning surface claimed in claim 1 is a stator vane; or ii) in addition to the aerodynamic turning surface, which is interpreted as additional secondary fan, no stator vane is also disposed between the first secondary fan and the second secondary fan.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-8, 15-16, 18-20, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Ostdiek 20210108597 in view of Johnson 4064692 and DiPietro, Jr. 6339927.
Regarding claim 1, Ostdiek teaches the invention as claimed: A gas turbine engine (Fig. 1) defining a radial direction (a direction perpendicular to engine axis 11, see Fig. 1) an a longitudinal centerline (engine axis 11, see Fig. 1) comprising:
a turbomachine (10, see Fig. 1) comprising a compressor section (45 and 27), a combustion section (28), and a turbine section (50 and 29) arranged in serial flow order (see Fig. 1), the turbomachine defining an engine inlet (70) to an inlet duct (annotated Fig. 1), a fan duct inlet (73) to a fan duct (annotated Fig. 1), and a core inlet (72) to a core duct (where 45, 27, 28, 29 and 50 are, see Fig. 1);
a primary fan (21) drivingly coupled to the turbomachine (10, via gearbox 60 see Fig. 1), wherein the primary fan (21) is unducted (see Fig. 1); and
a secondary fan assembly (formed by a single rotor stage 40) disposed downstream of the primary fan (21) within the inlet duct (71, see Fig. 1), wherein the secondary fan assembly comprises:
a single secondary fan (40) drivingly coupled to the turbomachine (the low pressure compressor 45 part and the low pressure turbine 50 part, see Fig. 1 and [0043]), each blade of the single secondary fan including a root (where letter “E” is in Fig. 1) proximate to the longitudinal centerline (11, see Fig. 1) and a tip (where letter F is marked in Fig. 1) opposite the root (where letter “E” is, see Fig. 1);
wherein each blade of the single secondary fan (40) is drivingly coupled to the turbomachine (the low pressure compressor 45 part and the low pressure turbine 50 part, see Fig. 1 and [0043]) via the root (where letter “E” is, see Fig. 1).
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Ostdiek does not teach said secondary fan assembly comprising a plurality of secondary fans, and the plurality of secondary fans comprising a first secondary fan and a second secondary fan, such that
the first secondary fan drivingly coupled to the turbomachine in a first rotational direction, each blade of the first secondary fan including a first root proximate to the longitudinal centerline and a first tip opposite the first root; and the second secondary fan drivingly coupled to the turbomachine in a second rotational direction, each blade of the second secondary fan including a second root proximate to the longitudinal centerline and a second tip opposite the second root; wherein each blade of the first secondary fan is drivingly coupled to the turbomachine via the first root, and each blade of the second secondary fan is drivingly coupled to the turbomachine via the second root; wherein the first secondary fan is the most upstream fan of the secondary fan assembly.
However, Johnson teaches a gas turbine engine (Fig. 7) comprising: a primary fan (66) drivingly coupled to the turbomachine (10, see Fig. 7); and a secondary fan assembly (62) disposed downstream of the primary fan (66) within the inlet duct (where rotors 71-72 are, see Fig. 7), wherein the secondary fan assembly comprises a plurality of secondary fans (71-72 in Fig. 7 and per col. 6, ll. 35-45, the secondary fan assembly may be formed by a single secondary fan or a plurality of secondary fans), and the plurality of secondary fans comprises:
a first secondary fan (71) drivingly coupled to the turbomachine (the low pressure turbine 16 part, see Fig. 7) in a first rotational direction (the rotational direction of 71), each blade of the first secondary fan (each blade of 71) including a first root (annotated Fig. 7) proximate to the longitudinal centerline (see annotated Fig. 7) and a first tip (annotated Fig. 7) opposite the first root (annotated Fig. 7); and
a second secondary fan (72) drivingly coupled to the turbomachine (the low pressure turbine 16 part, see Fig. 7) in a second rotational direction (the rotational direction of 72), each blade of the second secondary fan (each blade of 72) including a second root (annotated Fig. 7) proximate to the longitudinal centerline (see annotated Fig. 7) and a second tip (annotated Fig. 7) opposite the second root (annotated Fig. 7);
wherein each blade of the first secondary fan (each blade of 71) is drivingly coupled to the turbomachine (the low pressure turbine 16 part, see Fig. 7) via the first root (see annotated Fig. 7), and each blade of the second secondary fan (each blade of 72) is drivingly coupled to the turbomachine (the low pressure turbine 16 part, see Fig. 7) via the second root (see annotated Fig. 7);
wherein the first secondary fan (71) is the most upstream fan of the secondary fan assembly (62, see Fig. 7).
