solid works - URGENT!!!

ME 4383 MECHANICAL ENGINEERING DESIGN Fall 2015

Rapid Prototyping Design Project

Microwatt Wind Turbine Propeller (Due Monday, Dec. 7, 2015, 2:00 pm)

Problem Statement: A DC electric motor will be mounted on a base in the wind tunnel of the

Thermofluids Lab. The motor has a shaft diameter of 0.109” and is 0.325” long. The motor was

purchased from Alltronics, which provided the following information: The motor was removed from a

Buehler tape drive. They run well on 12VDC but will operate from 6V to 24V. This is also a generator

whose output voltage increases with speed. The motor size is 2.24" long X 1.29" in diameter.

A 100-ohm resistance load will be wired across the output from the motor/generator. The voltage will

be measured across the resistance and displayed digitally. The goal is to generate the greatest voltage

across the resistor, and therefore the greatest power (P = V 2 /R).

You must generate a solid model STL file of your design using SolidWorks (or any other software you

are comfortable with). The STL file will be used to make a 3D model of your propeller, using the

Objet 3D Rapid Prototyping machine in the McElroy Prototyping Lab.

You must make up to 3 different versions of your design and are permitted to make up to 10

(negotiable). This will enable you to vary design parameters and measure their effect experimentally.

YOU MUST vary your designs systematically, and evaluate the effect on performance

experimentally!!!

The propeller must mount to the shaft by lightly

pressing it onto a square tapered shaft using a hole the

hub of your blades as shown here. The hole is 0.160”

square at the surface and 0.150” square at its deepest

point, a depth of 0.270”. The minimum diameter of

your hub should be 0.375.

The maximum OD of your propeller must not exceed

3-inches in diameter and its maximum height must not

exceed 0.375-inches. It should therefore be able to fit

into a cylinder template that has those inside

dimensions. Such a template is provided by the wind

tunnel.

The objectives of your design are:

(a) to generate the maximum power from your turbine while air is moving at a fixed speed of 50 mph. (b) to use the least amount of raw material. (c) to fit into the 3” diameter by 0.375” length disk-shaped envelope:

Our Objet 3D printer uses the “FullCure 720” material with physical properties given in the table

below.

You have until the last day of the

semester to finish the project.

The grade is based on:

(a) the quality of your brief written description (60

points)

(b) the performance of your prototype, compared to the

rest in the class (ranking in

air speed and ranking in

weight of material used) (40

points)

Submit your blades online using the link: http://objet.thef0rge.org

Your “Group Access Code” is: tiptonProps15

Extra credit bonus points will be awarded on this assignment if 3 distinct STL files are uploaded,

provided you submit them according to the schedule below (prior to 1:00 pm on each date):

Sep. 25 10 points

Oct. 9 8 points

Oct. 23 6 points

Nov. 6 4 points

Nov. 20 2 points

The written report does NOT need to be lengthy. It should show views of each solid model you made

(save as .jpg files). It should explain the parameters you varied from model to model that you believe

should affect the performance of the propeller. It should present a table, clearly showing how each

prop performed relative to the other two. The table should have, at least the following headings:

Blade ID Description of

blade design

Voltage Output

(mV)

Volume of part

(in 3 )

(Note: In SW, you need to use the Tools - Mass Properties, and then click the “Options” button and

click “Use Custom Settings” and make sure the volume is in units of inches^3 and “Decimal Places” is

set to 3.)

Finally, it should have some brief conclusions about how the blade performed, and some specific

recommendations about what you would do differently to make your blade work better.

On Dec. 7, the last day of classes, we’ll meet in the ThermoFluids Lab and each person will

demonstrate their best propeller. Those results will be the used for the overall class ranking.