N241-042 TITLE: Compact Rapid Attack Weapon (CRAW) 100HP Electric Powerplant

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Directed Energy (DE)

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 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 a 100HP powerplant that fits into a 6.75" Compact Rapid Attack Weapon (CRAW) afterbody form factor while delivering performance similar to that of the existing CRAW propulsion system and integrating with existing interfaces.

DESCRIPTION: The CRAW is a very lightweight multi-mission torpedo with a 6.75" diameter that is launched out of the Virginia Class submarine external countermeasure launchers. CRAW development is ongoing, but leverages several existing technologies to reduce technical risks. As such, the propulsion system remains a cost and maintenance driver, but has shown to provide the performance that CRAW needs to meet its requirements.

A new 100HP electric powerplant that fits into the CRAW afterbody space to replace the existing propulsion system would be beneficial for various reasons, including reducing cost and maintenance complexity. Ideally, a small business industry partner would be capable of utilizing existing electric motor technology or developing new electric motors to fit the CRAW form factor. The CRAW program envisions a future state where electric propulsion could become the preferred method as electric motor performance meets existing propulsion performance requirements. One of the most difficult aspects of developing technologies for CRAW remains the tight 6.75" diameter form factor. The CRAW program anticipates that use of an electric motor could cut maintenance labor by 50%, which could reduce cost significantly. Ultimately, success of the new electric motor design will be measured by its ability to meet or exceed total energy of 2.5 kW/hrs and 100 hp at 7000 rpm.

The powerplant will consist of three components; 1) a primary or secondary battery capable of sourcing over 100 electric HP, 2) an electric motor capable of continuous 100HP for up to 10 minutes and 3) a small form factor motor controller able to control battery input to the electric motor at To Be Determined (TBD) current levels (type of motor selected and chemistry of the battery will determine current capability). The entire power plant system will be contained in a circular tube of the following dimensions; approximately 6" outside diameter (OD) by 38" in length overall. Details on shell components will become available as the proposed design matures.

Voltage requirements for a system of this compact nature should lean toward levels greater than 600Vdc to reduce conductor size for a lightweight and condensed packaging scheme.

In addition to the above, overall system weight is restricted to below 90 pounds counting the aluminum shells the devices are contained in; these are approximately 23 pounds. Details for the overall packaging scheme will be available.

Evaluation criteria for the electric powerplant system consists of battery load testing to determine overall available power, duration of the battery and any relevant US Navy testing for abuse and safety. The electric motor and controller performance will be verified via dynamometer testing to confirm the ability to make the expected 100HP.

PHASE I: Develop a concept for a design of a 100HP electric powerplant that meets the requirements in the Description. Provide all analyses supporting the design’s compliance with Navy safety requirements. Establish feasibility through modeling/simulation to meet propulsion performance requirements. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.

PHASE II: Develop and deliver a prototype 100HP electric powerplant system for testing and evaluation based on the results of Phase I. The prototype electric powerplant will be evaluated on its ability to meet propulsion system requirements and its ability to meet or exceed existing propulsion system performance. Likewise, the ability of the 100HP electric powerplant to integrate with the existing CRAW architecture and its set of interfaces will be paramount to the success of the prototype.

PHASE III DUAL USE APPLICATIONS: Assist the Navy to transition to low rate initial production while coordinating with existing CRAW partners. Particularly, Penn State University’s Applied Research Lab (PSU/ARL) will require integration support to integrate the 100HP electric powerplant into the electric CRAW variant for full system testing. It is anticipated that this size powerplant could be useful for other 6.75" devices launched out of external countermeasure launchers (e.g., acoustic countermeasures), as well as high powered Unmanned Aerial Vehicles and electric automobile applications.

REFERENCES:

1. Osborn, Kris. "The Navy has High Aspirations for its Multidimensional, Very Lightweight Torpedo." Warrior Maven – Center for Military Modernization, 13 January 2022. https://warriormaven.com/sea/very-lightweight-torpedo
2. Bennion, Kevin. "Electric Motor Thermal Management Research Annual Progress Report." National Renewable Energy Laboratory, May 2022. https://www.nrel.gov/docs/fy18osti/67121.pdf

KEYWORDS: Very Lightweight Torpedo; Compact Rapid Attack Weapon; Electric Motor; Virginia Class Submarine; External Countermeasure Launchers; High Power Density Battery

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