System Requirements Review

AAE 451 Aircraft Senior Design Spring 2007 Continuous Area Coverage via Fixed-Wing Unmanned Aerial Systems System Requirements Review Team 3 Sumitero Darsono Charles Hagenbush Keith Higdon Seung-il Kim Matt Lewis Matt Richter Jeff Tippmann Alex Zaubi

Table of Contents Table of Content. 1 1. Executive Summary... 2 2. System Requirement Review 3-5 2.1. Business Case.3 2.2. Target Market.4 2.3. Concept of Operation.5 2.3.1. Military..5 2.3.2. Law Enforcement...5 3. Payload and UAV Components...6-10 3.1. Camera 6-8 3.2. Avionics..8-9 3.3. Fuel Cells..9-10 4. Powerplant.11-17 4.1. Engine..11 4.2. Propeller Selection..11-17 5. Aircraft Sizing...18-21 5.1. Constraint Diagram.18-20 5.2. Current UAV Characteristic...20-21 6. Aircraft Concept Selection 22-27 6.1. Pugh concept selection method 22 6.2. Design Criteria 22-24 6.3. Evaluation...24-25 6.4. Hybrid Concepts.26-27 6.5. Improvements on design..27 7. Conclusion and Next Step...28 8. Reference 29 9. Appendix...30-32 Page 1

1. Executive Summary Unmanned Aerial Vehicles (UAVs) are remotely piloted or self-piloted aircraft that carry specific payloads such as cameras, sensors, communications and other equipments during a mission to perform specific task. This includes forward reconnaissance and surveillance. The Department of Defense (DoD) has classified the UAV into seven main categories, the Pioneer, Tactical UAV, Joint Tactical UAV, Medium Altitude Endurance UAV, High Altitude Endurance UAV, Tactical Control System and the Micro Unmanned Aerial Vehicles 9. Currently, there are large numbers of UAVs available in the market. However, the availability of a UAV that is small, light, portable, cheap, and that is able to provide an endurance of greater than four hours is very limited. This project aims to explore the small UAV market for military and law enforcement and to provide an unmanned aerial system that is more capable than those that exist in the current market. Throughout the initial trade studies and aircraft sizing, the approximate weight of the UAV is 10 lbs with endurance of approximately four hours. The dimension of the UAV will be small enough such that it can be stored inside a Humvee or a police car. The UAV must also be hand launched to allow for rapid deployment in case of emergency. In addition, the UAV will be powered by a fuel cell and carry a small thermal imaging camera for forward reconnaissance. The concept generation and evaluation of the UAV is developed from the Pugh s Method. The evaluation involved several different configurations of the UAV based on its ability to perform the design requirement of the project. The resultant design is the integration of all the different configurations into one optimum design. Future work for the project includes validation of the aircraft sizing code, selecting an airfoil, determining the basic structure layout and components placement, and estimation of the aircraft c.g. and static margin. Page 2

2. System Requirement Review Mission Statement: To provide a continuous aerial coverage using an UAS that is small, light, portable and allows for rapid deployment The business case of the UAV, target market, and the preliminary design concept and parameters were part of the system requirement review. Based on the system requirement review, the UAV design will feature small size, portability, light-weight, low cost, and rapid deployment as the main criteria in the design mission. 2.1. Business Case Currently, there are a large number of UAV available in the market. However, the idea of a small UAV that is light, portable, cheap, and allow rapid deployment is something that the market has yet to explore. The current UAVs available in the market either have a limited endurance or larger size. The design of this UAV will solve both problems. Figure 1.: Evolution XTS L3 BAI Aerosystems In order to provide continuous coverage, the unmanned aerial system (UAS) will consist of a system of multiple aircraft and support equipment. They will work in conjunction to provide continuous aerial coverage over the area within a five-mile radius. The aircraft will house a small payload consisting of a video camera, a thermal imaging camera, or a chemical detector. The aircraft will either have a module payload or will carry all of the payload types simultaneously depending upon the final payload weight and the weight of Page 3

