Micro Air Vehicle Senior Design team Zach Kilcer

Micro Air Vehicle Senior Design team Zach Kilcer, Bill Strong, Joe Olles, Sean Dittrich, Brian Stumper, Doug Brown

Introduction: MAV History • 1996 DARPA initiative to develop a small unmanned aircraft for military applications. • 1998 Aero. Vironment successful in launching the Black Widow. – six inches in linear dimension – transmits video, GPS, altitude, velocity and heading 2

Introduction: MAV Global View • Government funding of large-scale development has ended. • Possible private sector applications of MAV technology has kept interest alive. • Research has continued to flourish at Universities around the world. – UF, UA, Notre Dame, Brigham Young • Annual international competition to keep interest in the field strong. 3

Introduction: MAV at RIT • Fourth year MAV Team at RIT • Offshoot of the RIT Aero Design Team • Current MAV Senior Design effort in support of MAV Team which competes annually. 4

Introduction: Current SD Goals • Current senior design team will develop the 2005 -06 propulsion system to be implemented in the 2005 -06 airframe. • Design will surpass previous design specs: – – – 80 g thrust 80. 5 g total weight withstand the routine crash landings sustain flight for 15 minutes compatible with the future airframes/electrical components – cross-over with 2005 -06 winter/spring MAV team 5

Concepts for design • Internal combustion Engine with a Propeller • Jet Turbine Engine • Variable Pitch Propeller • Shrouded Propeller • Ducted Propeller 6

Internal combustion Engine with a Propeller • Loads of power (. 27 horsepower @17000 rpm) • No assembly or modification required 7

Jet Turbine Engine • Produces large amount of thrust (13 -50 lbs) • No assembly or modification required 8

Ducted Propeller • Significantly increase thrust • Reduce propeller tip vortices • Increase durability of propulsion system 9

Variable Pitch Propeller • Maximizes efficiency of the propeller blade at both cruise and takeoff • Would be groundbreaking for an MAV 10

Shrouded Propeller • Increase thrust and efficiency • Reduce propeller tip vortices • Increase durability of propulsion system 11

Concept Evaluation: Pugh Chart Evaluation Chart 05 MAV Jet turbine Internal combustion engine Ducted Prop Shrouded prop Variable Pitch Prop Cost 0 - 0 - weight 0 - - - thrust 0 + + + size 0 - - 0 0 0 durability 0 0 0 + + 0 drag 0 - - - 0 + number of parts 0 - - - ease of integration 0 - - + 0 - Complexity of Design 0 - - 0 0 - Total + 0 1 1 3 2 2 Total - 0 7 5 4 2 5 Sum 0 -6 -4 -1 0 -3 12

Pugh Evaluation rationale • In discounting the IC engine and the jet turbine, the groups main focus was on the complexity of these designs. – Both designs will require some sort of controlled fuel delivery system which will then need to be integrated to the propulsion system • Variable pitch was also hit hard by complexity of design – The system will require miniaturized components that most likely would not be located commercially – It would require additional powered components for movement • All these systems would require excessive funds to produce, as well as put additional (excessive-IC/Jet) weight onto the airframe. • Shrouded and ducted propellers seem to offer the best chance for an overall increase in thrust before propeller optimization 13

Design Concepts to be Explored • Based on Results from Pugh Chart – 3 Designs 1. ) Maximizing 2005 Design 2. ) Shrouded Propeller 3. ) Ducted Propeller 14

Maximizing 05 Design • Easy design to produce with the teams limited resources • New motor findings will increase performance 15

Propeller Slippage and Tip Vortices • Propeller Slippage – Difference in Geometric and Effective Pitch • Tip Vortices – tip vortices occur where the high pressure area of the blade tries to invade the lower pressure area 16

Shrouded Propeller • Reduce tip vortices and increase performance of a propeller • Increase durability of propulsion system • Easy design to produce with the teams limited resources 17

