What we knew and when we knew it
In Part 2, I’ll talk about our early baseball measurements.
In 2017, I had a notion to try to measure flow over a baseball with PIV. I hired an undergraduate student to build trigger electronics. He mostly completed that task before losing interest. I had totally forgotten about it until I started writing this and looked up his name (Nick Hudson) but in June he put a ball in our small wind tunnel and took a PIV shot. This image has never seen the light of day before. I had that ball for years. It had a burn mark on it from the laser and a hole from the sting. I tossed it in Sam’s ball bucket, so it’s lost now. It’s also funny to note that this image shows a seam-shifted wake (seam on top is causing early separation). We had no idea at the time.
Nazmus Sakib arrived at USU in the fall of 2018 and I took him on as a graduate student. The agency that would fund his PhD (Bettis in Pittsburgh) was slow arranging the contract. That summer, I suggested that he pick up the PIV trigger and he got it working quickly.
We found an old pitching machine and he began making measurements. Here’s our first flying ball picture. I was shocked at how good the ball itself looks in the data. I realized quickly that these shots would be pretty, and that was the main reason I decided pursue this stuff whole hog. This ball is spinning (a lot, I think), and we hadn’t yet learn how to keep the ball itself out of the PIV computation, leading to the red and blue on the surface of the ball.
In July of 2018, I showed one of Nazmus’s images to a colleague at TU Delft in Holland. He remarked that an American professor was traveling to his lab soon to take similar images. He introduced me to Lloyd Smith of Washington State University (WSU) and the Sports Sciences Lab. I visited the lab a couple of months later. It is an amazing place. They may be most known for bat certification work (such as USA and BBCOR) but they also do ground-truth pitch tracking work for MLB. The lab is a baseball nerd playground and I had so much fun there. Lloyd visited USU shortly after and offered to fund a small study at USU aimed at determining the reason for the low drag on MLB balls. He also agreed to lend us one of his slick cannons. I traveled to Lisbon and talked to an Italian professor about a measurement on baseballs that an American was going to make in the Netherlands. All of this was essential to what happened down the road.
I Met Alan Nathan, Nov 4, 2018, who was and remains the foremost baseball physics expert out there. He’s taught me so much about baseball aerodynamics and the odd ways baseball people express them.
Since baseball was quite a bit more sexy than most of my work, I decided to make a video as an entry to the Gallery of Fluid Motion, a yearly event sponsored by the American Physical Society. Nazmus acquired the images. I chose as a topic the difference between two seam and four seam fastballs. I concluded, incorrectly, that the difference comes from fingers leaving the ball at different times in the case of the 2S Pitch leading to an altered axis. This does happen sometimes, but this was my first of many lessons on placing too much emphasis on a single pitch. It was one of our early missteps in understanding the effects of seams.
We did show that a machine pitch 2S and 4S are the same and I began telling everyone (including Sam’s pitching coach) that there was no difference between the pitches. Jory let me know I was wrong, and that he saw the biggest difference when one of the seams of a 2S is clear and the other one is fuzzy. Jory didn’t get gyro, but he he did get seam orientation. And I didn’t believe him.
Nazmus’s data also showed that the seams on a spinning ball altered the separation points. At the time, we misconstrued them as acting like “paddles”.
But I think many people were excited just to see what the flow around a baseball looked like.
The video generated interest. Most notably, Rob Friedman (the PitchingNinja) contacted me on November 19 and began opening a lot of doors. On November 20, 2018, I received an email from Eric Jagers (then of Driveline, later of the Reds, now of the Mets) that would change everything. He sent video of two similar pitches. “In each case the release is virtually identical (as is the spin axis/direction), however due to seam orientation we see a drastically different result.” He already understood what he was looking at. I would take some time to catch up. The email mentioned the critical role of gyro spin, which remains the aspect of SSW that most struggle with. I remain amazed at how far ahead Eric was.
On January 15, 2019, Eric Jagers, Kyle Boddy, Joe Marsh and Dean Jackson visited USU to attempt to measure what they termed a “laminar express” sinker. This was going to be a challenge no matter what. The pitchers (mostly Marsh and Jackson) needed to throw a sinker into a space about 6 inches tall and about 1/4″ wide. Making matters worse, I set up the system assuming the ball would be traveling 90 mph. They threw closer to 60 mph. By the end of the day, we felt we’d captured a couple. I think everyone enjoyed it and it was fantastic to meet those guys.
The Driveline visit made me realize that we were heading in an important direction. But now it was up to us to show that we could provide information to the game that was useful. That would require some more luck.