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 .
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 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.
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 on 28 February 2026 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 20 January 2026 has been entered.
Claim Rejections - 35 USC § 103
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.
Claims 1-8, 10-14, and 16-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over the Aubisque A1 (Jane’s1, Bjorn2. Roux3) in view of Bjorn.
1 Jane’s Aero-Engines, Turbomeca Aubisque. 2009, HIS (Global) Limited
2 Bjorn Fehrm, Bjorn’s Corner: New engine development. Part 4. Propulsive efficiency, 19 April 2024, Leeham News and Analysis, https://leehamnews.com/2024/04/19/bjorns-corner-new-engine-development-part-4-propulsive-efficiency/
3 Elodie Roux, Turbofan and Turbojet Engines: Database Handbook, 2007, Editions Elodie Roux, GE-1019.004, p.78
Regarding claim 1, the Aubisque teaches a gas turbine engine (Turbomeca Aubisque engine of Figure 1 of Bjorn is an Aubisque 1A used on the Saab 105 jet per Bjorn’s Fig 1 caption on pp.1-2, and as also taught by Jane’s, p.2 para.2 of the Overview) comprising:
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a core (incl. compressor, combustor, turbine per Fig 1 above);
a nacelle (Fig 1 above) at least partially surrounding the core (Fig 1);
a flow bypass channel (Fig 1 above) defined between an inner surface of the nacelle and an outer surface of the core (Fig 1);
an axial shaft (multi-piece shaft, Fig 1 above) extending along a major axis of the core (Fig 1);
a fan (Fig 1 above) positioned at a leading end of the axial shaft (Fig 1);
a reduction gear assembly (Fig 1 above) coupling the fan to the axial shaft Fig 1);
a compressor (Fig 1 above) directly coupled to the axial shaft and positioned downstream relative to the fan (Fig 1);
a combustion chamber (Fig 1 above) defined by the core downstream from the compressor (Fig 1);
a turbine (Fig 1 above) directly coupled to the axial shaft and positioned downstream relative to the combustion chamber (Fig 1),
wherein the reduction gear assembly functions to reduce rotation of the fan relative to the axial shaft to effectively drive air through the flow bypass channel (Fig 1; last para. of p.4), and
wherein the reduction gear assembly provides a net gear ratio of 2.13 (Jane’s, p.2, section titled Fan); and
wherein the fan, the compressor, and the turbine are all mechanically coupled to the same single axial shaft, such that the gas turbine engine is a single-spool engine (Fig 1).
The Aubsique further teaches a fan speed of 15,245rpm at takeoff (T-O) and a shaft speed of 33,000rpm at an unidentified operating condition.
The Aubisque does not specifically or directly teach the gear ratio being in the range of “about 8:1 to about 3:1” (which Applicant’s specification teaches may include 2.7 and 8.8, based on the optional interpretations of the term “about”).
However, the gear ratio 2.13 is very close to (i.e. approaches) 2.7, which MPEP2144.05(I) provides establishes a prima facie case of obviousness.
Furthermore, Bjorn further teaches gear ratios upward of 3:1 were known and used for geared turbofans for decoupling the fan speed from the turbine speed (p.3 para.1).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the Aubisque turbofan gear ratio could be increased from 2.13:1 to 3:1 (or at least 2.7) as taught by Bjorn, for example to achieve/accommodate higher speed rotation of the turbine (e.g. up to 45,735rpm), or lower speed rotation of the fan (e.g. down to 10,833rpm), or both (e.g. turbine ≈ 36,692 rpm and fan ≈ 13,590 rpm). Additionally, it has been held that combining or simple substitution of prior art elements according to known methods to yield predictable results renders the limitation obvious (see MPEP 2141 (III)). In this case, increasing the gearbox ratio of the Aubisque from 2.13 to the known gearbox ratio of 3:1 as in Bjorn (or at least 2.7:1) would produce the predictable results of faster/smaller turbine and slower/larger fan. Whereas the turbine might be required to shrink in order to facilitate non-shock-wave operation at faster rpm, the fan may operate at slower speeds without changing diameter. In any case, reducing core/turbine size, increasing turbine speed, and increasing fan diameter (accompanied by slower fan rpm) were all desirable development directions for engines to increase propulsive efficiency (Bjorn, pp.2-3).
