LOCKHEED MARTIN CHALLENGE

PROJECT PLAN

ECPE 491/Engineering 466

CLIENT

Cory Tallman of the Lockheed Martin Corporation

FACULTY ADVISORS

Dr. Steve Holland Dr. Peter Sherman

TEAM MEMBERS

Jason Ekstrand

Tyler Fast

Peter Hodgell

Timothy Jacobs

Daniel Jason

Matt Krajewski

Jordan Lee

Aidan Rinehart

David Snyder

Matt Stemper

Scott Strong

Eric Villhauer

DATE SUBMITTED

October 12, 2009

Page | 1

REPORT DISCLAIMER NOTICE

DISCLAIMER: This document was developed as a part of the requirements of a multidisciplinary engineering course at Iowa State University, Ames, Iowa. This document does not constitute a professional engineering design or a professional land surveying document. Although the‐ information is intended to be accurate, the associated students, faculty, and Iowa State University make no claims, promises, or guarantees about the accuracy, completeness, quality, or adequacy of the information. The user of this document shall ensure that any such use does not violate any laws with regard to professional licensing and certification requirements. This use includes any work resulting from this student prepared document that is required to be under the responsible charge‐ of a licensed engineer or surveyor. This document is copyrighted by the students who produced this document and the associated faculty advisors. No part may be reproduced without the written permission of the course coordinator.

NOTE: * denotes work of 08-09 Lockheed Martin Challenge Team.

Page | 2

Table of Contents

REPORT DISCLAIMER NOTICE.............................................................................................................................................2

ABSTRACT..................................................................................................................................................................................... 5

EXECUTIVE SUMMARY............................................................................................................................................................ 6

ACKNOWLEDGEMENTS...........................................................................................................................................................6

CUSTOMER REQUIREMENTS...........................................................................................................................................7

STATEMENT OF NEED.............................................................................................................................................................7

CUSTOMER DESIGN CONCEPT.............................................................................................................................................7

SYSTEM DISCRIPTION..............................................................................................................................................................9

OPERATING ENVIRONMENT.................................................................................................................................................9

FUNCTION REQUIREMENTS...............................................................................................................................................10

NON-FUNCTIONAL REQUIREMENTS..............................................................................................................................10

USER INTERFACE REQUIREMENTS................................................................................................................................11

ACCOMPLISHED BY 2008-2009 TEAM..........................................................................................................................11

DELIVERABLES FOR 2009-2010 TEAM.........................................................................................................................12

MARKET LITERATURE SURVEY*.................................................................................................................................13

DESERT HAWK..........................................................................................................................................................................13

STALKER...................................................................................................................................................................................... 13

SCAN EAGLETM........................................................................................................................................................................... 14

DESIGN CONCEPTS.............................................................................................................................................................15

AUTOPILOT DESIGN............................................................................................................................................................... 15

Specifications...................................................................................................................................................................15

Capabilities........................................................................................................................................................................15

Sensors................................................................................................................................................................................15

Data Collection and Customization........................................................................................................................16

Backup of Automation Navigation System..........................................................................................................16

Turning Autopilot Navigation...................................................................................................................................16

Purchase of New Radio................................................................................................................................................16

Landing Procedure........................................................................................................................................................17

Page | 3

LAUNCH SYSTEM DESIGN....................................................................................................................................................17

Specifications...................................................................................................................................................................17

Bearing or Guide Design..............................................................................................................................................17

Slip Resistant Feet..........................................................................................................................................................18

Parachute Release System..........................................................................................................................................19

Leg Assembly................................................................................................................................................................... 19

IMAGING SYSTEM DESIGN.................................................................................................................................................. 20

Requirements for the Imaging System.................................................................................................................20

Current Camera Status.................................................................................................................................................20

Current Video Transmitter Status..........................................................................................................................23

Single Video Camera Approach................................................................................................................................24

Video Camera with Gimbal Approach...................................................................................................................24

Still Camera Approach..................................................................................................................................................24

Combination Video and Still Camera Approach................................................................................................25

PROPELLER DESIGN...............................................................................................................................................................26

WING DESIGN............................................................................................................................................................................ 27

Requirements...................................................................................................................................................................27

Aspect Ratio......................................................................................................................................................................27

Taper Ratio........................................................................................................................................................................28

Airfoil Cross Section......................................................................................................................................................28

Current State.................................................................................................................................................................... 29

FALL 2009 SEMESTER PLAN.........................................................................................................................................32

WORK BREAKDOWN STRUCTURE..................................................................................................................................32

RESOURCE REQUIREMENTS..............................................................................................................................................35

Resources Required for One Aircraft*..................................................................................................................35

Auxiliary Material Resources....................................................................................................................................36

Labor Costs........................................................................................................................................................................36

Total Cost...........................................................................................................................................................................36

FALL 2009 MILESTONES AND SCHEDULE...................................................................................................................37

Milestones......................................................................................................................................................................... 37

Fall 2009 Schedule.........................................................................................................................................................38

Page | 4

Page | 5

ABSTRACT

Currently, no unmanned aerial reconnaissance vehicle capable of vertical launch exists on the market. Lockheed Martin has asked us to design a prototype for them. The 2008 Team designed a plane capable of vertical launch but were not able to achieve stable video or a functioning autopilot system. We hope to finish these two features.

The existing UAV and launch system currently work to spec and no major changes are planned. However, the autopilot will need a number of new sensors and programmed to work with the plane. The camera system will likely need a complete redesign due to a number of issues that add together to create significant motion blur.

