DETAILED ACTION
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 03/27/2026 has been entered.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claim(s) 1, 2, 4, 5, 8, 9, 11, 12, 14, 15, 18 and 19 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. Claim 1 recites “the leading edge camber decreases from an engine hub to the fan blade tip”. One of ordinary skill in the art would interpreted this to communicate that the leading edge camber decreases starting at the engine hub and continuing to decrease until the fan blade tip. It is noted that “newly added claims or claim limitations must be supported in the specification through express, implicit, or inherent disclosure” (MPEP 2163 I.B.). There is not support for the instant limitation in applicant originally filed disclosure. This is not an inherent property of pylon fairings and the limitation does find express support in the specification. Applicant cites par. 125 and figs. 16-20. Par. 125 states “the leading edge camber 830 decreases from proximate the engine hub 870 to radially outward distances from the hub toward a fan blade tip 876”. This does not provided support for the leading edge camber curvature decreasing all the way until the fan blade tip. Such curvature 830 is shown in fig. 16. In addition Fig. 18 shows that the pylon fairing 802 does not extend radially outward all the way until the fan blade tip (see annotated figure below). In addition the leading edge curvature of figs. 18-20 increases from the hub towards the tip (compare the curvature of fig. 19A at cross section A in fig. 18 with the curvature of fig. 19C at cross-section C) rather than decreases. Fig. 20 shows the leading edge 806 but does not appear to show the instant limitation (the trailing edge 871 of a fan blade is shown however the required curvature of the leading edge 806 is not shown extending to a tip of the fan blade; as best understood the radial extent of the leading edge curvature is shown in annotated figure below). Therefore it appears that the instant limitation is new matter. Claim 11 recites a similar recitation and is rejected for the same reasons. Claims dependent thereon are also rejected for the same reasons.
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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.
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.
Claim(s) 1, 2, 4, 5, 8, 9, 11, 12, 14, 15, 18 and 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over French patent document FR3083207 A1 (Paul), as evidenced by NPL “Could an open fan engine cut carbon emissions for more sustainable aviation?” (Airbus), in view of Pub. No. US 20080226454 A1 (Decker) and US 2011/0081252 A1 (Li), as evidenced by US 2021/0332704 A1 (Furukawa).
Regarding claims 1, 8, 9, 11, 18 and 19, Paul discloses (see figs. 1 and 3) (claim 11) an open rotor 5 pylon system 2,2a,2b for (claims 1 and 11) an aircraft (see ll. 105-106) extending between a forward end and an aft end (the aircraft is a solid structure and thus has a forward end and an aft end), the aircraft comprising a fuselage (see l. 107) extending between the forward end of the aircraft and the aft end of the aircraft (the fuselage is within the forward and aft bounds of the aircraft); a wing assembly (see l. 106) extending laterally outwardly from a portion of the fuselage (one of ordinary skill understands when reading lines 105-17 that the aircraft is not a flying wing aircraft and thus the wing assembly would extend from a portion of the fuselage and away from the longitudinal centerline; see NPL Airbus showing this type of engine extending from wing on page 4); and an unducted turbofan engine (1; see ll. 14-15) defining an engine longitudinal centerline X and including an unducted fan 5 having fan blades 8 defining a fan blade tip (see annotated figures below) and rotatable about (see fig. 1 and ll. 130-135) the engine longitudinal centerline X and fan guide vanes 9 not rotatable (see l. 132: “blades 9 of the annular row 6 of the stator”; because the blades 9 form a “stator” such blades are not rotatable) about the engine longitudinal centerline X, (claim 11) the open rotor pylon system comprising: (claims 1 and 11) a pylon fairing (2,2a,2b; see aerodynamic portion 2b regarding fairing) that connects (see l. 106) the unducted turbofan engine 1 to the wing assembly, the pylon fairing defining a lengthwise direction X and comprising a leading edge section (see annotated figures below), the leading edge section defining a leading edge camber (see curvature in fig. 3) that varies (see annotated figures below) along the lengthwise direction of the pylon fairing (2,2a,2b; see aerodynamic portion 2b regarding fairing) that connects (see l. 106), wherein leading edge section defines a leading edge angle (see annotated figures below) between the leading edge camber and an axial line parallel to the engine longitudinal centerline (see annotated figures below) that extends through a pierce point (see annotated figures below) is a forwardmost point (see annotated figures below) of the pylon fairing, wherein the pierce point (see annotated figures below) is a forwardmost point (see annotated figures below) of the pylon fairing, and wherein the pylon fairing (2,2a,2b; see aerodynamic portion 2b regarding fairing) is discrete (see fig. 1) from the fan guide vanes 9, and wherein the leading edge section (see annotated figures below) has a variable thickness (see annotated figures below). Paul does not explicitly disclose the leading edge camber decreases from the engine hub to the fan blade tip, and wherein the leading edge angle is between 5 degrees and 60 degrees.