Regarding claim 11, the Aubisque teaches a gas turbine engine (Turbomeca Aubisque engine of Figure 1 of Bjorn is an Aubisque 1A used on the Saab 105 jet per Bjorn, p.1-2, Fig 1 caption and as also taught by Jane’s p.2 para.2 of the Overview) comprising:
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a core (incl. compressor, combustor, turbine per Fig 1 above);
a nacelle (Fig 1 above) at least partially surrounding the core (Fig 1);
a flow bypass channel (Fig 1 above) defined between an inner surface of the nacelle and an outer surface of the core (Fig 1);
an axial shaft (multi-piece shaft, Fig 1 above) extending along a major axis of the core (Fig 1);
a fan (Fig 1 above) positioned at a leading end of the axial shaft (Fig 1);
a reduction gear (Fig 1 above) coupling the fan to the axial shaft Fig 1), comprising:
an epicyclic gear train (Fig 1 including at least a sun gear and planet gears);
a compressor (Fig 1 above) directly coupled to the axial shaft and positioned downstream relative to the fan (Fig 1);
a combustion chamber (Fig 1 above) defined by the core downstream from the compressor (Fig 1);
a turbine (Fig 1 above) directly coupled to the axial shaft and positioned downstream relative to the combustion chamber (Fig 1),
wherein the reduction gear assembly functions to reduce rotation of the fan relative to the axial shaft (Fig 1; last para. of p.4),
wherein a diameter of the fan (e.g. tip diameter) is greater than or equal to a diameter of the core (an inlet diameter of the core is smaller than tip diameter of fan), and
wherein the reduction gear assembly provides a net gear ratio of 2.13 (Jane’s p.2 section titled Fan); and
wherein the fan, the compressor, and the turbine are all mechanically coupled to the same single axial shaft, such that the gas turbine engine is a single-spool engine (Fig 1 of Bjorn).
The Aubsique further teaches a fan speed of 15,245rpm at takeoff (T-O) and a shaft speed of 33,000rpm at an unidentified operating condition.
The Aubisque does not specifically or directly teach the gear ratio being in the range of “about 8:1 to about 3:1” (which Applicant’s specification teaches may include 2.7 and 8.8, based on the optional interpretations of the term “about”).
However, the gear ratio 2.13 is very close to (i.e. approaches) 2.7, which MPEP2144.05(I) provides establishes a prima facie case of obviousness.
Furthermore, Bjorn further teaches gear ratios upward of 3:1 were known and used for geared turbofans for decoupling the fan speed from the turbine speed (p.3 para.1).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the Aubisque turbofan gear ratio could be increased from 2.13:1 to 3:1 (or at least 2.7) as taught by Bjorn, for example to achieve/accommodate higher speed rotation of the turbine (e.g. up to 45,735rpm), or lower speed rotation of the fan (e.g. down to 10,833rpm), or both (e.g. turbine ≈ 36,692 rpm and fan ≈ 13,590 rpm). Additionally, it has been held that combining or simple substitution of prior art elements according to known methods to yield predictable results renders the limitation obvious (see MPEP 2141 (III)). In this case, increasing the gearbox ratio of the Aubisque from 2.13 to the known gearbox ratio of 3:1 as in Bjorn (or at least 2.7:1) would produce the predictable results of faster/smaller turbine and slower/larger fan. Whereas the turbine might be required to shrink in order to facilitate non-shock-wave operation at faster rpm, the fan may operate at slower speeds without changing diameter. In any case, reducing core/turbine size, increasing turbine speed, and increasing fan diameter (accompanied by slower fan rpm) were all desirable development directions for engines to increase propulsive efficiency (Bjorn, pp.2-3).
