Thank You DUNA-USA!

We are very happy to announce DUNA-USA Inc.’s sponsorship for Tachyon! DUNA-USA Inc. manufactures a large range of low and high density foams, as well as chemicals and equipment for utilizing these foams. They have sponsored CalSol with high-density tooling foam and specialty adhesives for joining the foam into larger blanks for milling, and we look forward to continuing our productive partnership through Tachyon and beyond.


DUNA-USA Inc.’s high-density tooling foam is dense enough to hold fine details when machined, and is also nonreactive with a wide range of primers and chemicals. These qualities are essential for making high-quality “positive” or “male” mold patterns, which can then be used to create “negative” or “female” molds for part fabrication.


Large pieces of high-density tooling foam can be very heavy, and a single piece of foam large enough for Tachyon’s molds would be prohibitively difficult to transport and store for long periods. We plan to use DUNA-USA Inc.’s specialty foam adhesive to join together pieces of tooling foam into the required shape and size for our machining blank. We had a chance to practice with their foam adhesive and were very happy with the result: the adhesive expands as it cures to fill any gaps or unevenness between the foam pieces. Not only does this result in a very strong bond, this will also allow us to create our mold patterns without having to fill-in the glue lines after machining.


Our positive patterns for Zephyr were machined from Styrofoam. While we were create successful molds from these plugs, the low density and chemical vulnerability of Styrofoam necessitated much additional sanding and extra protective layers. DUNA-USA Inc.’s generous sponsorship will help us avoid these issues for Tachyon and aid us in making our best molds yet!


DUNA-USA Inc.’s logo is proudly displayed our website, and will be carried on Tachyon as she races in American Solar Challenge 2018, World Solar Challenge 2019, and beyond. We encourage you to visit their website at for more information on their wide range of foams, chemicals, and equipment.


Keep posted for more blog posts and pictures as we begin our mold-making journey with the help of DUNA and other generous sponsors!


Thank You Airtech!

In addition to all of our generous sponsors for Zephyr, we would like to thank some of our new and returning sponsors for our upcoming 9th generation vehicle, Tachyon. We are proud to present Airtech Advanced Materials Group’s sponsorship for Tachyon.

Airtech Advanced Materials Group is the largest manufacturer of vacuum bagging and composites tooling materials, and has facilities all around the world. They have sponsored CalSol with vacuum bagging supplies since Goldrush, and we are glad to continue our partnership for next vehicle.


Airtech’s materials sponsorship with some members of the composites team.


CalSol uses vacuum bagging to ensure proper lamination in the finished part. In essence, we seal our composite layups inside an airtight bag and pump out all the air. This applies atmospheric pressure evenly to the composite part as it cures, making sure the layers stick together. While a large variety of bagging materials exist, we primarily use release ply, breather, and bagging film in our layups.

Example of Peel-ply. Photo Credit: Airtech International Online Store

Release ply (or “peel ply”) is the first layer we apply on top of the carbon fiber. This slick woven fabric prevents the epoxy in the carbon fiber from sticking to the other layup fabrics while allowing air to pass through. Furthermore, release ply leaves behind a textured surface on the finished part, making it easier for us to bond additional parts afterwards.

Example of breather. Photo Credit: Airtech International Online Store

Next, breather is a thick and “fluffy” layer which allows air to move laterally through the piece. This stops the formation of air pockets in the vacuum bag and cushions the bagging film from sharp protrusions in the part. Breather can also help to soak up excess resin in a layup, though this is less of a concern for our prepregnated carbon fiber layups.

Vacuum bagging film over a layup before vacuum is applied. Photo Credit: Airtech Global.

Finally, bagging film is an airtight sheet that holds the vacuum seal. This film has to be pleated so that no “bridging” occurs over concavities in the part. Airtech sponsored us with bagging film that allows up to 550% elongation, which makes it much easier for the film to reach and apply pressure to all parts of the layup.

Airtech’s generous support is crucial for Tachyon’s success, and we hope to create our best composites work yet with their help! Airtech’s logo graces our website, and will be displayed on Tachyon as she races in American Solar Challenge 2018, World Solar Challenge 2019, and beyond. We encourage you to visit their website at for more information on their wide product selection.


Preparing for Formula Sun Grand Prix, Part 1

Summer is drawing near. Tender green buds and new spring grass are giving way to lush spring growth, while the summer sun shines ever brightly in the cloudless sky. Well, this being Berkeley, the weather is like this most of the time. Still, you get my point…


The coming of summer also reminds us that we are creeping closer to Formula Sun Grand Prix 2017. This summer’s race will be taking place in Austin, Texas, on the Circuit of the Americas, and CalSol is enthusiastically preparing both our vehicle and our team for the competition. This past weekend, we focused on practicing pit operations and communications. Both are essential for success at the race: faster pit operations permit us to spend more time driving laps, while smooth communication skills help us facilitate personnel switches and reduce stress.


Ennzhi Chew, our Mechanical Coordinator, gave a detailed lesson on the intricacies of wheel and tire changing. We rely heavily on No-Mar’s tire changer to slip the rubber tires on and off the rim. Changing tires can be tricky, so several members took turns practicing.


