Extreme Range

1
Extreme Range

• Breguet Range eq.
• best values based on current technology
•  hp 0.9
•  cp 0.4 (piston engine gives the best sfc)
•  L/D f (A, e, CD0)
• CD0 f (Swetted, BL state, S)

2
Extreme Range

• Structural limits to max allowable A
• Aerodynamic limits to CD0
• Powered airplanes (L/D)max 25 very good value
  !
• Transports Wi / Wf 2.0
• Rmax 14,621 n. mi.
• Nonstop, unrefueled flight around the world
  R 28,000 n.mi. !
• This range requires a Wi / Wf 3.8
• Nothing you can do in a short time to overcome
  technology limitations! The only thing you can
  do is be creative in your design!

3
Extreme Range

• Rutan achieved Wi / Wf 4.5 in the Voyager with
  
• A 33.8
• Composites
• Special airfoils in the lifting surfaces and the
  propellers
• Place fuel outboard on the wing
• Reduce wing root bending moment
• Improve Wi / Wf
• Experimental regulations instead of civil or
  military airworthiness constraints, resulting in
  W savings

4
Rutan Voyager
5
Extreme Endurance

• Breguet Endurance eq.
• Same tradeoff between L / D and W as in the case
  of extreme range

6
Extreme L / D

• High-performance gliders Schleicher AS W22 B

7
Extreme L / D

• Need to maximize A and minimize CD0
• Solutions
• Very high A wings (Schleicher AS W22 has A
  38.3)
• Laminar flow wings
• Min size fuselage (pilot in reclined position)
• Advanced composite structures