Ducted Propeller • Reduce propeller tip vortices • Significantly increase thrust – acts as a nozzle, raising the exit velocity • Increase durability of propulsion system • Equation for Open and Ducted Props 18

Feasibility Testing • Static Test Stand Will be Used to: – Bench mark 2005 design – Effect of thrust by shrouding • Difference should be losses due to tip vortices – Prove thrust increase in ducted propeller • Limited research available on small scale propulsion systems 19

Feasibility Testing • Limited research available on small scale propulsion systems. • Need to benchmark 05 design. • Need to prove ducted propeller concept. 20

Test • Test uses load cell to compute force of propulsion system • Compare different concepts to each other -Thrust -Power Input -Drag 21

Test Matrix 22

Future Plans • Narrow to one main design concept • Optimize duct or shroud design • Optimize propeller design – Manufactured or molded – Plastic or composite • Electronics integration & optimization 23

Other Possible Features • Custom Propeller Blades – Would provide superior efficiency, weight, and durability – Requires custom built molds 24

Propeller Design • Two main theories used to design propellers: – Inverse Methods – Momentum/Blade Element Theory 25

Inverse Methods • Two Inverse methods to chose from: – First, based on the Prandtl-Betz Theory • Starts with an optimal circulation distribution and relates chord angle of attack for the best design case. – Second, computes profiles from velocity distributions • Based on propeller airfoil requirements • Tip requirements determined by compressible flow, hub determined by viscous effects. 26

Momentum Theory • Blade Element theory: – The airflow is treated as a 2 D flow with no mutual interaction between blade sections. – The blade is composed of independent elements – The differential element of fixed chord, is located at a specific radius-chord changes with respect to radius 27

The Velocity Triangle • The propeller blade does not only feel the effects of the upstream velocity, but also the velocity of rotation. • This is accounted for in the velocity triangle where actual velocity seen is the square root of upstream velocity squared plus tangential velocity squared. 28

Velocity Considerations • Since the foreward velocity of the MAV can be considered small compared to the rotational velocity of the propeller there isn’t much increase in velocity seen by the propeller • Even though small, the increase must be accounted for or errors in thrust analysis will occur 29

Velocity Considerations 30

Reynolds Number Considerations • As the radius is increased, the Reynolds Number curve grows steeper • Moving outward from the hub, Reynolds Number increases linearly 31

Reynolds Number Considerations 32

Electronic Considerations – Electric Motor • Electronic Motor includes three (3) types: – Brushed – Brushless – Coreless • Selection Criteria – – Brushless DC Motor Brushed DC Motor Coreless DC Motor Weight Current Thrust Propeller configuration • Optimize using gathered data given propeller specifications. 33

Electronic Considerations Battery • Li. Poly Batteries will provide the necessary power for all of the onboard electronics (present and future). • Li. Poly chosen over nickel metal-hydride (Ni. MH) and nickel-cadmium (Ni. Cad) for high charge density • Optimal battery selection by using the charts below Li. Poly Batteries 34

Electronic Considerations – Control System • Control System includes two (2) components: – RF receiver – Speed controller Speed Controller • Selection Criteria – Number of channels – Compatibility with existing RF transmitters – Size – weight – Range – Motor compatibility RF Receiver RF Transmitter 35

Electronic Subsystem Primary Electronics • RF Transmitter • RF Receiver • Battery • Electric Motor • Speed Controller Future Electronics • Servo Motors • Video Camera • Video Transmitter • Video Receiver Block Diagram of MAV Electronic System

Electronic Considerations – Future Requirements • Future Technology: – Two (2) servo motors – A video surveillance system Video Camera Video Transmitter Video Receiver Servo Motor • Considerations – Weight – Dimensions – Power requirements 37

Future Plans • Narrow to one main design concept • Communicate interface points with the MAV club • Select and purchase components • Build and test design • Use results for further optimization • Evaluate the performance of design 38