Cargo Pod Design

1. Cargo Pod Design Kyle Bergen Ejvin Berry Cody Candler Mike Gavanda

2. Individual Report • Ejvin Berry • 68 hours • Tasks • Initial Aerodynamics Optimization • Quick Prototype Modeling • Final Concept Modeling

3. Cirrus SR22 Cargo Pod

4. Cargo Pod Guidelines With 2 passengers (including pilot), 4 hours of fuel, carry one of the following: • 2 sets of skis with equipment • Required volume of 12in x 6in x 79 in • 2 sets of golf clubs (with drivers) • Required volume of 35in x 11in x 50in • Minimum 8” offset from firewall

5. Pod on Fuselage

6. Clearance/ Tail Strike Envelope

7. Bottom View

8. Attachment View

9. Front Fairing (2) Rear Fairing

10. Conclusions • Demonstrates • Practicality • Meets required tasks, loads • Ease of Operation • Location specific • Aesthetic Quality • Aerodynamics

11. Recommendations • Study feasibility of manufacturing contoured pod surfaces to mesh with fuselage. • Increased capacity • Fit CG envelope better • Aerodynamics Improved

12. Attachment Methods Individual Report by Kyle Bergen 80 hours worked

13. Attachment to Longerons Three points of attachment for stability and ease of attachment Use longerons as hard points to anchor mounting brackets which extend to belly. One piece assembly screwed to belly attachment. Bolts secure attachment pieces together from embedded pieces in pod fiberglass

14. Front Mounting Brackets (Two)

15. Rear Mounting Bracket (one)

16. Under belly attachment from bracket to Pod (three)

17. Embedded in Top of PodSlides into underbelly attachment

18. Belly Plugs when Pod is not attached

19. General Analysis Cosmos Express in Solid Works was used to diagnose the stresses on parts Maximum forces were used with total weight of Pod with load (120 lbs), with 4 G’s applied and safety factor of 1.5. Total force of 720 lbs. C.G. of front loaded pod (two golf bags) calculated

20. General Analysis Cont. 216 lbs on each front attachment and 288 lbs on rear attachment. All bolts to the longerons and to the pod/belly attachments are ¼ in. Screws to the belly bracket attachments are in.

21. Allowable Loads Allowable Load=(Allowable Stress/Safety Factor)(Area) For Bolts and Screws of 304 Stainless Steel, Tensile Strength Yield is used as 31200 psi, a shear strength of half the yield is used, 15600 psi, though online sources show it much higher, I will use a low number. Bolts through under belly attachments are in double shear so we see an allowable load of 2297 lbs. Screws in Tension see the yield strength of 31200 psi, we see allowable load of 2297 lbs as well. (since in double shear we use twice the area and Yield strength is twice the shear strength we see the same result.) These allowable loads are well above what the pod would see.

22. Stresses in bolts to longerons Since there are two bolts into the longerons on each front attachment we take the Total force on each bolt to be 216/2 on the front for a force of 108 lbs. For the rear bracket each bolt sees 72 lbs. These bolts have a smaller area so we see an allowable load of 510.5 lbs in shear for each bolt. These requirements are met by the 304 Stainless Steel bolts of ¼ inch diameter.

23. Deformation Picture of front attachment • Multiplied many times for show • Safety factor of 2.47

24. Statistics • Piece was run with both 304 S.S. and Alloy 2018. • 2018 is chosen because of lower weight and higher yield • Weight of Piece is .22 lbs • Max Stress in Piece 18560 psi • Max Displacement is .005 inches at base.

