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Design Project Plan

VIEWS: 12 PAGES: 30

  • pg 1
									PROJECT AIRNAUTILUS

       FALL 2009
                Statement of Need

 Assure that the U.S. maintains its tactical advantage
 for future coastal insertion missions
 (ref: DARPA BAA-09-06)
Motivation
Objective System
AirNautilus
Final Design Layout
           Operating Environment

 Carry up to eight personnel with equipment
 ~113 kg per person = ~900 kg total

 Carry an additional 900 kg of cargo


 Cruise altitude ~5,200 meters


 Tactical approach altitude ~5-10 meters
                        Requirements

 Sea state five conditions
    21-25 knot winds
    Wave height 2.5-3.7 meters
    Average period 5.5-7 seconds
    Average wave length 32-48 meters


 Submersing one atmosphere (~10 meters) to avoid
 detection

 Land on water
Communications
                 Communication



 Penetration ability of wave with various frequencies
  into sea water
 Antenna design to operate as a submarine as well as
  an aircraft
                        Communication

 Attenuation of wave into water
 •   Electrical conductivity 
 •   Fresh water = 0.01 S/m
 •   Sea water = 4 S/m

 •   Skin depth  =


 Sea water
 •   Thick electrical conductor, RF don’t travel well
 •   Non-magnetic material
 Balance between:
 •   Penetration and antenna length
                        Communication

 Types of submarine antenna
  HI-Q-4/2-30 Mast
   •   Short HF 2-30 MHZ
   •   ¼ wave length antenna
   •   Fully encapsulated for
       environmental protection
   •   h=50”, d=5.94”, m=18 lbs
       • Lower mast (drive motor 24 VDC)

       • upper mast (Re-entrant Coaxial Cap-hat)

       • loading coil (movable  continuously tuned
         in 2-30MHz range),
       • antenna controller
                         Communication

 Types of submarine antenna
  Buoyant cable
  •   VLF/LF/MF/HF
      (10 KHz - 35 MHz)
  •   l=610-730m, d=0.01651m,
      specific gravity=1.19kg/m
  •   Just for receiving when
       at max depth (1 way comm.)
  •   Slow transmission rate
       ~ few characters per minute
                                 Communication

 Air Craft Antenna
 •   VHF communication is light-of-sight
 •   One antenna at the top-one at the bottom
 VHF Civil Aviation Band (108 to 136.975 MHz)
 •   BW = 18.975 MHz
 •    ≈ 2.2 m
 Fiberglass Rigid Antenna
 •   Good Voltage Standing Wave Ratio (SWR)
 •   ¼ wave antennas
 •   Coax cable
     •   Must be 50 Ω coax (for aircraft)
     •   inner wire and an outer braid or shield
     •   outer braid is also ‘earths’, which suppresses
         outside interference
 •   BNC connector (light, weather proof)
 •   Radio
Electrical
                         Transition

 Start electric motor
 Seal all water entry points
 Shut down turbo-fan engines
 Perform nitrogen purge of turbo-fan engines
 Flood turbofans with fuel
 Flood the wings with surrounding sea water
 Increase motor RPM to 75% of total power
 Check battery charge status
                        Transition

 Reduce motor to idle (10%)
 Switch main power source to electric motor
 Verify electrical system operation
 Verify sife support systems are operational
 Presurize cockpit
 Slowly Submerge
Electrical Schematic
             Underwater Travel: Electrical

Powering the aircraft
 According to our research we found that the aircraft needed 50kW
  while submerged, safety factor included

 Total amount of power required for underwater operation both ways
  assuming we take 10 hours is 500kW

 A Reliance Baldor 1000HP electric motor will power the propellers

 The motor will draw power from an array of batteries

 Number of batteries on board: 44k
         Underwater Travel: Propeller

 Prop was optimized to find basic prop needs:
   5 knot Speed

   300 kW per prop

   1000 RPM

   0.5 Gearbox Reduction Ratio

   28 cm Diameter

   0.61 m Pitch

   56% Slip

   Four blades for smaller diameter
Resurfacing
Resurfacing
                                       Stability

   Longitudinal Stability
       The longer after-body as compare to fore-body will maintain longitudinal
        stability by adding adequate canard moment arms


   Lateral Stability
       Two water skis on the tips of each wing are providing;
           Lateral stability to submersible aircraft
           Weather-vane to face wind when at rest, or during taxiing at low speed
Miscellaneous
Propulsion
                 Water Landing: Impact Force

 Aircraft weight:
     266,893.297 N (60,000 lbs)

 Descent Rate:
     -3.5 meters per second
      normal to water

 Vertical Speed Stop Time:
     1 second

 Pressure:
     3.418 kN/m2

 Force:
     95.25 kN
                        Submersion


 Static Diving              Single hull design
   Ballast tanks              22m3 of free space for our
 For our aircraft              components
  specifications
   Fb = 207 kN

   21000 kg of water

   20.57 m3
                       Corrosion

 Titanium Alloy Ti-6Al-4V (Grade 5)
   90.0% Ti, 6.0% Al, 4.0% V, 0.25% Fe, 0.20% O

   Often used in airframes, blades, fasteners

   Great corrosion resistance

   Density: 4.43 g/cm3

   Thickness: 3 mm




                                  Ti-6Al-4V blisk manufactured for the JSF
Conclusions
Future Work

								
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