UNCLASSIFIED

UNCLASSIFIED

Distribution Statement A. Approved for Public Release. Distribution is unlimited.

FY17 Department of Navy Additive Manufacturing PrintFY17 Department of Navy Additive Manufacturing Print--aa--ThonThon

Printed Air Inlet for Solid Fuel RamjetPrinted Air Inlet for Solid Fuel Ramjet

Project Description—This NAWCWD internally funded

demonstration effort aims to accelerate the development of Solid

Fuel Ramjet (SFRJ) technology. The SFRJ air inlet design is

critical to system performance and conventional manufacturing

methods limit the part geometry that can be affordably achieved

to less than optimum designs. Utilizing metal additive

manufacturing, this effort explores the feasibility & performance

impact of a DMLS (Direct Metal Laser Sintering) steel printed air

inlet for a SFRJ test vehicle.

Transition:

AM parts currently undergoing ground test as

part of in-house R&D efforts with flight test

planned in FY17

Inlet development is critical to the success of

next generation high speed strike weapons

AM enables significant cost and schedule

savings positioning SFRJ technology to provide

the warfighter with increased range weapons

systems

Business Case:

SFRJ technology enables a 3x increase in delivered range

compared to a similar size solid rocket motor

Inert fuel grain and no moving parts

Inlet performance critical for high efficiency and

delivered impulse

Traditional machining requires multiple components to

create a high performance inlet

Interfaces have undesirable tolerance stack-up

Fasteners, welding, threading all incur additional

machine time and cost

Additive manufacturing enables single piece inlet design

Complex geometries to improve inlet performance

Free volume to reduce weight and improve packaging

Minimal post print machining

Design, print, ground test, and flight test at NAWCWD The Technology:

Process: Direct Metal Laser Sintering (DMLS)

Machine: EOS M290

Material: Maraging Steel MS1

Post-print heat treatment & minimal machining

required

Challenges:

Lack of sufficient material property database for

printed materials

As-printed surface roughness not ideal

Design to limit post-print machining

High speed (Mach 2-4) flight induces aerodynamic

heating and high localized temperatures

Uncertain mechanical properties at elevated

temperatures

Enhanced Capability ConceptEnhanced Capability Concept