Wyatt Wilkerson

Week 1 - 4/14/2022

The goal of my project is to establish experience in the aerospace engineering field, something that I wish to pursue in the next step of my education. To accomplish this I have started a project to design a pilotable glider, although due to time and financial constraints I will not move past the designing part. My mentor, Dr. Vanderhorst, is an experienced mechanical engineer and glider pilot. We started this week by meeting and establishing what specific kind of glider I wanted to design. I decided to make mine a 15-meter competition glider with the purpose of flying long distances. We talked over the general factors that helped gliders travel further such as increasing weight to increase speed and the longer wings allowing for tighter turns in air funnels both of which allow for a longer range. It was also decided that the glider will hold a water tank to increase weight during the flight and have it being releasable to ease the force of landing. There are some factors that have yet to be decided such as where on the fuselage the wings will sit and what specific tail design, but those will be decided in the coming few days. Dr. Vanderhorst also showed me resources to make sure the ideas would be FAA legal, so that if it were to be built it could be flown. Once the decisions are done I will proceed with showing how each choice affects the flight of the glider, both pros and cons.

Some resources I have been using for research:

https://www.fzt.haw-hamburg.de/pers/Scholz/HOOU/AircraftDesign_9_EmpennageGeneralDesign.pdf

https://www.ecfr.gov/current/title-14/chapter-I/subchapter-D/part-61

Mil-Spec 87 85 Charlie

This last week I did more research and decided on the final details of my glider. My wings will sit on the shoulder of the fuselage. This was decided by research through different studies on wing placement. It was shown that shoulder and mid wings were the best in terms of creating the least amount of drag on the glider. The specific airfoil I am going to use is the one from the Schleicher ASW 27. I also decided on a T-shaped tail and winglets that point down. A T-shaped tail allows for more speed due to its weight while also providing efficient horizontal stability and structural strength. The downward-pointing winglets give the advantage of better directional control. This is due to it minimizing the turbulence on the wing point leading to a less efficient wing in general. It also gives a structure to add wheels onto which makes landing the glider much easier and safer.

Using all of this information, I am currently calculating the theoretical weight of the glider. This is needed as one of the most important factors, lift, requires enough upwards force to cancel out the force of gravity. Once the lift is calculated then I will start on the calculations drag and creating a drag polar.

Pictured below is the Schleicher ASW 27 mentioned above

Week 3 4/28/21

This past week has been spent researching and calculating the amount of lift that my wings will create for the glider. The specific airfoil I have chosen is the SD7003 (Fig - 1). An important factor in choosing an airfoil is looking at the Coefficient of Lift vs Angle of attack curve of that specific airfoil (Fig - 2). This tells you what number you use for C_L in the lift equation based on the set angle of the wings. I chose the wings to have an angle of about 6 degrees so that when flying straight, it gives enough visual room to see the tow plane for takeoff or runway for landing. Another part of the graph to look at is the peak of the curve. This tells you at what angle you start to stall the glider, which is when it falls out of your control. This airfoil gives enough room, so that stalling would be harder to do. Once I found my C_L for 6 degrees (.85) then I am able to calculate the lift that is created using the lift equation (Fig - 3). For reference, the target tow speed I am using is 92 mph, my wing area is 94.7, and rho is 0.07647. After plugging the data in, I come out to a total lift force of 1741.7 pounds of force. A brief weight estimate of the glider comes out to around 1280lbs so the amount of lift gives enough room for drag and lower speeds to be worked around.

ADVICE FOR FUTURE PARTICIPANTS:

Some advice I have for future seniors interested in these projects is to pick something that interests you, yet isn't overly complex for your understanding. For me, there were some nights that I spent hours doing research on topics I hadn't really grasped yet, and wish I had planned around that better. However, if your project is on something you are passionate about it gives you that boost to power through those rough times to meet your end goal.