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It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention to modify Ostdiek with Johnson’s secondary fan assembly comprising a plurality of secondary fans that comprises a first secondary fan and a second secondary fan, such that
a first secondary fan drivingly coupled to the turbomachine in a first rotational direction, each blade of the first secondary fan including a first root proximate to the longitudinal centerline and a first tip opposite the first root; and a second secondary fan drivingly coupled to the turbomachine in a second rotational direction, each blade of the second secondary fan including a second root proximate to the longitudinal centerline and a second tip opposite the second root; wherein each blade of the first secondary fan is drivingly coupled to the turbomachine via the first root, and each blade of the second secondary fan is drivingly coupled to the turbomachine via the second root; wherein the first secondary fan is the most upstream fan of the secondary fan assembly
in order to obtain/alter a desired configuration by adding additional fans to the aft fan section, i.e., the claimed secondary fan assembly, (Johnson, col. 6, ll. 40-44).
Ostdiek in view of Johnson does not teach the second rotational direction opposite the first rotational direction, and wherein the second secondary fan is adjacent the first secondary fan such that no aerodynamic turning surface is disposed therebetween.
However, DiPietro, Jr. teaches a fan assembly (36 in Fig. 1) comprises: a first fan (18) drivingly coupled to the turbomachine (at a stage 22 of turbine 38 of turbomachine 10, see Fig. 1) in a first rotational direction (the rotational direction of 18), a second fan (27) drivingly coupled to the turbomachine (at a stage 14 of turbine 38 of turbomachine 10, see Fig. 1) in a second rotational direction (the rotational direction of 27) opposite the first rotational direction (col. 3, ll. 8-20 and ll. 40-55); and wherein the second fan (27) is adjacent the first fan (18) such that no aerodynamic turning surface (no additional fan or stator) is disposed therebetween (see Fig. 1 and col. 1, ll. 25-42).
It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention to modify the secondary fan assembly of Ostdiek in view of Johnson with DiPietro, Jr.’s teaching of counter-rotating two fans in a fan assembly, such that
the second rotational direction opposite the first rotational direction, and wherein the second secondary fan is adjacent the first secondary fan such that no aerodynamic turning surface is disposed therebetween (the modification is to counter-rotate the first secondary fan of Ostdiek in view of Johnson and the second secondary fan of Ostdiek in view of Johnson comprised by the secondary fan assembly of Ostdiek as taught by DiPietro, Jr., and thus, any structures/components that is required to perform said counter-rotation is inherently applied in said modification)
because by counter-rotating two fans, no stationary blade rows is needed between the two counter-rotating fans and between the turbine stages that drives the two counter-rotating fans, which can reduce module length and weight, reduce manufacturing and maintenance cost, and improve aerodynamic performance and efficiency (DiPietro, Jr., col. 1, ll. 18-40).
Regarding claim 2, Ostdiek further teaches wherein the inlet duct (annotated Fig. 1) comprises a splitter (annotated Fig. 1) separating the fan duct inlet (73) from the core inlet (72), wherein the splitter (annotated Fig. 1) is disposed downstream of the secondary fan assembly (where the inlet duct is, see annotated Fig. 1).
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Regarding claim 3, Ostdiek teaches comprising a core cowl (76) enclosing at least a portion of the turbomachine (10, see Fig. 1), the core cowl comprising a leading edge (the distal end of core cowl 76, see annotated Fig. 1) that at least in part defines the splitter (annotated Fig. 1).
