Summary: David Alciatore, PhD ("Dr. Dave") ILLUSTRATED PRINCIPLES
"Return of the Squirt Robot"
Note: Supporting narrated video (NV) demonstrations, high-speed video (HSV) clips,
technical proofs (TP), and all of my past articles, can be accessed and viewed online at
billiards.colostate.edu. The reference numbers used in the article help you locate the
resources on the website. If you have a slow or inconvenient Internet connection, you
might want to view the resources from a CD-ROM or DVD. See the website for details.
This is a follow-up to my February '08 article, where I presented experimental results from a
squirt-testing robot some mechanical engineering students and I designed and built last year at
Colorado State University. In my February article, I showed results for how squirt is relatively
constant for all speeds, how a laminated shaft can be very radially consistent at different cue twist
angles (i.e., the squirt is relatively constant for all laminate orientations), and how squirt varies
when mass is added at different distances from the tip. In this article, I present results of some
additional tests we did recently for hard and soft tips and stiffness variations.
My August '06 through April '08 articles cover squirt, swerve, and throw in detail, but here's a
quick review: squirt, also called cue ball (CB) deflection, refers to the angular change in the
initial CB direction due to an off-center hit. In other words, when you use English, the CB doesn't
go where you are aiming because of squirt (see NV 4.13 and NV A.17). When using English, it is
also important to be aware of the effects of swerve (see NV 4.14 and NV 7.12) and throw (see
NV 4.15, NV 4.16, NV A.21). Sometimes, the phrase "effective squirt" or the term "squerve" is