1. P16121: SAE Aero Aircraft Design & Build
Preliminary Detailed Design Review

2. Agenda Project Review Design Features Phase Objectives
Manufacturing techniques
Drawing formats
Project Status
Design Features
Timekeeping and Setback Management
Phase Objectives
Full System
Analysis and Theory
Task Assignment Justification
System Level View
Preliminary Phase
Wing
Design
Wingbox
Fuselage
Landing Gear
Electrical System
Analysis
Fuselage and Landing Gear
Final Phase
Tail
Control Surfaces
Nose Cone
Design Schematic
Optimization and revision
Bill of Materials
Design Philosophy
Part Numbers
Design for Manufacture
Controllability, Durability, and Payload Capacity
Totals
Subsystem Breakdown
Manufacturing Considerations

3. Project Review
Project Status, Timekeeping and Setback Management

4. Summary of Project State
Engineering Requirements unchanged
Two subsystem changes
Airfoil
Landing Gear
Two serious setbacks in the last week

5. Engineering Requirements (Unchanged)

6. Airfoils S1223 E423 Pro or Con Detail: + - Pro or Con Detail:
Higher Cl
Designed for low Re
Cruise α more forgiving for stall characteristics -
Cmac very high
CD high
Manufacturing challenges
Pro or Con
Detail: +
Cmac lower
Easier to trim
Smaller tail allows for more lifting area -
Lower Cl
Flight conditions outside of traditional flight regime
Thicker trailing edge is easier to manufacture
At a particular angle of attack E423 generates more lift and less drag
S1223
E423

7. Landing Gear Previous situation Change
We had originally intended to use a conventional tricycle gear
However, we were exploring the option of switching to a tail dragger configuration to save vertical space
Change
Further design work revealed that the vertical space savings were minimal and that various complications presented themselves
(Stall angle with eppler, Operational uncertainty)
We have officially reverted to a tricycle design

8. Setbacks Test fixture fabrication failure Data loss
Weld work performed in the machine shop was not done as instructed by the drawing. Rework is needed
Data loss
Drive failure on the 16th resulted in the loss of most of the CAD work done this cycle. Effort to recover have been mostly successful but we have not progressed as far as we had hoped to

9. Repair and rework of static test fixture
Test fixture needed to verify thrust equations
Welds not performed as indicated on drawing
Part excessively heated: warped as a result
Part not assembled properly prior to welding: holes do not line up correctly
Weld not properly centered, access to an internal bolt hole is obstructed
Assessment of feasibility of repairs vs. starting over delayed by other obligations

10. Data Recovery
Efforts to recover the data were unsuccessful due to how dramatic the storage hardware failed.
Edge remains unfriendly to solidworks assemblies
Current plan is to make more effective backups
We have remade what was lost and are now at 80% of where we had hoped to be at this time prior to the failure

11. Revised Gantt Chart
In the light of recent setbacks and success ahead of schedule we have adjusted our schedule. Available on edge in better resolution.

12. Plan moving forward
Structural analysis and optimization of existing parts
Design remaining parts and analyze their structure.
Now that the fuselage and landing gear are complete the final aerodynamic iteration can be completed. Results are promising and control surfaces will be sized soon.

13. Long Term Testing Plan
At the present we have identified 5 tests that will need to be performed. Three are in place to satisfy the engineering requirements. The other two are to verify the analysis.

14. Phase Objectives
Overview of objectives for content covered in this review and that upcoming goals

15. Preliminary Detailed Design Objectives
The major objective was to design as much of the aircraft as possible to leave time for revision in the next phase.
Priority was given to structures which would influence other structures.

16. Detailed Design Objectives
Finish first round design
Control surfaces and tail
Revise design work from preliminary phase and correct known problems
Reduce weight and takes steps to balance the aircraft

17. Design Philosophy
Discussion of methodology and design decisions not related to analysis

18. Design for Manufacture
Laser cut wood parts and waterjet cut aluminum
Accurate and quick operations to manufacture
Assembly not substantially easier or harder
Requires that we make ‘flat’ parts
Minimize welding
Experiences with welded parts in the machine shop do not inspire confidence in the quality of our parts, so we are attempting to avoid using the process as much as possible.
Tongue and groove construction is a good way to do this

19. Order of Priorities: To control our known risks
Controllability: Uncontrollable aircraft is a safety risk and a threat to the airframe.
Robustness: Pilot error is a risk that we cannot control, so we must make the airframe as able to survive an error as possible. We will have numerous flights over the testing cycle and it would be unfeasible financially to make substantial repairs.
Payload Capacity: Seems counterintuitive to place this as our lowest design directive, but failure to meet the others first represents a more serious form of failure than simply not doing well in the competition.

