Duma

Road bike (2015)

One of the early projects on form studies during my bachelor's program in product design was on nature inspired form. In my case, I was inspired by the lightweight, nimble and dynamic form of the cheetah, and designed a road bike conceptualized for urban commuters and passionate riders. The frame is a harmonious combination of hand-sculpted teak wood and mild steel, which compliments the aesthetic as well as the functionality of the product. While the wood gives a sculptural and dynamic form with a soft comfortable ride, the mild steel fork, seatstays and chainstays provide strength and durability to withstand uneven roads.

The first phase of the project involved a study of the inspiration and its characteristics. Particular emphasis was put on the light-weight structure of the body as well as the agility and the nimbleness of its stance. Through the sketches emerged an overall direction for form abstraction.

A key frame was selected depicting the characteristics of agility and nimbleness through the aerial glide mid-way of a cheetah's sprint. The form was abstracted to a sculptural element that captured the essence of the cheetah. The process of abstraction helped identify key visual and sculptural elements that would communicate the same characteristics in the design of the product.

The abstraction, in the form of a side-view sketch, was then translated to a 3D sculpture, by creating a thermocol mock-up, translating it to a Photoshop render and then creating a digital model using nurbs-modelling on Rhino. The form was then accurately prototyped using 3D printing for a more nuanced understanding of the elements. The prototype was created in two symmetric halves, joined together, sanded, and resurfaced using wall putty and then painted a neutral grey. This 3D sculpture helped identify the elements such as proportions, surfaces, edges and reflections that can be adopted in the design of the bicycle.

Having captured the characteristics of the inspiration I wanted to use in the bicycle, I moved on to the next phase of designing the bike frame. The primary focus of the bicycle design was on the frame, as the distinct scultptural form, stance and silhouette of the bike is captured in this part. Sketches of the envisioned frame structure were based on the abstraction of the cheetah as well as recent innovations in frames designed in carbon fibre.

To develop a working prototype, it was decided that the sculptural elements can be developed in wood, reinforced with mild steel chainstays, seatstays and the front fork. A preliminary sketch, as shown here, was developed to visualize the stance of the rider and the bicycle.

The sketches were then developed into 3D using Rhino. Component 3D models were sourced from GrabCAD and edited along with the frame using T-splines. The model was then rendered as key frames to visualize the product.

Once satisfied with the form and structure, the next phase of the project involved building a full-scale prototype. The wooden triangle was built in teak wood, for its strength to weight ratio, composed of five parts; bottom bracket, seat-tube, top-tube, head-tube and bottom tube. These were oriented to keep the grain in line with the normal forces, and butted with solid mild steel dowels and epoxy. A CAD overlay was used on each of the pieces, and the frame was sculpted by hand.

The marriage of wood and metal began with fixing the bottom bracket and connecting the crankset to ensure that the bracket was aligned correctly. To build the chainstays and seatstays, a frugal rig was created to align the parts and weld the mild steel structures. The dropouts were made separately using a 3mm mild steel sheet, manually cutting and grinding it.

The wooden triangle was finished with 2 coats of clear polyurethane, while the fork, chainstays and seatstays were painted a matte black. The idea was to keep the visual focus on the sculpted wooden triangle.

The product was tested in Delhi and was comfortable to use on smooth roads. The dropdown handlebars and the form of the bike meant that the riding stance was quite low.

Scope for improvement in the design include using metal inserts to connect the wooden triangle with the chainstays and seatstays instead of directly screwing them on, finding a stronger support for the bottom bracket which bears a signficant amount of the stress, and using suspension to reduce the impact forces on the wooden frame. More work can also be done in customizing the accessories and components. The idea is to work on Duma 2.0 in the near future.

The project was first displayed at the nid convocation display (January, 2016) and then at the auto expo motor show in Delhi with the nid contigency (February, 2016).