30 Minute Dawn Mulvihill
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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