the cameras. The aircraft itself will be a micro unmanned aerial vehicle (UAV) that can be hand launched and carried in a military style backpack. The entire system will be transportable by two or three people depending on the number of aircraft needed. The support equipment is very limited and will consist of a small transmission unit and a laptop to program waypoints and view the incoming video feeds. The aircraft and transmission equipment will both be portable so that they can be used anywhere that surveillance is necessary. 2.2. Target Market The proposed system focuses on a surveillance market, which includes mainly military and law enforcement personnel. The military will deploy the system UAS out of either a backpack when on foot or out of a Humvee when traveling. The main uses for the UAS by the military will be for surveillance around a temporary base or convoy or for forward reconnaissance. Law enforcement will deploy the UAS out of the back of a squad car. The main use for law enforcement will be for assessing a hazardous situation before committing personnel or providing continuous surveillance of large groups. Budget ($M) Projected Budget for Procurement of Small UA Systems 25 20 15 10 5 0 05 06 07 08 09 Fiscal Year Figure2.: Projected Budget for Procurement of Small UAS 8 Since the beginning of the War on Terror, the market for small Unmanned Aerial Systems for the military sector has grown dramatically. Due to advances in sensors, Page 4

materials and batteries, the mission capabilities of small UAVs are ever increasing. Combined with the changing scope of warfare, current small UA systems are seeing more and more use in places such as Iraq and Afghanistan, and the United States military has decided to invest substantially in similar systems. In addition, the Department of Defense also planned to spend more than $20M on small UAV over the next three years (figure 2) 8. 2.3. Concept of Operation 2.3.1. Military Current unmanned vehicles of this size, the Dragon Eye and Raven for example, provide simple over the hill type missions where they observe a target location for a few minutes and then return; our system provides the capability to observe a location or multiple locations for hours at a time. The system can be deployed with the infantry at the squadron or platoon level. Similar to other systems of this size, the aircraft is simply launched by hand and does not require a runway. In addition, the entire system: aircraft, laptop, and supporting equipment would be transported via backpack or a small container in a Humvee (refer to Appendix III). 2.3.2. Law Enforcement Typically, police agencies can use the UAV to provide overhead surveillance in assessing hazardous situations before committing personnel. Similar to the military, police officers need to gather information on each mission before performing their actions. Usually, the law enforcement personnel carry out these missions. However, placing a police officer in a situation that is relatively unknown risky may jeopardize the police officer s safety. Currently, the alternative method is aerial surveillance provided by helicopter. Helicopters are very expensive to buy and operate, require dedicated pilots, and their availability is limited. Law enforcement agencies can use UAVs as a perfect substitute for a helicopter in the aerial surveillance role. 3 Page 5

3. Payload and UAV Components The payload weight for the UAV incorporates the sensor and communication equipment. Looking at sensors of the low resolution type, these components typically have weights around 2 4 lbs. The UAV will carry a system of visual and infrared cameras to provide day and night surveillance. A study conducted on many visual and infrared cameras to find the best set of cameras, communications package, and fuel cells. The selected components have to be light but and capable of performing the designed mission. Currently, the selected camera is the Photon OEM Core IR Camera with two lens option, 35 mm and 50 mm. For the avionics is the Advanced Miniature UAV, MP2128LRC, Autopilots by Micro Pilots and the fuel will be the Protonex Procore fuel cell. The current estimated of all the components weight can be seen from Table 1. Component 35 mm Lens 50 mm Lens Camera 0.275 lbs 0.275 lbs Lens 0.470 lbs 0.560 lbs Avionics 0.727 lbs 0.727 lbs Fuel Cells 4.41 lbs 4.41 lbs Total Weight 5.882 lbs 5.972 lbs Table 1: Current Estimate of UAV Component s Weight 3.1. Camera 5 For the aircraft payload, the limiting factor is the higher weight of the thermal imaging camera. The camera, the Photon OEM Core IR camera, is a small, rugged thermal imaging camera that is currently used in many micro unmanned aerial vehicles. The camera is produced by FLIR systems and has 320 by 240 pixels resolution. The camera updates 30 times a second, which produces continuous video to the human eye. The camera fits the current needs of the aircraft being produced because of its small weight and power consumption. The camera, without the lens, weighs about a quarter of a pound. It also has a very small volume slightly less than eight cubic inches. The camera also has Page 6