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Decker teaches vane 50 (see figs. 1 and 10) receiving airflow from rotating fan blades 42 and further teaches (claims 1 and 11) camber (this corresponds with the leading edge section (see annotated figures above) of the pylon fairing of Paul because such leading edge section acts aerodynamically like the adjacent stationary vanes 9, see fig. 1 and ll. 135-153) decreases (see decrease from 0 to 50% span in fig. 7A) from hub (0% span in fig. 7A) to the fan blade tip (100% span) (the instant decrease in camber is also taught at par. 9, bottom; for example, the camber at the hub, mid-span and tip can be for example 70 degrees, 60 degrees and 50 degrees, respectively).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the current invention to provide Paul with the leading edge camber decreases from the engine hub to the fan blade tip as taught by Decker in order to facilitate improved aerodynamic efficiency, improved de-swirling of the fan flow and reduced noise (see pars. 3, 34 and 113). It is noted that Decker is considered analogous art at least because the reference is reasonably pertinent to the problem faced by the inventor. For example, applicant disclosure points out problems such as de-swirling of the airflow exiting the fan and encountering the pylon, and acoustics (see pars. 41 and 116). Decker is pertinent to this because the leading edge of the Paul pylon is shaped to correspond to the other adjacent outlet guide vanes (see ll. 135-153) and a goal of Paul is to de-swirl the flow from rotation fan blades 8 (see ll. 110-116).
Paul in view of Decker teach all the essential features of the claimed invention except (claims 1 and 11) the leading edge angle is between 5 degrees and 60 degrees; (claims 8 and 18) the leading edge angle is between 10 degrees and 50 degrees; and the leading edge angle is between 15 degrees and 45 degrees (9 and 19).
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). 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).
Here, Li teaches in paragraphs 15 and 39, and figs. 2 and 4, that varying the leading edge angle α, for example at the hub, of a vane of an axial flow compressor (see par. 2) has the effect of minimizing aerodynamic losses by reducing boundary layer thickness and flow separation at the area wherein vane structure meets the hub. In addition, and varying the leading edge angle at the midspan improves the choke margin thereby reducing flow disturbances when the flow encounters the leading edge (one of ordinary skill understands a choked flow may result in blockage or otherwise cause inefficient flow conditions). Therefore, an ordinary skilled worker would recognize that the leading edge blade angles at the hub and mid-span are a result-effective variables that control aerodynamic efficiency and smooth flow. Thus, the claimed the leading edge angle is between 5 degrees and 60 degrees; the leading edge angle is between 10 degrees and 50 degrees; and the leading edge angle is between 15 degrees and 45 degrees is found to be an obvious optimization of the prior art obtainable by an ordinary skilled worker through routine experimentation. It is noted that one of ordinary skill is knowledgeable that the problem solved by varying the leading edge angle is also applicable to vanes of fans as discussed in Furukawa par. 3 wherein Furukawa also explains the basic concept that compressors and fans each have upstream rotating airfoils and downstream stationary vanes in par. 2 (Furukawa points out in pars. 33 and 38 that separation of flow is a problem at the hub portion of a fan vane). This is relevant to the leading edge angles of the pylon of the combination because the forward portion 2b (see annotated figures above) of the pylon disclosed by Paul of the combination acts aerodynamically similar to the adjacent annular row 6 of guide vanes 9, the purpose of the guide vanes 9 being to straighten the flow from fan blades 8 (see ll. 135-153). In addition, Decker points out that flow separation is a problem where a vane meets a hub, for example, an end wall of the vane (see annotated figures below; and par. 14, middle, and par. 44, bottom). Thus varying the leading edge angles of the combination of Paul in view of Decker would be beneficial to reducing flow separation as taught by Li.
