Vertical Takeoff Rescue Amphibious Firefighting Tiltrotor

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Ryan Berg Alex Carra Michael Creaven Joseph Diner Meagan Hom Ryan Paetzell Jason Smith Alan Steinert James Tenney Bryant Tomlin

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Purpose: Rescue Missions, and Aerial Firefighting

Vertical Take Off and Landing (VTOL) Amphibious Landing and Take Off Range of 800 nm 50 passengers Cruise of 300 kts

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4

5

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Weight Quad-Rotor Dual Fuselage ConventionalPower Required (VTOL) 8 1.82 1.16 1

L/D (Cruise @ 10,000 ft) 7 1.41 1.07 1

Fuel Weight 6 2.1 1.11 1

Disk Loading 5 2.52 1.1 1

Max Bending Moment 4 1.15 1.09 1

CG Movement 3 1 2 2Quantitative TOTAL 57.23 39.29 36

Ease of operation 6 2 3 1

Water stability 12 3 1 3

Rescue Operations 8 3 1 2

System complexity 6 3 1 1

Maintenance 4 3 2 1

Service Life 3 3 1 2

Qualitative TOTAL 111 55 74

OVERALL TOTAL 168.23 94.29 110

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Wing Span = 76.5 ft Wing Area = 625 ft2

Cruise L/D = 12 Gross Takeoff Weight (VTOL) = 62,460 lb Gross Takeoff Weight (short takeoff) = 70,000 lb Fuel Weight = 10,175 lb Max Power Available = 12300 shp Max Speed = 333 kts Rotor Diameter = 42 ft Range = 800 nm

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0 20 40 60 80 100 120 140 160 1800

2000

4000

6000

8000

10000

Alti

tude

(ft)

Time (min)

1

2

4

5

5

6 7

8

10 11

1314

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12

1 Vertical Takeoff (2100ft/min)2 Transition(30sec)3 Climb4 Cruise5 Glide down6 Conversion7 Landing8 Vertical Takeoff (2100ft/min)9 Transition

10 Climb11 Cruise12 Glide down13 Conversion14 Landing

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Engine: Rolls- Royce AE 1107C-Liberty Turboshaft

Shp

6150

Dimensions 78.1 by 43.2 inWeight 971 lbs14 stage compressor/2 stage high and 2 stage low pressure turbineSelf- lubricating system for VTOL operation

Maximum Thrust Produced: 77053 lb

Thrust Produced in VTOL: 6950 lb

(Rolls- Royce)

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Airfoil r/R

XN25 0.06

XN18 0.12

XN12 0.5

XN08 0.75

XN06 0.99

Rotor airfoil sections and positions as fraction of rotor length

Radius 21 ft

Number of blades 6

Chord 2.97 ft

Twist 39 deg (-48 deg inboard/-30 deg outboard)

Material Fibrous Composite with titanium alloy abrasion strip

Disk Loading 21.98 lb/ft2

Solidity 0.27

Figure of Merit 0.81

Propeller Efficiency 0.78

Coeff. Of Thrust 0.02

Tip Speed Ratio 1.78

(Romander)

• NACA 65(216)-415 a = 0.5 airfoil was selected for all three wings.

• Airfoil Characteristics:• High CL at 0 degrees AOA

• Maintains performance characteristics even at low Reynolds number

• Promotes laminar flow over middle wing

Source: Raymer, Aircraft Design: A Conceptual Approach

Planform Area = 625 ft2

L/D in cruise was calculated over a range of wingspans using a MATLAB drag estimation program

Max obtainable L/D = 12 Corresponding wing span = 76.5 ft

AR = 9.36

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0 10 20 30 40 50 60 70 80 90 1000

2

4

6

8

10

12

14

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Wing Span (ft)

Lift

to

Dra

g R

atio

Maximum wing span basedon structural constraints

Design PointL/D = 12

Speed = 300 knotsAltitude = 10000 ft

A drag estimation program provided by Dr. Gur was used to verify the calculated L/D for the aircraft.

A basic VSP representation of the aircraft, as shown on the right, was analyzed at cruise conditions.

An L/D value of 12.5 was calculated by the program.