a power consumption of about 1.5 watts. This small power consumption will allow for longer flight time. The camera can be seen in figure 3. Figure 3.: the Photon OEM Core IR camera 5 The camera has the option of multiple lenses to suit different purposes. For the purposes of the aircrafts prescribed mission, the camera needs a resolution of greater than one pixel for every two square feet. Table 2 shows the necessary lens focal length for the given number of pixels per square foot. Distance (ft) Dimension (ft) Resulting Pixels Focal Length (mm) 2000 7 4 43 1500 5 4 46 1000 5 4 30 Table 2: Projected Results from the Camera 5 From the data in Table 2 the aircraft will have two lens options of 35.0 mm or 50.0 mm. The 35.0 mm lens operates well at altitudes of 1000 ft or less AGL. The 50.0 mm lens will operate at altitudes of greater than 1000 ft and up to 2000 ft AGL. The 35.0 mm lens has a horizontal field of view of 20 degrees and weighs.19 lbs giving a total camera weight of.47 lbs. The 50.0 mm lens has a horizontal field of view of 14 degrees and weighs.28 lbs giving a total camera weight of.56 lbs. The camera and lenses can be seen in Figure 4. Page 7

Figure4.: the Photon OEM Camera with Lenses 3.2. Avionics 4 For the UAV to be able to perform the specify capabilities, it needs a controller for the aircraft. Based on the design of the aircraft, the autopilot chips need to be light and consume minimum power. Currently, there are several miniature UAV autopilot controllers available on the market. Based on the mission criteria of the UAV, the autopilot chips must be able to perform both the autonomous flight using the GPS and the manual control flight. The design of the autopilot chip comes with aluminum enclosures. With the enclosure the weight of the component will be 0.727 lbs. With a volume of 38.5 inch 3, it is small enough to fit in inside the fuselage of the UAV design. However, it is under study that the aluminum enclosure could possibly be replaced by composite material to reduce the weight of the UAV. Figure 5: The Micropilot UAV Chip Weight at 28 g (0.06lbs) 4 The Advanced Miniature UAV, MP2128LRC, Autopilots by Micro Pilots is the world smallest UAV autopilot currently available in the market. The chip only weighs 0.06 lbs Page 8

(includes the GPS receiver) with an extremely low power requirement of 1 Watt. The autopilot chip has the capability to perform GPS waypoint navigation while maintaining constant altitude and airspeed. The autopilot can be controlled using three different modes, autonomous flight using the GPS, manual control flight, and the emergency direct servo control. The emergency direct servo control will be activated when the UAV loses contact with the transmitter, and it will direct the UAV back to the starting or predetermined location. Figure 6: The Micropilot UAV Chip Weight at 28 g (0.06lbs) 4 In addition, the transmitter has a range of more than 30 miles. This excess range of the transmitter allows the UAV to operate in the urban environment without the need to worry about the interference created by additional building. Parameters Value Weight 0.06 lbs Weight with Aluminum Enclosures 0.727 lbs Power Requirement 1 W Volume 38.5 in 3 Table 3: Specification for the Avionics 4 3.3. Fuel Cells 6 Based on preliminary trade studies performed in the System Requirements Review, the UAV requires a power system with a power density beyond the range of current batteries. This provides the necessary endurance and hand launch capability. Fuel cells have Page 9

shown promise in providing these high power densities and are just now entering the market. Protonex has developed the ProCore fuel cell system, which is specifically tailored to miniature UAV applications. The fuel cell relies on sodium borohydride as the fuel rather than hydrogen, which could be dangerous in a military UAV application. 1 The specifications of the fuel cell are shown below in Table 4 and a picture of the product is shown in Figure 7 6. Parameters Output Power Output Voltage Value 50-200 W 20-30 V Output Current 1-10 Amps Total Available Energy Weight 770 W-h 2000 g (4.41 lbs) Volume 170.8 in 3 Table 4: Specifications of Protonex ProCore Fuel Cell Figure 7: Protonex ProCore Fuel Cell As seen in, Table 4 this power system has an energy density of 335 W-h/kg, which is well above the 200 W-h/kg that the best batteries can provide. The power and voltage supplied by the ProCore system also appear to be sufficient to power the propulsion system as well as the payload and avionics. Page 10

