Senior Design ProjectCirrus Design AEM 4331 Jon Anderson Mike Asp Kyle Bergen Ejvin Berry Cody Candler Jim Forsberg Mike Gavanda Alex Messer Dan Poniatowski www.cirrusdesign.com
Agenda Introduction Problem Overview Requirements and goals Program Plan Wing Trade Study Overview and Results Cargo Pod Design Overview and Results FMEA and Conclusion
Problem Overview • Wing Trade Study • Improve wing performance and design high lift devices that maintain current stall performance. • Cargo Pod Design • Design a cargo pod for the SR-22 that is able to carry two golf bags or two pairs of skis.
Wing Trade Study • Requirements • New wing design shall increase lift by 300 pounds at all flight conditions. • High lift devices shall allow for the same stall speed as the current wing. • Goals • No increase in drag • No increase in wing area • No increase in wingspan
Cargo Pod Design • Requirements • Pod shall not interfere with the safe operation of the SR-22. • Pod shall be designed for optimum user utility. • Pod shall not move the aircraft out of its intended center of gravity limits. • Pod shall be at least 8 inches from the exhaust. • Goals • Less than 15% drag increase • Pod is capable of holding two golf bags or two pairs of skis. • Pod is stylish and has good aesthetics
Wing Trade Study • Requirements: • Lift 300 more pounds of payload • Fly at same cruise speed and stall speeds Results: We were able to provide several solutions based on hand calculations. Our original approach using CFD failed.
Belly Pod design Requirements: • 2 sets of skis with equipment • 2 sets of golf clubs (with drivers) • Fishing poles Results: • Have a design that meets these goals
Alex Messer FlowWorks Validation 90 hrs
Simulation in FlowWorks • Goal: • Reproduce data found from wind tunnel test in FlowWorks • Method: • Build the same bodies that were tested in the wind tunnel in SolidWorks • Simulate various ways of building the same object • Simulate the same angles of attack and airspeeds used in the wind tunnel • Test different mesh resolutions • Compare resulting forces
Models Open Return Tunnel: Closed Return Tunnel:
Varying Reynolds Number Re = 3.0x105
Re = 3.4x105 Varying Reynolds Number
Re = 4.0x105 Varying Reynolds Number
Conclusions • What can we learn? • FlowWorks does not give realistic lift results • Drag results are reasonable • What can be done? • Numerical approximation • Xfoil • Wind tunnel tests
Conclusions Raymer, Daniel P. Aircraft Design: A Conceptual Approach, 4th ed., AIAA education series, Blacksburg VA, 2006
Derived requirements Current Cl in landing configuration at sea level at 60 knots is 1.98 We want to carry 300 extra pounds, so we need a Cl of 2.16 Must increase Cl by .18. From Raymer, we can calculate the increase in Cl due to the current high lift system being used on the SR-22.
Derived requirements From the current wing design at 60 knots, we have From Raymer, using a fowler flap Therefore, So we need to design a high lift system that will increase Cl by .83
Fowler flap • Jonathan Anderson • Hours: 100 • Designed a fowler flap system which produces the required
Fowler flap • Ways to increase Cl • Extend the offset hinge distance • Increase the flap deflection angle • Change the flap shape • Change the flap cove shape • Use a track system instead of an offset hinge • Experiments have shown that increasing the flap deflection angle to 40 degrees will produce the greatest in many different airfoils, (with a chord of .3c to .4c.) • Planes using flaps with 40 degrees deflection • Cessna 150, 172, 206, • DHC Beaver, Otter • Piper Seneca, Cherokee • The shape of the flap cove and the flap itself will also play a role in determining the maximum flap deflection angle and . Much of my time was spent looking for the right shapes in Floworks.
Fowler flap If we increase offset distance to 16 inches, and flap deflection angle to 36 degrees, we get a c’/c = 1.178. In increasing the flap deflection angle to 36 degrees, will also increase above 1.3. It is possible to get at least 1.5 depending on the design. More investigation of these ideas will be shown, but the actual number (1.5) is based on technical reports using Reynolds numbers within 10%. With these considerations, we can solve for using We find that
Fowler flap • This requires a flap that is 111.2 inches long • 5.2 inches longer than the current flap • Would impede on aileron • Need to move aileron down by about 5.2 inches. This is possible because there is 18 inches of room for the aileron to move. • Notes: • if the same flap span were to be used, the hinge offset distance below the wing would have to be 19 inches for a deflection of 36 degrees. • If the current flap—12 inch offset distance, 32 degrees deflection—were to be extended, it would need to be 145 inches long, pushing the aileron all the way to the tip and shrinking it 37% in length.
