PFR - Aerospace Engineering Sciences Senior Design Projects ...

More documents

Recommendations

Info

Project Final Report – CUDBF April 30 th , 2009 ASEN 4028: Aerospace Senior Projects The maximum stress from COSMOSWorks produces a stress of 951.1 psi at a stress concentration close to the wing root. This is expected due to the maximum bending moment at the root. Using the balsa tensile yield strength of 2,900psi, the minimum safety factor of the wing is 3.05. The wing also shows a stress drop across the motor mount. 8.4.4 Folding Wing System The ability of the aircraft to fit into the 2ft x 2ft x 4ft box is feasible only with a well designed folding wingtip that can withstand the forces along the wing, minimize vibrations, and fold enough to allow the aircraft ample storage room within the required space. The final wing folding design can be seen in Figure 60. Figure 60: Wingtip Hinge Design First, the hinge selected. A traditional cabinet hinge, a concealed Half-Mortise/Integral hinge, was used for its ability to provide a degree of pre-stress to the wingtip to minimize excessive movement during flight. Figure 61 shows the integral hinge [26] . Figure 61: Integral Hinge When the hinge is folded, the spring forces the moving parts into the recessed cavity in the door leaf. This allows the hinge to pull the wingtip into the main section of the wing. Both the tip and main section are lined along the edge by rubber sheeting. When pressed together, free-play in the hinge system is mitigated by the pre-stress and frictional force enacted by the rubber bushing. 88
Project Final Report – CUDBF April 30 th , 2009 ASEN 4028: Aerospace Senior Projects The hinge is connected to a long balsa spar that runs through most of the length of the wingtip. This spar rigidly connects the wingtip to the main body, and distributes the load along the wing. It is screwed into the integral hinge and glued into the underside of the wingtip foam. Since the door leaf has a relatively small surface area and is metal, it is not feasible to glue this into the foam itself. Rather, the hinge is screwed into the balsa mount, which is then glued into the foam. The balsa mount increases the surface area where the forces on the hinge are distributed, increasing the overall load the entire wingtip hinge system can withstand. The balsa mount itself is shown in Figure 62, and the actual placement in the wing can be seen in Figure 60. Figure 62: Balsa Mounting Block Finally, in order to increase the strength of the hinge in the direction that it opens as well as provide more pre-stress to the rubber sheeting, a small clasp was fastened to the trailing edge side of the hinge, seen in Figure 60. This limits movement even further and strengthens the entire system to withstand the loads expected. 8.4.5 Landing Gear Positioning and Stability The Buff-2 Bomber must be stable and controllable while on the ground because of the possibility of extended ground taxi during the missions. To that end, the main landing gear was placed far apart on the aircraft to provide longitudinal and lateral stability as seen in Figure 63. The nose wheel is 1.5 inches behind the nose and the main gear wheels were 13 inches aft of the nose and 17 inches outboard of the aircraft centerline. The landing gear placement is show in Figure 63. 89
Page 1:
University of Colorado Design/Build
Page 4 and 5:
Project Final Report - CUDBF April
Page 6 and 7:
Page 8 and 9:
Page 10 and 11:
Page 12 and 13:
Page 14 and 15:
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41: Project Final Report - CUDBF April
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166:
show all

PFR - Aerospace Engineering Sciences Senior Design Projects ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?