Trend Analysis

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• Trend Analysis initial sizing
• Based on existing helicopters

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Technion Team

• Main rotor design
• Prokopov Oleg
• Khodos Gregory
• Schreiber Ilanit
• Simulations and Trim
• Perelman Andrey
• Rind Elad
• Fuselage design and Weights
• Kipervaser Galit
• Adler Gabriela

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• Main requirements
• 2 place training helicopter
• Turbine engine.
• Payload of 440 lb 220 kg.
• Fuel capacity for 2 hours HOGE.
• 6000 ft hovering altitude.
• Good autorotation capability.

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Required Payload 440 lb
Exceptions
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• Gross Weight Vs. Payload
• Fuel capacity for off-trend line designs is about
  15-20 gallons.
• PSU design group has estimated 60 gallons, for
  the total required hover time.
• Dragonfly 333 Ultrasport 496 have about the
  same payload but less gross weight.
• Aerokopterza 6 Air Commander Elite can trade
  payload for fuel capacity.

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Gross Weight Vs. Payload

• Both trend lines match the statistics.
• Therefore the simpler linear trend can be used.
• Resulting weight-payload function
• W3.41PL46 lb
• Gross weight initial estimate 1540 lb.

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MDL vs. Gross Weight

• Quadratic estimation slope closer to 1, hence the
  quadratic estimation is the most appropriate for
  light weight helicopters.
• Weight and MDL calculated by PSU design team
  nearly fits the quadratic trend line.

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Main rotor diameter vs. Main rotor diameter
estimation.

• Quadratic fitting based estimation is the most
  suitable for lightweight helicopters.
• Max Disc Loading function
• MDL-4.610-8W20.001W1.4 lb/ft2

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Tip speed Vs. Tip speed estimation

• We chose the quadratic function is
• Vtip speed -0.3D225D180
• Tip speed Estimation using PSUs rotor diameter
  According to the quadratic fitting
• Vtip speed 640ft/s (about 450 rpm)
• Data presented here is inaccurate since the
  updated PSU data that we received did not include
  RPM or Tip Speed

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Empty Weight Vs. Gross Weight

• We chose the simple linear function
• EW0.55W19 lb
• PSUs empty weight 976 lb (443kg) and gross
  weight 1600lb (730kg) nearly fits the trend lines.

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Useful Weight Vs. Gross Weight

• We chose the linear function
• UW0.45W-19 lb
• Again, the useful weight and gross weight
  calculated by PSU nearly fits the trend lines.

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Rotor Angular velocity Vs Rotor Dia.

• We can see that the angular velocity of the Main
  Rotor is of about 470RPM.
• We chose the linear function
• Omega-10.8D746 RPM

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Tail Rotor Diameter Vs. Gross Weight

• We chose the linear function
• DTail rotor 0.001W2.45 ft
• The tail rotor diameter hasnt been decided yet
  by Penn State (2 ft. at least)

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Schweizer HUGHES 300C
Low Hub
Robinson R22
High Hub
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Hub

• Uniform approach to Hub sizing wasnt found
• Two common trends were tested low and high hub.
• Main conclusions
• Hub height will be determined after cabin design.
  
• Aerodynamic considerations and FAR will be taken
  into account.
• Solid body drag can be reduced by using a wing
  shape for the Hub cover.

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• Referring to other helicopters, and aerodynamic
  advantage we can make initial estimation of hub
  height 2.42 ft 0.74m.

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Helicopter Power

• Parameters - Gross Weight, blade chord, ceiling
  altitude, and main rotor diameter
• Gross weight - 1540lb (700kg).
• Chord length - 0.66ft (20cm).
• Ceiling altitude - 10000ft.
• Main Rotor Diameter estimated by statistical
  formulae.
• Those sizes were used everywhere except in
  figures where they were a parameter
  

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• Engine Power was calculated using the relations

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• Standard atmospheric model was used.

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• Preq increases linearly with Gross Weight at a
  rate of about 7 HP/100lb
• Power required increases with number of blades

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• Ceiling Alt. Preq increases with number of
  blades
• Preq increases with altitude

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Boundary Layer separation

• Chord decreases ? Power decreases
• Increasing number of blades allows for smaller
  chords
• Small chords demand higher AOA? boundary layer
  separation
• Flow separation must be taken into account

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• Preq decreases rapidly with rotor diameter
  increase
• Preq increase at the highest diameters is due to
  induced drag increase at low speeds
• Increasing the main rotor diameter is desired,
  however, the results should be checked for a
  global optimum.

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Engine losses

• Installation losses 5-16 (according to Prouty)
• Inlet pressure losses due to duct friction
  1-4
• Inlet pressure losses due to a particle separator
  3-10
• Exhaust back pressure due to friction
  0.5-2
• Height losses 1/(0.8_at_6kft)24
• Wear-out (deterioration) 5-10
• Engine-mounted accessories 10-15 HP
• Misc. up to 5

Preq 95 HP gt Peng 145 175 HP Note This
estimation is for continuous power!
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Preq 95 HP gt Peng 145 175 HP Note This
estimation is for continuous power!
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Initial Sizing - Summary

• According to the trend analysis results and the
  demand for 440(lb) 200kg payload
• Gross Weight 1540 (lb) 700Kg
• Empty Weight 860 (lb) 400Kg
• Fuel weight 240 (lb) 109Kg
• Main Rotor Dia. 26 (ft) 7.9m
• Maximum DL 2.9 (lb/ft2) 14.2 kg/ m2
• Angular Velocity 470 RPM
• Tail Rotor Diam. 3.8 (ft) 1.17m
• Tail Rotor Arm 15.4 (ft) 4.7m
• Continuous power 145-175 (HP)
• In general, approximately Tail Rotor
  Armft(DDtail)/20.5