Page | 6

EXECUTIVE SUMMARY

Modern warfare has seen a shift in location to more urban settings. Urban structures are the new terrain for soldiers. These structures can be a large hindrance to military operations because they block large lines of sight. To better equip the modern solider a new system needs to be implemented. This new system should allow soldiers to see around urban structures which will provide them with an advantage over their opponent. The Multidisciplinary Design Class has the task of continuing the work of the Multidisciplinary Design Class of 2008-2009. The end result will be a Unmanned Aerial Vehicle (UAV) that can be utilized in urban settings for revealing dangerous situations. One of the largest differences of this UAV compared to other UAV already in use is the vertical launch capabilities. This will allow the UAV to maneuver over the top and in the midst of urban buildings. The UAV system should be completely autonomous ensuring simple use for soldiers. The UAV will be designed to launch, provide surveillance, and land autonomously. The soldier’s requirement is to input the waypoints. The camera system mounted on the UAV will provide live feedback to the launch station. The current task is divided into three sub groups; optics, which will research new cameras and implement a device capable of meeting resolution requirements, aeronautics, which will improve on the wing design from last year, and avionics, which will model the current aerodynamics to program the autopilot. These three groups will be integrated throughout the process to develop a seamless UAV vertical launch surveillance system.

ACKNOWLEDGEMENTSThe LM Challenge Team would like to thank Dr. Sherman, Dr. Holland, and Cory Tallman from Lockheed Martin Skunk Works out of Fort Worth, TX for all of their guidance and support on this project. The LM Challenge Team would also like to extend thanks and gratitude to last year’s team who made so many great steps towards accomplishing the goals set out for us.

Page | 7

CUSTOMER REQUIREMENTS

STATEMENT OF NEED

Currently, UAV technology is not capable of launching vertically for use in an urban environment. This makes it difficult for soldiers to see dangers in an urban combat zone. Due to this problem, Lockheed Martin has asked the ISU Multidisciplinary Design Team to design a UAV that can be launched within the confines of an urban setting. This vehicle will be used to fly low reconnaissance missions prior to U.S. ground troops occupying the designated area.

CUSTOMER DESIGN CONCEPT

Figure 1 - Detailed SolidWorks model of assembled UAV*

Page | 8

Figure 2 - Exploded SolidWorks model of UAV*

Page | 9

SYSTEM DISCRIPTION

Lockheed Martin recommends the design of the UAV to have an approximate gross weight of ten pounds which includes a target avionics payload of three pounds. This system should be able to fly for approximately one hour with fifteen minutes of setup time. The avionics subsystem must include video and navigation systems that are capable of communicating with a ground station. The UAV must be vertically, pneumatically rail launched. When launched, the UAV must be able to clear a forty foot tall obstacle located twenty feet down the flight path which represents buildings in an urban environment. After launch, the UAV must reach a cruise altitude of 100 feet and a cruise speed of 40 to 50 knots. The UAV will be designed for a belly landing. Lastly, this UAS must be able to fit in the back of a military Humvee for easy transport.

OPERATING ENVIRONMENT

The system will be designed to operate when wind is minimal, and no severe weather conditions exist such as rain, sleet, or snow. No provisions will be made for the possibility of operation in inclement weather.

The system will be designed to allow for transportation in a military Humvee (5'x2.5'x1.5') without damage to components or failure of subsystems.

Page | 10

Figure 3 - System Flowchart*

Page | 11

FUNCTION REQUIREMENTS

FR01- The UAV shall be capable of flying at a cruising speed of 40-50 knots.FR02- The UAV shall be capable of flying for 1 hour.FR03- The UAV shall be capable of resolving a 6 inch target 100 feet below the aircraft.FR04- The UAV shall be capable of vertical or near vertical launch from a pneumatic rail system.FR05- The UAV shall be capable of climbing to an altitude of 100 feet.FR06- The UAV shall be capable of clearing a 40 foot tall obstacle, 20 feet downrange.FR07- The UAV shall not be very noticeable to a ground observer.

NON-FUNCTIONAL REQUIREMENTS

NFR01- The UAV shall use an electric motor.NFR02- The UAS shall fit into the back of a Military Humvee (5’x2.5’x1.5’).NFR03- The UAV shall only fly under moderately calm, clear conditions.NFR04- The UAS shall be capable of autonomously navigating through GPS waypoints.

Page | 12

USER INTERFACE REQUIREMENTS

UIR01- The ground station for the UAS shall display real time video as transmitted from the onboard camera.

UIR02- The ground station for the UAS shall have the controls necessary for manual override of the UAV.

UIR03- The ground station for the UAS shall have the ability to transmit and receive flight data to the onboard autopilot system.

UIR04- The ground station for the UAS shall be mobile and have the ability to be transported in the back of a Military Humvee.

UIR05- The launch and control systems will be designed for easy set-up, taking approximately 15 minutes.

UIR06- Safety of operators and observers of the UAS will be of high priority when designing the system.

UIR07- The operator must have the ability to override the autopilot system through a remote control system.

ACCOMPLISHED BY 2008-2009 TEAM

A01- Rail launch UAV under R/CA02- Rail launch UAV-autopilot control for steady level flight, R/C control for take-off and

landingA03- Demonstrate in-flight live video feed.A04- Size constraints met

Page | 13

DELIVERABLES FOR 2009-2010 TEAM

D01- Project Plan–Sept 25th, 2009D02- Launch system verified—Oct 25, 2009D03- Simulink airplane model complete–Oct 31, 2009D04- Additional prototype body–Nov 18, 2009D05- Simulink control system complete–Nov 29, 2009D06- Testing of airplane and launch system–Dec 1 , 2009D07- New video system installed—Dec 1 , 2009D08- Final report –Dec 2, 2009D09- Complete positive identification test with camera system – February 15, 2010D10- Reduce total system weight to 10 lbs – March 15, 2010D11- Achieve a predetermined flight path under full auto pilot – April 15, 2010D12- Resolve an assault type weapon under autonomous flight – May 1, 2010

Page | 14

MARKET LITERATURE SURVEY*

Unmanned Aerial Vehicles have become a staple for modern military operations, ranging from tiny hand launched spy bots to massive aircrafts that can scan an area the size of Illinois in 24 hours. After conducting research on current UAS technology, three systems have similar capabilities as put forth by Lockheed Martin. These are the Lockheed Martin Desert Hawk and Stalker, and the Boeing Scan EagleTM.