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Therefore, since the general conditions of the claim, i.e., the leading edge blade angle, were disclosed and taught in the prior art by Paul in view of Decker, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Paul in view of Decker’s invention to include (claims 1 and 11) the leading edge angle is between 5 degrees and 60 degrees; (claims 8 and 18) the leading edge angle is between 10 degrees and 50 degrees; and (claims 9 and 19) the leading edge angle is between 15 degrees and 45 degrees in order to provide continuous efficient flow at the leading edge as suggested and taught by Li in paragraphs 15 and 39, and figs. 2 and 4. It has been held “where 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).
Regarding claims 2 and 12, Paul in view of Decker and Li teach the current invention as claimed and discussed above. Paul further discloses (see fig. 1) (claims 2 and 12) the fan blades 8 that extend outward from the engine hub (see annotated figures above; this is consistent with applicant hub 870 in fig. 20) to the fan blade tip (see annotated figures above).
Regarding claims 4, 5, 14 and 15, Paul in view of Decker and Li teach the current invention as claimed and discussed above. Decker of the combination teaches (claims 4 and 14) the leading edge camber is a maximum at the engine hub (see par. 9: here 75°is a max value that is the camber angle shown in fig. 5); and (claims 5 and 15 the leading edge camber is a minimum at the fan blade tip (see par. 9).
Response to Arguments
Applicant's arguments filed 03/27/2026 have been fully considered but they are not persuasive. Applicant argues against the drawing objection in the final office action mailed 12/29/2026. In response, the issue addressed by the drawing objection is still pending however it is explained via a 112 new matter rejection above. In summary of the 112 section above there does not appear to be support for the leading edge camber decreasing “from the engine but to the fan blade tip” as recited in claim 1. For example, par. 125 states “the leading edge camber 830 decreases from proximate the engine hub 870 to radially outward distances from the hub toward a fan blade tip 876”. This does not provided support for the leading edge camber curvature decreasing all the way until the fan blade tip. Such curvature 830 is shown in fig. 16. In addition Fig. 18 shows that the pylon fairing 802 does not extend radially outward all the way until the fan blade tip (see annotated figure below). In addition the leading edge curvature of figs. 18-20 increases from the hub towards the tip (compare the curvature of fig. 19A at cross section A in fig. 18 with the curvature of fig. 19C at cross-section C) rather than decreases. Fig. 20 shows the leading edge 806 but does not appear to show the instant limitation (the trailing edge 871 of a fan blade is shown however the required curvature of the leading edge 806 is not shown extending to a tip of the fan blade; as best understood the radial extent of the leading edge curvature is shown in annotated figure below). Therefore the instant limitation appears to be new matter.
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Applicant argues that the leading edge thickness of Paul fig. 3 has a constant thickness. In response the leading edge section has a variable thickness (see annotated Paul fig. 3 below.
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Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MARC J AMAR whose telephone number is (571)272-9948. The examiner can normally be reached M-F 9:00-6:00.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Devon Kramer can be reached at (571) 272-7118. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/MARC AMAR/Examiner, Art Unit 3741 /DEVON C KRAMER/Supervisory Patent Examiner, Art Unit 3741
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