IkelosIkelosVirginia Tech and Loughborough University present:Virginia Tech and Loughborough University present:

2001/2002 Interdisciplinary/International 2001/2002 Interdisciplinary/International Aircraft Design ProjectAircraft Design Project

Key Requirements:

• Aircraft fits on trailer

• Lightweight and Simple

• STOL or VTOL

• Land in 46m (150ft) over 5m obstacle

• Cruise > 90 kts

• Range > 150nm

• 1 Seat Aircraft

Original SpecificationOriginal Specification

Each group produced 3 concepts:

• Counter-rotating Helicopter

• 2 Gyroplanes

• VTOL tilt duct

• Vectored jet

• Pusherprop

Selected VTOL Tilt duct:

• Most adaptable

• Most Original

Initial Design IdeasInitial Design Ideas

VTOL Tilt Duct

Pusher Prop

Initial ConceptsInitial Concepts

Reviewed advantages and disadvantages of:

• STOL

• VTOL

• Vectored Thrust

Modified Design to:

• STOL as standard aircraft

• Vectored thrust option

Design DevelopmentDesign Development

• 46m (150ft) ground roll

• Meet SSTOL requirement 150m (500ft) over 15m (50ft) obstacle

• Cruise speed to be competitive with GA aircraft:

110kts – 150kts

• Range - 500nm at cruise speed

• 2 Seat Aircraft

Revised SpecificationRevised Specification

ConfigurationConfiguration

ConfigurationConfiguration

Fuselage Structure LayoutFuselage Structure Layout

LoughboroughUniversity

Wing Structure LayoutWing Structure Layout

• Trailer criteria of 2.2m max. width

• Front Wing:

•I – section spars overlap in fuselage, bolted

together in hollow box structure

• Rear Wing:

•Connected to top of tail using two “3-way”

brackets

• Vertical Spars:

•Bolted to outer ribs using hollow tube

connections

Wing DetachmentWing Detachment

• Glass epoxy skin on wings and fuselage

• Skin is honeycomb sandwich

• Kevlar reinforcement on fuselage bottom and

lower wing skins

• Structure framework of carbon fiber with metal

reinforcements in critical areas

• Aluminum firewalls and steel undercarriage

MaterialsMaterials

V-n diagram

-5.0

-4.0

-3.0

-2.0

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

0 10 20 30 40 50 60

Velocity (m/s)

n

Clean Cruise Pos Clean Cruise Neg Stall Pos Maneuvering Limit Neg Maneuvering Limit

Vc Vd Full Flaps Gust (50) Gust (25)

Neg Gust (50) Neg Gust (25) Neut Gust

V-n DiagramV-n Diagram

ManufacturingManufacturing• Planes assembled in individual baysPlanes assembled in individual bays

• Composites used where possibleComposites used where possible • Internal skeletonInternal skeleton

• Assembly team at each bay Assembly team at each bay

• Team unity and pride in workTeam unity and pride in work

• Important due to the complexity of Important due to the complexity of wiring, controls, and electronicswiring, controls, and electronics

• Non-planar vortex lattice method

• Incorporates various wing features

Tornado VLMTornado VLM

• Box-wing design

• Front wing twisted

• Unswept inboard TE flap

Wing LayoutWing Layout

• Based on forward wing area

• CLMAX = 4.19

• Leading edge devices

• Front wing flapped

• Fowler te flaps, fixed vane

Lift CharacteristicsLift Characteristics

• Induced drag reduction

• CD0 = .045 in cruise

UNDERCARRIAGE24%FUSELAGE

17%

DUCTS5%

WINGS35%

INLETS ANDOUTLETS

12%VERTICALTAIL

4%

OTHER12%

SIDE PLATES3%

Drag CharacteristicsDrag Characteristics

• Static Stability

• Design Criteria: Acceptable static margin in all configuration, FAR 23 compliance

• Final Configuration balanced (positve Cm0L) with positive pitch stiffness (negative

Cm)

• Lateral-Directional stability satisfied but nearly neutral to retain maneuverability

• Dynamic Stability

• Design Criteria: MIL-F-8785C specifications with Level 1 flight qualities

Stability and ControlStability and Control

• Aircraft equipped with standard elevators, ailerons, and rudder

Area (sq m) % Chord Span (m) Sizing ConditionAilerons 0.586 30 0.9 Comparable Aircraft

Elevators 1.496 30 1.9 Take-off Rotation

Rudder 0.41 24 1.29 Maximum Crosswing Landing

Control SurfacesControl Surfaces

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

CL

Cm -10 deg

0 degrees

+10 deg

Xcg = Xcg forward

Xcg = Xcg aft

CLmax

v = 65 m/sS = 8.65 sq. m

Trim DiagramTrim Diagram

• Used Roskam methods to determine control forces

• Analysis shows that FAR 23 stick force limits are satisfied

Control Forces vs. Control Deflections in Cruise

0

20

40

60

80

100

120

0 1 2 3 4 5 6 7

Deflections (deg)