20. Manufacturing Considerations
Manufacturing techniques and considerations as well as the drawing format

21. Manufacturing Techniques: Materials
Laser cut balsa and basswood: All parts not part of the direct payload support
Waterjet cut 6061T0 and T6 Aluminum: Parts which directly support the payload
Prof. Bonzo suggests that parts thicker than 0.125” will not get good results on the water jet without finishing machining work
Jet is Ø.040 and round- limiting our smallest radius
“Unsatisfactory results” producing round holes less than Ø such holes need to be drilled

22. Drawing Format
We have several drawing formats that we need to operate around.
Despite internal debate, we have chosen Solidworks as our CAD suite. Solidworks drawings are acceptable for our purposes.
Laser cutter requires autocad style .dwg files. Solidwork drawings use the .dwg extension but they are different.
The water jet also requires autocad style .dwg files and paper drawings. It is acceptable for the paper drawings to be made in Solidworks.

23. Design Features
The model broken down into its smaller components and analyzed

24. Full System Analysis and Theory
Most of this semester so far has been devoted to aerodynamic analysis of the system.
Our structural design constraints come from the aerodynamic analysis.

25. Aerodynamic Design and Sizing: Final Iteration
“Frozen” as of October 5th, 2015
Optimized for lift generation
Maintain static stability in accordance with cargo-transport aircraft criteria
Overall dimensions drive structural design

26. Final Sizing Diagram
This is the master sizing document. Requirements of this document and several auxiliary documents drove the structural design efforts.

27. Final Wing Design

28. Final Horizontal Stabilizer Design

29. Final Vertical Stabilizer Design

30. XFLR5 Aerodynamic Model

31. Fuselage Sizing

32. Aircraft Longitudinal and Directional Static Stability

33. Zero-Lift Parasite Drag Calculations

34. Overall Aircraft Aerodynamics (From XFLR5 Convergence)

35. Aircraft Performance

36. Full System View

37. Partial System View
Not seen: port wing, wing sheathing, motor, monokote, tail, control surfaces

38. Side View of System
Bolting not shown.

39. Top View
Of particular note is the wingbox- wing spar interface which will be elaborated on more later

40. Wing Design

41. Control surfaces are not included in this iteration of the design as their sizing is sensitive to these designs
The complete wing
In order to prevent the monokote from shrinking too much and distorting the shape we intend to sheath it in balsa. Sheathing not shown for clarity.

42. Top View of Wing Tip Main Spars Foam Wing Tip
Present in image is the transition between all three wing profiles as well and other areas of interest

43. Side View of Wing Main Spars Lightening/Wiring Holes Outer Spars
Demonstrating tendency of wing ribs to migrate down and backward as a result of decreasing rib size

44. Wingbox Design

45. The Wingbox
Interfaces wings, tail and fuselage. Accommodates the wiring that will run from the electronics bay to the control surfaces.

46. Side View of Wingbox Spar interfaces
Bolt holes to interface with fuselage
Side View of Wingbox
1”x0.5” rectangular aluminum spars connect each wing to the wing box. Each will be pinned in place through the bottom of the box.

47. Top View of Wingbox showing servos and spar connections
Likely Pin Locations
Top View of Wingbox showing servos and spar connections
Aluminum plates will run on above and below the spars. This will provide for stability of the wingbox even when the wings are not present and help to secure the spars after assembly.

48. Detail of tail boom interface and tail servos
The tail boom will be rectangular and will be bolted to the wingbox.

49. Outer Wingbox Bracket

50. Inner Wingbox Bracket

51. Cross Strips

52. Wingbox Analysis

53. Stress Analysis

54. Stress Analysis

55. Fuselage Design

56. Detail View of the Fuselage
Payload Bay
Electronics Bay
Motor Mount
Detail View of the Fuselage
The electronics bay is located forward of the payload bay. Fuselage area aft of payload bay is simply present to support the arming plug and for aerodynamic reasons.

57. Aeronautical Landing Gear Design

58. Aeronautical Landing Gear Design Cont.

59. Aeronautical Landing Gear Design Cont.

60. Landing Gear
Placement of gear is selected to ensure that the main gear (rear) support 80% of the load

61. Channel down the middle of the Platform
Arming plug support
Arming plug cable goes here
Channel down the middle of the Platform
The arming plug must be located aft of the payload bay. For this reason we will be running a high voltage line back through the middle of the floor to reach the arming plug

62. Rear View
Track is wide enough to ensure ground stability

63. Fuselage Analysis

64. Stress Analysis

65. Stress Analysis

66. Stress Analysis

67. Electronic System Design Schematic
Design is the standard for model aircraft modified only to accommodate the power limiter.

68. Bill of Materials
What we have, what we need, and how we plan to get it

69. Part Numbers
We devised a simple part numbering scheme to assist in keeping track of our parts and files as they multiply
Designations:
A#### – Assembly
N#### – Multi-use
P#### – Fasteners
F#### – Fuselage
W#### – Wing
E#### – Electrical
C####- Control Surface
G#### – Landing Gear
T#### – Tail
B#### - Wingbox

70. Totals Budget is as of current bill of materials
Not Included: Tail, Landing Gear, Fasteners
Cost will increase as design progresses

71. Fuselage

72. Wingbox

73. Wings

74. Electronics

75. Tail

76. Landing Gear

77. Fasteners

78. Risk Assessment

79. Questions? Suggestions?