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Regarding claim 4, Ostdiek in view of Johnson and DiPietro, Jr. further teaches a first shaft (DiPietro, Jr.’s 12 in DiPietro, Jr.’s Fig. 1) drivingly coupled to the turbomachine (at DiPietro, Jr.’s stage 14 of Ostdiek’s low pressure turbine 50; because as taught by DiPietro, Jr.’s Fig. 1 and col. 3, ll 45-55, in order to counter-rotate Johnson’s first secondary fan 71, the turbine that drives the two counter-rotating fans needs to comprising two counter-rotating stages, i.e., DiPietro, Jr.’s stage 14 and stage 22; therefore the modification of Ostdiek in view of Johnson and DiPietro, Jr. requires Ostdiek’s low pressure turbine 50 that drives the secondary fan assembly as taught by Ostdiek’s Fig. 1 and [0043], which comprises Johnson’s first secondary fan 71 and Johnson’s second secondary fan 72 as taught by Johnson’s Fig. 7, to include DiPietro, Jr.’s stage 14 to counter-rotate Johnson’s first secondary fan 71 and DiPietro, Jr.’s stage 22 to counter-rotate Johnson’s second secondary fan 72) and driving the first secondary fan (Johnson’s first secondary fan 71 as taught by Johnson’s Fig. 7, which is counter-rotating as taught by DiPietro, Jr.’s first fan 18 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) in the first rotational direction (the rotational direction of DiPietro, Jr.’s 18, see DiPietro, Jr.’s col. 3, ll. 8-20 and ll. 40-55); and
a second shaft (DiPietro, Jr.’s 20 in DiPietro, Jr.’s Fig. 1) drivingly coupled to the turbomachine (at DiPietro, Jr.’s stage 22 of Ostdiek’s low pressure turbine 50; see the teaching as explained above) and driving the second secondary fan (Johnson’s second secondary fan 72 as taught by Johnson’s Fig. 7, which is counter-rotating as taught by DiPietro, Jr.’s second fan 27 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) in the second rotational direction (the rotational direction of DiPietro, Jr.’s 27 opposite to the rotational direction of DiPietro, Jr.’s 18, see DiPietro, Jr.’s col. 3, ll. 8-20 and ll. 40-55).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
Regarding claim 5, Ostdiek in view of Johnson and DiPietro, Jr. further teaches wherein the first shaft (DiPietro, Jr.’s 12 in DiPietro, Jr.’s Fig. 1) is concentric with (as taught by DiPietro, Jr.’s Fig. 1 and col. 3, ll. 12-18) the second shaft (DiPietro, Jr.’s 20 in DiPietro, Jr.’s Fig. 1).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
Regarding claim 6, Ostdiek in view of Johnson and DiPietro, Jr. further teaches wherein the first shaft (DiPietro, Jr.’s 12 in DiPietro, Jr.’s Fig. 1) is further configured to drive the primary fan (Ostdiek’s 21 in Ostdiek’s Fig. 1; per Ostdiek’s [0063 and 0068], Ostdiek’s low pressure turbine 50 in Ostdiek’s Fig. 1 may comprise two counter-rotating stages that each drives a respective LP shaft, wherein both of the two respective LP shafts drive Ostdiek’s secondary fan assembly and Ostdiek’s primary fan 21, e.g., the configuration as shown in Ostdiek’s Fig. 11, and thus, Ostdiek’s [0063 and 0068] and Fig. 11 teaches both of the two counter-rotating shafts, i.e., DiPietro, Jr.’s first shaft 12 and DiPietro, Jr.’s second shaft 20 drive the Ostdiek’s primary fan 21, which read on the claim limitation).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
Regarding claim 7, Ostdiek in view of Johnson and DiPietro, Jr. further teaches wherein the second shaft (DiPietro, Jr.’s 20 in DiPietro, Jr.’s Fig. 1) is disposed circumferentially about (as taught by DiPietro, Jr.’s Fig. 1 and col. 3, ll. 12-18) the first shaft (DiPietro, Jr.’s 12 in DiPietro, Jr.’s Fig. 1).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
Regarding claim 8, Ostdiek further teaches a third shaft (26) drivingly coupled to a high pressure turbine (29) and a high pressure compressor (27, see Fig. 1).