Regarding claim 17, the Aubisque teaches a gas turbine engine (Turbomeca Aubisque engine of Figure 1 of Bjorn is an Aubisque 1A used on the Saab 105 jet per Bjorn p.1-2, Fig 1 caption, and also taught by Jane’s p.2 para.2 of the Overview, which is a single shaft geared turbofan engine) comprising:
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a core (incl. compressor, combustor, turbine per Fig 1 above);
a nacelle (Fig 1 above) at least partially surrounding the core (Fig 1);
a flow bypass channel (Fig 1 above) defined between an inner surface of the nacelle and an outer surface of the core (Fig 1);
an axial shaft (multi-piece shaft, Fig 1 above) extending along a major axis of the core (Fig 1);
a fan (Fig 1 above) positioned at a leading end of the axial shaft (Fig 1);
a reduction gear assembly (Fig 1 above) coupling the fan to the axial shaft Fig 1);
a compressor (Fig 1 above) directly coupled to the axial shaft and positioned downstream relative to the fan (Fig 1);
a combustion chamber (Fig 1 above) defined by the core downstream from the compressor (Fig 1);
a turbine (Fig 1 above) directly coupled to the axial shaft and positioned downstream relative to the combustion chamber (Fig 1),
at least a starter-generator attached to the axial shaft proximate to the leading end of the axial shaft (a starter/generator in the bullet fairing of the intake per section titled “Intake” on p.2),
wherein the reduction gear assembly functions to reduce rotation of the fan relative to the axial shaft to effectively drive air through the flow bypass channel (Fig 1; last para. of p.4), and
wherein the reduction gear assembly provides a net gear ratio of 2.13 (Jane’s, p.2, section titled Fan); and
wherein the fan, the compressor, and the turbine are all mechanically coupled to the same single axial shaft, such that the gas turbine engine is a single-spool engine (Fig 1).
The Aubsique further teaches a fan speed of 15,245rpm at takeoff (T-O), and a shaft speed of 33,000rpm at an unidentified operating condition.
The Aubisque does not specifically or directly teach the gear ratio being in the range of “about 8:1 to about 3:1” (which Applicant’s specification teaches may include 2.7 and 8.8, based on the optional interpretations of the term “about”).
However, the gear ratio 2.13 is very close to (i.e. approaches) 2.7, which MPEP2144.05(I) provides establishes a prima facie case of obviousness.
Furthermore, Bjorn further teaches gear ratios upward of 3:1 were known and used for geared turbofans for decoupling the fan speed from the turbine speed (p.3 para.1).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the Aubisque turbofan gear ratio could be increased from 2.13:1 to 3:1 (or at least 2.7) as taught by Bjorn, for example to achieve/accommodate higher speed rotation of the turbine (e.g. up to 45,735rpm), or lower speed rotation of the fan (e.g. down to 10,833rpm), or both (e.g. turbine ≈ 36,692 rpm and fan ≈ 13,590 rpm). Additionally, it has been held that combining or simple substitution of prior art elements according to known methods to yield predictable results renders the limitation obvious (see MPEP 2141 (III)). In this case, increasing the gearbox ratio of the Aubisque from 2.13 to the known gearbox ratio of 3:1 as in Bjorn (or at least 2.7:1) would produce the predictable results of faster/smaller turbine and slower/larger fan. Whereas the turbine might be required to shrink in order to facilitate non-shock-wave operation at faster rpm, the fan may operate at slower speeds without changing diameter. In any case, reducing core/turbine size, increasing turbine speed, and increasing fan diameter (accompanied by slower fan rpm) were all desirable development directions for engines to increase propulsive efficiency (Bjorn, pp.2-3).
Regarding claim 2, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above.
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The Aubisque further teaches the reduction gear assembly comprises a gearbox (Fig 1 of Bjorn, above).
Regarding claims 3 and 12, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above. The Aubisque in view of Bjorn also teaches the gear ratio in the range from about 6:1 to about 3:1 (which Applicant’s specification teaches may include 2.7 and 8.8, based on the optional interpretations of the term “about”).
