Propulsor Geometric Certification System

Navy SBIR 21.1 - Topic N211-056
NAVSEA - Naval Sea Systems Command - Mr. Dean Putnam -
Opens: January 14, 2021 - Closes: February 18, 2021 (12:00pm EDT)

N211-056 TITLE: Propulsor Geometric Certification System

RT&L FOCUS AREA(S): General Warfighting Requirements

TECHNOLOGY AREA(S): Ground / Sea Vehicles

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Develop and integrate a digital solution for naval propulsor repair and new manufacture geometric certification for greater war readiness, performance, and affordability.

DESCRIPTION: The certification of the geometric properties of propulsors are a key factor in meeting many Key Performance Parameters and Key System Attributes for United States Navy (USN) ships. Proper execution of propulsor geometric inspection and certification supports ship powering, signature, and vibration performance requirements. Current practice for USN propulsor certification requires the application of highly maintained sets of physical gages in a controlled and detailed process. The cost and time involved in this process can lead to delays in delivery to ship and degraded ship propulsor performance. The Navy seeks a fast and practical way to inspect and certify new and repaired propulsor assets to create a more resilient and agile logistics path and support on time delivery of ships and submarines.

USN propulsors are large, finely machined assets that have unique and complex manufacturing tolerances, both of which present challenges to geometry certification and challenge the current state of the art in digital surface scanning and assessment. Certification of propulsors requires both very tight local surface profile tolerance over a wide area, as well as local and global derived geometric characteristic tolerances unique to propulsors. Current commercially available components lack the required speed and accuracy of data collection, the analytical capability to assess against relevant propulsor tolerances, and the capability to easily direct repair; and they are not integrated systems. Development is required to allow for a 23’ diameter x 5’ deep volume to be captured on a newly machined metallic surface at sufficient accuracy to verify tolerances of 0.005". Specialized software development is required to process the captured data in a manner consistent with USN propulsor tolerances. Innovation can also be applied to the interpretation of the data analysis and its application in identifying corrective actions and conveying them to the machinist.

This SBIR topic seeks to develop an integrated survey, analysis, and reporting system for use in new manufacture and repair of USN propellers. The survey system shall be able to measure a representative NiAlBr propeller of 23’ diameter to a precision of at least 0.00025" in less than 6 hours. The analysis software shall quality control the surveyed data, and analyze it in a fashion consistent with USN guidance on propeller dimensional inspection in near-real time with minimal user involvement.

The system will be assessed against a standard inspection of a test monobloc propeller or controllable pitch propeller (CPP) blade and a process review of the analysis method. The system shall document the blade condition and aid the inspector/machinist in identifying dimensional exceedances and coordinating corrective actions.

PHASE I: Propose a concept for an integrated system solution for geometric inspection, evaluation, and result output of monobloc propellers and controllable pitch propeller (CPP) blades. Demonstrate the capability to optically evaluate a representative article to the required accuracy. Provide a concept for blade dimensional analysis and demonstrate ability to produce and develop similar software. Provide and demonstrate a concept for utilizing the analysis data to assist in the remediation of the blade to determine feasibility. The Phase I Option, if exercised, will include initial design specifications and description of capabilities to build a prototype in Phase II.

PHASE II: Build and demonstrate a prototype system of the solution on a USN asset provided by the Government team, i.e., a USN propeller and a controllable pitch propeller (CPP) blade will be arranged in a repair facility along with required reference information. Demonstrate that the prototype can perform all aspects of the inspection process on the provided propeller and CPP blade, including setup, data acquisition, data analysis, and reporting. Assess prototype performance against a standard inspection of the test articles, as well as on the design specifications and capabilities outlined in the Description.

PHASE III DUAL USE APPLICATIONS: Assist the Navy in transitioning the technology by providing systems (4-20) for procurement by 2SCog Propulsion Program, USN Regional Maintenance Centers or other NAVSEA facilities, and/or industry vendor partners as well as training in their use. The resulting systems should include surveying devices and associated items required for operation, analysis software, and any software or items required for output/utilization of analysis data.

These systems will be used to support all Navy surface ship assets, particularly DDG, LPD, CVN, and LCS classes. These systems will allow rapid evaluation of units in the field and in facilities, providing better and faster assessment of required repairs and performance impacts. This would allow for a reduction in repair lead times of roughly 60-360 days, creating a shorter, more flexible logistics chain to support fleet needs. This would also reduce non-recurring engineering (NRE) and capital costs on designing and manufacturing the blade gages required for traditional inspection, 0.5-2M over the next five years, as well as virtually eliminating the $50-200K expense of each inspection leading to more affordability in ship procurement and availabilities. Not including new delivered ships or emergent repairs, the 2SCog program plans to procure at least 46 new or refurbished propellers and blade sets over the next 5 years. This system could also likely be extended to virtually any foil-like high performance part, such as turbines or aviation for both DoD and commercial applications.


  1. Allen, David W., et al. "Propeller Geometric Parameter Extraction From Inspection Data Clouds." Journal of Ship Production, Vol. 21, No. 4, NOV 2005, pp. 203-208.
  2. Allen, David W., Harsh, Albert F., and Machin, James D. "Computer-Aided Marine Propeller Inspection Data Analysis." Naval Engineers Journal, Vol 107, No. 2, MAR 1995, pp. 33-40.
  3. Li, Feng; Stoddart, David and Zwierzak, Iwona. "A Performance Test for a Fringe Projection Scanner in Various Ambient Light Conditions." Procedia CIRP - 10th CIRP Conference on Intelligent Computation in Manufacturing Engineering, Vol 62, DEC 2017, pp. 400-404.
  4. Contrarotating Prop Set 5525/5526 – CAD Program Required - This link provided, will download a compressed file which will contain a representative propeller surface geometry file in ASCII Initial Graphics Exchange Specification (IGES) format and text description file which provides a typical example of some of the Navy standard features which would need to be inspected by the proposed system. This is provided as an example article for information, it is not the Phase II article, nor does it represent all of the challenges associated with the SBIR (overlapping blades, for example). While this is an example of standard surface definition formatting, proposers are free to outline modifications to this format as required by their system. See

KEYWORDS: Propeller Inspection; Airfoil Metrology; Propeller Gages; Geometry Certification; Laser Scanning; Optical 3D Scanning


The Navy Topic above is an "unofficial" copy from the overall DoD 21.1 SBIR BAA. Please see the official DoD Topic website at for any updates.

The DoD issued its 21.1 SBIR BAA pre-release on December 8, 2020, which opens to receive proposals on January 14, 2021, and closes February 18, 2021 at 12:00 p.m. ET.

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