Fo

rce

(N

)

Ailerons

Rudder

Elevators

Control ForcesControl Forces

350

400

450

500

550

600

650

1.70 1.80 1.90 2.00 2.10 2.20 2.30 2.40

CG Position From Wing Apex [m]

Con

figur

atio

n M

ass

[kg]

OEM

MTOM

MTOM with6% fuel

Rear Pilot Only

Front Pilot OnlyHeavy Pilot

Stability limits

Landing Gear limits

CG Excursion GraphCG Excursion Graph

1.8

1.82

1.84

1.86

1.88

1.9

0 1 2 3 4 5 6 7

Flight Segment

CG

po

sit

ion

fro

m a

pe

x (

m)

Taxi T.O. Climb

Cruise Descent Land

Conclusion: Stable Aircraft

CG Travel in MTOM FlightCG Travel in MTOM Flight

The Rand Cam EngineThe Rand Cam Engine

• Innovative diesel rotary engineInnovative diesel rotary engine

• Inherently simple, no pistons, timing values,Inherently simple, no pistons, timing values,

spark plugsspark plugs

• Uses a system of axial vanes that rotate in aUses a system of axial vanes that rotate in a

cam shaped housingcam shaped housing

• Light weight – High power to weight ratioLight weight – High power to weight ratio

• Fuel efficientFuel efficient

• Costs similar to that of an equivalent Costs similar to that of an equivalent

automotive engineautomotive engine

• Low noiseLow noise

• Very little vibrationVery little vibration

• Low maintenanceLow maintenance

The Rand Cam EngineThe Rand Cam Engine

Oil Pump

Oil Tank

Intake

Cooling AirIntake

Cooling AirExhaust

Fuel Tank

Engine

Alternator

Starter

Cooling Fan

Oil Cooler

Intake Plenum

Exhaust Pipes

Engine LayoutEngine Layout

• Higher thrust per horsepower for a given Higher thrust per horsepower for a given diameter than a propellerdiameter than a propeller

• Better performance at low speeds than Better performance at low speeds than propellers – no recirculation at the tipspropellers – no recirculation at the tips

• Quieter than propellers – noise damping Quieter than propellers – noise damping material used in ductsmaterial used in ducts

• Duct provides an additional safety feature.Duct provides an additional safety feature.

• Duct diameter 0.92 m (3 ft)Duct diameter 0.92 m (3 ft)

• Fan consists of 5 rotor blades and 12 stator Fan consists of 5 rotor blades and 12 stator bladesblades

• Fans attached to engine via a 1:2 helical Fans attached to engine via a 1:2 helical spiral bevel gearspiral bevel gear

• Low noise 60dBs. Tip speed 113 m/s (370 Low noise 60dBs. Tip speed 113 m/s (370 ft/s)ft/s)

Ducted FansDucted Fans

• Static thrust calculated using disc actuator Static thrust calculated using disc actuator theorytheory

• Dynamic thrust found using general thrust Dynamic thrust found using general thrust equationequation

• Efficiency found by reading from chart of Efficiency found by reading from chart of empirical data chartsempirical data charts

3/2

S A2PT

V

PT

Thrust CalculationsThrust Calculations

0

1000

2000

3000

4000

5000

0 50 100 150

Airspeed (knots)

Thr

ust

(N)

General thrustequation

Disc actuatortheory

Thrust CurveThrust Curve

Cockpit LayoutCockpit Layout

CockpitCockpit• Designed for 95th percentile male Designed for 95th percentile male

(tallest male) and adjustable to 5th (tallest male) and adjustable to 5th percentile female (shortest female)percentile female (shortest female)

• Adjustable seats and ruddersAdjustable seats and rudders

• Center stickCenter stick

• Energy absorbing Confor™ foam Energy absorbing Confor™ foam seats for high impact landingseats for high impact landing

• Canopy door allows ease of entranceCanopy door allows ease of entrance

• Harness seatbelts for pilot and Harness seatbelts for pilot and passenger safetypassenger safety

• Base Cockpit Instrumentation:

• EFIS:

• Display

• EFIS Computer

• AHRS Computer

• PFD & Engine instrumentation

• Transmission & Reception devices:

• NAV/COMM Radio

• Mode A/C Transponder

AvionicsAvionics

TRANSMISSION & RECEPTION EQUIPMENT

PRIMARY FLIGHT DISPLAYSAND ENGINE INSTRUMENTS EFIS DISPLAY

AvionicsAvionics

• Safety

• Anti-lock brakes

• Ballistic parachute

• 5 Point seat belt

• Control surface actuation

• Mechanical

• Canopy

• Single piece with gas struts

SystemsSystems

• Cabin Conditioning

• Warm air taken from oil cooler

• Mixed with external air

• Provides de-misting (de-frosting)

• Electrical

• Standard 28V system

• 120 Ampere alternator

SystemsSystems

• Original Specification – 46m (150ft)

landing distance over 5m obstacle

46m150ft

5m7o

14m46ft

5m9o

If stall speed = 25ktsand free roll = 1 secondfree Roll = 15m

Landing IssuesLanding Issues

• Target ground roll – 46m (150ft)