DESERT HAWK

Military forces use the Desert Hawk system primarily for surveillance and reconnaissance during the day or night. The system is especially designed for portability, with a wingspan of 54 inches and an overall length of 36 inches. It weighs 6.5 pounds dry, with the possibility of adding 2 pounds of plug and play payload. The payloads range from a rotating camera that can be used to fix on targets at greater distances to a fixed camera which utilizes IR technologies to conduct surveillance during the day or night. Also A third camera can be used to allow the Desert Hawk to see in total darkness.

The Desert Hawk UAS has a lightweight, portable ground station that is capable of pre-flight planning and uploading waypoints for the UAV. It is also capable of sending real-time information, such as waypoints to dynamically change the flight path as needed.

The Desert Hawk also incorporates stealth characteristics. With its ultra quiet motor, it is not easily seen or heard within a 100 foot range.

STALKER

The Lockheed Martin Stalker is a UAS created by Skunk Works in 2006. The Stalker was created by the same team that made the Desert Hawk. The Stalker has a ten foot wingspan, its maximum take-off weight is fourteen pounds, and the endurance of the plane is two hours. The plane is hand launched and belly landed. The Stalker uses an ultra quiet electric motor and propeller, and it carries a camera payload along with the ability to carry other payloads. The Stalker’s camera system is quite advanced: it has modules for daylight, low light, and infrared cameras. The camera system can be detached to allow for droppable payloads. When landing the payload system retracts into the fuselage.

Page | 15

SCAN EAGLETM

The Scan Eagle™ is a UAS that was developed by Boeing for autonomous surveillance of the battlefield and introduced to the armed forces in 2005. The Scan Eagle™ carries a payload that consists of an inertial stabilized camera and turret for taking surveillance video. The camera can be swapped out for an infrared camera. Also onboard the Scan Eagle™ is a Synthetic Aperture Radar (SAR). The radar system on the UAV is the world’s smallest SAR. The Scan Eagle™ has a communication range of about 100 kilometers and has a flight time of over twenty hours at seventy knots. The Scan Eagle™ is launched using a pneumatic launching system that has been patented by Insitu®. For the landing phase of the flight, the Scan Eagle™ uses a hook retrieval system that uses a forty to fifty foot tall pole which has a hook on it that catches a hook on the UAV. Using differential GPS on the pole and on the UAV, the UAV is able to navigate to the pole and catch on the hook.

Page | 16

DESIGN CONCEPTS

This section reviews the design concepts which will be explored throughout the semester in order to better the current design.

AUTOPILOT DESIGN

A major goal of this year’s team will be to improve image quality by flying on a predetermined flight path about the target to focus video capture on the target. The flight path will be determined from flight testing and simulation and will most likely be in the form of a conic section. A flight path of this nature would focus the camera on a single point on the ground eliminating the blur associated with the moving airplane.

Specifications

MicroPilot Model 2128 Weight: 28g Dimensions: 100 (L) x 40 (W) x 15 (H) mm Power Requirements: 140mA at 6.5VDC Supply Voltage: 4.2-26VDC

Capabilities

This model from MicroPilot includes ground station software (Horizon), can handle up to 1000 waypoints with in-flight modification possible (FR01), and is capable of controlling up to 24 servos simultaneously. The on-board GPS updates at a rate of 4 Hz.

Page | 17

Figure 4 - MicroPilot Model 2128

Sensors

The 2128 provides support for airspeed (up to 500kph), altimeter (up to 12,000 MSL), IMU (3-axis rate gyro/accelerometers), and GPS. The accelerometers saturate at 4 G’s.

Data Collection and Customization

The integrated sensors – 4 Hz GPS and compass – provide the necessary data to ensure reliable launch and recovery of the aircraft (FR08). The number of I/O ports and user-defined telemetry allow for unparalleled customization of the autopilot, ranging from a special launch sequence initiation to in-flight refinement of PID control loops to the ability to monitor system performance and power usage. This autopilot also increases the modularity of the design (NFR02) by allowing for a broad range of changes during any future iteration or work on the project. Additional systems or redesigned systems may be easily incorporated into and controlled by the autopilot.

One of the primary limitations of the autopilot, with regard to our current launch sequence and mission, is the relatively low saturation point of the IMU accelerometers (4 G’s). Due to the high G-load, the accelerometers are unreliable during the launch phase. However, this issue can be overcome by implementing a custom launch configuration that does not rely on the accelerometers, but rather, on other peripherals that are unaffected by the G-forces.

Backup of Automation Navigation System

Currently, the UAV is set up to navigate using GPS signals exclusively, and is not prepared with backup support for the event of loss of GPS signal. The plan this year will be to add a 3D compass unit built by MicroPilot to the autopilot system to provide backup to GPS navigation. The ground station software or the autopilot can record the UAV’s position, altitude, and velocity at the time of GPS signal loss, then use the 3D compass and AGL to navigate to a preprogrammed landing position or towards the subsequent waypoints.

Turning Autopilot Navigation

This year, we will need to tune all PIDs to allow for waypoint navigation. Last year’s team was able to tune for pitch and yaw but we will be finding a way to tune all PIDs to allow for more confidence in our results and uniformity in our solutions. A large number of test flights will be necessary.

Page | 18

Purchase of New Radio

In case of loss of radio signal to the ground station, the current autopilot configuration is not compatible with the radio controller presets and does not allow for the UAV to return on a set path through the autopilot. In order for the flight to be completely autonomous in the event of a signal loss, a new radio system will need to selected, purchased and installed.

Landing Procedure

The UAV will not be required to land under autopilot control. The system will be switched to radio control once the UAV has returned from completing its mission and then landed manually.

LAUNCH SYSTEM DESIGN

Specifications

Launch a 10 lb UAV using a pneumatically power system Clear 40 foot tall obstacle within 20 feet down range Achieve a final speed of 35 knots 40 feet above ground Entire launch system must fit with the confines of a military Humvee. Launch must be nearly vertical

Bearing or Guide Design

The current launch system has a significant gap between the ceramic bearing and guide system, allowing for undesired degrees of rotation.

