The Race Is Not Always To The Swiftest

Taking a student-designed vehicle and technology education as far as it will go.

Nathan Hale-Ray High School in East Haddam, Connecticut, is a tiny four-year school with about 370 students. Conventional wisdom would tell us that not much could be done in the realm of technology education with the limited financial resources of such a small rural community. This school has proven otherwise.

Bruce Freeman is a hands-on guy who teaches all of the technology education classes. He had 20 years experience as a Boatwright carpenter before he got his BA and began teaching at the Nathan Hale-Ray High School eight years ago.

Today, all his classes are filled with students who are for the most part enthusiastic, hard working, and motivated. What’s more, in four of the past six years, Freeman’s seniors have been winners in the regional Electrathon Vehicle Competition in which students race energy-efficient vehicles they have designed and manufactured themselves, not to see how fast they can go but how far they can be driven in an hour.

Things Happen Fast

In an Introduction to Manufacturing course, students obtain and receive a cerebral eye-opening overview of what modern manufacturing is all about. Many students are surprised to discover that it is a lot more about brain than brawn. In the next course, they get immersed in manufacturing themselves.

Some of the sophomore and junior students entering Freeman’s Introduction to Manufacturing class may have already taken a CAD (Computer Aided Design) course, but most have not. He does not consider this to be a problem. He teaches the students CAD and CAM (Computer Aided Manufacturing) simultaneously.

His classroom has 15 seats of Mastercam (from CNC Software Inc., Tolland, CT), the world’s most widely used CAD/CAM software. Maximum class size is held at 15 students, so each student has access to the computer and software for the entire class.

The students are lead through a series of tasks in which they learn to draw and create manufacturing toolpaths for increasingly difficult 2D objects like shaped boards, engraved signs, picture frames, etc. Once they have gotten that right, they learn to fixture the materials and manufacture the parts using one of the school’s three CNC (Computer Numerical Control) routers.

Two students at a time work on a router. One student has already performed the assigned task and is available if needed to help the next student complete his assignment. So, in effect, they get to perform or closely observe each task twice.

Freeman said it only takes the students two weeks to achieve a solid working familiarity with Mastercam and the routers. Then they progress to more advanced manufacturing activities. As this half-year class progresses the students learn more advanced drawing and manufacturing skills, including drilling, pocketing, and even creating more sculptured solids and surfaces.

Every year, Freeman chooses a theme for his Advanced Manufacturing Technology class in the hope of interesting a broader cross section of students. He noted the Nathan Hale-Ray High School has an excellent music department and many students are involved in musical programs and activities. Next year, the course’s theme will be musical instruments and students will design and manufacture prototypes of electric guitar bodies.

Techno Routers used in the course are in front of a window that many students pass each day. Freeman noted that the visibility of uniquely styled guitar bodies being automatically manufactured should create a lot of interest in the program.

Off to the Races

These two introductory courses lead into what Freeman considers to be his capstone course, a full-year program of Engineering and Product Design. During the year students create, manufacture, and ultimately race an electric vehicle about the size of a go-cart in the Connecticut Electrathon Challenge. This culminating event is held at the pristine Lime Rock Park (Lakeville, CT), one of the premiere road racing facilities in North America. Contestants come from Connecticut and many nearby states.

The Connecticut Electrathon Challenge is not a competition to see who can go fastest but, rather, who can go farthest on the power produced by two 12 volt batteries that can weigh no more than 67 pounds. One of the goals of the competition is to raise participant awareness of the challenges involved in building the energy-efficient cars of the future. In June of 2006, Freeman’s class took first place in the composite vehicle class with a run of 113 quarter-mile laps in about an hour’s time.

What does it take to be a winner? Freeman starts about a year ahead of the next competition getting his best CAD/CAM students familiar with designing exterior car surfaces by working with Mastercam’s C02 car program to become familiar with such concepts as “lofting”, “surfaces”, and creating optimal cutter toolpaths for aerodynamic designs. Then they create a scale model of next year’s design and refine it based on wind tunnel tests.

