GoJett: A Supersonic Unmanned Aerial Flight System

Rocky Mountain Regional Technical Symposium Sibylle Walter

Graduate Research Assistant, PhD Student, CU Boulder, Aerospace Engineering Sciences

http://www.colorado.edu/busemann

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Introduction

• The Aerospace Engineering Sciences department at the University of Colorado, Boulder introduced projects for graduate students in the spring of 2009 – Two semester course designed to expose students to

project management and systems engineering while working on a complex engineering design problem

– Various projects in progress now, including a low speed blended wing UAV, hybrid sounding rocket, CubeSat, Dream Chaser cockpit design, and GoJett

• GoJett is a supersonic unmanned aerial system (UAS) that aims to break the world UAS speed record for a vehicle under 50 kg and utilize a fluid injection thrust vectoring control system.

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Small. Sleek. Supersonic.

Goals: • Build a UAV capable of achieving Mach 1.4 • Aircraft mass less than 50 kg • Fabricated for less than $50k • Break FAI* Class U-2.b world speed record

*FAI = Federation Aeronautique Internationale (world governing body of aeronautic and astronautic records)

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FAI Mission Profile

• Two 15 km cruise sections in opposite directions • 5 km approach sections • Maintain level flight (± 100 m) through speed run and

approaches • 2000 m ceiling above cruise course at all times

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2000 m

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Design Challenges • Aerodynamic design – Sears-Haack fuselage design with pitot inlet and a

cranked delta wing • Control system – Fluidic injection thrust vectoring system for yaw (& some

pitch) control allows for a tailless design; elevons for pitch and roll control • Landing Gear – Fast take-off (60 m/s) with a tricycle configuration • Propulsion system – COTS miniature turbojet with a custom afterburner to

provide 200+ lbf thrust • Structural design – Lightweight, smooth shell that can withstand supersonic

thermal gradients • Robust system – Redundant flight computers, onboard video to stream to

ground station

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Wet Mass Budget

Total Mass = 50 kg

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Progress

Sep 2009 – Project initiated (started as only propulsion work) May 2010 – First engine test cart completed and data collected Sep 2010 – Vehicle concept and goals established Sep 2011 – Prototype model tested at US Air Force Academy tri-sonic wind tunnel to validate CFD May 2012 – PDR completed Jul 2012 – Engineering test unit frame built Feb 2013 – Afterburner test (expected) May 2013 – CDR (expected) Jun 2013 – Maiden flight of test unit (expected)

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Wind Tunnel Testing at USAFA

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USAFA Mach 1.32 Tests

• Double Cranked Arrow wing design • Sears-Haack analysis used for fuselage design • Wind tunnel testing at M = 1.32 (USAFA Trisonic Tunnel) • Extensive computational fluid dynamics (CFD) conducted for validation using

ANSYS Fluent and ZEUS

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Landing Gear

Elevon

Rudder

Inlet

Servo

Bulkhead

Fuel Tanks

Antenna

Engine

Engineering Test Unit Overview

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Manufacturing Composite Skin

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90% of all work went into creating the tool

Patent Pending Patent Pending Patent Pending Patent Pending

Patent Pending Patent Pending Patent Pending Patent Pending Patent Pending

Patent Pending Patent Pending Patent Pending Patent Pending Patent Pending

Special thanks to EBS Composites for their help and support in building the engineering test unit.

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Future Work

Short Term: • Static system test of engineering test unit

• Weight and balance confirmation • Internal clearance of all systems • Hardware-in-the-loop testing • Taxi tests

Longer Term: • Flight test in the spring of 2013 • Updated design/construction to allow for

supersonic flight

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2012 Graduate Team

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Diane Dimeff Executive Director, eSpace

Chris LaPanse Aero Engineer

Brandon Bosomworth Structural Engineer

Manufacturing

Brad Wyatt Aero Engineer

Joe Tanner Senior Instructor

Chad Chaffin Systems Engineer Controls Engineer

George Miyata Project Manager

Electronics Engineer

Edgar Flores Structural Engineer

Tim Beatty Controls Engineer

Scott Christian-Dold Landing Gear Engineer

Propulsion Engineer

Sibylle Walter Propulsion Engineer

Greg Rancourt Electronics Engineer

Dr. Ryan Starkey Faculty Advisor

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Sponsorship

• eSpace: the Center for Space Entrepreneurship • United States Air Force Academy

– Transonic Wind Tunnel Testing (Mach 0.8, 1.2, 1.4) • Zona Technologies, Inc.

– Aerodynamic (Zeus)/Aeroelastic (Astros) software • EBS Composites

– Providing space and resources to build the shell

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Special thanks to the 25 seniors and ~50 grad students who have worked on various aspects of this project over the last 4 years.