ikelos virginia tech and loughborough university present: 2001/2002 interdisciplinary/international...
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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