That is, as discussed above, the gear ratio 2.13 is very close to (i.e. approaches) 2.7, which MPEP2144.05(I) provides establishes a prima facie case of obviousness.
Furthermore, Bjorn further teaches gear ratios upward of 3:1 were known and used for geared turbofans for decoupling the fan speed from the turbine speed (p.3 para.1).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the Aubisque turbofan gear ratio could be increased from 2.13:1 to 3:1 (or at least 2.7) as taught by Bjorn, for example to achieve/accommodate higher speed rotation of the turbine (e.g. up to 45,735rpm), or lower speed rotation of the fan (e.g. down to 10,833rpm), or both (e.g. turbine ≈ 36,692 rpm and fan ≈ 13,590 rpm). Additionally, it has been held that combining or simple substitution of prior art elements according to known methods to yield predictable results renders the limitation obvious (see MPEP 2141 (III)). In this case, increasing the gearbox ratio of the Aubisque from 2.13 to the known gearbox ratio of 3:1 as in Bjorn (or at least 2.7:1) would produce the predictable results of faster/smaller turbine and slower/larger fan. Whereas the turbine might be required to shrink in order to facilitate non-shock-wave operation at faster rpm, the fan may operate at slower speeds without changing diameter. In any case, reducing core/turbine size, increasing turbine speed, and increasing fan diameter (accompanied by slower fan rpm) were all desirable development directions for engines to increase propulsive efficiency (Bjorn, pp.2-3).
Regarding claim 4, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above.
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The Aubisque further teaches the gearbox comprises a plurality of spur gears (in epicyclic gear train in Fig 1 of Bjorn above; see also “Fan” section of p.2 in Jane’s), wherein at least a first spur gear (Fig 1 above) is coupled to the axial shaft (Fig 1) and a second spur gear (Fig 1 above) is coupled to the fan (via various intermediate components), the first gear and the second gear being in mechanical communication with each other (meshing per Fig 1).
Regarding claims 5 and 19, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above. The Aubisque further teaches the reduction gear assembly comprises an epicyclic gear train (Fig 1 of Bjorn).
Regarding claims 6-7, 13-14, and 20, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above. The Aubisque further teaches a bypass ratio of air in the flow bypass channel to the core (Fig 1 of Bjorn, air flowing through each channel during operation, thus provides a bypass ratio) is in a range from about 0.5 to about 5 (claims 6, 13, and 20) or to about 3 (claims 7 and 14) (Roux, p.78 under section “Aubisque 1A” teaches a bypass ratio, BPR, of 2).
Regarding claim 8, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above. The Aubisque further teaches the compressor is one that is ordinarily referred to in the prior art as an impeller compressor, a radial-type compressor, or a centrifugal compressor (Fig 1 of Bjorn, pp.2-3 of Jane’s in section titled “Compressor”; see also evidentiary reference: Wikipedia, Centrifugal Compressor, retrieved from Wayback Machine, archived 19 July 2022, https://web.archive.org/web/20220719014835/https://en.wikipedia.org/wiki/Centrifugal_compressor).
Regarding claims 10 and 18, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above. The Aubisque further teaches (in Fig 1 of Bjorn) a diameter of the fan (tip diameter) is greater than a diameter of the core (an inlet diameter of the core is smaller than tip diameter of fan).
Regarding claim 16, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above. The Aubisque further teaches at least a vane joining the nacelle and the core, wherein the vane can be movable or actuatable to manipulate the flow from the flow bypass channel (Jane’s sections titled “Fan” and “Accessories” teaching variable inlet guide vanes for the bypass channel at the front of the outer casing).
Claim 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over the Aubisque in view of Bjorn, and further in view of Clarke 10744566.
Regarding claim 4, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above.
Additionally, further reference Clarke, teaches the substitutional equivalence of using one set, or two sets of either helical or spur gears in an epicyclic gear train of a geared turbofan engine (col.4 ll.55-64).
