Flying Tigers

1
Flying Tigers

• Wind Tunnel Development

8 June 2006
Don Hurd
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Agenda for Tonight

• Present Wind Tunnel Architecture (30 min)
• 8 subsystems
• You decide which subsystem you would like to
  participate in
• Break into working groups by subsystem (30 min)
• Choose a leader
• Discuss design development concepts
• Clarify interfaces
• Keep notes!

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Wind Tunnel Subsystems
A Wind Tunnel Tube
C Propeller / Motor
E Model
D Runway
B Base
F Model Support
G Pilot Console
H Electrical Control
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Subsystems Interfaces

• Architecture supports independent development
  testing of each subsystem
• Key Concepts
• Interfaces must be well defined!!!
• All teams must understand agree on how they
  will interface
• Document your subsystems!

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Functional Description

• Visitor sits at console cockpit
• HOTS
• Views model airplane tunnel propeller
• Colored control surfaces
• Pressed start button
• Power applied until timer expires
• Observes motion of control surfaces
• Coordinated with stick movement
• Observes wind tunnel propeller speed with
  throttle

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Functional Description .

• Observes tries to control model
• Lift off the runway
• Experiments with airspeed (tunnel propeller)
  elevator
• Experiments with low airspeed high AOA
• Observes stall characteristics
• Observes tries to control bank angle for
  movement from side to side
• Experiments with aileron control
• Combined aileron elevator
• Experiments with making
• Take-off
• Flying within movement limitation
• Successful landing
• Gets Flight Certificate

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Key Design Areas

• Smooth responsive control
• Throttle control of propeller speed
• Control surfaces servos
• Proper balance coordination of
• Model weight, shape aerodynamics
• Gimbals counterbalance support
• Model responds smoothly at low airspeeds
• Physical constraint limitations
• Physical constraints with shock absorption in the
  gimbals / counterbalance support
• Sensor feedback via mixers in the Tx to provide
  aerodynamic control of desired physical
  movement extremes

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A Wind Tunnel Tube

• Plywood aluminum safety glass nice finish
• 8 long, 5 diameter
• Honeycomb for streamlining the air
• 1/2 holes 5 thick
• Filter to prevent particles gt 1/16 from entering
• Slight reduction in the middle to increase
  further smooth out the air
• Viewing window on both sides
• View both model tunnel propeller
• Circular shroud to house the propeller / motor /
  support assembly
• Propeller at least 15 from exit screen
• Protective exit screen
• 1/2 holes
• Strong enough to withstand deliberate hand blow

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A Wind Tunnel Tube

• Interfaces
• Wind tunnel base
• Provisions for model support assembly
  electrical control wiring into the model
• Runway
• Mounting provisions
• Propeller (/ motor / ESC / support )
• Attachment of the propeller support assembly to
  the inside of the tunnel shroud
• Provisions for electrical control wiring into the
  base

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B Base

• plywood nice finish no sharp edges / corners
• 8 long, 5 wide, 30 high
• Structurally support tunnel tube
• Attach to pilot console
• Internal support structures
• Model support subsystem
• Electrical control subsystem
• Interfaces (mostly structural attachment)
• Wind tunnel tube
• Model support subsystem
• Electrical control subsystem

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C Propeller / Motor

• Propeller 5 with 2 pitch
• Wood or aluminum
• Structually capable of 1500 rpm
• Brushless motor
• Long life under heavy use
• 500 W continuous
• 24 VDC, 20 A continuous
• lt 130 degrees operating at room temperature
• Gearbox
• Support propeller speeds 0 to 600 rpm _at_ max motor
  efficiency
• Long life under heavy use low maintenance
• ESC
• 30 VDC 30 A continuous
• lt 120 degrees operating at room temperature

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C Propeller / Motor

• Support structure
• Propeller hub, bearing
• Motor / gearbox / ESC attachment
• Attach to the wind tunnel shroud
• Provisions for routing wiring
• Power supply
• 24 VDC 30 A continuous
• 110 VAC input
• Necessary cooling (i.e. fan etc.)
• Interfaces
• Wind tunnel tube structural attachment, wiring
• Base structual support of power supply, wiring
• Electrical control subsystem servo signal
  wiring to ESC

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D Runway

• Semi-scale runway
• Attached to bottom of wind tunnel tube
• 3 wide 4 long
• Provision for clearance for model support
  assembly
• Interfaces
• Wind tunnel tube
• Model support subsystem

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E Model

• ARF model OK with 2 wingspan
• Suitable airfoil for low speed flight docile
  stall
• Attractive to kids e.g.
• Balsa stick structure with transparent monocoat
• Semi-scale warplane
• 3 servos for ailerons, elevator, rudder
• Heavy duty servos with long life
• Interfaces
• Model support assembly gimbals attachment
• Electrical control subsystem servo wires

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F Model Support Subsystem

• Support structure to hold the model
• Gimbals to allow model to pitch, bank yaw
• Counterbalance to support part of the model
  weight
• To allow low speed airflow 10 mph
• Allows model to move
• Up down
• Right left in arc to simulate turning
• Provide constraints for maximum motion
• Dampeners to absorb shock at maximum motion
• Interfaces
• Model support motion
• Base structural support
• Electrical control subsystem wire routing

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G Pilot Console

• plywood nice finish no sharp edges or corners
• Simulated cockpit
• Excellent viewing of model wind tunnel
  propeller
• Easy access to joystick throttle lever
• Provisions for wheelchair access
• Attached to wind tunnel base
• Interfaces
• Wind tunnel base structural attachment
• Electrical control subsystem mounting joystick,
  throttle lever power button routing of wiring
• Wind tunnel tube positioned for excellent
  viewing

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H Electrical Control Subsystem

• Converts visitor joystick throttle level into
  appropriate simulated flight characteristics
• Tx without RF module (e.g. Futaba 8U or 9C)
• Rx with DSC port (direct servo control)
• Arcade quality joystick
• Durable (aluminum) throttle lever
• Buddy box interface from joystick throttle
  level to Tx
• Power button timer
• Interfaces
• Pilot console joystick, throttle power button
  mounting wire routing
• Base structural support wire routing
• Propeller / motor / ESC control of motor
• Model servo connections
• Model support subsystem wire routing

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Schedule

• July meeting
• Complete design concept to present to club
• Document your interfaces with other subsystems
• Rough budget estimate
• Include ideas for getting donations
• August meeting
• Complete subsystem designs, interfaces, budgets
• Begin construction