Regarding claim 15, Ostdiek in view of Johnson and DiPietro, Jr. further teaches wherein the first secondary fan (Johnson’s first secondary fan 71 as taught by Johnson’s Fig. 7 that counter-rotates as taught by DiPietro, Jr.’s 18 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) is the most upstream fan of the secondary fan assembly and defines a radial span (the first second fan that is Johnson’s 71 as taught by Johnson’s Fig. 7 and DiPietro, Jr.’s 18 as taught by DiPietro, Jr.’s Fig. 1 is the most upstream fan comprised by Ostdiek’s secondary fan assembly that located at Ostdiek’s inlet duct as marked in Ostdiek’s annotated Fig. 1 in claim 1; thus, a radial span of the first secondary fan is defined as Ostdiek’s radial distance between letter F and letter E in Ostdiek’s Fig. 1).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
It is noted that Ostdiek in view of Johnson and DiPietro, Jr. teaches all the structures of the first secondary fan resulting in the claimed radius ratio.
Ostdiek in view of Johnson and DiPietro, Jr. does not teach a radius ratio of said first secondary fan being 0.2 to 0.9.
However, Ostdiek further teaches the radius span of the most upstream fan (radial distance between E-F in Fig. 1) of the secondary fan assembly (located at Ostdiek’s inlet duct as marked in Ostdiek’s annotated Fig. 1 in claim 1) is variable and can be tailored to provide the desired engine operating characteristics at desired flight and operating conditions ([0064]), wherein said operating conditions comprising a desired thrust split between the primary fan (21, i.e., the unducted fan per [0066]) and the secondary fan assembly (located at Ostdiek’s inlet duct as marked in Ostdiek’s annotated Fig. 1 in claim 1, i.e., the ducted fan per [0066]), and the secondary fan assembly (located at Ostdiek’s inlet duct as marked in Ostdiek’s annotated Fig. 1 in claim 1) can produce between 60% thrust and a few percent of the total thrust ([0066]).
A particular parameter is a result-effective variable when the variable is known to achieve a recognized result. See In re Antonie, 559 F.2d 618, 620, 195 USPQ 6,8 (CCPA 1977). Therefore, an ordinary skilled worker would recognize that the radial span of the most upstream fan of the secondary fan assembly, i.e., the radius ratio of the claimed first secondary fan, is a results-effective variable that controls the thrust produced by the secondary fan assembly. Thus, the claimed limitation of a radius ratio of the first secondary fan being 0.2 to 0.9 is found to be an obvious optimization of the prior art obtainable by an ordinary skilled worker through routine experimentation.
Further, it appears that one of ordinary skill in the art would have had a reasonable expectation of success in modifying the first secondary fan of the secondary fan assembly of Ostdiek in view of Johnson and DiPietro, Jr. to have the radius ratio being 0.2 to 0.9, as it involves only adjusting the radial span of the most upstream fan, i.e., the claimed first secondary fan, disclosed to require adjustment.
"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation", In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). The presence of a known result-effective variable would be a motivation for a person of ordinary skill in the art to experiment to reach another workable product or process. See KSR; MPEP 2144.05(II)(B).
Therefore, it would have been obvious to one of ordinary skill in the art at the time of effective filing to modify the invention of Ostdiek in view of Johnson and DiPietro, Jr., such that the first secondary fan defines a radius ratio of being 0.2 to 0.9 in order to provide the desired engine operating characteristics at desired flight and operating conditions (Ostdiek, [0064]).