• Total landing and take off – NASA SSTOL

• 9o Glideslope used in NASA analysis

DEFINITIONDEFINITION LANDING DISTANCE LANDING DISTANCE OVER 50ft OBSTACLEOVER 50ft OBSTACLE

CTOLCTOL 2000ft2000ft

STOLSTOL 1000ft1000ft

SSTOLSSTOL 500ft500ft

VTOLVTOL 100 ft100 ft

Revised SpecificationsRevised Specifications

Ground Roll

20

25

30

35

40

45

50

55

60

4000 4500 5000 5500 6000 6500

Take-off weight (N)

Gro

un

d R

oll

(m

)

• Target met at all take-off weights

• Landing Target met with 1 pilot and full fuel

Target

Landing

Take-off

Landing and Take-offLanding and Take-off

• Certification over 50ft (15m) obstacle

• SSTOL requirement met at all conditions

Ground Roll

120

125

130

135

140

145

150

155

4000 4500 5000 5500 6000 6500

Take-off weight (N)

Gro

un

d R

oll

(m)

Target

Landing

Take-off

Landing and Take-offLanding and Take-off

Cruise PerformanceCruise Performance

• Max Range Full Payload 650nm @ 80 knots Max Range Full Payload 650nm @ 80 knots

• 500 nm @ 124 knots500 nm @ 124 knots

• Max Endurance over 8 hours @ 64 Knots Max Endurance over 8 hours @ 64 Knots

Range at different Cruise Speed 10Kft

0

100

200

300

400

500

600

700

800

0 20 40 60 80 100 120 140 160

Speed (knots)

Ra

ng

e (

nm

)

MTOW

1 Pax FullFuel

Climb PerformanceClimb Performance

• 10,000 ft in under 10min @ 85 % and 90 Knots10,000 ft in under 10min @ 85 % and 90 Knots

• Max Climb 1364 ft/min @ 90 KnotsMax Climb 1364 ft/min @ 90 Knots

Climb Rate at Cruise speed and Throttle Settings

0

200

400

600

800

1000

1200

1400

1600

38 58 78 98 118 138 158

Speed (Knots)

Cli

mb

Ra

te (

ft/m

in)

100%

90%

80%

70%

50%

60%

Turn RatesTurn Rates

• Max Turn Rate 70 Deg/sec @ 57 knotsMax Turn Rate 70 Deg/sec @ 57 knots

Turn Rate Curve @ 1000 ft

0

10

20

30

40

50

60

70

80

0 20 40 60 80 100 120 140

Velocity (knots)

Tu

rn R

ate

(d

eg

/se

c)

Corner Speed @ 57 knots

Stall Limit

Structural Limit n = 3.8

n=4n=3

n=2

n=1.5

kg lb %kg lb %

Structure 235 486 37Structure 235 486 37

Propulsion 112 246 18Propulsion 112 246 18

Equipment 28 62 4Equipment 28 62 4

OEM 375 794 59OEM 375 794 59

Payload 182 400 29Payload 182 400 29

Fuel 78 172 12Fuel 78 172 12

MTOM 635 1366 100MTOM 635 1366 100

Mass BreakdownMass Breakdown

• Target price – luxury sports carTarget price – luxury sports car

• US $200,000 price ceilingUS $200,000 price ceiling

• Costing analysis is conducted using Roskam Costing analysis is conducted using Roskam

methodsmethods

• Anticipated cost reductions from avionics Anticipated cost reductions from avionics development are not yet considereddevelopment are not yet considered

Aircraft Cost AnalysisAircraft Cost Analysis

• Certify under Joint Airworthiness Requirements Very Light Aircraft Category

• Federal Airworthiness Requirements Sport aviation category:

Revise requirements

Certification PhilosophyCertification Philosophy

40 60 80 100 120 140 160

Cruise Speed (kts)

Aeris 200

Europa XS

Mission M212

Ikelos

Cessna 172

Slingsby Firefly

Jabiru

Zenith CH701

Storch

Cruise Speed

StrengthsStrengths

0 100 200 300 400

Landing Ground Roll (m)

Storch

Zenith CH701

Ikelos

Jabiru

Cessna 172

Europa XS

Mission M212

Aeris 200

Slingsby Firefly

Landing Ground Roll

StrengthsStrengths

• Risk – Unproven propulsion system

• Control authority in landing – more analysis required

• Specialized product for SSTOL market.

Weaknesses and ThreatsWeaknesses and Threats

Range of aircraft – basic to high performance

High performance options:

• More advanced avionics

• Thrust vectoring

• Circulation control

• Higher end of Market

• Military or law enforcement possibilities

OpportunitiesOpportunities

• Innovative modern technology employed.

• Large scope for adaptability

• Configuration set – but still opportunity for adjustments

• Project still in progress

ConclusionsConclusions