The first 8N Ford tractor was built in 1947 and deemed Red Belly because of its unique and striking color combination. Today’s retro version had to be prototyped and redesigned for manufacturability, while offering the same reliability as the original tractor.

The final models of the Boomer 8N met all the design criteria of the original 1947 tractor, while offering the accuracy and production available with today’s technologies.

There is a point at which someone who doesn’t necessarily need a tractor wants to buy one anyway. This point takes a special design that’s attractive, nostalgic, and capable. The Boomer 8N tractor was meant to attract those buyers as well as those who actually need a tractor but want something with a classic look and feel.

Originally built in 1947, by 1952 more than 500,000 8N tractors were produced, and today 50% of them are still working the land. The 8N was recently updated, designed, and manufactured by Case New Holland, New Holland, Pa. The tractor was also “slightly” redesigned for the latest manufacturing capabilities and to improve ease-of-use. Some of the updates, meant to hold to the classic look of the tractor while also bringing it into the 21st century, included a redesigned hood, seat, and fenders. The hood, in particular, was drawn from the spirit and character of the original machine and married with a more modern design.

Conceptual drawings were created for the boomer 8N throughout its design cycle. This is a sample of how the hood went through several iterations before it was even sent to the design team for prototyping.

The mechanical engineering design team at Case New Holland worked closely with the industrial design team from the Fiat Automotive Style Center to hone in on the original classic details. Once the style was agreed upon, the engineers went to work building two mock-ups prior to going into full production.

Building the Mock-Ups
The Case New Holland team used Pro/E to produce the CAD drawings used in the production of the original prototypes for the retro version of the Boomer 8N. During the design cycle a variety of elements had to be prototyped and tested not only for function, but also for manufacturability. According to the design team, the hoods for the two mock-ups were the most challenging to create because they were to be a single piece rather than the multiple pieces that were used on the original tractor. To allow the hood to be removed as one piece, the new design had to incorporate the light mounting and the grill mounting. For example, the signature headlights from the original 8N were separate standalone components, where the retro version of the tractor required that they be integrated more as part of the new hood design. This helped to keep costs down, made the Boomer 8N look more streamlined, but also created a stronger, sturdier light source for the tractor.


The hood of the Boomer 8N made it through a vigorous cycle of drawings and engineering to create the single piece component.

The new design also meant that the hood would have to open and close differently than the original 8N manufactured in the 1940s. The hood hinges needed to be located so that the newly designed single piece component could be opened easily and with-out coming into contact with any of the critical engine parts while doing so. It also had to open to provide clear engine access for maintenance purposes.

The prototype for the hood was a hand lay-up fiberglass done by the expert team at Midwest Composite Technologies, Hartland, Wis. Midwest provides full CAD capabilities, rapid prototypes in either metal (DMLS) or plastic (SLS) components, FRP Fiberglass molding, and short run injection molding to its customers. Midwest can also create very large parts using their 5-axis CNC Router with an envelope of 23-ft x 10-ft x 5-ft. According to Helmut Keidl, President and CEO of Midwest Composite, “The 8N project was one of our more interesting endeavors because we were able to employ multiple processes for a single job. All components had to fit together perfectly and present the aesthetic our customer required.”

For the hand lay-up of fiber-glass parts for the hood compo-nent, engineers applied a gel coat to a cleaned and prepared mold. The first coat was cured before a second coat was applied. After this the fiberglass was laid in layers to create the needed thickness of the final part. On a large lay-up the fiberglass laminate that hangs over the edge of the mold can be trimmed using a saber saw and prepped using coarse sandpaper. While curing, the part had to be supported to maintain its shape. Once removed, the part – in this case, the Boomer 8N hood – was finished and painted to spec.

In keeping with the classic look of the original 8N, the creative team updated the seat to a self-skinning polyurethane foam for comfort.

Accuracy for the hood prototype was important because the final model not only represented a precise version of what the manufactured vehicle would look like, but it was also used to prove out the design parameters selected for the part. The Case New Holland engineering team was able to test and finalize the design after the second prototype was produced.

Most of the prototyping work for the Boomer 8N was done by Midwest Composite Technologies. According to the New Holland design team, having a supplier that understands your time restraints and cost limits is critical in ultimately producing a quality end product – on time and on budget.

Fully understanding the end product allowed Midwest to create each component of the mock-ups from the appropriate prototyping process. For example, although the hood was created using fiberglass molds, the newly designed seat was fashioned using a self-skinning polyurethane foam. Like other processes for this application, the mold was made in-house. The final product had to match the conceptual drawings from CAD, the required mechanical specs, and the aesthetic that Case New Holland wanted for the tractor. Overall, the seats were designed for comfort and utility, yet maintained the classic look of the original 8N.

According to the Case New Holland design team, working with as few vendors as possible enabled them to assure that each part was consistent with the quality and craftsmanship of all the other parts being produced. It also allowed for a smoother flow of components and less handholding. The final tractor is a testament to the quality of collaboration between the companies for this project.

Midwest Composite Technologies
www.midwestcomposite.com

MPF