Introduction

Introduction

Objective

"To design and manufacture an ultra-streamlined human powered land vehicle to participate in international racing competitions."

Problem Statement

Based on this objective, a more elaborate problem statement was formulated which gathered the requirements for a racing vehicle with the above mentioned characteristics.

Design

1. A fully faired aerodynamic vehicle, that achieves the least possible drag/frontal area configuration.

2. A rigid frame that holds paramount the driver safety, comfort and applies special care for human ergonomics.

3. A steering system that achieves the maximum possible turning radius without harming the minimal frontal area requirement.

4. A power transmission system that achieves speeds that enable the vehicle to compete in international racing competitions.

5. A safe braking system that maintains an acceptable level of safety.

Manufacture

1. A light, stiff and durable fairing that surrounds all the non-aerodynamic components with the least possible cost.

2. A light, strong, stiff, and durable frame with the least possible cost.

3. A durable and light drive train and steering components.

Scope

The problem statement narrowed down the focus into certain areas of interest. The theoretical knowledge and practical experience gained in the previous four years were combined to narrow down the areas of interest to:

1. Structural design using finite elements analysis (FEA)

2. Dynamic analysis of streamlined land vehicle

3. Aerodynamic design and analysis for streamlined vehicles using computational fluid dynamics (CFD)

4. Fiberglass reinforced plastics (FGRP) manufacturing

5. Braking design and types

6. Steering systems design and analysis

7. Aluminum alloys, properties and welding techniques

8. Human ergonomics, which is the study of the compatibility of the machine design with the user needs (Webster's Dictionary)

9. Machine design: roller chain design

10. Modeling

Approach

There are two approaches for streamlined vehicles design:

1. The ground-up approach: in which the design of the aerodynamic body is formed first, then the other components of the vehicle are fitted within the design.

2. The improvement approach: in which the design of non-aerodynamic components is started with to satisfy non-aerodynamic conditions imposed on the designer (power, speed, turning radius, stability, steering, frame, etc..), followed by the design of the aerodynamic fairing, and finning it to fit all the other components of the system (Tamai:ix).

Due to the design requirements that were imposed on the vehicle (safety, speed, power), the improvement approach was followed. In a chronological order, the design process has gone through the following steps:

1. Deciding on the vehicle configuration (number of wheels, streamlining concept, steering requirements, braking requirements)

2. Frame conceptual design, followed by finite elements analysis

3. Steering design

4. Vehicle dynamics design

5. Aerodynamic design using the improvement approach, followed by CFD analysis to check the vehicle aerodynamics.

6. Braking system selection

7. Preparation of the blueprints

8. Design modification, followed by final design

9. Workshop drawing

10. Manufacturing

11. Testing

Main results

Most of the set requirements were almost successfully met. The final testing stage revealed very important results. Based on the available financial and technical resources in Egypt, the project is considered satisfactory. One important factor that contributed to the acceptance of the quality of the produced work is that the project, being a capstone project, gathered several areas of engineering sciences, such as: mechanics of materials, materials selection, advanced manufacturing, modeling, fluid mechanics, vehicle dynamics, machine design, and other areas.

Specifications

The specifications of the vehicle is as follows:

Number of wheels	3 (tadpole)
Drive	Rear wheel
Steering	Front wheel
Wheelbase	140m
Track width	60cm
Total Height	100cm
Total length	270cm
Weight	55Kg
Maximum Speed	Actual: 55Km/hr Design: 80Km/hr N.B. testing was not completed. Higher speed is expected.
Braking Distance	6m (from 30km/hr to 0km/hr)
Cornering Radius	7m (at a speed of 25 km/ hr)
Speed at maximum cornering radius	25Km/hr