Transcript 30 Minute Dawn Mulvihill

Design of a Dawn Mulvihill
Competition Model Airplane
Presented by:
Jacob Gomez
And
Daniel Heinrich
Advisor:
Professor Fazal B. Kauser, P.E.
Overview
Design and construction of an elastic
powered, free-flight, model airplane
conforming to the rules of Dawn
Mulvihill.
Introduction
More
from less.
Flying for time.
Elastic powered.
Introduction
Dawn
Mulvihill
Absence of thermals
Most efficient model wins
Purpose

Maximum utilization of energy
 1/8 inch rubber strip power source
 Dawn Mulvihill Classification
 Double the existing high time
Dawn Mulvihill

Must be rubber strip powered
 Projected wing area under 300 in²
 No maximum flight time
 Models flown at 7:00AM
Rationale

Indoor models fly for
more than one hour
 Indoor models have
limited ceiling
 Outdoor models have
virtually unlimited
ceiling
 Outdoor times 25% of
indoor times
Hypothesis

Sample rubber motor test curve
Torque (in/oz)
Current designs not at
maximum efficiency.
 30 minute flight times
should be attainable.
 Utilization of energy.
 Maximization of
thrust.
40
30
20
10
0
0
20
40
60
80
Number of winds / 10
100
120
Research

Most research passed
on orally
 Current designs
evaluated
 Interviewed the “Top
Guns” of Mulvihill.
 The canard proven
more efficient
Methods to Achieve Goal

Aircraft Design
 Testing Equipment
 Evaluation and Analysis of Data
 Flight Testing
Design
Equipment - testing
PRELIMINARY DESIGN FOR RUBBER MOTOR TORQUE TESTER
Jacob Gomez and Dan Heinrich
1
3
9
9
A
2
4
4
4
4
ASSEMBLY KEY
TOP VIEW
1) Electric Motor
A
FRONT VIEW
A
2) Photo Gate Sensor
3) Test Motor
6
8
4) Fixed Supports
6
7
5
5) Electric Balance (for calibration)
5
8
6) Light Gauge Steel Post to Balance Hard Joined
7) Double Strain Gauge Assembly
8) Attachment to Balance
9) Wire Shaft
A] Separate Balance Assembly
----] Indicates Cut Away
7
Generated Torque Curves
Tru Torque Torque Band
10.000
8.000
6.000
Tru Torque
2 per. Mov. Avg. (Tru Torque)
4.000
2.000
0.000
-2.000
0
100
200
300
400
500
600
Number of Winds
FAI Sport Torque Band
10.000
9.000
Average Torque (in - oz)
Average Torque (in - oz)
12.000
8.000
7.000
6.000
5.000
FAI Sport
4.000
3.000
2.000
1.000
0.000
2 per. Mov. Avg. (FAI Sport)
-1.000 0
100
200
300
400
Number of Winds
500
600
Equipment - flying

Winding stooge.
 Stretch winding.
 Efficient winding.
Evaluation and Analysis

Selection of motor with most linear torque
curve.
 Matching propeller design to torque output.
 Allowing the propeller to operate in a
narrower band of torque values.
 Propellers of varying design and initial
pitch settings.
Flight Testing

3 Models to be constructed
 First model approximately 170 in²
 Second model full size with standard prop
 Third model full size with optimal prop
Time Table (rev 1)
8/03
9/03
10/03
11/03
12/03
2/04
3/04
4/04
6/04
7/04
Interviews and research
Model design
First model construction
First model testing
Second model construction
Second model testing
Rubber testing
Propeller design
Propeller testing
Final model construction
Final model testing

Project began in August 2003 with design and
evaluation process. Table is subject to revision.
8/04
Closing Thoughts