08. Code AV_Final MKL.pdf

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Aeromechanics Branch Code AV

Haley Cummings Deputy Project Lead | Code AV

Aeromechanics Branch NASA Ames Research Center

National Aeronautics and Space Administration

Overview of NASA Rotorcraft Aeromechanics Requirements Under ASSESS RFP

Presented at the ASSESS Industry Day NASA Ames Research Center

October 2022

Haley Cummings Principal Investigator, Rotor Optimization for the Advancement of Mars eXploration

(ROAMX) Project Deputy Project Lead. Mars Sample Retrieval Helicopter Project

Outline

•Planetary rotorcraft technology requirements •Mars rotorcraft flight challenges •Potential science and improvements enabled on Mars •Methodology •Outcomes

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ROAMX

Computational optimization and experimental validation of rotorcraft rotors for Mars

3Aeromechanics Branch – NASA Ames Research Center

4Aeromechanics Branch – NASA Ames Research Center

• Computational rotor design

• Understanding of low-Re high subsonic Mach number aerodynamics

• Airfoil optimization

• Blade planform optimization for hover

• Design methodology/framework development

• Experimental validation

• Upgrades to Ames Planetary Aeolian Laboratory

• Test stand development for unique Mars atmospheric simulation testing

• Single rotor hover test of optimized blade set and Ingenuity blades in identical configuration

ROAMX

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Comparison of travel speed between rover and advanced helicopter

First ever powered extraterrestrial flight

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Flight Conditions on Mars

Parameter Earth Mars Density (kg/m3) 1.225 0.017 Temperature (C) 15 -50 Air composition N2-based CO2-based Sound speed (m/s) 340.3 233.1

Aeromechanics Branch – NASA Ames Research Center

Flight Conditions on Mars Parameter Earth Mars Density (kg/m3) 1.225 0.017 Temperature (C) 15 -50 Air composition N2-based CO2-based Sound speed (m/s) 340.3 233.1

Parameter Earth Mars Reynolds number (rotorcraft flight) ~106 ~104

Tip Mach number ~0.6 0.7-0.95

Airfoils

Rec = 15,000

Rec = 15,000

Mission Capabilities Enabled by ROAMX Work

• Initial airfoil (Cl/Cd)0.75R = 25% increase when compared to Ingenuity

• Current results show 39% increase in (Cl/Cd)0.75R

Enabled Science

• Mapping of Mars

• Polar Science

• Atmospheric Science

• Subsurface Geophysics

Examples of Science Instruments Mass (g)

VNIR spectrometer 500

Tunable spectrometer 300

Magnetometer 20

Environment sensors (temp, humidity, wind, etc) 100

Camera for imaging 250

Soil sensors 100

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ROAMX Goals

1. Computational optimization and experimental validation of rotorcraft rotors for Mars

2. Development of design methodology

ROAMX Methodology

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Computational Rotor Optimization

• Develop optimized airfoils for different radial stations

• Optimize blade planform

• Generate 3D CFD model to compare with experiments

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• Airfoil optimization code completed:

• Performance indices used:

• Dual objective mode - maximize lift, minimize drag

• Triple objective mode - maximize lift, minimize drag, maximize structural property of choice

Current results show 39% drag reduction at equal lift

• Write code to use optimized families of airfoils to optimize rotor:

• Vary airfoil choice, blade planform, and blade twist

• Optimize for thrust and power simultaneously

• Compare comprehensive analysis with full 3D high-fidelity CFD

Aeromechanics, Structural, and Mechanical Rotor Design

• Structural considerations required because of use of thin, unconventional airfoils

• Minimum leading and trailing edge thickness provided by AeroVironment based on manufacturing limits

• University of Maryland executing internal structural design in rotating analysis of blades for validation testing using in-house X3D code

Analysis of Manufactured Blades

Advanced Mars Helicopter blades manufactured for risk reduction

• Ensure manufacturability

• Ensure repeatability

• Validate internal structural design

Experimental Validation

• Validate simulations through experimentation

• Simulate Mars flight conditions

• Test in a vacuum chamber

• Match Re and M number

• Compare blade performance against Ingenuity performance

Planetary Aeolian Laboratory at NASA Ames Research center

• Facility improvements for Mars rotor testing

• Pressure sensor selection and installation

• Improved facility pressure control

• Maintain constant pressure at Mars densities

For the experiment:

• Full scale rotor test

• Tip Mach number 0.7 to 0.95

• Hover flight

• Vary collective angle

For the experiment:

• Full scale rotor test

• Tip Mach number 0.7 to 0.95

• Hover flight

• Vary collective angle

Rotor performance: thrust, torque, RPM, collective angle and atmospheric conditions

Sensors, motor, controllers, and hardware

Hover stand design

Future Efforts

Future forward flight rotor testing of novel rotor blades in 2m x 2m cross-section wind tunnel

Tunnel to be operated in N242 PAL facility at Martian densities

Both wind tunnel design/ construction and forward flight rotor test stand to be completed and tested

Outcomes of Planetary Rotorcraft Research

• Understanding of low-Re high subsonic M aerodynamics

• Optimized airfoils and rotors for aerodynamic performance with structural design considerations

• Experimental validation – airfoil and rotor

• Design methodology/framework

• Increase Technology Readiness Level in support of future Mars rotorcraft missions

08. AV ASSESSIndustryDay_CodeAV_Cummings 11012022 final.pdf