4. Powerplant 4.1. Motor 1 The aircraft motor was chosen on the constraints of most power for the least amount of weight. To improve efficiency characteristics such as a brushless motor and non-ferrite magnets should be used. Because of the aircraft weight, the motor selection was limited to motors with the ability to lift 10 lbs on take-off as well as low rpm motors so that a gear box was not necessary to slow the motor rpm to a value that could be used to turn the chosen propeller. From the necessary characteristics, a motor study was done from available remote control aircraft motors. Through the study, the best motor for the aircraft was chosen to be the Model Motors AXI 4120/18 Gold Line. This motor is brushless and boasts neodymium magnets that produce larger magnetic fields than ferrite magnets and thus more torque. The motor can spin as fast as 9,000 rpm and has a maximum efficiency of 86%. The motor is applicable to aircraft weighing 2 kg to 5 kg, which encompasses the current aircraft weight. The motor can be seen in figure 8. Figure 8: AXI4120/18 Goldline Engine 1 4.2. Propeller Selection The propeller affects a number of different aspects of the aircraft. It affects the thrust of the aircraft, the speed of the aircraft, and the amount of power required from the fuel cell in order to fly at a specific speed. The efficiency of the propeller also has a large affect Page 11

on the range and endurance of an aircraft. Due to the small size of our aircraft, as well as the desire to keep development and acquisition costs as low as possible, existing model aircraft propellers became the focus of the selection process. There are a number of different model aircraft propellers available, varying both in geometry and material. There are several different types of materials such as wood, aluminum, plastic, nylon, and composite material available in the current market. Since weight is a major consideration, choosing a lightweight propeller is of major importance. The lightest propellers are made of nylon, and are very flexible, which would aid in survivability on landing. However, the efficiency of a nylon propeller is very low, and would not achieve the necessary flight performance in order to operate. Composite propellers are both lightweight and efficient, but they are not very rugged and are more expensive than most other types of propellers. Aluminum propellers are efficient, but very heavy. A plastic propeller is the best choice for our aircraft, as it has a good balance of efficiency, low weight, and durability. A two bladed propeller was chosen over three- or four- bladed propellers because of the low power availability from the fuel cell. While the thrust produced by the propeller is lower, the power required is significantly less. In addition to this, a tractor-type propeller was chosen over a pusher. The reason for this is the increased efficiency of a tractor propeller over a pusher propeller, because the airflow into a tractor propeller is undisturbed, or clean. The airflow into a pusher propeller has been disturbed by the wing and fuselage, so the efficiency of a pusher propeller is less than that of a tractor. In conducting trade studies and analyses of different types of propeller geometry, several variables were considered. These variables were propeller rotation speed, flight velocity, propeller pitch and diameter, thrust provided, power consumed, and propeller efficiency. Certain flight regimes and equipment place limitations on many of these variables, and from these limitations, the propeller best suited to for the UAV can be selected. The two flight regimes analyzed are takeoff and cruise/loiter. Takeoff is particularly important due to the fact that the aircraft is hand-launched. This places minimum requirements on Page 12

