2005 Georgia Tech Heavy Lift Tandem Acknowledgements We wish to thank the following individuals for their special assistance: Dr. Daniel P. Schrage Dr. Robert G. Loewy Dr. Lakshmi Sankar Dr. Jou-Young Choi Hangil Chae Chang Chen Srinivas Jonnalagadda CAPT Andy Bellochio Academic Credit All members of this design team received academic credit for this proposal. This design was the capstone project for AE6334, Rotorcraft Design II, a four-hour credit graduate course offered by Georgia Tech and instructed by Dr. Schrage. 2005 Georgia Tech Graduate Design Team _____________________________ ____________________________ Aaron Pridgen (Masters Student) Ludvic Baquie (Masters Student) _____________________________ ____________________________ Alex Moodie (Ph. D. Student) Mandy Goltsch (Ph. D. Student) _____________________________ ____________________________ Byung-Young Min (Ph. D. Student) Sameer Hameer (Masters Student) _____________________________ ____________________________ Dominic Scola (Masters Student) Vivek Kaul (Masters Student) _____________________________ James Rigsby (Ph. D. Student) i 2005 Georgia Tech Heavy Lift Tandem Executive Summary The need for rapid vertical deployment of the Future Combat System (FCS) from ship to shore necessitates the generation of new designs in Heavy-Lift VTOL rotorcraft. Special considerations, such as their shipboard capability and performance constraints, were outlined in the 2005 Request For Proposal (RFP) as part of the 22nd Annual Student Design Competition sponsored by Boeing and AHS International. A graduate team from the Georgia Institute of Technology presents their results for the preliminary design of a configuration capable of performing all mission profile requirements and meeting all required system capabilities. The Georgia Tech Tandem (GTT) is their proposal for this competition. The GTT was generated through a series of system level processes and analyses beginning with the decomposition of a clear problem statement. A measure of merit for designs and their comparison was created in an Overall Evaluation Criteria (OEC). Then an initial concept selection indicated that a tandem type rotorcraft would best meet the RFP requirements, and—through a detailed sizing and synthesis process utilizing the RF Method—the pure tandem configuration was chosen as the proposal candidate. Special consideration was made to justify and validate all the results that led to the GTT selection. Preliminary design of the GTT continued through the entire range of rotorcraft design disciplines as the selection of design parameters continued with greater fidelity. An aerodynamic analysis of the main rotor and hub design that included aircraft performance was performed. Then other aspects of the hub design were determined that included results of the blade dynamics. A broad structural design for the GTT is proposed as well as details for the aircraft’s stability and control design. Additionally, the power plant selection and unique drive system design are presented. Finally, an evaluation of the GTT cost analysis is summarized. All the elements of GTT design combine to offer the best proposal for the Heavy Lift VTOL Aircraft requested in the 22nd Student Design Competition. ii 2005 Georgia Tech Heavy Lift Tandem Table of Contents ACKNOWLEDGEMENTS .......................................................................................................................... I ACADEMIC CREDIT .................................................................................................................................. I 2005 GEORGIA TECH GRADUATE DESIGN TEAM............................................................................ I EXECUTIVE SUMMARY ..........................................................................................................................II TABLE OF CONTENTS ........................................................................................................................... III LIST OF TABLES ....................................................................................................................................... V LIST OF FIGURES ................................................................................................................................... VI LIST OF ACRONYMS ........................................................................................................................... VIII LIST OF SYMBOLS .................................................................................................................................. IX COMPLIANCE MATRIX ........................................................................................................................... X 1 INTRODUCTION ............................................................................................................................... 1 2 FUNCTIONAL ANALYSIS ............................................................................................................... 1 2.1 FUNCTIONAL DECOMPOSITION ....................................................................................................... 1 2.2 PROBLEM STATEMENT .................................................................................................................... 3 3 AIRCRAFT CONFIGURATION TRADE STUDY ......................................................................... 3 3.1 CONCEPT DEVELOPMENT ............................................................................................................... 3 3.1.1 Single Main Rotor ............................................................................................. 3 3.1.2 Tandem .............................................................................................................. 4 3.1.3 Tilt Rotor ........................................................................................................... 4 3.1.4 Quad Tilt Rotor ................................................................................................. 5 3.1.5 Slowed Rotor Compound .................................................................................. 5 3.2 PRELIMINARY CONCEPT ANALYSIS - OVERALL EVALUATION CRITERIA ........................................ 6 3.3 TANDEM ROTOR TRADE-OFF STUDY .............................................................................................. 8 3.4 CONFIGURATION ANALYSIS ........................................................................................................... 9 3.5 CONFIGURATION SELECTION – OEC ANALYSIS ........................................................................... 11 4 PERFORMANCE .............................................................................................................................. 13 4.1 DRAG BUILDUP............................................................................................................................. 14 4.2 PERFORMANCE ANALYSIS ............................................................................................................ 15 4.3 AUTOROTATION ............................................................................................................................ 18 5 ROTOR DESIGN .............................................................................................................................. 20 5.1 ROTOR DIAMETER ........................................................................................................................ 20 5.2 TIP SPEED ..................................................................................................................................... 20 5.3 BLADE AREA ................................................................................................................................ 21 5.4 SOLIDITY ...................................................................................................................................... 21 5.5 BLADE TWIST AND TAPER ............................................................................................................ 22 5.6 AIRFOIL DESIGN ........................................................................................................................... 23 5.7 BLADE TIP DESIGN ....................................................................................................................... 30 5.8 ROOT CUT-OUT ............................................................................................................................ 31 6 HUB DESIGN .................................................................................................................................... 31 6.1 SELECTION OF CANDIDATE HUB SYSTEMS ................................................................................... 31 6.2 HINGE OFFSET AND POWER BLADE FOLDING ............................................................................... 32 6.3 MATERIAL SELECTION .................................................................................................................. 33 6.4 ROTOR HUB WEIGHTS AND PARTS COUNT ................................................................................... 33 6.5 CONTROL POWER REQUIREMENTS ............................................................................................... 34 6.6 CONTROL POWER IN AUTOROTATION ........................................................................................... 34 6.7 PRECISION MANEUVERING/CARGO HANDLING ............................................................................ 34 iii 2005