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Ikelos. Virginia Tech and Loughborough University present:. 2001/2002 Interdisciplinary/International Aircraft Design Project. Original Specification. Key Requirements: Aircraft fits on trailer Lightweight and Simple STOL or VTOL Land in 46m (150ft) over 5m obstacle
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Ikelos Virginia Tech and Loughborough University present: 2001/2002 Interdisciplinary/International Aircraft Design Project
Original Specification • 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
Initial Design Ideas • 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 Concepts VTOL Tilt Duct Pusher Prop
Design Development • Reviewed advantages and disadvantages of: • STOL • VTOL • Vectored Thrust • Modified Design to: • STOL as standard aircraft • Vectored thrust option
Revised Specification • 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
Wing Detachment • 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
Materials • 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
Manufacturing • Planes assembled in individual bays • Composites used where possible • Internal skeleton • Assembly team at each bay • Team unity and pride in work • Important due to the complexity of wiring, controls, and electronics
Tornado VLM • Non-planar vortex lattice method • Incorporates various wing features
Wing Layout • Box-wing design • Front wing twisted • Unswept inboard TE flap
Lift Characteristics • Based on forward wing area • CLMAX = 4.19 • Leading edge devices • Front wing flapped • Fowler te flaps, fixed vane
Drag Characteristics • Induced drag reduction • CD0 = .045 in cruise INLETS AND OUTLETS WINGS SIDE PLATES VERTICAL TAIL 35% 3% 12% 4% 12% OTHER 17% 5% FUSELAGE 24% DUCTS UNDERCARRIAGE
Stability and Control • Static Stability • Design Criteria: Acceptable static margin in all configuration, FAR 23 compliance • Final Configuration balanced (positve Cm0L) with positive pitch stiffness (negative Cma) • Lateral-Directional stability satisfied but nearly neutral to retain maneuverability • Dynamic Stability • Design Criteria: MIL-F-8785C specifications with Level 1 flight qualities
Control Surfaces • Aircraft equipped with standard elevators, ailerons, and rudder
Control Forces • Used Roskam methods to determine control forces • Analysis shows that FAR 23 stick force limits are satisfied
CG Travel in MTOM Flight Conclusion: Stable Aircraft
The Rand Cam Engine • Innovative diesel rotary engine • Inherently simple, no pistons, timing values, • spark plugs • Uses a system of axial vanes that rotate in a • cam shaped housing
Light weight – High power to weight ratio Fuel efficient Costs similar to that of an equivalent automotive engine Low noise Very little vibration Low maintenance The Rand Cam Engine
Engine Starter Exhaust Pipes Alternator Cooling Air Exhaust Cooling Fan Intake Intake Plenum Oil Pump Fuel Tank Oil Cooler Cooling Air Intake Oil Tank Engine Layout
Higher thrust per horsepower for a given diameter than a propeller Better performance at low speeds than propellers – no recirculation at the tips Quieter than propellers – noise damping material used in ducts Duct provides an additional safety feature. Duct diameter 0.92 m (3 ft) Fan consists of 5 rotor blades and 12 stator blades Fans attached to engine via a 1:2 helical spiral bevel gear Low noise 60dBs. Tip speed 113 m/s (370 ft/s) Ducted Fans
Thrust Calculations • Static thrust calculated using disc actuator theory • Dynamic thrust found using general thrust equation • Efficiency found by reading from chart of empirical data charts
Cockpit • Designed for 95th percentile male (tallest male) and adjustable to 5th percentile female (shortest female) • Adjustable seats and rudders • Center stick • Energy absorbing Confor™ foam seats for high impact landing • Canopy door allows ease of entrance • Harness seatbelts for pilot and passenger safety
Avionics • Base Cockpit Instrumentation: • EFIS: • Display • EFIS Computer • AHRS Computer • PFD & Engine instrumentation • Transmission & Reception devices: • NAV/COMM Radio • Mode A/C Transponder
PRIMARY FLIGHT DISPLAYS AND ENGINE INSTRUMENTS EFIS DISPLAY TRANSMISSION & RECEPTION EQUIPMENT Avionics
Systems • Safety • Anti-lock brakes • Ballistic parachute • 5 Point seat belt • Control surface actuation • Mechanical • Canopy • Single piece with gas struts
Systems • Cabin Conditioning • Warm air taken from oil cooler • Mixed with external air • Provides de-misting (de-frosting) • Electrical • Standard 28V system • 120 Ampere alternator
5m 7o 46m 150ft 14m 46ft 5m 9o Landing Issues • Original Specification – 46m (150ft) landing distance over 5m obstacle If stall speed = 25kts and free roll = 1 second free Roll = 15m
Revised Specifications • Target ground roll – 46m (150ft) • Total landing and take off – NASA SSTOL • 9o Glideslope used in NASA analysis
Landing and Take-off Landing Target Take-off • Target met at all take-off weights • Landing Target met with 1 pilot and full fuel
Landing and Take-off • Certification over 50ft (15m) obstacle • SSTOL requirement met at all conditions Target Landing Take-off
Cruise Performance • Max Range Full Payload 650nm @ 80 knots • 500 nm @ 124 knots • Max Endurance over 8 hours @ 64 Knots
Climb Performance • 10,000 ft in under 10min @ 85 % and 90 Knots • Max Climb 1364 ft/min @ 90 Knots
Turn Rates • Max Turn Rate 70 Deg/sec @ 57 knots
kg lb % Structure 235 486 37 Propulsion 112 246 18 Equipment 28 62 4 OEM 375 794 59 Payload 182 400 29 Fuel 78 172 12 MTOM 635 1366 100 Mass Breakdown
Target price – luxury sports car US $200,000 price ceiling Costing analysis is conducted using Roskam methods Anticipated cost reductions from avionics development are not yet considered Aircraft Cost Analysis
Certification Philosophy • Certify under Joint Airworthiness Requirements Very Light Aircraft Category • Federal Airworthiness Requirements • Sport aviation category: • Revise requirements
Weaknesses and Threats • Risk – Unproven propulsion system • Control authority in landing – more analysis required • Specialized product for SSTOL market.
Opportunities • 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