the initial velocity and thrust needed to successfully maintain flight after the UAV is released. The cruise and loiter regime is important because the flight conditions there determine the endurance of the aircraft, which is of major importance. The takeoff regime requires a velocity of approximately 30 ft/s, or 20 mph, and the motor operates at a rotational speed of 9000 rpm. This is a reasonable speed at which to expect the person hand-launching the aircraft to throw it. In order to maintain flight while climbing to its operational altitude, the aircraft requires slightly more than 2 pounds of thrust. This is based on a thrust-to-weight ratio of.2. The maximum power available for use from the fuel cell is 200 W, and there are approximately 5 W of power required to run the other onboard systems. This leaves a maximum available 195 W for use by the motor. Using plots of velocity, efficiency, thrust and power, the operating areas are obtained, and the best propeller geometry is chosen. These plots are given in Figure 9, with the design point marked on each graph. The curves on the plot are different pitch/diameter ratios. The diameter is held constant at 10 inches, limited by the geometry of the airplane. If the propeller were larger, it would strike the ground on landing. 1 Propeller Efficiency vs Velocity for Several Different Pitch/Diameter Ratios 0.9 0.8 0.7 0.6 η 0.5 0.4 0.3 P/D=0.9 0.2 P/D=0.8 P/D=0.7 0.1 P/D=0.6 P/D=0.5 0 0 20 40 60 80 100 120 140 V (ft/s) Figure 9a. Propeller Velocity vs. Efficiency for Takeoff Regime Page 13

4 3.5 3 Propeller Efficiency vs thrust for Several Different Pitch/Diameter Ratios P/D=0.9 P/D=0.8 P/D=0.7 P/D=0.6 P/D=0.5 2.5 Thrust 2 1.5 1 0.5 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 η Figure 9b: Propeller Efficiency vs. Thrust for Takeoff Regime 300 Propeller Efficiency vs Power for Several Different Pitch/Diameter Ratios 250 200 P (watt) 150 100 50 P/D=0.9 P/D=0.8 P/D=0.7 P/D=0.6 P/D=0.5 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 η Figure 9c: Propeller Efficiency vs. Power Plot for Takeoff Regime Page 14

The cruise regime requires a velocity of approximately 50 ft/s, or 34 mph, and a motor rotation speed of 7000 rpm. According to the thrust matching principle for steady, level flight, the thrust-to-weight ratio should be equal to the inverse of the lift-drag ratio. The estimated lift-drag ratio for the aircraft is 15. The minimum required thrust-to-weight ratio is then.067. The maximum available power is the same in this case as for takeoff, though the aircraft requires more power during takeoff, so that is the limiting condition. The plots for the cruise condition are given in Figure 10, with the operating point being indicated. The propeller size is limited by the takeoff condition, so the operating point simply reflects the point of operation at the previously selected pitch and diameter. 1 Propeller Efficiency vs Velocity for Several Different Pitch/Diameter Ratios 0.9 0.8 0.7 η 0.6 0.5 0.4 P/D=0.9 P/D=0.8 P/D=0.7 P/D=0.6 P/D=0.5 0.3 0.2 0.1 0 0 20 40 60 80 100 120 V (ft/s) Figure 10a: Propeller Velocity vs. Efficiency for Cruise Regime Page 15

2.5 2 Propeller Efficiency vs thrust for Several Different Pitch/Diameter Ratios P/D=0.9 P/D=0.8 P/D=0.7 P/D=0.6 P/D=0.5 1.5 Thrust 1 0.5 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 η Figure 10b: Propeller Efficiency vs. Thrust for Cruise Regime 140 Propeller Efficiency vs Power for Several Different Pitch/Diameter Ratios 120 100 P (watt) 80 60 40 20 P/D=0.9 P/D=0.8 P/D=0.7 P/D=0.6 P/D=0.5 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 η Figure 10c. Propeller Efficiency vs. Power for Cruise Regime Page 16

As can be seen from Figures 9 and 10, the chosen propeller has a pitch of 7 inches in addition to the 10-inch diameter. A plastic propeller of these dimensions is readily available from many different suppliers, costing approximately $3 $5. Compared to the overall cost of the aircraft, this is a small amount. The low cost also enables easy replacement of any propeller that may be broken on landing. Page 17

