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Fuselage Design Day 10

Tail hinge design and wing strut attachments

Today we added in the hinges for the elevator and rudder, which are simply a couple bent steel U brackets riveted to the proper tubes and then loosely bolted together as a hinge. The inspiration for this came from the Terry’s aileron hinges used in his Affordaplane build. We also considered using piano hinges, but we decided against it because it would be difficult to install with our circular tubing and would be too prone to binding.

In addition, Design Team updated the tail design so it can be separated into two pieces to make it easier to transport and to allow the removal of the horizontal stabilizer for transport. During flight, the two elevator halves are connected through a 1⅛” x 0.058” 6061 T6 aluminum sleeve. Prior to our decision to make the elevator removable, we had gone through several iterations of making the horizontal stabilizer removable as well. We soon realized that it was only necessary to remove the elevator to make room for the horizontal stabilizer to be taken out and therefore opted to leave the horizontal stabilizer as one piece. Lastly, since our horizontal stabilizer is constructed of circular tubing, we’ll be using some steel support wires attached to the vertical stabilizer and truss to keep it level during flight.

Wing Strut Attachments

After doing some research into streamline struts, we found that it created much less drag but weighs substantially more than a fuselage beam of the same length. Like many other components, streamline wing support struts and jury struts have their pros and cons giving the Design Team an important decision to make. For example, the Affordaplane uses circular wing support struts, but the Legal Eagle uses streamline ones. We decided to CAD the streamline struts in the meantime while the Physics Team gets some specific numbers to inform our final decision. Because the streamline struts are so wonky in shape, they do not attach easily anywhere. To fix this, we decided to bolt a smaller circular beam to the inside of the streamline strut, so this beam can then attach easily into our U brackets. The strut-spar attachment is currently based on that used by the Legal Eagle since we’ll likely be controlling our ailerons through cables running along the jury struts similar to the Legal Eagle. We decided to use their aileron control system because it uses cables rather than control rods, saving a little weight.

To add these wing attachments, we also had to change the length of the cabin so that the attachment points for the struts are located on the vertical beams, rather than horizontal ones to prevent buckling. If the struts are to be normal to the cabin, then the cabin must be the same length as the distance between the leading and aft spars of the wing.

*Editors' note: the thought processes and design choices presented in this article don't necessarily represent those implemented into the final design and are subject to change. Flight Club Aerospace is a group of amateur students with no formal education in any fields of engineering. We present this information for educational purposes only, with the understanding that it is not to be re-created without adequate professional oversight and mentorship. For our latest designs and updates, please see our most recent blog posts.

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