Fowler flap Offset hinge length is 16 inches Flap deflection angle is 36 degrees Length of flap is 111.2 inches Aileron is moved 5.2 inches toward tip
Figure on right is from reference 1, Reynolds number of 2.2e6
Slotted flap design guidelines • Optimum position of flap leading edge depends primarily on the shape of the slot, and is best determined by experiment • In general, moves inward when lip is increased but is generally about .01c forward of lip • Usually a slot opening on the order of .01c or slightly more is best. • Best Cl’s are achieved using flaps with a wing shape. Avoid flaps with a blunt leading edge. from “Theory of wing sections”, Ira H. Abbott and Albert E. von Doenhoff, p. 212-213. Dover Publications, NY, 1959. (reference 4)
Slotted flap design Two different shapes of slots with different flap shapes. The one on the left is a smooth slot with max cl=2.535, the one on the right has a small lip with max cl=2.57. For this experiment, Cl clean at the same (or near) angle of attack is about 1.3, and Reynolds number was about 8e6.
Slotted flap design Slot with a larger lip and with a maximum Cl=2.65. from “Wind-tunnel investigation of an NACA 23012 airfoil with various arrangements of slotted flaps”, Wenzinger, Carl J; Harris , Thomas A, Langley Research Center, 1939, ID: 19930091739 (reference 5)
Conclusions • The design will produce the required extra lift to carry 300 more pounds • The aileron needs to be moved by about 5 inches • If aileron can’t be moved, then the offset hinge must be 19 inches long • track system seems more practical in this case Remark: It is possible to get a higher than 1.5, provided a detailed study of the flap cove shape, flap shape, and location are optimized, therefore 1.5 seems like a reasonable value, but experiments must be performed to confirm this.
Jim ForsbergHours worked: 107 Designed a Plain Flap with leading edge slats system that achieved the required Designed a Fowler Flap with leading edge slats system that achieved the required
What will be considered to increase • Extend chord length, by changing position of slat. • Increase deflection angle (around ) on the Fowler and Plain flap. • Modify the shape of the Flap and Slat
Technical Reports In these graphs is around 1.4 for .16c Schwier, W., “Lift increase by blowing out air, tests on airfoil of 12 percent thickness, using various types of flap,” NACA Deutsche Luftfahrtforschung, Forschungsbericht, 1947
Technical Reports (continued) Quinn, John H. Jr., “Tests of the NACA 641A212 airfoil section with a slat, a double slotted flap, and boundary layer control by suction,” NACA Langley Memorial Aeronautical Laboratory, Langley Field, VA, 1947 From looking at the table and other technical reports it is reasonable to estimate that: At a 16% chord increase
Plain Flap and Slats Using this relationship: Withand an increase in chord of 16%, our = 5728 in^2 This requires the Flap Span to be 118 in.; 12 in. longer than thecurrent flap span Note: slat gets in the way of the transition cuff
Fowler and Slats Based on Raymer, the optimal for slats is 0.4. • Looking at technical reports, and interpolating, the slats need to produce around a 12% chord increase to get this . • Using the same relationship as before but now having be 0.18. This requires the slat span to be 92.6 in. long and the Fowler Flap to remain at 106 in.
Drawback to having Slats Known to create some drag compared to a non-slotted wing at cruise. Thus reducing the cruising speed. Heavier and more complex than other leading edge devices (slots). Deicing gets more complicated
Conclusion • Both the designs willproduce the required 300 more pounds. • The Plain Flap and Slat system require to have 12 in. more span than the current span. Moving the Aileron toward the tip and getting in the way of the cuff. • The Fowler with Slat system requires no change in span of the current wing and that the slat span does not interfere with the transition cuff.
Conclusion Going further: • Experiment with the Fowler and Slat system, to get a more accurate position for the Slat. • Continued research in finding a more precise for the Plain Flap and Slat system.
Michael AspHours Worked 105 I was in charge of designing a flapperon that would meet the design requirement for CL.
Mechanical Configuration Option 1 Option 2 *This would be investigated if we had more time to determine which set-up is more effective