Engineering

1. Management, systems integration and reporting2011Daniel, Matt, Tony, Sam, Mayur

Mission Task Search and rescue UAV

Requirements

Allocations of Groups & Members 1. Management

2. Mayur - Payload & Electrical Power

3. Matt - Aerodynamics

4. Daniel - Structures

5. Sam - Propulsions

6. Tony - Weights and Balance

7. Matt - Launch & Retrieval

Communications Overall group meeting

Management meeting

Management attending sub group meetings

Resolving conflict Good vs bad

Optimal design vs realistic

Engineering

Payload and Electronics

Payload Design

Payload - Contents• One man life raft• EPIRB• Flares • Heliograph• Food Supplies• 1.2L water• Heat Packs• Torch• Circuitry for lights

Payload - Final Design 

Payload - Final Design 

Payload - Final Design 

Payload - Layout 

Payload - Final Design

Payload - Dropping and Retrieval• The payload is dropped to land upwind of the person

o This means the wind will push it back towards the person • A rope follows the payload with a drogue, landing near the

person for retrieval•  The person can then access everything that is stored in the

payload,  which is attached with velcro

Engineering

Payload and Electronics

Autopilot and Flight Control

Autopilot SystemMission Computer• Decides where to fly• Is responsible for

communications• Searches for person (via FPGA)

Flight Computer•  Controls the aircraft• Gets info from sensors• Continually monitors

location/speed/attitude

Search Pattern

Search Pattern

Electronic Connections

Engineering

Payload and Electronics

Control and Comms

ControlRequires +-20 degree deflection

4 bar linkage chosen, directly driven by servo

Servo mounted inside wing, linkage mount attached directly to the surface of the flap. 

Battery Powered.

Chosen for relatively light weight and small size compared to alternatives: hydraulic actuators, direct rotation

For greater range of motion, or higher torque, gearing can be be implemented for relatively small weight gain.

For wing servo PS-105, high torque servo 35Nm, +-45 degree range of motion, requires 18 W each

For tail servo, K-2000 servo, 10 Nm torque, +-45 degrees of motion, requires 9 W each

For throttle, Futaba Brushless servo, 3Nm torque, low power requirements.

Flap Actuator

Radio BroadcastDirect Line of sight impossible at search height

Typical video surveillance (Ku, C and S) bands affected by rain

Broadcast in L Band to avoid effects of Rain fade

Satellite phone for telemetry broadcast

1.5" square Iridium Antenna for receiving signal

RF unit to receive radio signal close to ship for direct control in case of emergency

h =781m above search height of 200mL = 100km no change to range

Telemetry SentDuring normal flight

Status(Cruise, Search, Loiter, Return)Location (from Gps) SpeedAltitude

Distance to search area

During search

As above plus wind speed

For positive identification, photo location

Sends 50 by 50 pixel relevant section of photo to minimise bandwidth

Termination protocol

Ship sends confirmation signal every 10 seconds, if UAV loses contact for 10 minutes vehicle will terminate.

If ship is not receiving telemetry, ie. satellite link down, will send instruction to UAV to re-establish uplink every 10 seconds, if UAV continues to receive this signal for 10 minutes will terminate.

Telemetry Display

Engineering

Group 4 Structures

Leo PasukovThomas SleeAmanda NealNabil ChowdhuryNayeem Chowdhury

Initial wing structure for first iteration structural analysis

A representation of the complete wing and fuselage attachment system

Initial Fuselage Design to accommodate payload and air cannon launch with pusher propellers located under the wing facing the back of the vehicle

Hermes 450 on left and RQ7 Shadow on right

Structural components of the Fuselage

Modification of fuselage for payload and wing

Forces acting on the Fuselage

Stresses on the fuselage

Total Deformation on Fuselage Structure

Forces and moments acting on the Motor Mount

Determining the total deflection of the Motor Mount and equivalent Stress of Motor Mount

The general shape of the inverted V-tail

The ruddervators end before the apex of the inverted V, and provide the design with some aesthetics.