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0 50 100 150 200 250 300 350 4000

2

4

6

8

10

12

14

16

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Cruising Speed (knots)

Lift

to

Dra

g R

atio

Altitude = 30000 ft

Altitude = 20000 ft

Altitude = 10000 ft

Altitude = Sea Level

50 100 150 200 250 300 350 4000

2000

4000

6000

8000

10000

12000

14000

16000

Cruising Speed (knots)

Pow

er (

hp)

Power Required

Power Available

Stall Speed

Rotor Tip Speed Limit

Roll rate 3.0o/sec per inch of stick

Yaw rate 3.0o/sec per inch of stick

Pitch rate 4.5o/sec per inch of stick

A total of 6 in of stick Aircraft is Dynamically stable

7%MAC static margin Flaperons 35% chord and are

deflected The rudder is a symmetrical

airfoil (NACA-0012) and the rudder is located at 25% chord

The horizontal tail is at an incidence angle of -1.2o, and the elevator is located at 35% chord

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Structural design of a rib with the Flaperon

Angle of Attack -8o to 12o

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-20 -15 -10 -5 0 5 10 15 20-2

-1

0

1

2

3

4

Minimum Cl with Flaperons Deflected

Maximum Cl with Flaperons Deflected

Cl without Flaperons

Upper Control Limit

Lower Control Limit

Cl

-20 -15 -10 -5 0 5 10 15 20-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Lower Control Limit

Upper Control Limit

Cm

Nacelles rotate at 3o per second◦ Due to excessive vibrations in transition◦ Pilot Safety

Nacelle limits are 0o to 100o

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Transition

0 0.2 0.4 0.6 0.8 1 1.2 1.40

500

1000

1500

2000

2500

3000

Alti

tud

e (

ft)

Time (min)

Capable of takeoff in a sea state of up to 4. Sea State 4

◦ Waves of 5 to 8 ft and wind speeds of 17 to 27 kts Determined through static wave analysis

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Design for Multiple Loading Conditions◦ Aerodynamic Loading◦ Vertical Takeoff/Helicopter Loads◦ Water Loads

Lightest Possible Structure◦ Strut Braced Wing◦ Composite Materials◦ Wing Skin Tapering

Simple Mediation of Aeroelastic Effects◦ Static Wing Tip Deflection Constraints

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0 50 100 150 200 250 300 350 400 450-2

-1

0

1

2

3

4

Velocity, V knots

Load

Fac

tor,

n

Gust Envelope

Maneuver Envelope

Dive SpeedCruise Point

Maximum Load Factor: 3Minimum Load Factor: -1

Cruise Speed: 300 ktsDive Speed: 405 kts

CLmax= 1.5CLmin= -1.0

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-30 -20 -10 0 10 20 30-6

-4

-2

0

2

4

6

8x 10

4

Wing Location, ftS

hear

, lb

Shear-Aerodynamic Loading

-30 -20 -10 0 10 20 30

0

5

10

15x 10

5 Moment-Aerodynamic Loading

Wing Location, ft

Mom

ent,

ft-lb

-30 -20 -10 0 10 20 30-6

-4

-2

0

2

4

6

8x 10

4 Shear-Vertical Takeoff

Wing Location, ft

She

ar,

lb

-30 -20 -10 0 10 20 30

0

5

10

15x 10

5 Moment-Vertical Takeoff

Wing Location, ft

Mom

ent,

ft-lb

With resulting shear and moment diagrams for traditional wing

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0 5 10 15 20 25 30 350

0.5

1

1.5

2x 10

6 Vertical Takeoff

0 5 10 15 20 25 30 350

0.5

1

1.5

2x 10

6

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Vertical Takeoff

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Traditional Wing Strut Braced Wing (Outboard)

Strut Braced Wing (Inboard)

Strut

Thickness Flange 0.0475 ft 0.019 ft 0.095 ft N/AThickness Web 0.0390 ft 0.018 ft 0.021 ft N/AArea Wing Box 0.4191 ft2 0.1812 ft2 0.7951 ft2 0.1 ft2

Wing Spar Weight 5739 lb 1836 lb 2835 lb 454 lb# of Stringers 4 4 9 N/ARib Spacing 2 ft 2 ft 1.83 ft N/AArea Stringer 0.0035 ft2 0.001 ft2 0.0025 ft2 N/A

Strut Braced wing divided into two sections due to large stresses imparted on the center wing

Weight reduction from strut minimal due to center wing stresses

Total SBW Weight: 5569 lb Weight Reduction: 170 lb

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Wingbox idealized as rectangle◦ Rear Spar placed at 54.3% chord◦ Front Spar at 16.6% chord

MATLAB routine written to vary size of structural components

Combination of structural components yielding the lightest structure selected

Wing skin thickness tapered linearly from outboard wing root to tip◦ Wing tip skin thickness 0.005 ft

Materials- ◦ PEEK/IM Carbon Fiber (0°, 90°, ±45°)- Spars◦ Cyanate Ester/HM Carbon Fiber (0°, 90°, ±45°)