This problem can be remedied by the following solutions:

1.) Re-Coat Guide Rail

Using a Teflon coating will lower the coefficient of friction between the rail and UAV, allowing for higher velocities at launch. Dupont’s Lube-Coat cost $200 per unit and is heat, chemical, and weather resistant.

Page | 19

2.) Lower fit tolerance between bearing and guide rail

The ceramic bearing has a 90 degree cut-a-way allowing for additional play to prevent the launch from seizing (see figure to right). Reducing this cut-a-way should prevent rotation and focus more force on the UAV. Additional ceramic bearings will cost approximately $30.00 per unit.

3.) New Bearing Material

After researching various materials, the ceramic bearing in contact with steel proved to be most cost-effective combination. Harder materials may not scratch, but they are more expensive and will cause greater friction build up.

Slip Resistant Feet

Since the setup isn’t completely vertical, the support system is slightly displaced due to the horizontal component of the launch force. Utilizing slip resistant feet will limit, if not eliminate, this issue.

Solutions:

1.) Increase Pad Size

Using larger slip resistant feet will provide extra stability and help spread out the force over a larger area.

2.) Add Weight to Launch System

By adding weight to launch system will create a greater normal force to offset the large launch force. This can be done by adding sandbags to support legs, which are priced at $3.00.

3.) Using More Slip Resistant Materials

Rubber is currently priced at $0.95 cents / pound and would be a minor expense when compared to the stability it would add to the support legs.

Page | 20

Parachute Release System

Currently, the air cylinder propels both a PVC push rod and the UAV along the guide rail and into the air during launch. A string is attached to the end-cap of the PVC rod, which releases a parachute when the string reaches its end. The PVC rod decelerates, but still acts as a projectile and could cause harm to anyone down range.

Solutions

1.) Helicopter design

Utilizes a “helicopter-like” fin which releases immediately after launch. This design decelerates the rod a quicker rate which prevents it from gaining enough speed to cause any harm for bystanders.

2.) Bungy Chord

Currently, the string attached to the end-cap breaks nearly every launch. Installing hooks onto the end-cap and air cylinder would restrict the PVC rod from turning into a projectile. Using a bungy cord allows for multiple launches, and cuts down on set up time.

3.) Timed Fuse

Eliminate string attachment and utilize a timing mechanism for parachute deployment. This limits abrupt jerks during launch and fluent launch.

Leg Assembly

Support legs are currently (3) Aluminum square stock pieces with are attached to launch rail by (12) wing nuts. Although the supports fit it the confines of a Humvee, it makes for long assembly. Attachment of the legs to the launch rail needs to be improved to decrease assembly time. A part on one of the leg assemblies will need to be replaced.

Solution

1.) Collapsing Legs

This system incorporates folding legs allowing for a uniform launch system that can be easily assembled and broken-down.

2.) Telescoping Legs

This system will use a push-pin design to decrease assembly time and eliminate additional loose parts.

Page | 21

IMAGING SYSTEM DESIGN

Requirements for the Imaging System

The customer requirements for the imaging system are decidedly vague. We have decided to further constrain “resolve a 6” target” to be able to positively identify a handgun (approximately 7.25” x 4”).

The design of the plane adds further constraints.

The payload limits of the plane restrict the full camera system to approximately one pound This further limits us to requiring a simplistic design with minimal onboard electronics. The camera must have a suitably high resolution. Image size is constrained by air-to-ground bandwidth The camera system must work with the existing plane with minimal modifications.

Current Camera Status

Specifications

Weight: 137g

Dimensions: 55 (L) x 31 (W) x 31 (H) mm

Power: 180mA at 12VDC

Effective pixels (NTSC): 768 (H) x 494 (V)

Page | 22

Figure 5 - KT&C Model KPC - 650

The 2008 group choose the KT&C KPC-650 camera with a varifocal lens (Tamron 13VG550ASIISQ 5-50mm) to provide video capabilities to the aircraft. However, in-flight tests did not provide a meaningful assessment as to whether or not this camera will work in this application. The camera was tested in-flight, but an erratic flight path contributed to blurred video. While portions of the video were able to identify objects on the ground, most of the video was not useful.

This year’s group will first evaluate the camera performance on three fronts:

Mathematical calculations and simulation to assess the effects of vibration and flight path In-flight tests using the autopilot and a more stable flight path Lab testing using a moving camera

An expected limitation with this camera is a lack of manual control. This camera is designed to automatically adjust to the optimal lighting condition; most commonly by increasing the shutter time. However, at the speeds the plane will be moving this will lead to considerable motion blur. It is also limited to NTSC video (768x494) which necessitates the use of a high powered zoom lens to be able to identify a small target. This limits the time an object is in view (under .25 seconds in many cases) and introduces significant blur due to plane vibration. A higher resolution still camera (2 megapixel) would allow for a significant reduction in zoom and while retaining or improving the resolution capabilities.

If it is determined that the current camera will not meet the requirements, a new camera system will be purchased and added to the aircraft. The camera must be able to positively identify a 6-inch handgun at an altitude of 100 feet in face of challenges such as motion-blurring.

To simulate camera performance, a Matlab program was created which would take a variety of inputs and output a typical image frame and the corresponding values.

Page | 23

Figure 6 - Matlab Camera Blur Simulation

By inputting the parameters Height, Focal Length, Speed, Camera Resolution, Shutter Speed, CCD Size, and the rates of Pitch, Roll and Yaw, the program is capable of generating a predicted image frame and the values for Horizontal and Vertical image size (in feet), the size of a pixel (inches), expected motion blur, and the time an object will remain in view of the camera.

