Frame

Frame

The design of the frame was based on the following requirments:

It must allow the rider to sit comfortably in order to transmit maximum power to the drive train.
It should be stiff enough so that little energy is wasted by the rider in deforming the frame. Also rigidity is important for stability purposes.
The frame should be light enough so as to reduce total weight. This is particularly important during acceleration.
Deflection is set to be: 1.27 cm. This value is the mean for deflection for bicycle frames

From the above requirments it was decided to use Aluminum alloys in the building of the frame. Aluminum is known to be difficult in welding and loses much of its strength during welding. However, its light weight makes it a strong competitor as a material for HPVs. The alloy used was AA6061 T6. Some components used AA6063 T6 where AA6061 was not available.

Also, the design of the frame took the shape of a space frame in which many tubes with small diameters and thicknesses are used. In that kind of frame, all members are loaded in compression or tension. Obviously, because the tubes are welded, they carry some moment. However, the majority of the moments are held by the structure, and not in the individual members. This gives more rigidity to weight ratio to the whole structure.

Thus, by using aluminum for the tubing and a space frame, both requirements of lightweight and strength can be achieved. The following picture shows the frame after welding.

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For more information about the frame design and manufacturing, contact:

hossam@aucegypt.edu