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NASA Design Team Tiltrotor Aircraft

NASA Design Team Tiltrotor Aircraft. Vertical Takeoff Rescue Amphibious Firefighting Tiltrotor. Group Members . Ryan Berg Alex Carra Michael Creaven Joseph Diner Meagan Hom Ryan Paetzell Jason Smith Alan Steinert James Tenney Bryant Tomlin. RFP.

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NASA Design Team Tiltrotor Aircraft

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  1. NASA Design TeamTiltrotor Aircraft Vertical Takeoff Rescue Amphibious Firefighting Tiltrotor

  2. Group Members • Ryan Berg • Alex Carra • Michael Creaven • Joseph Diner • Meagan Hom • Ryan Paetzell • Jason Smith • Alan Steinert • James Tenney • Bryant Tomlin

  3. RFP • 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

  4. Conventional Concept

  5. Quad Rotor Concept

  6. Dual Fuselage Concept

  7. Reasoning

  8. 3 View Drawing of V.T. R.A.F.T.

  9. V.T. R.A.F.T.

  10. Specifications • 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

  11. Mission Profile 4 10 11 3 5 9 12 2 5 8 13 1 14 6 7

  12. Engine Maximum Thrust Produced: 77053 lb Thrust Produced in VTOL: 6950 lb (Rolls- Royce)

  13. Nacelle Design

  14. Gearbox Configuration

  15. Rotor Design Rotor airfoil sections and positions as fraction of rotor length (Romander)

  16. Airfoil Selection • 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

  17. Wing Sizing • 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

  18. Full Configuration Drag Estimation • 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.

  19. Aerodynamic Results

  20. Stability and Control • 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 Structural design of a rib with the Flaperon

  21. Control Limits • Angle of Attack -8o to 12o

  22. Transition • Nacelles rotate at 3o per second • Due to excessive vibrations in transition • Pilot Safety • Nacelle limits are 0o to 100o Transition

  23. Water Stability • 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

  24. Structures-Goals • 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

  25. V-n Diagram Maximum Load Factor: 3 Minimum Load Factor: -1 Cruise Speed: 300 kts Dive Speed: 405 kts CLmax= 1.5 CLmin= -1.0

  26. Wing Loading Conditions With resulting shear and moment diagrams for traditional wing

  27. Strut Feasibility Study Vertical Takeoff Moment, ft-lb

  28. Strut Feasibility Study Vertical Takeoff Moment, ft-lb

  29. Strut Feasibility Study • 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

  30. Wingbox Design • 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°)

  31. Wingbox Design • Wing Skin tapering • 0.5 ft maximum tip deflection constraint • Moments of inertia for each configuration checked versus contour plot • Weight Reduction: 327 lb

  32. Results • 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)

  33. Validation • 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

  34. Validation

  35. Fuselage Design Loading Conditions • Aerodynamic 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

  36. Fuselage Design Results • Aerodynamic loading caused much larger moments • Aero Load Factor=4.5 • Water Load Factor=8.34 • Aerodynamic loading case turned out to be the limiting case

  37. Cabin layout • 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

  38. Cockpit and Landing Gear • Cockpit • Utilizes electronic controls • Features HUD • Landing Gear • Bicycle design • 66.3% TOGW on main wheels at 35° off CG

  39. Main Systems • 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

  40. Rescue and Firefighting Capabilities • 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

  41. Recommendations for Further Study • Water Tank Tests • Water Ingestion • Sea State Tests • H-V Diagram • Wind Tunnel Tests • Aeroelastic Effects • Interference Drag • Downwash Verification

  42. Questions

  43. CFD Analysis of Airfoil

  44. Cost • 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

  45. V.T. R.A.F.T.

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