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At least 703 records · Page 39

Marsbee - Swarm of Flapping Wing Flyers for Enhanced Mars Exploration: NASA Innovative Advanced Concepts (NIAC) - Phase I: Final Report

Mars exploration has received significant interest from academia, industry, government, and the general public. Despite continued interest, flying on Mars remains challenging, mainly due to the ultra-thin Martian atmospheric density. Although the gravitational acceleration on Mars is 38 percent of Earth's 9.8 meters per second squared, the Martian atmospheric density is only 1.3 percent of the air density on Earth. The aerodynamic forces are proportional to the ambient fluid density. Therefore, flying near the surface of Mars has been considered nearly impossible. The proposed mission architecture (Fig. 1) consists of a Mars rover (already existing) that serves as a mobile base for Marsbees - a deployable swarm of small bio-inspired flapping wing vehicles. In one ConOps scenario, each Marsbee would carry an integrated stereographic video camera and the swarm could construct a 3D topographic map of the local surface for rover path planning. These flying scouts would provide a "third-dimension" to the rover capabilities. In other scenarios, each part of the swarm of Marsbees could carry pressure and temperature sensors for atmospheric sampling, or small spectral analyzers for identification of mineral outcroppings. In each scenario, the rover acts as a recharging and deployment/return station and data and communication hub. Human exploration of Mars is one of the major objectives of NASA and commercial entities such as SpaceX and Boeing. The identified innovations unique to the bio-inspired flapping Marsbee provide viable multi-mode flying mobility for Martian atmospheric and terrain exploration. A swarm of Marsbees provides an enhanced reconfigurable Mars exploration system that is resilient to individual component failures. These Marsbees can carry sensors and wireless communication devices in combination with a Mars rover and helicopters. These enhanced sensing and information gathering abilities can contribute to the following NASA Mars mission objectives: i) "Determine the habitability of an environment", ii) "Obtain surface weather measurements to validate global atmospheric models", and iii) "Prepare for human exploration on Mars." Various commercial entities, e.g. SpaceX and Boeing, are investing in technologies to transport humans to Mars.

Kang, Chang-kwon↗

Static Aeroelastic Modeling of a Sub-Scale Wind Tunnel Model with Novel Flap Concept

This paper examines the static aeroelastic modeling of a flexible wind tunnel model equipped with a novel control effector known as the Variable Camber Continuous Trailing Edge Flap (VCCTEF) system. The wind tunnel model is an approximately 10 percent sub-scale version of a wing designed to be equipped on a commerical transport aircraft such as the full-scale NASA Generic Transport Model (GTM). The structure of the model is made highly flexible such that a 10 percent of semi-span wing tip deflection is expected at a design lift condition, and a representation of the VCCTEF concept is incorporated on the model. Static aeroelastic modeling is conducted by using a representative single beam structural finite-element model coupled to a vortex-lattice aerodynamic model. The resulting aeroelastic model of the flexible wind tunnel model is compared against experimental wind tunnel test results from the actual model tested at the University of Washington Aeronautical Laboratory (UWAL). Comparison cases are made using reference and VICON measurements of VCCTEF flap deflections from the wind tunnel test data, and percent errors between the lift curve parameters are presented. The results show up to a maximum percent of error of <10% with regards to lift curve slope values between the aeroelastic model and the UWAL test data. The agreement of lift curve slope values from the aeroelastic model and experimental test results serves as validation for the coupled vortex-lattice finite-element static aeroelastic model.

Aeroelasticity↗

Real-Time Drag Optimization of Aspect Ratio 13.5 Common Research Model with Distributed Flap System

This paper presents a real-time drag optimization study of the aspect ratio 13.5 Common Research Model (CRM) with a distributed mini-plain flap system. A surrogate aerodynamic model of the aspect ratio 13.5 CRM is developed based on an aerodynamic database computed by a transonic panel method to capture the aerodynamic coefficients as functions of the angle of attack, flap deflections, and Mach number. A recursive least-squares parameter estimation algorithm is designed to estimate the aerodynamic parameters of the surrogate model. The estimated surrogate model is then used in an on-line drag optimization strategy based on an adjoint method. The results of the real-time drag optimization indicate a drag reduction of 2.46% for Mach 0.80, 3.37% for Mach 0.85, and 1.95% for Mach 0.88. The results show the convergence of all parameter estimates.

Drag Optimization↗

Dynamic Force Reconstruction of Transient Flap Control Force Experiments in a Hypersonic Wind Tunnel

This work details the design of a sliced-cone model with a flap embedded within the slice. The flap is controlled by a fast acting servo to simulate a control force of a hypersonic vehicle. Design considerations such as sensor placement, expected loading, servo arm selection, and cavity temperatures are detailed in this work. Such a design imparts a dynamic response of the test article and as such, dynamic force measurement methodologies are required to reconstruct the control forcing. Three methods are of particular interest: the Sum of Weighted Accelerations Technique, Time Domain Deconvolution Method, and Frequency Domain Inverse Method. Novel versions of each method have been applied to this dataset to improve the reconstruction accuracy.

dynamic balance↗

Dynamic Force Reconstruction of Transient Flap Control Force Experiments in a Hypersonic Wind Tunnel

This work details the design of a sliced-cone model with a flap embedded within the slice. The flap is controlled by a fast acting servo to simulate a control force of a hypersonic vehicle. Design considerations such as sensor placement, expected loading, servo arm selection, and cavity temperatures are detailed in this work. Such a design imparts a dynamic response of the test article and as such, dynamic force measurement methodologies are required to reconstruct the control forcing. Three methods are of particular interest: the Sum of Weighted Accelerations Technique, Time Domain Deconvolution Method, and Frequency Domain Inverse Method. Novel versions of each method have been applied to this dataset to improve the reconstruction accuracy.

dynamic balance↗

Performance of Elevated Hinge Flap Wavemaker

This data includes a sweep of regular wave runs characterizing the performance of an elevated hinge flap wavemaker. Maximum wave heights were run for 13 periods in a range from 0.5 s to 6 s. Data is saved in several formats including 'raw' analog voltages, 'mat' matlab files,'txt' csv, and 'dat' ASCII.

16 TIDAL AND WAVE POWER↗

An Investigation of Flow Characteristics at Mach Number 4.04 over 6- and 9-percent-thick Symmetrical Circular-arc Airfoils Having 30-percent-chord Trailing-edge Flaps

Section data obtained from wind-tunnel tests at Mach number 4.04 and Reynolds numbers of about 5.0 times 10 to the 6th power and 8.4 times 10 to the 6th power are presented for 6- and 9-percent-thick symmetrical circular-arc airfoils with 30 percent chord trailing-edge flaps. Pressure distributions, Schlieren photographs, and force and moment coefficients are included.

FLOW, VISCOUS↗

Theory of flapping flight

Before attempting to construct a human-powered aircraft, the aviator will first try to post himself theoretically on the possible method of operating the flapping wings. This report will present a graphic and mathematical method, which renders it possible to determine the power required, so far as it can be done on the basis of the wing dimensions. We will first consider the form of the flight path through the air. The simplest form is probably the curve of ordinary wave motion. After finding the flight curve, we must next determine the change in the angle of attack while passing through the different phases of the wave.

FLAPPING FLIGHT↗