In the image, the red dashed line is the field of view of the camera. The center red box is the relative size of a 6” square and the overlapping blue box shows the corresponding motion blur for a given frame. The upper two boxes sets of boxes show the path an object will take while moving through the cameras field of view. With the creation of a predetermined flight path, the presence of motion blur will be minimized. This can be accomplished by focusing on the target for a longer period of time.

Page | 24

Current Video Transmitter Status

Specifications

Weight: 30g

Dimensions: 26 x 50 x 13 mm

Power: 500mA at 12VDC

Output: 1 Watt transmission signal

Operating Frequency: 2.4 GHz

The current video transmitter is not able to provide video transmission at the required distance. It is not possible to purchase a video transmitter at a power higher than 1W due to civilian regulations, but a higher power transmitter could be used in a final military product. While a directional antenna would provide greater range than the omnidirectional antenna used, a directional antenna would not work in the application of an aircraft transmitting data throughout its flight. The group plans to investigate purchasing a different antenna at the base station to improve the range of the video transmission system.

For testing and prototype purposes, onboard storage may be introduced. This would eliminate bandwidth and range issues while a military production model would be able to overcome these limitations with higher powered transmitters.

Page | 25

Figure 7 - LawMate Model TM-241800

Single Video Camera Approach

The existing video camera will likely be unsuitable due to lack of manual exposure controls, however a video camera with more features would still meet requirements.

Pros

Simple Use off-the-shelf NTSC video equipment to return data to ground Light

Cons

Low Resolution Current camera has no manual control

Video Camera with Gimbal Approach

Pros

Some correction for vibration blur Cons

Heavy Complicated - requires three servos that must react in real time to plane rotation No correction for velocity blur Vibration/rotation likely too rapid to provide much correction

Still Camera Approach

Pros

High resolution Lightweight

Cons

Complicated transmission protocol Limited refresh rate - 10 frames/second likely generous

Page | 26

Combination Video and Still Camera Approach

Pros

Combines fast refresh rate of video and high resolution still cameraCons

Heaviest two cameras Requires modification of plane Requires high bandwidth

Requirements Weighting

Existing Camera Gimbal Still Camera Combination Still/Video

Weight 3 4 2 3 2Simple 1 4 1 3 2Framerate 2 3 3 2 4Resolution 3 2 2 4 4Bandwidth 1 4 4 3 2Work w/ plane 3 4 1 3 2Total: 44 29 40 36

Figure 8 - Imaging System Design Matrix

Page | 27

PROPELLER DESIGN

It was suggested in the report from spring 2009 in the “Recommendations for Future Work” section that a 16 x 10 propeller should be tested in replace of the 14 x 10 propeller .The report states the motivation for using the 16 x 10 propeller would be to “produce a more significant amount of thrust at lower speeds…. [It] will be a better trade off for the launch portion…” Although the 16 x 10 propeller will produce more thrust for launch portion of the flight, it will have a significantly lower cruise speed and endurance.

Although a simple analysis can be conducted with respect to each propeller’s efficiency, to completely understand the extent of the tradeoffs between the two propellers they will need to be tested with the completed aircraft. Propeller efficiency is defined as

PA=ηpr P

Where PA is the power available from the motor propeller combination, ηpr is the propeller

efficiency, and P is the shaft power transmitted to the propeller from the motor. The propeller efficiency is a function of the advance ratio, J , which is defined as

J=V ∞

NDWhere V ∞ is the free stream velocity of the aircraft, N is the number of propeller

revolutions per second, and D is the diameter of the propeller. As J increases so does the propeller efficiency therefore a larger diameter propeller would make J smaller decreasing the propeller efficiency. This conclusion suggests that it would be more beneficial to try to reduce the weight

instead of increasing the propeller diameter if the thrust generated by the propeller is not sufficient at launch.

The 14 x 10 costs $4.98 and the 16 x 10 propeller costs $7.50 which compared to the rest of the aircraft are both relatively cheap. Compared to each other the 16 x 10 propeller costs more than one and half times the 14 x 10 propeller.

It may be such that the weight of the aircraft cannot be reduced and the thrust generated by the 14 x 10 propeller cannot be sufficient during launch. In this case a more powerful power plant configuration may need to be considered in order to obtain the desired cruise speed and endurance with the 16 x 10 propeller. Ultimately fight tests will need to determine the capability of each propeller.

Page | 28

WING DESIGN

Requirements

The requirements for this wing are outlined in the previous year’s report. The performance requirements are high enough lift to steady state cruise at 40– 50 knots with an all up weight of approximately 10 lbs. The wing must also develop enough lift at low velocities to accommodate the vertical launch sequence when the aircraft transitions from a nearly vertical trajectory to horizontal flight. Structurally the wing must be able to withstand the launch acceleration in excess of 20 g’s. Last year’s construction strategy using spyder foam cores with a carbon fiber skin proved to have adequate structural integrity. Utilizing the same construction method will produce a wing with enough strength and an adequately low weight.

Aspect Ratio

AR=b2

S

Aspect ratio has the most effect on the maximum coefficient of lift of a wing, more so than taper ratio. The equation is wingspan squared over the wing area. Increasing ARwill increase the

maximumCL and potentially the maximum lift force. Drag also decreases with an increase in AR,

and the maximum speed of the aircraft can increase. However, when AR is increased for a limited wingspan the total wing area can decrease which could lead to a lower actual lifting force. Decreasing chord also decreases the effective Reynolds number of the airfoil section which can lead to poor characteristics at low speed if the airfoil is not chosen carefully.

The AR effect on the maximumCL of a wing can be determined analytically using the following

equation and the 2D airfoil data.

dCL

dα=C Lα=

Cl α∗AR

(2+(4+AR2 )12 )

To utilize this equation the 2D lift slope is input as C l α and the equation is solved with a given AR

to find the lift slope of the 3-dimensional wing, per degree. Then, the 2D airfoil characteristics are used to determine the zero lift angle of attack, αL=0. Then, to find the total lift the difference in

degrees between the zero lift angle and the desired cruise angle is multiplied by the 3D lift slope.