5. Aircraft Sizing 5.1. Constraint Diagram After selecting an initial concept, the aircraft must meet the desired performance capabilities specified by the customer or the concept of operations. Clearly, there are many variables and factors that influence the performance of the aircraft, so a constraint analysis is used to narrow down the choices to a specific region where further decisions can be made. The constraint analysis is a graphical method that is based on specific excess power, and plots the power to weight ratio as a function of the takeoff wing loading. The main equation in the constraint analysis is given below as Equation 1 1, 2 P SL βv q CD0 1 nβ WTO 1 dh 1 = + + + WTO αη p β W S ear TO / π q S V dt g For this aircraft, the stall speed will also be a dominant constraint as it defines the speed at which the aircraft must be thrown for takeoff. The wing loading for a specified stall speed is given in Equation 2, W S TO dv dt (1) 1 2 = ρvstall C L max (2) 2 To continue with the constraint analysis, the requirements of the customer and concept of operations must be translated into terms that can be used in the above equation. The following constraints were used to satisfy our specific requirements: - climb at 200 ft/min at 20% above stall speed in order to clear any obstacles near takeoff - perform a 2-g turn at a speed of 30 knots in order to maneuver in urban environments - loiter at 30 knots - accelerate at 0.35 ft/s 2 at 10% above the stall speed - stall speed must be less than 15.7 knots (18 mph) because that is the speed required for hand-launching the aircraft Page 18

The resulting constraint diagram is shown below in Figure 11, and the values chosen for the unknown parameters in Equation 1 are shown in Table 5. Note that this constraint diagram was done for sea level standard day conditions. Figure 11: Constraint Diagram Parameters Value Propeller Efficiency (η p ) 0.7 at Loiter 0.5 at Takeoff C D0 0.02 C Lmax 1.3 Efficiency factor (e) 0.8 Aspect Ratio (AR) 6 Fuel Fraction (β) 1 (electric power) Thrust Lapse Rate (α) 1 (electric motor) Table 5: Parameters used in Constraint Analysis Page 19

From the diagram in Figure 11, the design point is the intersection between the stall speed constraint and the 2-g turn requirement, where the region above the 2-g turn constraint and left of the stall speed constraint defines the design space. This sets the design point at a power to weight ratio of approximately 15 W/lb and a wing loading of approximately 1.1 lb/ft 2. As a sanity check, the target takeoff weight of the aircraft is 10 lbs, which, from the constraint analysis, puts the power requirement at nearly 150 Watts, well below the 200 Watts available from the chosen fuel cell 2. It appears that the current design point is a feasible solution that will allow the aircraft to meet the concept of operations; however, should the parameters in Table 5 change significantly or additional requirements arise, the constraint diagram will have to be revisited. 5.2. Current UAV Characteristic The current design of the UAV depends on the mission that the UAV needs to perform. Currently, the constraints for UAV characteristics are: - For the aircraft to be able to be hand launched, the aircraft must launch at a speed that is above the stall speed of the aircraft. To do this, the aircraft has to be small and light weight. Currently, the estimated weight of the aircraft is 10 lbs. - Endurance of the UAV will allow the aircraft to be deployed for a longer period. This factor is limited by the battery, the amount of power available, and the powerplant efficiency. Currently, the battery will allow the UAV to operate for approximately 4 hours. - Similar to endurance, the range of the UAV will be limited by the battery and the power plant. In addition, the communication relay and avionics of the aircraft will also affect the range. Since the CONOP of the UAV is to operate it near personnel or a ground station, the range of 5 miles should be sufficient. - Payload weight is determined by the weight of the camera, lenses and the avionics. The selections of these three components have been completed and it is estimated that the three components will weight approximately 1.395 lbs. - A fuel cell will be used due to lower weight and provide higher energy density. From the selected fuel cell, approximately 770 Watt-Hr will be available. Page 20

Parameters Current Target Threshold Units Value Weight 10 10 20 lbs Endurance 3.5 4 4 hrs Range 5 5 10 miles Payloads Weight 1.395 2 4 lbs Components Weight 5.972 6 6.5 lbs Weight Fraction 0.4028 0.4 0.5 We/Wo Table 6: Current Estimated of the UAV Characteristic Page 21

