1. Daniel Graves –Project Lead James Reepmeyer – Lead Engineer Brian Smaszcz– Airframe Design Alex Funiciello – Airfoil Design Michael Hardbarger – Control Systems

2. Project Definition Mission Statement: The goal of the UAV Airframe C project is to provide an unmanned aerial platform used for an aerial imaging system. The airframe must support the weight and interfaces for the designed imaging system. The aircraft must be operated remotely and be a viable alternative to current aerial imaging methods. This is a second generation airframe, expanding on the previously laid ground work established by the P09232 UAV B Senior Design Project.

3. Risk Management

4. Customer Needs Key Project Goals:  Airframe must be able to carry a fifteen pound payload  Easy integration with measurement controls box and different aerial imaging systems  Ability to remotely control aircraft and activate payload  Ability for flight communication between aircraft and ground relay  Aircraft provides twenty minutes of flight time for local area photography  Aircraft has the potential to take off and land on site  Easy assembly and disassembly of the aircraft for transportation

5. Lessons Learned From P09232  The aircraft’s wings sheared off shortly before impact. The failure was determined to be from the bending stress applied to the wings during the banked turned.  After analysis, it was concluded that the main fiberglass spar used to support the wing was not selected properly to handle the flight loading.  High bend in the wing during flight inhibited the pilot’s control of the aircraft by reducing the effectiveness of the control surfaces.

6. Design goals based on lessons learned from P09232  Reduce wingspan (reduced bending moment)  Re-enforce wing spar  Reduce plane weight  Re-evaluate electric propulsion

7. Engineering Specifications  The aircraft shall have a maximum weight of 25 lbs without payload (40 lbs gross)  The aircraft shall have a flight ceiling of 1000 ft  The aircraft shall be able to sustain a flight of at least 40mph in calm conditions  The aircraft shall be capable of stable flight with a 15 lb payload  The aircraft shall utilize an open architecture payload interface

8. Engineering Specifications  The aircraft shall provide a mechanical interface to the payload  The aircraft shall provide a secure anchoring connection for the photographic instrument payload  The aircraft shall provide a secure mounting location for the flight control electronics package (P10236)  The aircraft shall sustain steady flight in a controllable manner for at least 20 minutes  The aircraft shall be able to re-launch as soon as it has been re-fueled or re-charged

9. Engineering Specifications  The aircraft shall be able to operate for at least 12 regular flights without needing routine maintenance  The aircraft shall be able to take off under its own power from a 1000 ft grass runway The aircraft shall have a sufficiently powerful motor  The aircraft shall be able to be transported in a motor vehicle when disassembled  The aircraft should be easy to assemble and disassemble by one person  The aircraft shall be able to navigate while on the ground

10. Engineering Specifications  The final cost shall be less than the cost of renting a Cessna for a day (~$8000)  The aircraft should have similar flight characteristics to a trainer RC plane  The wing shall support the plane’s gross weight under +4/-2 G loading The wings shall not become detached from the plane while in flight The wings shall not deflect to a degree that interferes with the operation of the flight control surfaces (will not jam the servos)

11. Engineering Specifications  The propulsion system shall provide uninterrupted, constant power for at least 20 min  The landing gear shall hold the plane at an optimal angle of attack while on the ground  The servos shall be of sufficient power to control the plane’s control surfaces at speeds up to 50 mph  The aircraft shall be structurally sound; no parts shall leave the aircraft while in flight

13. Learning from Airframe B  Based on Airframe B, worst case would be a wing failure  Airframe B was successful in meeting the total lift requirement

14. Design Objectives  Reduce the moment on the wing by reducing the wing span  Provide enough lift to lift the 40lb plane/payload

15. Wing Sizing  With a 9% cambered airfoil the same lifting capabilities are possible with a wing of 68% the total area  A NACA 9412 airfoil was chosen 10ft span 16in chord AR of 7.5 Based on initial analysis using NASA’s FoilSim at an AOA of 6 and a Speed of 30 mph

16. Level Flight Speed vs AOA

17. Bending Moment Reduction

18. Optimum Cruise  Cruise at best Cl/Cd ratio possible  Speed of ~41 mph  Wing AOA of 2.5 degrees

19. Tail Design  Horizontal Tail Area S HT =2.222 ft 2  Vertical Tail Area S VT =1.333 ft 2 Equations from Aircraft Design by Daniel P. Raymer

20. Horizontal Tail  Tail located 4 feet behind wing  Inclined at -4 degree to the planes axis  Symmetric Foil – NACA 0408

21. Cruise Pitching Moment  Zero moment at cruise speed  Allows for level flight at cruise

22. Control Surfaces  Horizontal Tail C e /C HT =.45 C e =3.375 in  Vertical Tail C r /C VT =.40 C r =3.2 in  Ailerons Placed on outer wing segments Surface of 2.5ft ○ Covering a total of half the wingspan Chord of 3in ○ 0.1875 the Wing Chord Suggested size ranges from Raymer’s Aircraft Design

25. Takeoff Analysis www.leancrew.com

26. Ground Friction Experiment dept.physics.upenn.edu

27. Climb www.grc.nasa.gov Climb Angle of 8 o Flight Ceiling of 1000ft

28. Cruise Segment www.grc.nasa.gov

29. Propulsion Analysis  After lots of decisions decided to go with empirical method of electric motor selection  Use 50W per pound minimum to takeoff  Use 75W per pound to attain “Trainer”- like Flight  Our Motor Needs to be minimum of 2000W to takeoff  The more motor power the more flight control