25. Deformation Picture of Rear Attachment • Lowest Factor of Safety in design is 4.82

26. Statistics • Piece was run with both 304 S.S. and Alloy 2018. • 2018 is chosen because of low weight (3 times less) and higher yield • Weight of piece is 1.4 lbs • Max Stress in piece is 13880 psi • Max Displacement is .005 inches

27. Deformation in Under belly attachment to pod piece • Safety Factor of 1.95

28. Statistics • Piece was run with both 304 S.S. and Alloy 2018. • 2018 is demonstrated here • Data taken was for 288 lbs, so pieces are not exclusive to one attach point, three identical pieces. • Weight of piece is .31 lbs • Max Stress in piece is 1798 psi • Max Displacement in piece is .00005 inches

29. Displacement of Embedded Pod Piece • Safety Factor 25.48

30. Statistics • The piece was run testing both 304 Stainless and Alloy 2018. • 2018 is recommended because of its slightly higher yield strength and much less weight • Weight of piece is .32 lbs • Max Stress in piece is 1804 psi • Max displacement is .00005 inches.

31. Final Statistics • Total weight of the attachment method is 3.73 lbs • 304 SS would have worked for all pieces as well, and even reduced some of the displacement, however, the weight would have been significantly increase. • 304 SS is used for bolts since that is a primary use of 304 SS. • Alloy 2018 is chosen because it is a high strength alloy. It is very easily machined and is a tough alloy that can be used for heavy duty structural parts.

32. Conclusions • The attachment methods as designed work for the support of the cargo pod. • Front attachments are placed on the inside of the longerons at 19 inches behind firewall and rear attachment is placed between longerons at 69 inches behind firewall. Inspection of longerons looked to be good placement. • Would have liked to do further analysis on the Longerons and get more accurate dimensions. • Wish we would have nailed down a design sooner since a lot of the semester was spent on investigation of workable/do-able pod designs. • Further work would include optimization of current design pieces and trying different designs. • I would like to thank my team and Steve Hampton for all the support throughout the project!

33. Individual Report • Mike Gavanda • 70 hours • Worked on • Ground clearance • Tail strike clearance • Pod access

34. Solid works attached Pod model 3:07 AM

35. Clearance 3:07 AM

36. Solid Works model 3:07 AM

37. Clearance/ Tail Strike Envelope

38. Pod wheel Clearance 3:07 AM

39. Golf Bag Average Golf Bag Size 3:07 AM

40. Golf Bag Clearance 3:07 AM

41. Skis 3:07 AM http://www.salomonski.com/us/products/XW-Sandstorm-1-1-1-788918.html

42. Skis and pod

43. Access

44. Access Seal Camloc 4002 Studs* 2600 and 2700 series made of steel Shear: 1050 lbs. (ultimate) Tensile strength: 700 lbs. (rated) Rated to 450° F Example of watertight hatch seal** *www.aircraftspruce.com/catalog/hapages/camloc4002.php **www.trimlok.com/detail.aspx?ID=933

45. Conclusion • Meets clearance and size goals • Clears fully loaded landing • Clears tail strike • Safe distance from exhaust • Fits a pair of golf bags or 2 pairs of skis • Easy access

46. Recommendations Find more on how the exhaust affects pod See if clearance can be increased for landing and tail strike More study of water tight seal on access door

47. Individual Report • Cody Candler • 70 Hours • Tasks • Location of the center of gravity • Ensure it meets ground requirements • Aerodynamics Analysis • Range Optimization

48. Reference points of the front and back of the cargo pod while attached (Figure 6-1 out of the Cirrus Manual)

49. C.G. of the aircraft with the pod attached C.G. of pod located at FS 148.0 • No Luggage • Luggage – 25 lbs • Luggage – 50 lbs Sample Loading • Pilot – 200 lbs • Passenger – 200 lbs • Fuel – 486 lbs (full tank) • Cargo Pod – 100 lbs Center of Gravity Limits Moment Limits

50. Estimate CD for cargo pod Used Component Buildup Method out of Aircraft Design: A Conceptual Approach by Raymer Approach used: Find flat-plate skin-friction drag coefficient (Cf) • Assumed complete turbulent flow Find the component “form factor” (FF) • estimates the pressure drag due to viscous separation • assumed the pod to be a fuselage where • Amax is the maximum cross-sectional area of the pod which is 3.224 ft2 • l is the length of the cargo pod (6.583 ft)