6. Aircraft Concept Selection Many current small UAV s performing similar missions were looked at for ideas for concept designs. Three designs, the AeroVironment Raven, Elbit Skylark IV, and L3 Evoution XTS each have unique characteristic. A successful design, and one to beat out the market, needs to look at what each of those aircraft provide, include the positive features and leave out the negative ones. 6.1. Pugh concept selection method The team developed the UAV concept using Pugh s Selection Method 2. By having a concept generation phase, many ideas can be created. With each design critiqued against an existing UAV, the team developed a matrix to aid in the selection of the best design. The matrix compares each design to the existing UAV by a set of design criteria. The design criteria are set by the mission and operations of the aircraft. Most often, a second iteration of Pugh s method is performed. Hybrid designs are added into the second iteration based on the key positive and negative features from the first iteration. 6.2. Design Criteria 6.2.1. Hand Launch Capabilities Figure 12 Hand launching of AeroVironment Raven The AeroVironment Raven has a very well suited fuselage for a hand tossed aircraft as can be seen in Figure 12. Just as the landing gear on an airplane is carefully placed, the Page 22

fuselage must be able to be held and thrown at the takeoff speed. Also, any propellers must also be placed in a spot which will not strike the throwers hand or arm.. 6.2.2. Propeller Performance The propeller performance of a pusher design is less efficient than the performance of a tractor propeller 7. Because the goal of this UAS is to provide longer coverage than existing UAS s, the plane needs to be as efficient as possible. 6.2.3. Crash Worthiness The design requirement of having the plane land without landing gear makes the bottom of the fuselage more rigid for harder landings. Any surface on the bottom of the fuselage will be damage prone. Because the front is where the visual sensors need to be, a replaceable cheap plastic cover will need to be placed over the visual camera as protection. 6.2.4. Handling In order to operate in an urban environment where other buildings obstruct the view and streets turn very quickly, the UAV will need to have sufficient handling abilities. The handling characteristics also need to be steady enough for an operator to control the aircraft remotely when the occasion arises. 6.2.5. View from Sensor Figure 13 - L3 Evolution XTS, side mounted camera The sensor needs to be mounted in the front of the aircraft to provide the need viewing capabilities. The view from the sensor of the Skylark has front and side capabilities, allowing the operator to pan to his target of interest. However, the Evolution XTS and Page 23

Raven have a fixed side mounted camera, allowing only one direction on the camera. Another important feature to consider is when the camera is in the front, the target being monitored becomes bigger rather than further away. 6.3 Evaluation With the design criteria, each design was compared to the Skylark I. Figure 14 - Elbit Systems Skylark I Design Criteria 1 2 3 4 5 6 7 8 Grip - E E - E - - - Stall Speed + E E E E E E E Propeller Performance - E E E - - - - Crash Worthiness - E - E + - - - Handling - E + E E + E + View from Sensor E E E + E - - E Minus 4 0 0 1 1 4 4 3 Plus 1 0 1 1 1 1 0 1 Even 1 6 5 4 4 1 2 2 Table 7: Aircraft Concept Selection Comparison Page 24

Figure 14: Aircraft Design Concept from top left to right: Concept #1 to 8 Page 25

6.4 Hybrid Concepts Though some designs have more negative comparisons, a couple of the other positive traits are merged into two hybrid concepts. The first hybrid takes Design 6 and improves on the grip by making the fuselage taller, but keeps the dual propellers. The dual propellers can be designed to survive a crash by keeping the blade out of the horizontal plane when tilted. Though front propellers have greater risk, the increase in performance is needed. However, if it is determined there is not enough power for one motor, then two will be used. V-Tail Detachable Wings Two Propellers Sensor Detachable Figure 15: Hybrid Model of the UAV Design The second hybrid design takes Design 2 and keeps the single propeller, sensor placement, and fuselage shape. The conventional tail is replaced by a V-tail to improve the handling characteristics and keep the tail surfaces safe from damage during landing. The second design is the chosen concept for this UAV as propeller data shows one propeller will be sufficient. Page 26

