Rocket Acceleration Report

Section One

Introduction, Background and Research

Introduction

1. The purpose of this project is to consolidate the theory of the Petty Officer Engineering Course within a practical environment. The aims of the project are listed below.

a. To assess your ability to investigate problems, analyse them and generate and evaluate solutions.

b. To assess your ability to plan and organize effort as an individual and team member

c. To assess your working and communication skills.

d. To assess your sense of responsibility and self assurance at the same time as broadening your outlook.

2. One of the other aims of the period is to introduce some of the business management techniques and terminology used in industry.

3. The class was divided up randomly into five groups. Each group has software and hardware developers. The following are a list of (Group 3) members:

a. C******** - Software Development.

b. ********* - Hardware Design.

Statement of the Problem

4. The initial project brief to the class was based around a Hydro Explorer water Rocket, pictured on the front cover. The entire classes projects where add-ons to the original design, where alterations could be made to the rocket the fundamental principle of propulsion must stay the same.

5. Design and manufacture the electronics payload to fit into a rocket nose cone with the following criteria:

a. Record height at apogee (farthest or highest point).

b. The data is to be down-loadable to PC/Laptop

c. The data is to be in NMEA format.

Background Information

6. During the initial design phase an abundance of information was obtained from all the sources available, some through discussion with the staff, but mainly information was discovered from the internet.

7. The rocket project that the group had been given has a large amateur following, with a plethora of ways of solving all the problems each group is faced with. Picking out which path was the best to investigate was a task within itself. Many of the amateur web pages described different ways to achieve the same aim with recommendations on what components to use. The general idea tended to be an accelerometer to determine apogee with a pressure sensor to determine the height at that point. At that point a parachute would be deployed to prevent damage to the payload.

8. Other ideas included Radar, Wire spool, GPS and Magnetic detectors. Each had its own merits and advantages, but due to time constraints and the technical abilities of the group the simplest form was determined to be the best avenue to achieve successful results.

9. The method of downloading to a PC/Laptop was considered and again many routes opened themselves up to investigation, the ones that where considered where USB, SD Memory card and serial data cable. Each again had advantages but where eliminated due to the complexity of the supporting software programming, with the exception of the Serial data cable. This had the advantage of being simple and compact with the supporting software already embedded on the PIC Microprocessor.

10. The data had to be in the National Marine Electronics Association (NMEA) format which is defined as the specification that is the recognized interface between various pieces of marine electronic equipment. The standard permits marine electronics to send information to computers and to other marine equipment.

Brainstorming Ideas

11. After much discussion and research the following brainstorm was developed:

Design Considerations

12. From a vast amount of research conducted by the group a number of designs ideas were produced. It was decided that all of the designs would need to consider the following:

a. Durability. The components and design of the equipment would need to be resilient to withstand a high degree of impact.

b. Size. A major consideration was the size of the equipment used, due to the constraints of the payload area.

c. Weight. Due to the minimal amount of thrust available from the launch system, the weight would have to be kept as low as possible.

d. Processing. Due to the nature and time constraints of the project, the least amount of mathematical processing, that was done in real time, would be kept to a minimum. With the short duration of the flight the sampling rate and accuracy of the readings would be paramount.

e. Memory. With the possibility of loss of power on impact the system would need some sort of memory to retrieve information after impact.

f. Connectivity. To retrieve the data from the equipment and to reduce the components required the need for a data link would be required.

g. Power. Due to the nature of the equipment, the power supply would have to be self contained and durable.

h. Cost. As with any project the constraint of cost would be an issue, therefore the cost would have to be kept within budget.

13. Encompassing the design features given above four designs were produced, each with there own additional design features, for the first customer meeting.

14. Research conducted online �Goggle is your friend’ by the group; found that there are hundreds of similar amateur rocket enthusiasts with various ideas of how to achieve the height at apogee problem.

15. Two sensors where considered, to solve the problem, these where an accelerometer and a pressure sensor. The way in which the sensors would be utilized have been considered and discussed below:

a. The initial thought was to use the acceleration and time taken to first 0 �G’ from the launch pad,