Page | 29

XFLR5 is a freely downloadable program and is a GUI for the XFoil airfoil analysis FORTRAN code developed by Mark Drela. XFLR5 also a very effective means of 2D and 3D wing analysis. XFLR5 was used to determine 2D airfoil characteristics and to verify lift approximations.

Taper Ratio

Taper Ratio=crootctip

The Taper ratio increases the maximumCL, and decreases induced drag, but to a lesser degree than

the aspect ratio.

Airfoil Cross Section

The airfoil 2D cross section affects the wingCL and theCD. Balanced airfoil characteristics are

necessary for this project because there are a variety of different flight conditions the aircraft must adequately perform in. The takeoff and landing require stable flight (no stall), low moment, and high lift at low velocity. The cruise portion requires optimal lift at minimal drag with a low moment so not very much elevator trim will be required. For this project an airfoil with smooth transient response is also required because an autonomous navigation and stabilization system will be used. An airfoil with high moment and poor stall reattachment properties could saturate the autopilot and lead to stability problems.

An airfoil with higher camber will have a higher maximumCL and be thicker which will make it

structurally stronger longitudinally and more resistant to torsion. However, a highly cambered airfoil will not always perform better at low velocity because at extremely low Reynolds numbers the flow will separate causing a stall condition. A high cambered airfoil will also have higher drag because of the increased cross section and flow separation.

A moderately cambered airfoil will perform better at intermediate velocity and have better all around characteristics. It will not have the lowest drag possible for the cruise portion of the mission, and it won’t have the maximum lift for the takeoff and landing conditions. However, a medium camber airfoil will have a moderate moment and usually good stall characteristics.

Winglets and Boundary Layer Control Devices:

Winglets and other flow modification devices, when implemented correctly can positively modify the wing’s performance. Martin Hepperle’s model aircraft website provides information about winglet benefits and design guidelines. From his experiments the most beneficial and easy to implement winglet design is a sharp angle transition from wing to winglet shifted downstream 50% of the tip chord. The winglet’s function is to increase the effective AR and prevent the formation of tip vortices and induced drag. However, the size of the winglets and the orientation must be chosen

Page | 30

carefully to prevent the planform and skin friction drag increases from negating the positive aerodynamic effects of adding winglets. Winglets which are angled out from the center of the wing would also increase the lateral stability by inducing a dihedral effect even if the rest of the wing is flat.

Pneumatic and mechanical turbulators are used on low Reynolds number wings to trip the boundary layer flow from laminar to turbulent before the natural transition occurs. The intent is to decrease the size of the flow separation bubble and decrease the pressure drag created by the bubble. Turbulators are difficult to design because at intermediate Reynolds numbers they are very thin, are very sensitive to angle of attack, and require a very smooth wing surface to function correctly.

Current State

The current state wing design is outlined below and was tested with XFLR5 to verify performance predictions.

Airfoil: Clark Y

Wingspan: 56 inches

Root Chord: 10 inches

Tip Chord: 8.5 inches (taper starts 18 inches from wing tip)

Mounted with 2.5 degree AOA with respect to motor thrust line

Below are wing design tables which calculate the wing size needed based on the aspect ratio, velocity, weight and steady state flight conditions. Approximations made included a linear lift slope,

Page | 31

rectangular wing, and that the specifications of the airframe match the report. The numbers are generated using the lift slope correction equation and lift equation.

The constants used are:

Weight=10 lb

V ∞=45knots ≈64.29 ft / s

Clark Y

Current State

Weight, lbsCruise

Velocity, ft/s

Aspect Ratio

dCL/d_alpha, CL/deg

Steady State AOA,

degrees

Steady State C_L

S, Wing Area, ft^2

b, wingspan

inches

b in feet

c, chord inches

c in feet

10.00 64.29 4.00 0.06 7.00 0.43 4.71 52.06 4.34 13.02 1.0810.00 64.29 5.00 0.07 7.00 0.47 4.30 55.62 4.63 11.12 0.9310.00 64.29 6.00 0.07 7.00 0.50 4.04 59.05 4.92 9.84 0.8210.00 64.29 7.00 0.08 7.00 0.53 3.86 62.34 5.20 8.91 0.7410.00 64.29 8.00 0.08 7.00 0.55 3.73 65.51 5.46 8.19 0.6810.00 64.29 9.00 0.08 7.00 0.56 3.63 68.55 5.71 7.62 0.6310.00 64.29 10.00 0.08 7.00 0.57 3.55 71.48 5.96 7.15 0.6010.00 64.29 11.00 0.08 7.00 0.58 3.49 74.30 6.19 6.75 0.5610.00 64.29 12.00 0.08 7.00 0.59 3.43 77.03 6.42 6.42 0.5310.00 64.29 13.00 0.09 7.00 0.60 3.39 79.66 6.64 6.13 0.5110.00 64.29 14.00 0.09 7.00 0.61 3.35 82.22 6.85 5.87 0.49

Using this above analysis with the Clark Y airfoil data generated a wing planform very similar to last year’s design. This is the most efficient wing which will provide adequate lift and have a wingspan less than 5 feet to fit in the vehicle’s cargo area. So if a collapsible wing were feasible, efficiency could be increased by using a larger aspect ratio. Using a multiple piece wing would increase the weight of the design at the joint and create a failure point where the carbon fibers are discontinuous. However, a longer wing would allow for a greater aspect ratio without losing wing area. The maximum lift coefficient would increase and the drag coefficient would decrease which would allow for more efficient cruising conditions and higher maximum payload.

