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