Regarding claim 16, Ostdiek in view of Johnson and DiPietro, Jr. further teaches wherein the first secondary fan (Johnson’s first secondary fan 71 as taught by Johnson’s Fig. 7, which is counter-rotating as taught by DiPietro, Jr.’s 18 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) and the second secondary fan (Johnson’s second secondary fan 72 as taught by Johnson’s Fig. 7, which is counter-rotating as taught by DiPietro, Jr.’s 27 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) are adjacently arranged such that no stator vane is disposed therebetween (as taught by DiPietro, Jr.’s Fig. 1 and col. 1, ll. 25-42).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
Regarding claim 18, Ostdiek in view of Johnson and DiPietro, Jr. further teaches wherein the turbine section (Ostdiek’s low pressure turbine 50) of the turbomachine comprises a first turbine stage (DiPietro, Jr.’s stage 14; because as taught by DiPietro, Jr.’s Fig. 1 and col. 3, ll 45-55, in order to counter-rotate Johnson’s first secondary fan 71, the turbine that drives the two counter-rotating fans needs to comprising two counter-rotating stages, i.e., DiPietro, Jr.’s stage 14 and stage 22; therefore the modification of Ostdiek in view of Johnson and DiPietro, Jr. requires Ostdiek’s low pressure turbine 50 that drives the secondary fan assembly as taught by Ostdiek’s Fig. 1 and [0043], which comprises Johnson’s first secondary fan 71 and Johnson’s second secondary fan 72 as taught by Johnson’s Fig. 7, to include DiPietro, Jr.’s stage 14 to counter-rotate Johnson’s first secondary fan 71 and DiPietro, Jr.’s stage 22 to counter-rotate Johnson’s second secondary fan 72) and a second turbine stage (DiPietro, Jr.’s stage 22; see the teaching as explained above) arranged adjacently such that no stator vane is disposed therebetween (as taught by DiPietro, Jr.’s Fig. 1 and col. 1, ll. 25-42).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
Regarding claim 19, Ostdiek in view of Johnson and DiPietro, Jr. further teaches wherein the first turbine stage (DiPietro, Jr.’s stage 14) drives the first secondary fan (Johnson’s first secondary fan 71 as taught by Johnson’s Fig. 7, which is counter-rotating as taught by DiPietro, Jr.’s 18 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) in the first rotational direction (the rotational direction of DiPietro, Jr.’s 18, see DiPietro, Jr.’s col. 3, ll. 8-20 and ll. 40-55) and the second turbine stage (DiPietro, Jr.’s stage 22) drives the second secondary fan (Johnson’s second secondary fan 72 as taught by Johnson’s Fig. 7, which is counter-rotating as taught by DiPietro, Jr.’s 27 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) in the second rotational direction (the rotational direction of DiPietro, Jr.’s 27 opposite to the rotational direction of DiPietro, Jr.’s 18, see DiPietro, Jr.’s col. 3, ll. 8-20 and ll. 40-55).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
Regarding claim 20, Ostdiek in view of Johnson and DiPietro, Jr. further teaches wherein the primary fan (Ostdiek’s 21 in Ostdiek’s Fig. 1) defines a primary fan radial span (Ostdiek’s radial distance between letter A and letter B in Ostdiek’s Fig. 1) and the first secondary fan (Johnson’s first secondary fan 71 as taught by Johnson’s Fig. 7 that counter-rotates as taught by DiPietro, Jr.’s 18 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) is the most upstream fan of the secondary fan assembly and defines a first secondary fan radial span (the first second fan that is Johnson’s 71 as taught by Johnson’s Fig. 7 and DiPietro, Jr.’s 18 as taught by DiPietro, Jr.’s Fig. 1 is the most upstream fan comprised by Ostdiek’s secondary fan assembly that located at Ostdiek’s inlet duct as marked in Ostdiek’s annotated Fig. 1 in claim 1; thus, a first secondary fan radial span is defined as Ostdiek’s radial distance between letter F and letter E in Ostdiek’s Fig. 1).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
It is noted that Ostdiek in view of Johnson and DiPietro, Jr. teaches all the structures of the primary fan and the first secondary fan resulting in the claimed ratio of a tip radius for the primary fan to a tip radius of the first secondary fan.
Ostdiek in view of Johnson and DiPietro, Jr. does not teach a ratio of a tip radius for said primary fan to a tip radius of said first secondary fan being 2 to 10.