30. Propulsion BOM

31. Propulsion Summary DC Brushless Motor – AerodriveXp SK Series 63-74 - Produces 3200W at 37V Power Source – Zippy MaxFlight - 18.5V and 5000mAh per pack - 4 Total Needed (2 in Series, 2 in Parallel) - Total of 10000mAh at 37V Speed Controller – Turnigy Sentilon - 100A UBEC – Turnigy 5-7.5A UBEC for Lipoly Propeller – XP Type B Propeller 24x10

33. Landing Gear Summary  Front landing gear used will be the one designed for UAV B, in order to save on cost.  Tail landing gear will be an off-the-shelf system designed for large airplanes. Ohio Superstar Maxi Tail Gear (30-50lb planes)

34. Landing Gear Layout http://www.jacksonrcclub.org/images/landing_gear_types.jpg

35. Front Landing Gear Analysis  Front landing gear was designed and analyzed for UAV B and fitted for UAV C.  Since the landing gear was designed for the impact load of a higher weight plane it will work in this application.  Detailed analysis and method is unavailable  Complete FEA analysis of the part in the future to ensure reliability.

36. Tail Landing Gear Assembly  Tail landing gear was selected as an off-the-shelf system from an online hobby shop.  Due to the high weight application and high cost, retractable tail landing gear was not justified.  Three possibilities for tail Gear: Ohio Superstar Haigh Super Tail Gear (30-50lb plane) Ohio Superstar Maxi Tail Gear (30-50lb plane) Sullivan Tail Wheel Bracket (16-35lb plane) Information selected from Tower Hobbies. http://www.towerhobbies.com/

37. Tail Landing Gear Selection  Sullivan Target weight of UAV C is 40 lbs or less. Sullivan tail gear does not meet this maximum load.  Ohio Superstar Haigh Meets the target requirement Contains all necessary parts (wheel, bracket, etc) Costs $32.00  Ohio Superstar Maxi Target weight of UAV C is 40 lbs or less. Sullivan tail gear does not meet this maximum load. Contains all necessary parts (wheel, bracket, etc) Costs $22.60

38. Final Landing Gear Selection  The front landing gear will be the one designed for the UAV B. This is because it is readily available and inexpensive. Cost: Free  Tail landing gear will be the Ohio Superstar Maxi Tail Gear (30-50lb planes) because it meets the necessary plane requirements while being the least expensive option. Cost: $22.60 Total System Cost: $22.60

40. Main Spar Design Summary  Dragon Plate braided carbon fiber circular tubing will be used as the main spar. Cost: $237.00 Dimensions: ○ OD:0.79” ○ ID: 0.54” ○ Length: 48”

41. Main Spar Analysis  Assumptions At steady, level flight the wing is loaded uniformly across the span. Main spar supports the entire weight of the plane by itself. From the wing root outwards the spar behaves as a cantilevered beam. Normal flight load is 40 lbf Design will be to 5 g acceleration per guidelines in the RCAdvisor’s Model Airplane Design handbook. Due to symmetry, half the wing will be analysis.

42. Main Spar Analysis  Design Considerations Must remain under materials yield strength (elastic region) to avoid permanent deformation. Must not deflect excessively at flight load (less than 1 foot) in order for control surfaces to maintain effectiveness. Must be light in order to keep the weight of the aircraft at a minimum. Must be competitively priced compared to other options.

43. Main Spar Analysis  Materials Materials were selected that are readily available and have associated engineering data provided for analysis.  A supplier for fiber glass tube could not be found which supplied the correct spar dimensions as well as the appropriate engineering data for analysis.

44. Main Spar Analysis

45.  Aluminum 2024-T6 Yield Strength: 50 ksi Modulus of Elasticity: 10500 ksi  Aluminum 6061-T6 Yield Strength: 40 ksi Modulus of Elasticity: 10000 ksi  Dragon Plate Braided Carbon Fiber Yield Strength: 600 ksi Modulus of Elasticity: 43000 ksi Material properties for aluminum are taken from http://www.matweb.com Material properties for Dragon Plate are taken from http://www.dragonplate.com

46. Main Spar Analysis  The target size for the spar was set at an approximate OD of 0.75” and an ID of 0.5”  Since Dragon Plate carbon fiber has the best tensile strength, a tube profile which is readily available was selected to test against.  Aluminum 6061-T6 was not analyzed as it has provides less benefit than 2024-T6.  Test Profile: OD: 0.79” ID: 0.54”

47. Main Spar Conclusions  Please see accompanying handout for Analysis  Dragon Plate braided carbon fiber rods will be used as the main spar Superior factor of safety at flight loads Better at resisting deflection Lower weight Higher cost but provides vast improvement over Aluminum 2024-T6 ($87.24 difference).

49. Airframe Design

52. Payload Interface

54. Aft-Section Design

55. Control Hardware Mount

57. Front Landing Gear Mount

58. Wing Mount

59. Control Interfaces (physical)

60. Control Interfaces (electrical)

61. Daniel Graves –Project Lead James Reepmeyer – Lead Engineer Brian Smaszcz– Airframe Design Alex Funiciello – Airfoil Design Michael Hardbarger – Control Systems