The internal structure of the tail

Screws hold the boom and tail structure together via these screw holes

Layout Drawing Wing

Layout Drawing Wing Mount

Layout Drawing Fuselage

Layout Drawing: Motor Mount

Layout Drawing: Tail

Engineering

UAV Propulsion system

Michael Hamilton – 21490902Tom Mason – 21456038Timothy Robinson – 22052577Jordan Hannagan – 22084843Nick Tegg – 22063617Neeraj Chadee - 21739897

Initial Concepts Rejected Concepts

– Twin engine tilt rotor• To Heavy• To complex

– Twin engine wing mounted• To heavy• Power not required

Pursued Concepts

– Ducted Fan• Analysed but later dismissed

– Final Pusher prop design

Ducted Fan Can significantly increase aircraft

velocity

– <190Km/h– Beneficial for Search and

rescue Beneficial for low speeds and TOL

where high thrust demands

Introduces significant aerodynamic design considerations

Ultimately to heavy and hence design was scrapped

– Weight increase equivalent to second engine

Engine Selection Chosen engine is Wankel AR731

Heavily influenced by historical evidence

Specifically designed UAV Engine

Weight of 10kg

Zero radial Vibration

– Due to rotary motion

Engine Components The Engine requires:

– Generator– Intake and Filter– Carburettor– Oil and Fuel Pump– Oil Tank

These components will fit in the space between engine and rear bulkhead

Engine Mounting Must be able to transmit engine

loads to main fuselage frame

Four point frame made from Titanium

Will weight only 0.136kg Leaves sufficient room

for engine components Maximum deflection

under maximum load < 0.002 mm

Propeller Design and Selection Historical comparisons were used for

initial design and analysis

Simplistic then more refined methods were used to calculate output

Custom sized and shape propeller was designed based on scaling approach

– Commercially available would be betted due to

– Expendable nature Material Selection

– Wood or Fibreglass• Chosen because• Relatively cheap 0 20 40 60 80 100 120

050

100150200250300350400450 Thrust vs. Velocity

5400 RPM6000 RPM6600 RPM7200 RPM7800 RPMCruise VelocityDrop Velocity

Velocity (m/s)

Thru

st (N

)

Group Interactions Could undertaken majority of analyses independently

At time couldn’t proceed as waiting out other groups results

– spiral effect Had to assume accuracy of other teams results and conclusions

– Possibly leads to over Engineering Group meetings were critical to Progress

Engineering

6. WEIGHTS AND BALANCE

6. WEIGHTS AND BALANCE

Importance of Weights and Balance Total weight of aircraft ≤ Lift produced by the wings

Weight changes

Things to be considered before flying

Weight

=+

Initial Assumptions

Unit

kg 62 19.836 29 10 91 120.836

Weight of UAV along the mission

Take-off

Search

Cruise

Climb

Cruise

Drop

Descend

Land

Weight of UAV along the mission

• ???? initial assumption not good• Iterate with • Iterate until , apply factor of 2 for fuel reserve

Unit

kg 62 19.836 7.31 10 91 99.146

1 0.9967 0.9953 0.9042 0.9924 0.995 1

Balance Find the CG

Requirement??

- Wings and tail designed with CG at 0.25MAC

- Tail moment arm length = 60% UAV length

- Length of UAV = 3400mm

NO! Just keep CG at 0.25MAC

Changes made while balancing UAV

- Fuselage was short and fat, CG is around 0.8MAC

- Lengthen fuselage

- Reduce diameter of fuselage

Final Layout of UAV

Final Layout of UAV Total Length = 4925mm

Fuselage Length = 2600mm

Fuselage Diameter = 400mm

Tail Moment Arm Length = 2600mm

Difficulties Conflicts that arose during calculations

Conclusion Contributions of Weights and Balance group in the UAV project

Visions

Engineering

7. Launch & Retrieval

Requirements

Accelerate the UAV to suitable speed.

Be installed and maintained on a marine vessel.

Reusable

Must in no way damage the aircraft.

Operate in an easily controlled and consistent manner.

Be safe and simple to operate

Launch System

Possible Solutions

Primary Design Considerations Mass to be launched Structural loads

– On UAV and within the launch system Reliability Available resources (electrical power etc.) Spatial constraints (boat)

Final Design

Pneumatic launcher

Final Design

Launch ‘Cradle’

Requirements

Decelerate the UAV to rest

Be installed and maintained on a marine vessel.

Reusable

Must in no way damage the aircraft.

Operate in a consistent manner.

Be safe and simple to operate.

Retrieval System

Possible Retrieval Solutions

Primary Design Considerations Mass to be decelerated

Structural loads – On UAV and within the retrieval system

Spatial constraints (boat)

Reliability

Final Design

Final Design

Ratchet System

Spring -Damper System

Engineering

End of Slides, thank you!