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Wing Skin tapering 0.5 ft maximum tip

deflection constraint Moments of inertia

for each configuration checked versus contour plot

Weight Reduction: 327 lb

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Number of Stringers 6

Rib Spacing 2.0 ft

Area of Stringers 0.01 ft2

Spar Thickness 0.0075 ft

Root Skin Thickness 0.0233 ft

Tip Skin Thickness 0.005 ft

Cross Sectional Area of Wingbox◦ Root 0.3156 ft2

◦ Tip 0.2036 ft2

Weight of Wingbox 2161 lb Maximum Tip Deflection :

◦ 0.44772 ft (5.37 in)

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Structural Solidworks CAD Model of outboard wing structure created

Finite Element Analysis conducted using ANSYS v.12

FEA results for tip deflection compared to MATLAB results

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Loading ConditionsAerodynamic Loading

◦ All weights assumed to be equally distributed or a point force

◦ Fuselage pinned at the center of lift

Water Landing◦ Fuselage must have a zero

moment around the center of gravity

◦ Buoyancy Force must counteract the moment force around the center of gravity caused by the weight distribution

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ResultsAerodynamic loading caused much larger moments Aero Load Factor=4.5Water Load Factor=8.34Aerodynamic loading case turned out to be the limiting case

0 10 20 30 40 50 60-1.5

-1

-0.5

0

0.5

1

1.5

2x 10

4

Length (ft)

She

ar F

orce

(lb)

Shear Force Diagram

Aerodynamic Loading

Water Landing

0 10 20 30 40 50 60-10

-8

-6

-4

-2

0x 10

4

Length (ft)

Ben

ding

Mom

ent (

ft-lb

)

Bending Moment Diagram

Water Landing

Aerodynamic Loading

Final Calculated Values

Bulkhead Spacing (ft) 3

Longeron Width (in) 3

Longeron Thickness (in) 0.0629

Skin Thickness (in) 0.05

Can hold 50 passengers and 6 crew

Two side doors Can carry standard 40x48 in

pallet Uses new seats in V-22 from

Golan Industries/Army Division Winches for cargo loading and

rescue

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1 Multifunctional Displays2 HUD3 Misc. Switches4 Standby Flight Display5 Flight director6 Altimeter and Airspeed7 Throttle Controls8 Control Pedals9 Control Stick

10 Engine Instrument Alert Sys.11 ECS and Landing Gear Controls12 Lights, Icing and Radio Controls

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  SizeSpeed (mph)

Max Load (lb)

Max Pressure (psi)

Max width (in)

Max diam. (in)

Wheel diam. (in)

PLY Rating

Front tire 21 x 7.25-10 210 6400 166 7.2 21.25 10.0 12

Main tire27.75 x 8.75-14.5 225 21500 320 8.75 27.75 14.5 24

Cockpit Utilizes electronic

controls Features HUD

Landing Gear Bicycle design 66.3% TOGW on main

wheels at 35° off CG

Flight Control Sys.◦ Triple redundant FCCs◦ FADEC and AFCS

Electrical Control Sys.◦ Four Honeywell 90 kVA generators◦ Hamilton Sundstrand Power System T-62T-46-2 APU ◦ Single lead acid battery, which provides 24

VDC Hydraulic Control Sys. Environmental Control Sys.

◦ Oxygen-enriched air for crew breathing is provided at 6 stations

◦ GKN Aerospace deicing sys. Fuel System

◦ 1000 gal of fuel in 18 tanks◦ Fuel transfered between tanks to maintain

balance◦ Aerial and ground capabilities

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Rescue◦ Goodrich 42305 rescue winch 600 lb of lift and

200 ft of useable cable length◦ Can carry 36 litters◦ Aeromedical bay in left fuselage

Firefighting◦ In water or hovering at 10 ft◦ 1500 gal (750 gal in each fuselage)◦ American Turbine AT-309 pumps◦ released through a 20 x 35 in door

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Water Tank Tests◦ Water Ingestion◦ Sea State Tests

H-V Diagram Wind Tunnel Tests

◦ Aeroelastic Effects◦ Interference Drag

Downwash Verification

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Cost

RDT&E + Flyaway

$ 52,603,400

Operation and Maintenance (per year)

Fuel Cost $ 792,947

Crew Cost $ 770,964

Maintenance Costs

$ 1,277,213

TOTAL $ 2,841,125

Methods described in Raymer

Based mainly off empty weight, maximum speed, the desired production output in five years, number of flight test aircraft, cruise velocity and take off gross weight

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Addition of a strut can reduce structural weight but also increases aerodynamic drag

Traditional and Strut Braced wings were designed to satisfy the loading conditions specified

Weights for each design compared to judge the benefits

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