Ennzhi teaches how to change tires.
Ennzhi (left) teaches how to change tires using our No-Mar tire changer


Meanwhile, Harrison Zheng (Engineering Director) and Hersh Sanghvi (Electrical Coordinator) led a quick lesson on the use of amateur (ham) radios. CalSol uses ham radio to communicate during the American Solar Challenge, when cell service can be spotty or nonexistent. We continue to use ham radio during Formula Sun Grand Prix as well, in part to maintain our proficiency for the next road race. New team members learned to use handheld radios and vehicle-mounted sets, while veteran members received a valuable refresher. Harrison and Hersh finished off the lesson with a radio relay, where a pair had to assemble and configure a pair of radios to transmit a code word. Geoffry Ding and Avinash Jois won the race along with Harrison’s reward of boba tea.

April 2017 FSGP Prep radio relay
Radio relay: assembling “vehicle mounted” radios. Their partners are far away configuring the handheld sets.

Finally, we tested Zephyr’s onboard radio range by driving in laps around our work space at the Richmond Field Station. It was great to see the vehicle driving again, and we look forward to continuing out preparation this weekend!

Elizabeth Li driving Zephyr near Building 460, our main workspace at the Richmond Field Station.
Elizabeth Li driving Zephyr near Building 460, our primary work space at the Richmond Field Station.

Thank You Rockwell Collins!

Rockwell Collins-Teklam manufactures aero-space grade honeycomb sandwich panels for aerospace interiors, spacecraft, marine, rail, and automotive applications. They were a major sponsor of Zephyr, and we are very grateful for their generosity. We used their phenolic-resin and honeycomb core panels in the majority of Zephyr’s interior stiffening bulkheads and ribs. These high-quality and machineable panels were also used to attach Zephyr’s carbon fiber shell to her aluminum chassis. Thank you Rockwell Collins for your invaluable support!

As discussed in our previous blog post, honeycomb sandwich panels offer great weight savings over solid panels of comparable flexural strength and stiffness. However, the strength of a sandwich panel, like that of most composites parts, depends on a solid bond between the different component layers. Rockwell Collins’ sandwich panels are bonded under high pressure to achieve superior and consistent lamination. In turn, this translates to stronger and more consistent bulkheads on Zephyr. Furthermore, Rockwell Collins is able to manufacture panels in very large sheets, allowing us to cut long ribs in a single continuous piece. These factors combine to make Rockwell Collins, Inc. a great choice for our honeycomb panels, and Zephyr benefited greatly from their sponsorship.

Rockwell Collins’ logo is featured on our website, and will be displayed on Zephyr as she races in this summer’s Formula Sun Grand Prix. We encourage you to visit their website at for more information on their wide range of products and capabilities.



Blog post updated on June 5th to reflect B/E Aerospace-Teklam’s acquisition by Rockwell Collins.


Thank You Hexcel!


Hexcel is an industry-leading manufacturer of composites materials, with products ranging from carbon fiber prepreg to honeycomb core and adhesives. We are very grateful for their sponsorship during Zephyr’s construction, and used their lightweight honeycomb core in both the exterior shell and interior stiffening panels. The aerospace-grade Nomex honeycomb was manufactured at Hexcel’s Casa Grande facility, and allowed us to strengthen our parts without adding unnecessary weight. In addition, Hexcel’s core was easy to work with in manufacturing, aiding our fabrication process. Thank you Hexcel for all your help!

The value of Hexcel’s sponsorship can be further demonstrated through a quick overview of composites sandwich panels. Sandwich panels comprise of a “core” material (Hexcel’s honeycomb core) sandwiched between two “facings” (carbon fiber in our case). While the facings provide tensile and compressive strength along the plane of the panel, the crush-resistant core stiffens the sandwich structure against out-of-plane bending. Since the honeycomb core is mostly hollow, very little weight is added. In this way, it acts much like an I-beam: the webbing in the middle adds stiffness and strength with very little increase in weight. The advantages can be substantial, as this table from Hexcel’s Sandwich Panel Fabrication Technology Datasheet demonstrates:

Demonstrates strength/stiffness benefits of using honeycomb core.

For this reason, we tried to incorporate Hexcel’s honeycomb core into the majority of our carbon fiber shell. Their core materials can be engineered to facilitate bending along a chosen axis, helping us lay core along the complex curves of the outer shell.

We proudly display Hexcel’s logo on our website, and look forward to racing with their logo at this summer’s Formula Grand Prix. We encourage you to visit their website at for more information on their cutting-edge products and facilities.


Thank You Patz Materials and Technologies!


Patz Materials and Technologies manufactures cutting-edge composite materials for a wide range of applications, and has been a generous sponsor of CalSol throughout Zephyr’s build cycle. Their carbon fiber prepreg was an essential part of Zephyr’s success and forms the structure of our lightweight aerodynamic shell. Their high-performance materials were a great improvement over our previous composite processes in both performance and ease of use, and we can’t thank them enough for their help! We look forward to continuing our partnership through Tachyon’s build cycle and beyond.

In addition to material support, Patz Materials and Technologies also gives us valuable advice in material selection and layup practices, and has offered to validate our layup samples with their ASTM-standard testing equipment. Finally, Patz Materials and Technologies led us on a tour of their manufacturing facilities in January. They showed us their impressive core and prepreg-manufacturing facilities, and taught us a lot about the manufacture and processing of these cutting-edge materials.

Patz_01_Uni_Spools     Patz_04_Uni_Done

Spools of carbon fiber being made into unidirectional prepreg



Patz_06_Weave_Done   Patz_08_Joseph

Finished roll of woven carbon fiber prepreg and Joseph Talosig, our wonderful guide


The Patz Materials and Technologies logo is proudly blazoned on Zephyr and our website, and we look forward to representing them on Tachyon as well. We encourage you to visit their website at for more information on the amazing work that they do.