Your case study is due at the end of the module week.

Research two aircraft that are notably different. Compare and contrast cost, performance, design, material selection, and maintenance requirements. Estimate variables (e.g. cost) which aren’t readily available. Where estimates are used, justify your thought process.

For one of the aircraft, discuss three design features and associated tradeoffs (performance and/or structural) engineers likely contemplated. For one of the tradeoffs, outline the pros and cons of the decision.

Within your report, discuss the relationship between aerodynamic performance and structural design and how each influences one another.

For one of the aircraft, estimate the maximum normal bending stress at the wing-fuselage interface using the following simplifying assumptions:

There exists a primary spar carrying the bending load.

The spar can be modeled as an “I-beam.”

1. Estimate a reasonable spar size (length, depth, height) and material.
2. Note: You will need to look up the Modulus of Elasticity (“E”) based upon your pick of the material you chose for your spar.
3. The “Second Moment of Area” (I) from our stress equation, Stress = My/I, can be determined similar to the following image, Figure 1.
   
   Figure 1. Stress equation for I-beam.
   Please view detailed alt text for Figure 1. Stress equation for I-beam (DOCX).

The only force acting on the wing is gravity (weight).

1. The weight of the wing is distributed evenly across its length.

Based upon the spar material you selected, calculate the wing spar Factor of Safety. Also, estimate the maximum wingtip deflection(?max) based upon the case of a “Cantilever Beam with a Uniformly Distributed load”as shown in these slides of Cantilever Beam equations images (PPTX).

1. Within your report, show all calculations in an appendix, discuss the findings, and comment on the reasonableness of the simplifying assumptions.