Page | 32

NACA 4414

Weight, lbsCruise

Velocity, ft/s

Aspect Ratio

dCL/d_alpha, CL/deg

Alpha, degrees

Steady State C_L

S, Wing Area, ft^2

b, wingspan

inches

b in feet

c, chord inches

c in feet

10.00 64.29 4.00 0.06 8.00 0.49 4.12 48.70 4.06 12.18 1.0110.00 64.29 5.00 0.07 8.00 0.54 3.76 52.02 4.34 10.40 0.8710.00 64.29 6.00 0.07 8.00 0.58 3.53 55.23 4.60 9.21 0.7710.00 64.29 7.00 0.08 8.00 0.60 3.37 58.32 4.86 8.33 0.6910.00 64.29 8.00 0.08 8.00 0.62 3.26 61.28 5.11 7.66 0.6410.00 64.29 9.00 0.08 8.00 0.64 3.17 64.12 5.34 7.12 0.5910.00 64.29 10.00 0.08 8.00 0.66 3.10 66.86 5.57 6.69 0.5610.00 64.29 11.00 0.08 8.00 0.67 3.05 69.50 5.79 6.32 0.5310.00 64.29 12.00 0.08 8.00 0.68 3.00 72.05 6.00 6.00 0.5010.00 64.29 13.00 0.09 8.00 0.69 2.97 74.52 6.21 5.73 0.4810.00 64.29 14.00 0.09 8.00 0.69 2.93 76.91 6.41 5.49 0.46

Using an airfoil with greater camber would have a positive effect on the low speed characteristics of the wing. The 2D lift slopes for the Clark Y and NACA 4414 are the same, but the NACA 4414 has a lower α L=0 which means at the same angle of attack the 4414 will generate more lift and has a

higher maximum lift coefficient. The camber of the Clark Y is approximately 3.5% and the NACA 4414 has a camber of 4%. While producing more lift the NACA 4414 also is thicker and would increase the wing weight because of volume and increases drag due to greater drag due to lift. Increasing the drag at steady state cruise will increase the power required if the planform is not modified accordingly to decrease the induced drag. As can be seen in the table above using the NACA 4414 would allow for a smaller chord still with a wingspan less than 5 feet, increasing the aspect ratio.

If a two piece wing structure was selected adding dihedral to the wing planform would be beneficial in providing lateral stability. Increased lateral stability would decrease the load on the stabilization system and pilot. Winglets could provide the same effect, but possibly to a lesser degree. Winglets would allow the current wings to be retrofitted and the wing design would not necessarily have to be changed.

Page | 33

Requirements WeightIncrease Aspect Ratio

Increase Span,

Sectioned

More Tapered

Wing

Higher camber airfoil

WingletsBoundary

Layer/Stall Control

Weight 7 7 6 7 7 8 10Manufacturabi

lity5 8 6 5 4 6 7

Efficiency 9 6 9 7 4 9 6Compatibility 7 9 5 7 6 9 9

Cruise Velocity 7 6 9 6 4 8 6Durability 6 6 5 6 6 7 8

Total 284 281 264 211 328 312

Page | 34

FALL 2009 SEMESTER PLAN

WORK BREAKDOWN STRUCTURE

Scott Strong Jordan Lee David Snyder Peter HodgellCreate prototype        Inventory/Order Prep        Material Lead Time 10     10Assembly 10     10Video System        Prepare Aircraft for Flight   15    Flight Tests   10    Evaluate Video System in Lab   10    Research Alternative Camera Systems   5    Finalize Design and Order New Parts   5    Integrate New Video Parts   5    Improve Wiring of Electrical Components        Rewire Electrical Components 10 5 10 10Document Wiring 10 5 10 10Improve GPS Back-Up System        3-D Compass        

Research Compasses and Order Part     10  Integrate Compass     10  

Integrate AGL Sensor     10  Video Transmission Range        Conduct In-Flight Range Tests 5 10   5Conduct Video Transmission Range Lab Tests   10    Research Alternative Video Transmission Systems   10    Finalize Design and Order New Parts   10    Integrate New Video Transmission Parts   10    Launch System Testing        With a tennis ball or t-shirt 5     5With a dummy airplane 10     10With essential flight systems 10     10Full Systems Test 10     10Computer Modeling of Airplane Dynamics        Wind Tunnel Testing for Dynamic Coefficients 10   15 10Derivation of 6 Degree of Freedom Dynamic Model 10   10 10Creation of Model in Simulink 10   15 10Design of Feedback Control System        Determine PID Loops to be Used     5  Integrate Control System with Airplane Model in Simulink

    5  Control System Gain Tuning in Simulation     5  In-Flight Control System Gain Tuning     5  

Totals: 110 110 110 110

Page | 35

Page | 36

  Aidan Rinehart Matt Krajewski Tyler Fast Eric VillhauerCreate prototype        Inventory/Order Prep   5    Material Lead Time 10 10 10 10Assembly 10 10 10 10Video System        Prepare Aircraft for Flight        Flight Tests        Evaluate Video System in Lab        Research Alternative Camera Systems        Finalize Design and Order New Parts        Integrate New Video Parts        Improve Wiring of Electrical Components        Rewire Electrical Components 10 10 10 10Document Wiring 10 10 10 10Improve GPS Back-Up System        3-D Compass        

Research Compasses and Order Part        Integrate Compass        

Integrate AGL Sensor        Video Transmission Range        Conduct In-Flight Range Tests 5   5 5Conduct Video Transmission Range Lab Tests        Research Alternative Video Transmission Systems        Finalize Design and Order New Parts        Integrate New Video Transmission Parts        Launch System Testing        With a tennis ball or t-shirt 5 5 5 5With a dummy airplane 10 10 10 10With essential flight systems 10 10 10 10Full Systems Test 10 10 10 10Computer Modeling of Airplane Dynamics        Wind Tunnel Testing for Dynamic Coefficients 10 10 10 10Derivation of 6 Degree of Freedom Dynamic Model 10 10 10 10Creation of Model in Simulink 10 10 10 10Design of Feedback Control System        Determine PID Loops to be Used        Integrate Control System with Airplane Model in Simulink

       Control System Gain Tuning in Simulation        In-Flight Control System Gain Tuning        