At the beginning of the following school year, students participate in the Connecticut fall Electrathon using the car Nathan Hale-Ray students designed for the previous year’s spring competition. The idea is to get the students used to the techniques and teamwork that will be required to compete effectively. That includes learning to freewheel (back off the power) down hill, make efficient pit stops, and change drivers (this includes adding ballast to compensate for lighter weight drivers competing at less than 180 lbs). They also must learn to monitor progress of the race and communicate necessary tactical adjustments to the drivers via radio.

Even though only two students will drive in the competition, everybody will have to make important contributions during race day. This experience factor is so important that Freeman has found a way to get in an additional practice prior to competitions. Thanks to the generosity of Consumers’ Union, the students get to make a practice run on a nearby test track where Consumer Reports puts late model automobiles through their paces.

Scaling Up and Manufacturing

In the fall, Nathan Hale-Ray HS students begin scaling up and manufacturing their new vehicle design. Actually, there is nothing in the rules of the contest requiring the students to design or manufacture parts for their vehicle. They can use a kit, which is exactly what the Nathan Hale-Ray students did the first year.

Today, however, it’s a point of pride. If the students can design and build it, they will. That even includes producing the sprockets for the chain drives, which are designed and toolpathed for CNC machining in Mastercam and cut from aluminum with a router. Many other parts are made from wood, plastic, and aluminum.

“The kids have a three-wheeled vehicle design that allows them to use a BMX bicycle wheel on the front spindle. They designed a spindle bracket that accommodates the Ackerman steering system, making it possible to go around turns without having a lot of tire scuffing,” Freeman explained.

The advantage of making your own parts is being able to find ways to manufacture to closer tolerances. This, in turn, reduces weight or friction so the vehicles will travel as far as they possibly can.

“We have done really well at Electrathon competitively,” said Freeman. “I won’t say it is just because we have the fancy equipment and Mastercam. I give the kids a lot of credit for their creativity. Having these tools allows our students to design and build things to incredibly close tolerances.”

The manufacturing processes by which students ultimately produce the Electrathon vehicle bodies are not always the same. This year’s students used a complex composite manufacturing process similar to those frequently used by Connecticut’s military and aerospace manufacturers. A scale model of the vehicle is produced a slice at a time by cutting two-inch thick sections from Styrofoam. Each section is drilled so that they can be held in place with internal rods. The completed “plug” is finished with a Duratec primer, which produces a high gloss finish. This plug is used as a form for fiberglass, which is draped around it to create a mold. Finally, the mold is used to produce the composite plastic car body.

“This can be pretty high tech stuff,” Freeman said. “This year we used a vacuum bagging method where you wet-out your materials in the mold with the resin, and then you put a plastic layer over the mold and suck all the air out of that area between the mold and the plastic bag. That allows you to use atmospheric pressure (about 14 lbs per square inch) over the entire surface to really squeeze all the excess resin out of the material. That way we get a high fiber resin ratio for a really strong lightweight component.”

Looking Down the Track

While they were assembling this year’s competition vehicle, some of the students were thinking ahead to processes that might be used to make next year’s. One thoughtful student noted that the school’s new Techno router has a large work envelope (4’ x 8’ x 11”) that would make it possible to cut the mold directly instead of making a plug. That would eliminate many steps and save a lot of manufacturing time. “I love it when kids come up with ideas like that,” said Freeman. “So that is what we are going to do next year.”

As for this year’s car, he said, “I think the kids have a really good one coming along. It’s a carbon fiber Tevlar car. It’s incredibly lightweight. I think it has a nice aerodynamic shape. It is just a matter of how well the kids do with their wheel alignments to cut down on the roll resistance. I leave a lot up to the kids. I let them work it out so they learn. Sometimes I throw an idea out. Sometimes they pick up on it and sometimes they don’t.”

This March, as in previous years, Freeman was a little concerned about all the pieces of this year’s project coming together in time so that the kids could field a vehicle of their own design and manufacture for the competition in late May or early June. Nothing is guaranteed. There are a lot of pieces to the puzzle, and Freeman is not about to step in and rescue his class. It’s all about the students figuring out what needs to get done and doing it on schedule.

If the very worst happened, the kids would wind up competing with the vehicle last year’s class made. Making that adjustment would, in itself, be another learning experience.