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use either helical or spur gears in the epicyclic gear train of the Aubisque in view of Bjorn, because Clarke teaches their substitutional equivalence for geared turbofan applications (Figs 1-2. Col.4 ll.55-63). See also MPEP 2144.06(II).
Claims 9 and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over the Aubisque in view of Bjorn, and further in view of Brooks 11181046.
Regarding claim 9, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above. The Aubisque further teaches the turbine is an axial turbine (Fig 1).
The Aubisque in view of Bjorn does not teach the turbine is a radial turbine.
However, Brooks teaches a gas turbine engine (Figs 1-3) comprising:
a core (incl. 11, 22, 14, 12);
a flow bypass channel (for air 15);
an axial shaft (14, 13, 18) extending along a major axis of the core (Figs 1-3);
a fan (21) positioned at a leading end of the axial shaft (Fig 3);
a reduction gear assembly (23) coupling the fan to the axial shaft (Fig 3);
a compressor (11) directly coupled to the axial shaft and positioned downstream relative to the fan (Figs 1-3);
a combustion chamber (22) defined by the core downstream from the compressor (Figs 1-3);
a turbine (12) directly coupled to the axial shaft and positioned downstream relative to the combustion chamber (Figs 1-3),
wherein the reduction gear assembly functions to reduce rotation of the fan relative to the axial shaft (col.3 ll.9-25).
Brooks further teaches the turbine may be either an axial turbine or a radial turbine (col.2 ll.28-32).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the axial turbine of the Aubisque in view of Bjorn to be a radial turbine as taught by Brooks because Brooks teaches the substitutional equivalence of using an axial turbine and a radial turbine (col.2 ll.28-32). See also MPEP 2144.06 (II).
Regarding claim 15, the Aubisque in view of Bjorn teaches all the limitations of the claimed invention as discussed above. The Aubisque further teaches the compressor is one that is ordinarily referred to in the prior art as an impeller compressor, a radial-type compressor, or a centrifugal compressor (Fig 1 of Bjorn and section titled “Compressor” on pp.2-3 of Jane’s; see also evidentiary reference: Wikipedia, Centrifugal Compressor, retrieved from Wayback Machine, archived 19 July 2022, https://web.archive.org/web/20220719014835/https://en.wikipedia.org/wiki/Centrifugal_compressor).
The Aubisque further teaches the turbine is an axial turbine (Fig 1).
The Aubisque in view of Bjorn does not teach the turbine is a radial turbine.
However, Brooks teaches a gas turbine engine (Figs 1-3) comprising:
a core (incl. 11, 22, 14, 12);
a flow bypass channel (for air 15);
an axial shaft (14, 13, 18) extending along a major axis of the core (Figs 1-3);
a fan (21) positioned at a leading end of the axial shaft (Fig 3);
a reduction gear assembly (23) coupling the fan to the axial shaft (Fig 3);
a compressor (11) directly coupled to the axial shaft and positioned downstream relative to the fan (Figs 1-3);
a combustion chamber (22) defined by the core downstream from the compressor (Figs 1-3);
a turbine (12) directly coupled to the axial shaft and positioned downstream relative to the combustion chamber (Figs 1-3),
wherein the reduction gear assembly functions to reduce rotation of the fan relative to the axial shaft (col.3 ll.9-25).
Brooks further teaches the turbine may be either an axial turbine or a radial turbine (col.2 ll.28-32).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the axial turbine of the Aubisque in view of Bjorn to be a radial turbine as taught by Brooks because Brooks teaches the substitutional equivalence of using an axial turbine and a radial turbine (col.2 ll.28-32). See also MPEP 2144.06 (II).
Response to Arguments
Applicant's arguments filed 15 September 2025 and 20 January 2026 have been fully considered but they are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Correspondence
Any inquiry concerning this communication or earlier communications from the examiner should be directed to STEPHANIE SEBASCO CHENG whose telephone number is (469)295-9153. The examiner can normally be reached on 0600-0900 AM ET M-F and 1-2PM T/R.
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/STEPHANIE SEBASCO CHENG/Primary Examiner, Art Unit 3741
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