Design of a Dawn Mulvihill Design of a Dawn Mulvihill Competition Model AirplaneCompetition Model Airplane
Presented by:
Jacob Gomez
And
Daniel Heinrich
Advisor:
Professor Fazal B. Kauser, P.E.
OverviewOverview
Design and construction of an elastic powered, free-flight, model airplane
conforming to the rules of Dawn Mulvihill.
IntroductionIntroduction
More from less.Flying for time.Elastic powered.
IntroductionIntroduction
Dawn MulvihillAbsence of thermalsMost efficient model wins
PurposePurpose
Maximum utilization of energy1/8 inch rubber strip power sourceDawn Mulvihill ClassificationDouble the existing high time
Dawn MulvihillDawn Mulvihill
Must be rubber strip poweredProjected wing area under 300 in²No maximum flight timeModels flown at 7:00AM
RationaleRationale
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
HypothesisHypothesis
Current designs not at maximum efficiency.
30 minute flight times should be attainable.
Utilization of energy. Maximization of
thrust.
Sample rubber motor test curve
010203040
0 20 40 60 80 100 120
Number of winds / 10
To
rqu
e (i
n/o
z)
ResearchResearch
Most research passed on orally
Current designs evaluated
Interviewed the “Top Guns” of Mulvihill.
The canard proven more efficient
Methods to Achieve GoalMethods to Achieve Goal
Aircraft DesignTesting EquipmentEvaluation and Analysis of DataFlight Testing
DesignDesign
Equipment - testingEquipment - testing
ASSEMBLY KEY 1) Electric Motor
2) Photo Gate Sensor
3) Test Motor
4) Fixed Supports
5) Electric Balance (for calibration)
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
1
4 4 4 4
9
2
3
9
A
5
876
7
5 8
6
TOP VIEW FRONT VIEW
PRELIMINARY DESIGN FOR RUBBER MOTOR TORQUE TESTER
Jacob Gomez and Dan Heinrich
A A
Generated Torque CurvesGenerated Torque CurvesTru Torque Torque Band
-2.000
0.000
2.000
4.000
6.000
8.000
10.000
12.000
0 100 200 300 400 500 600
Number of Winds
Av
era
ge
To
rqu
e (
in -
oz)
Tru Torque
2 per. Mov. Avg. (Tru Torque)
FAI Sport Torque Band
-1.000
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
9.000
10.000
0 100 200 300 400 500 600
Number of Winds
Av
era
ge
To
rqu
e (
in -
oz)
FAI Sport
2 per. Mov. Avg. (FAI Sport)
Equipment - flyingEquipment - flying
Winding stooge.Stretch winding.Efficient winding.
Evaluation and AnalysisEvaluation 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 TestingFlight Testing
3 Models to be constructedFirst model approximately 170 in²Second model full size with standard propThird model full size with optimal prop
Time Table (rev 1)Time Table (rev 1)
Project began in August 2003 with design and evaluation process. Table is subject to revision.
8/03 9/03 10/03 11/03 12/03 2/04 3/04 4/04 6/04 7/04 8/04
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
Closing ThoughtsClosing Thoughts