However, Ostdiek further teaches the primary fan radial span (the radial distance between A-B in Fig. 1) of the primary fan (21) and the radial span (the radial distance between E-F in Fig. 1) of the most upstream fan, i.e., the claimed first secondary fan, of the secondary fan assembly are variable and can be tailored to provide the desired engine operating characteristics at desired flight and operating conditions ([0064]), wherein said operating conditions comprising a desired thrust split between the primary fan (21, the unducted fan per [0066]) and the secondary fan assembly (located at Ostdiek’s inlet duct as marked in Ostdiek’s annotated Fig. 1 in claim 1, i.e., the ducted fan per [0066]), and the secondary fan assembly (located at Ostdiek’s inlet duct as marked in Ostdiek’s annotated Fig. 1 in claim 1) can produce between 60% thrust and a few percent of the total thrust ([0066]).
A particular parameter is a result-effective variable when the variable is known to achieve a recognized result. See In re Antonie, 559 F.2d 618, 620, 195 USPQ 6,8 (CCPA 1977). Therefore, an ordinary skilled worker would recognize that the primary fan radial span of the primary fan and the radial span of the most upstream fan of the secondary fan assembly, i.e., a ratio of a tip radius for the primary fan to a tip radius of the first secondary fan of the secondary fan assembly, is a results-effective variable that controls the thrust split between the primary fan and the secondary fan assembly. Thus, the claimed limitation of a ratio of a tip radius for the primary fan and a tip radius for the first secondary fan being 2 to 10 is found to be an obvious optimization of the prior art obtainable by an ordinary skilled worker through routine experimentation.
Further, it appears that one of ordinary skill in the art would have had a reasonable expectation of success in modifying a ratio of a tip radius for the primary fan and a tip radius for the most upstream rotor stage, i.e., the claimed first secondary fan, of Ostdiek in view of Johnson and DiPietro, Jr. being 2 to 10, as it involves only adjusting the primary fan radial span of the primary fan and the radial span of the most upstream rotor stage, i.e., the first secondary fan, disclosed to require adjustment.
"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation", In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). The presence of a known result-effective variable would be a motivation for a person of ordinary skill in the art to experiment to reach another workable product or process. See KSR; MPEP 2144.05(II)(B).
Therefore, it would have been obvious to one of ordinary skill in the art at the time of effective filing to modify the invention of Ostdiek in view of Johnson and DiPietro, Jr., such that a ratio of a tip radius for the primary fan to a tip radius for the first secondary fan being 2 to 10 in order to provide the desired engine operating characteristics at desired flight and operating conditions (Ostdiek, [0064]).
Regarding claim 22, Ostdiek in view of Johnson and DiPietro, Jr. further teaches wherein the first secondary fan (Johnson’s first secondary fan 71 as taught by Johnson’s Fig. 7 that counter-rotates as taught by DiPietro, Jr.’s 18 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) comprises a single stage of first secondary fan blades (see Johnson’s Fig. 7 and col. 6, ll. 30-45 and DiPietro, Jr.’s 18 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55), and wherein the second secondary fan (Johnson’s first secondary fan 72 as taught by Johnson’s Fig. 7 that counter-rotates as taught by DiPietro, Jr.’s 27 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55) comprises a single stage of second secondary fan blades (see Johnson’s Fig. 7 and col. 6, ll. 30-45 and DiPietro, Jr.’s 18 in DiPietro, Jr.’s Fig. 1 and col. 3, ll. 8-20 and ll. 40-55).
The motivation of the modification of Ostdiek in view of Johnson and DiPietro, Jr. is same with reasons cited in the rejection of claim 1 above.
Response to Arguments
Applicant's argument filed 11/20/2025 and entered 13/30/2025 has been fully considered but it is moot because the argument does not apply to the new combination of previously applied references and the new reference being used in the current office action, necessitated by amendment. However, to the extent possible, Applicant's arguments have been addressed above, at the appropriate locations.
Conclusion
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/JINGCHEN LIU/Examiner, Art Unit 3741