Designing evtol for the Mission NDARC NASA Design and Analysis of Rotorcraft. Wayne Johnson From VTOL to evtol Workshop May 24, 2018

Transcription

1 Designing evtol for the Mission NDARC NASA Design and Analysis of Rotorcraft Wayne Johnson From VTOL to evtol Workshop May 24,

2 Conceptual Design of evtol Aircraft Conceptual design Define aircraft to perform required mission Identify aircraft type, including propulsion system Size components and subsystems (weight, power, energy) Component design and optimization Estimate performance and cost Emphasis on breadth and speed of analysis Followed by preliminary design and detailed design Of Vertical Take-Off and Landing aircraft VTOL required for air taxi operations Efficient VTOL requires low disk-loading rotors, flying edgewise at low speed (possibly transition to high speed configuration) With electric propulsion Including hybrid configurations 2

3 Design Tools Aircraft design capability is required to support research in a government laboratory Technology impact assessments Show how technology will affect future systems System level context for research Support level of investment for technology maturation Concept exploration, decision, and refinement Must conduct quantitative evaluation and independent synthesis for wide array of aircraft configurations and concepts Such a tool is useful in the community of innovation 3

4 NDARC NASA Design and Analysis of Rotorcraft Conceptual/preliminary design computer program Design task: Develop consistent description of system to perform mission and satisfy design requirements Size aircraft: determine dimensions, weight, power, energy of all components and subsystems Iterate with external optimization of primary design variables (eg disk loading, tip speed) With aircraft and rotor optimization using higher fidelity analyses Analysis task: Off-design mission performance, flight performance for point operating conditions NDARC initial release (1.0) May 2009 Current release (1.13) May 2018 NDARC has been distributed to 140+ organizations 4

5 Key Attributes of NDARC General aircraft and propulsion system architecture Aircraft model built from set of components Flexible sizing constraints, based on multiple missions and performance points Capture technology impact, at system and component levels Surrogate models of component performance and weight Allows for very short runtime and rapid concept iteration Requires calibration of the models Accurate prediction of future aircraft design depends on Identification of all aircraft subsystems Calibration of surrogate models for performance and weight Skill at estimating technology impact 5

6 Simple Mission Altitude 5k/ISA+20 o C V BR Reserves 20 V BE or 10% Fuel Mission 1 Takeoff HOGE 2 min Landing HOGE 2 min SL/ISA+20 o C Mission 2 0 X nm Range 6

7 More Complex Mission Profile Segment Atm. Time (min) Dist. (km) Speed (KTAS) VROC Cap. (fpm) Engine Rating 1 Taxi 4k 95 F =100% MCP 2 Hover 4k 95 F 2 - HOGE % MRP 3 Climb - ISA - Credit ~Vy Fallout 100% IRP 4 Cruise Best ISA V BR - 100% MCP 5 Dash 4k 95 F V DASH - =90% MCP 6 Loiter 4k 95 F 30 - V BE - 100% MCP 7 Hover 4k 95 F 2 - HOGE % MRP 8 Dash 4k 95 F V DASH - =90% MCP 9 Climb - ISA - Credit ~Vy Fallout 100% IRP 10 Cruise Best ISA V BR - 100% MCP 11 Hover 4k 95 F 1 - HOGE % MRP 12 30min/ 10% Res. Best ISA - - V BR - 100% MCP Altitude (ft) Best (ISA) 4,000 (95 o F) 30min/ 10% Fuel Reserves 5 min (Start Up/Taxi) 0 V BR TO HOGE 2 min LD HOGE 1 min 324 Dash Payload Retained 30 V BE (Loiter) HOGE 2 min Radius 424 (km) Notes: Sizes aircraft design gross weight and power 2500lb internal payload HOGE: Hover out of ground effect; aircraft has capability for 500fpm VROC VROC: Vertical rate of climb (purely vertical flight, no horizontal component to velocity) Best: Selected for configuration s best performance V BE : Best endurance speed; minimum fuel flow V BR : Best range speed. May elect to use long range cruise speed; 99% of maximum specific range, high side V DASH : Dash or penetration speed V Y : Best rate of climb speed Reserve fuel is that required for either 30 minutes at V BR or 10% of mission fuel, whichever is greater 7

8 NDARC Components to Construct Aircraft rotors, propellers, ducted fans connects rotating components turbojet, turbofan, reaction drive turboshaft, motor, generator, compressor fuel cell, solar cell energy source: burned, renewed, or stored 8

9 Aircraft with Rotors 9

10 Lots of Rotors 10

11 Rotors and Wings 11

12 Aircraft without Rotors 12

13 Fixed Geometry 13

14 Tilting and Swiveling and Stopping Things 14

15 NDARC Propulsion Architecture Turboshaft 15

16 Reciprocating Engine 16

17 Turbojet / Turbofan 17

18 Fuel Cell 18

19 Solar Cell 19

20 Electric Motor 20

21 Hybrid 21

22 Turbo-Electric 22

23 Quadrotor Aircraft with Various Propulsion Concepts Electric propulsion Rotor speed control Collective control Turboshaft or reciprocating engine Collective control 23

24 Side-by-Side Aircraft with Various Propulsion Concepts Turboshaft propulsion Turboshaft Hybrid Electric propulsion 24

25 Tiltwing Aircraft with Various Propulsion Concepts Turbo-electric propulsion Turboshaft 25

26 NDARC Documentation 70 published papers and reports on NDARC development and applications Principal documentation of development: Johnson, W. "NDARC. NASA Design and Analysis of Rotorcraft." NASA TP , April Johnson, W. "NDARC NASA Design and Analysis of Rotorcraft. Theoretical Basis and Architecture." American Helicopter Society Specialists' Conference on Aeromechanics, San Francisco, CA, January Johnson, W. "NDARC NASA Design and Analysis of Rotorcraft. Validation and Demonstration." American Helicopter Society Specialists' Conference on Aeromechanics, San Francisco, CA, January Johnson, W. "Propulsion System Models for Rotorcraft Conceptual Design." American Helicopter Society 5th Decennial Aeromechanics Specialist's Conference, San Francisco, CA, January "NDARC Theory Manual, Release 1.13" and "NDARC Input Manual, Release 1.13." May

27 How to Get NDARC Software NDARC software is available to US companies, laboratories, universities, and individuals Distribution controlled by Software Release Authority at NASA Ames Research Center Request software at by submitting information for Software Usage Agreement NDARC web page ( contains Executables for current release (PC and Mac) Documentation, training materials, model calibration procedures Sample cases and reference models 27

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