Totals: 110 110 110 110

Page | 37

  Tim Jacobs Dan Jason Jason Ekstrand Matt StemperCreate prototype        Inventory/Order Prep        Material Lead Time        Assembly        Video System        Prepare Aircraft for Flight 10 10   10Flight Tests 10 10 10 10Evaluate Video System in Lab   10 10  Research Alternative Camera Systems   10 10  Finalize Design and Order New Parts   5 10  Integrate New Video Parts   10 10  Improve Wiring of Electrical Components        Rewire Electrical Components 15 10   10Document Wiring 5 10    Improve GPS Back-Up System        3-D Compass        

Research Compasses and Order Part 10 10    Integrate Compass 10 5    

Integrate AGL Sensor 10 10    Video Transmission Range        Conduct In-Flight Range Tests 10   10 10Conduct Video Transmission Range Lab Tests     15  Research Alternative Video Transmission Systems     10  Finalize Design and Order New Parts     10  Integrate New Video Transmission Parts 5   10  Launch System Testing        With a tennis ball or t-shirt        With a dummy airplane        With essential flight systems 5      Full Systems Test 10 10 5 10Computer Modeling of Airplane Dynamics        Wind Tunnel Testing for Dynamic Coefficients        Derivation of 6 Degree of Freedom Dynamic Model        Creation of Model in Simulink        Design of Feedback Control System        Determine PID Loops to be Used       15Integrate Control System with Airplane Model in Simulink

      15Control System Gain Tuning in Simulation       15In-Flight Control System Gain Tuning 10     15

Totals: 110 110 110 110

RESOURCE REQUIREMENTS

Resources Required for One Aircraft*-(electronics/motors will be shared between aircrafts)

Bill of Materials (1 Aircraft)

       

  Quantity Vendor Category Part

$272.00 1 GraphiteStore.com Carbon Tube 1” IN/1.12”, OD 72” long carbon tube

$167.97 3 yards Soller Composites Carbon Fiber 3 yard by 40’’ piece of carbon fiber material

$18.99 1 yard Soller Composites Kevlar 1 yard by 50’’ piece of Kevlar

$26.97 3 yard Soller Composites Fiber Glass 3 yard by 38’’ piece of Fiber Glass $15.00 1 of each ACE Hardware 30 min

Epoxy/Hardener 

$1.20 2 ACE Hardware Wing T-Nuts 1/4” X 20 thread

$3.00 5 ACE Hardware Avionics T-Nuts 24 thread

$6.00 2 Hobby Lobby Internal Balsa Wood Strips for T-Nut Connections

$8.00 3 Hobby Lobby Tail Balsa Wood 4” X 36” ¼ inch sheets

$4.00 1 Hobby Haven Aileron Balsa Wood 1’’ X 36’’

$3.00 1 Country Plastics Firewall 3.5’’ X 3.5’’ X .5’’ Polycarbonate

$240.00 1 ACP Composites Spider Foam  

$360.00 4 Horizon Hobby Metal Gear Servos Digital Mini MG Servos

$5.00 2 ACE Hardware U-Straps Bag of ¾ inch plastic pipe straps $8.00 1 ACE Hardware Aluminum 1/8th inch by ½ inch bar stock

$3.60 6 ACE Hardware Nylon Bolts ¼’’ X 20 bolts

$3.00 5 ACE Hardware Avionics Nylon Bolts 10 X 24 bolts

$5.00 1 N/A U-Channel Aluminum 1’’X 0.5’’, only need 6’’ long (will have to buy longer) $18.00 3 ACE Hardware Spray Paint Vibrant Color Spray Paint for

visibility $3.00 3 Hobby Haven Control Horns  

$23.45 5 Tower Hobbies Propeller (+ extras) 14 X 10 Propellers

$6.00 1 Lowe’s Dowel (Launch Connection)

1’’ Dowel Rod

$14.00 2 ACE Hardware Double Lock Velcro 1’’ X 3’’ strips

$28.00 1 Lowe’s Industrial Velcro 15’ strip (Don’t need this much)

Page | 38

$12.00 2 Lowe’s Duct Tape Duct Tape for Strapping Plane together

Total Cost $895.18      

Auxiliary Material Resources

Material Cost    

Camera $200.00    

Remote Control $340.00 RC Transmitter/Receiver

Spectrum DX7 Package

Total Cost $540.00    

Repair Cost Estimation

Material Cost    

Carbon Fiber $200    

Hardware $50 Nylon bolts, u-brackets, hinges

Electronics $500 Servos, gears, propulsion batteries

Total Cost $750.00    

Labor Costs

Member Hours: Labor @ $20/hrScott Strong 160 $3,200.00Jordan Lee 160 $3,200.00

David Snyder 160 $3,200.00Peter Hodgell 160 $3,200.00

Aidan Rinehart 160 $3,200.00Matt Krajewski 160 $3,200.00

Tyler Fast 160 $3,200.00Eric Villhauer 160 $3,200.00

Tim Jacobs 160 $3,200.00Dan Jason 160 $3,200.00

Jason Ekstrand 160 $3,200.00Matt Stemper 160 $3,200.00

Peter Sherman (advisor) 25 $1,250.00Cory Tallman (industry professional) 10 $1,000.00

  Total $40,650.00

Page | 39

Total CostThe total predicted cost for this project is projected to be $42835.18

Page | 40

FALL 2009 MILESTONES AND SCHEDULE

Milestones

D01- Project Plan–Sept 25th, 2009D02- Launch system verified—Oct 25, 2009D03- Simulink airplane model complete–Oct 31, 2009D04- Additional prototype body–Nov 18, 2009D05- Simulink control system complete–Nov 29, 2009D06- Testing of airplane and launch system–Dec 1 , 2009D07- New video system installed—Dec 1 , 2009D08- Final report –Dec 2, 2009D09- Complete positive identification test with camera system – February 15, 2010D10- Reduce total system weight to 10 lbs – March 15, 2010D11- Achieve a predetermined flight path under full auto pilot – April 15, 2010D12- Resolve an assault type weapon under autonomous flight – May 1, 2010

Page | 41

Fall 2009 Schedule

Page | 42