Author: obinna_modilim

Today was my final day at NC State. I spent the morning continuing to work on my model of the F-5A. I think I was able to successfully able to replicate the engine and main body of this jet. Dr. Gopalarathnam talked to me about how students in his department use programs that simulate airflow to test models that they design. Apparently, the program is fairly complicated, so it would be unrealistic for me to learn the program during my time here. After I finished the model, I got the chance to observe an experiment being conducted in the subsonic wind tunnel. Some students had 3D-printed a segment of a wing and placed it inside the wind tunnel. They were able to record data on the forces and torques acting on the wing segment while the wind tunnel was on. They observed how those values changed when the wing was placed at different angles. This kind of experiment can be used to calculate how much lift a wing design would get in the air. I really enjoyed observing this experiment, and the information and experience that I gained here at NC State were truly invaluable.

 

There was even more modeling to be done today. I started by editing the Douglas Skytrain model. Among other touch-ups and reworkings, I managed to finish the wheels that retract into the body of the plane. Now that the landing gear has been added, my model of the Douglas Skytrain is complete. Next up was my model of the F-5A. Modeling this jet is much more difficult than the first two planes I modeled. The nose of the F-5A is in a shape that is difficult to replicate with the fuselage option in Open VSP. I eventually had to experiment with settings that I’ve never used before which involved the skin cross-sections on the fuselage. Another issue is the awkward shape of the engines in the back of the jet. Hopefully, I can model them properly and finish my final model.

I started my day by continuing my work on the model for the Douglas Skytrain. I refined its shape, edited the wings, and finally added the propellers to each side. Something that was challenging was trying to figure out how to add the wheels and landing gear to the model since the wheels retract and extend in the real plane. I think I will create a model with the wheels retracted, using ellipsoids to model the wheels. I also decided to look into modeling another plane. While looking for planes, I wanted to find something that seemed difficult but was still possible to make good progress on by the end of my time at NC State. I finally decided upon the F-5A, shown in the drawings below. I also got to visit the James B. Hunt Jr. Library. This library is surprisingly large, with five floors, a café, and lots of space to work or relax. I stepped inside and explored what it had to offer. One interesting part of the library was the section dedicated to the Institute for Emerging Issues. I think that their goal, which is to work together in order to understand and resolve health, economic, and educational issues in North Carolina, is quite admirable.

 

Citation for 3-view drawing:

“File:F-5A 3-View line art.svg.” Wikimedia Commons, the free media repository. 29 Jun 2014, 06:30 UTC. 4 Jun 2019, 21:49 <https://commons.wikimedia.org/w/index.php?title=File:F-5A_3-View_line_art.svg&oldid=127724438>.

Today I spent my time working in OpenVSP. I managed to finish my model of the Yak 54, so I decided to create a second model. After a bit of searching, I decided upon the Douglas C-47 Skytrain. This airplane bears a closer resemblance to commercial planes, but still uses propellers to fly. I found this 3-view drawing of the Douglas C-47 Skytrain and used it to create my model. One of the challenges I faced was getting the right shape for the fuselage, especially near the front of the plane. While working, I learned how to utilize the symmetry controls in the program in order to replicate certain parts of the plane. I’ve made decent progress so far, and I can’t wait to complete this model.

 

 

 

Citation for Drawing:

“File:Douglas C-47 Skytrain drawings.svg.” Wikimedia Commons, the free media repository. 31 Aug 2014, 22:07 UTC. 3 Jun 2019, 14:52 <https://commons.wikimedia.org/w/index.php?title=File:Douglas_C-47_Skytrain_drawings.svg&oldid=133301824>.

Today I met an NC State student named Michael. He and some other students were working in the Control & Optimization for Renewables & Energy Efficiency Lab. Their focus is creating systems that can precisely control autonomous movement. This can apply to self-driving automobiles, coordinating ships, stabilizing flying objects, and maximizing fuel efficiency. Michael and the other students often use simulations to work on their control systems, but when they need to test physical models, they have a water channel to experiment with. I also got to visit the Unsteady Fluid Mechanics Lab, where the water channel resides. The water channel is a very cool machine. It pumps water in an oval loop so that there is a constant flow of water through the testing chamber. This is very useful for testing the aerodynamics of objects and controlling their movement mid-flight. I really enjoyed learning about autonomous control and optimization in moving systems with Michael today.

 

Pictures of the water channel:

My third day started with a tour of the Spray and Engine Diagnostics Lab. In this lab, students were experimenting with diesel and finding ways to increase efficiency in engines. Fujun and Kaushik explained the process behind spraying diesel and how it was used in an experiment. They had ways to record the spray distance, pressure, and speed within the span of a few milliseconds. Using their experimental setup, students could observe how diesel behaves at extremely high injection speeds. I was also able to visit the High-Pressure Combustion and Laser Diagnostics Lab. In this lab, lighter gases can be injected into special chambers and ignited. I was able to see the setup used for this process, as well as footage from previous combustions. In these experiments, many variables are closely monitored and controlled, including pressure, temperature, injection speed, and the components of the air in the lab room. Something as small as 2% more oxygen in the combustion chamber can drastically alter the resultant temperature, so students have to be very careful. I was also lucky enough to observe an experimental setup that could record the temperature of a flame using lasers. Later in the day, I visited the Intelligent Structures and Systems Research Lab. There I learned about artificial muscles, drone flight, and aeroelasticity. Something that was being studied in this lab was the small fluttering motions that plane wings sometimes made during flight. There were several ideas for turning that motion into a source of energy.

An “artificial muscle” using air and a meticulously woven fabric

 

 

 

A presentation about the injection of diesel at high pressure.

 

 

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a video of gases combusting in a small chamber

Today I continued learning how to work with OpenVSP. Dr. Gopalarathnam suggested that I use a 3 view drawing to create my next model. A 3 view drawing shows an airplane from three different angles: the top view, the side view, and the front view. I found a 3 view drawing for the Yak 54 and based my model off of it. The Yak 54 is a small airplane with a relatively simple design, so I thought that it would be a good starting point. I combined wings, wheels, a fuselage, and other plane parts in order to create the model shown below. It took a while for me to figure out how to give each part the right size and shape, but I think I’ve made good progress.

 

Citation for 3 view drawing:

“RCU Forums.” RCU Forums, 2005, www.rcuniverse.com/forum/giant-scale-aircraft-3d-aerobatic-110/2754267-3-view-drawing-edge-540t.html.

 

Today was my first day with Dr. Gopalarathnam at the Department of Mechanical and Aerospace Engineering. Dr. Gopalarathnam spends his time researching aerodynamics and experimenting with aircraft design. My day started with a program that Dr. Gopalarathnam uses for his research. The program is called OpenVSP, and it is an open-source modelling software where different types of aircraft can be created. Dr. Gopalarathnam had me download this program onto my computer and showed me how to create models. With help from some tutorial videos and reference images, I was able to create the airplane shown below, as well as a very rudimentary helicopter design. I also met Pranav, a PhD. student at NC State. He showed me two wind tunnels that NC State students could use to research aerodynamics, and explained how the wind tunnels could be used to collect data on the force, pressure, and moments acting on a flying body.

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