Dane Batema Benoit Blier

Drew Capps Patricia Roman

Kyle Ryan Audrey Serra

John Tapee Carlos Vergara

Team 1:

Propulsion PDR 1Team 1

September 21, 2006

AAE 451 Team 1 2

Propulsion System Design Method• Goal: Design a single propulsion system capable of performing the design mission

(one prop, one gearbox, one battery system).– Undesirable to require two propulsion systems to complete design mission– Superior marketability of multi-functional aircraft

• Method:

1.) Select P/D ratio for largest efficiency flexibility (P/Dmax=1.0 ~ MaxCim Motors)

2.) Size propulsion system to meet dash requirements

2a.) Maximum propeller diameter 10 in (minimize landing gear length)

2b.) Select motor capable of providing necessary power to propeller

2c.) Set gear ratio to ensure efficient motor operation

2d.) Select batteries to supply the necessary voltage and current

3.) Ensure that loiter requirement can be met with dash-optimized system

3a.) 500 ft radius circular flight path

3b.) 50 ft/s air speed

3c.) 7 minute requirement

AAE 451 Team 1 3

Propeller Pitch & RPM• Initial Starting Point

for Pitch and RPM

• RPM ≈ 9000 – 10000• Pitch ≈ 9 – 10 in

Design Region

Source: The Basics of R/C Model Aircraft Design, p. 89

AAE 451 Team 1 4

Propeller Diameter• Based on RPM

and Vdash

• D ≈ 11 in

Vdash = 100 mph

RPM = 9500

Initial Estimate

Source: Simons, Model Airplane Aerodynamics, p. 217

AAE 451 Team 1 5

Pitch/Diameter Ratio

• (P/D)max = 1.0

• Higher P/D– Broader Efficient

Range of J– Greater J for Max

Efficiency

AAE 451 Team 1 6

Aircraft System• Aircraft Constants:

– CD0=0.25

– Aspect Ratio=8.5– Oswalds Efficiency e=0.75 – Weight = 5 lbf– Wing Area = 4.16 ft2

• Dash Observations– CL very low at high speed

Two Propulsion Systems:

• Ideal: 150 ft/s requires 0.89 hp

• Cost-conscious alternative: 100 ft/s requires 0.27 hp

AAE 451 Team 1 7

Ideal Propulsion System• Max Speed 150 ft/s ~ 102 mph

• Propeller

– APC 10x10 Sport Propeller ($2.49)

• Gearbox

– Kontronik Planetary Gear Drive 4.2:1 for 480 Motor ($59.99)

• Motor

– Kontronik Fun 480-42 40A Brushless Motor ($129.99)

• Speed Controller

– Kontronik Jazz 40-6-18 Brushless ESC ($169.99)

• Batteries (in series)

– 2 x Apogee 2-Cell 7.4 V 2500mAh 20C LiPo ($62.99)

• Total Propulsion Chargeable Cost = $318.46 (neglects speed controller)

AAE 451 Team 1 8

Alternative Propulsion System• Max Speed 100 ft/s ~ 68 mph

• Propeller

– APC 10x10 Sport Propeller ($2.49)

• Gearbox

– Great Planes ElectriFly Gearbox S280 3.8:1 ($9.99)

• Motor

– MEGA ACn 16/15/2 ($84.50)

• Speed Controller

– Phoenix 35 Brushless Speed Controller ($89.95)

• Battery

– 1 x Great Planes LiPo 7.4V 1500mAh 20C Discharge ($34.99)

• Total Propulsion Chargeable Cost = $131.97 (neglects speed controller)

AAE 451 Team 1 9

Propeller Selection• CP, CT, found from gold.m

• Assumed Inputs (to be refined when blade purchased)

– zero_lift = -6°

– flat_meanchrd= 0.5°

– slopelift_curve= 2

– CD0= .00655;

– kinduced_drag= .01

– Num_Blades= 2

– chord/radius=.09

• Max for 18* in prop

• 10 in propeller suffers small efficiency hit =85.5%

* This was true despite different motors/power requirements.

AAE 451 Team 1 10

“Ideal” System Motor/Battery• Dash

– Motor Voltage input: 13.0 V – Motor Current input: 58.3 A* (Motor Max Surge 65 A)– Motor RPM: 53,500 RPM (Motor Maximum 60,000 RPM)– Motor : 92.6%– Mtip,prop < 0.6

* Max battery continuous output: 50 A

AAE 451 Team 1 11

“Ideal” System Motor• Loiter

– Estimated Loiter Time: 49.4 mins (far exceeds requirement)

– Motor Voltage input: 4.6 V

– Motor Current input: 9.8 A (Motor Max Continuous 45 A)

– Motor RPM: 18,900 RPM

– Motor : 79.0%

AAE 451 Team 1 12

“Alternate” System Motor/Battery• Dash

– Motor Voltage input: 7.3 V– Motor Current input: 33.8 A* (Motor Max Surge 35 A)– Motor RPM: 31,800 RPM (55,000 Motor Maximum RPM)– Motor : 86.2%– Mtip,prop < 0.3

* Max battery continuous output: 30 A

AAE 451 Team 1 13

“Alternate” System Motor• Loiter

– Estimated Loiter Time: 13.7 mins (exceeds requirement)

– Motor Voltage input: 3.8 V

– Motor Current input: 12.5 A

– Motor RPM: 17,100 RPM

– Motor : 73.3 %

AAE 451 Team 1 14

Summary• No need for multiple propulsion systems

• Battery required for dash exceeds loiter requirements

• Tradeoff between cost and desired performance