Selected Concept V-Tail Detachable Wings Detachable Boom Sensor Single Propeller Figure 16: Selected Concept of the UAV Design 6.5 Improvements on design The wing span, tail size, fuselage depth and height, boom length, and airfoil will change the shape of the selected concept based on final sizing parameters and component layout. Page 27

7. Conclusion and Next Step The design of the UAV that is small, light, low cost, and allows rapid deployment will provide the military and law enforcement greater reconnaissance and surveillance capability. Currently, the general concept of the UAV has been determined along with the components of the UAV, including the camera, avionics, fuel cell, engine and the propellers. In addition, preliminary constraints on the characteristics of the aircraft have been determined from the constraint analysis. As a next step, the team will further detail the dimensions and weights of the aircraft. Further study on the aerodynamic of the aircraft including the airfoil selection, aircraft drag polar, and aircraft performance will be performed. Work will also be put into the basic structural layout, component placement, and the stability of the aircraft. Page 28

8. Reference 1. AXI4120/xx. Model motors S.R.O. http://www.modelmotors.cz/index.php?page=60&kategorie=4120 2. Clausing, Don. Total Quality Development. New York: ASME Press, 1994 3. Law Enforcement UAVs. Aeronautics Defense System Ltd. January 25, 2007. http://www.aeronautics-sys.com/index.asp?categoryid=116&articleid= 280&Page=1 4. MicroPilot World Leader in Small UAV Autopilot. http://www.micropilot.com/index.htm 5. Photon OEM Core Camera. http://www.visioncom.co.il/m4_thremal_photon.asp 6. Protonex Technology Corporation. http://www.protonex.com/procoreuav.html. 7. Raymer P, Daniel. Aircraft Design: A Conceptual Approach.Blacksburg, Virginaia: AIAA Education Series. 2006 8. Unmanned Aerial Systems Roadmap 2005-2030, Department of Defense, August 2005, pp 39-51. 9. Unmanned Aerial Vehicle (UAVs) Military Aircraft. March 1, 2007. March 01, 2007 http://www.fas.org/irp/program/collect/uav.htm Page 29

9. Appendix Appendix I: QFD Page 30

Appendix II: UAV Database Vehicle Name Empty Weight (lbs) Gross Weight (lbs) Payload Weight (lbs) Maximum Endurance (hrs) Cruise Velocity Altitude We/w0 Azimuth 14.3 5.5 4.4 2 31.1 985 0.3846 AEROS 4.994 7.194 2.2 0.75 20.02 3000 0.6942 Pointer FQM-151A 4.994 8 2.002 1.5 40 12500 0.6243 Swift - Eye 3.96 14.08 6.6 0.67 29.92 14000 0.2813 Javelin 8.69 18 6 2.5 55 3000 0.4828 azimut 2 5.5 19.8 4.4 2 65 984 0.2778 Biodrone 15.4 22 6.6 1.5 70 984 0.7000 Aerosande 4 19.8 33 11 24 24.3 19880 0.6000 Seascan 24.25 33.95 7.054 15 56.38 16000 0.7143 MKY 66 35.2 30.8 2 67 9840 0.5333 Luna X-200 66 44 6.6 3 43.73 9800 0.6667 Phantom 88 50.6 18.04 3 56.4 9800 0.5750 MKY2 132 57.2 74.8 3 80.5 13120 0.4333 APID-2 121 77 44 4 62.1 985 0.6364 Mini- Vanguard 84.7 104.72 20.02 2.5 40.27 3000 0.8088 Tern 44.88 125 29.92 5 75 10000 0.3590 Dakota 70.84 132.66 49.94 3.4 126.585 15000 0.5340 Fox Tx 264 143 66 5 56.4 11500 0.5417 Futura UCAV 44 154 33 1.1 195 984 0.2857 Chacal 2 66 165 44 4 173 9840 0.4000 MK-105 Flash 105.6 198 59.4 3 50 10000 0.5333 Vixen/ Hellfox 139.7 199.54 49.94 4 64 2500 0.7001 Page 31

Appendix III: Military CONOPS Page 32