Flying Off the Grid
Copyright 2019 by Paul Niquette. All rights reserved.

trusswing

The SUGAR Volt applies the Boeing Truss-Braced Wing in a future design concept for a subsonic, electrically powered airliner in response to a request for aircraft research proposals by NASA

The key aerodynamic feature of the SUGAR Volt is its extremely high aspect ratio of 27, using a wingspan of 39 m (127 ft).  That's too long for the SUGAR Volt to be accommodated at standard airline gates, so the outer wing is hinged for foldingTo achieve high aerodynamic efficiency, the wing must be both slender and thin, so the design applies a truss-braced configuration.  The truss has the form of an airfoil, which provides lift to augment that of the wing.

Let us imagine a SUGAR Volt airliner configured for markets now served by Boeing 737s, the highest-selling airliner in history, with more than 10,000 in service as of this writing.  The table below makes technical comparisons based on [a] specifications for the Classic version of the Boeing 737, [b] reference literature for the SUGAR Volt and [c] an elementary model...




B737 Classic

SUGAR Volt

Payload Equivalence (kg)




Maximum Wt

62,822

62,822


Empty Wt

32,821

49,713


Zero Fuel Wt

49,713

N/A


Fuel Wt

13,109

N/A


Battery Wt

N/A

13,109


Payload Wt

49,713

49,713

Airframe Comparison




Wing Span  (m)

28.9

38.7


Wing Area (m^2)

91.0

55.5


Aspect Ratio

9.2

27.0

Aerodynamic Comparison




Lift-to-Drag Ratio

15.0

25.7


Drag (N)

4,188

2,442


Service Ceiling (ft)

37,000

37,000

Cruise Performance Summary




Speed (km/hr)

876

876


Range (km)

4,176

4,176


Duration (hr)

4.8

4.8



You are invited to observe that 'equivalencies' are highlighted in yellow. Each invokes an explicit assumption for the model.  One key assumption is indicated in green.  It signifies a 'weight budget' for the SUGAR Volt's lithium-iron batteries based on the B737 Classic's Fuel weight.

Can lithium-ion batteries really do the job?

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