CLASSIFICATION of the WINGRID

1. Key discriminators of airtransport aircraft
What are the key discriminators (key features) of airtransport aircrafts (see also the detailed presentation)?

2. Wingtip-Classifications
Since the winggrid has a different topology compared to other wing-tip devices it is essential to classify
it and understand its effects.

	Performance of wingtips	Zimmer	Kroo	La Roche , Smith
classification	N.A.	pure geometrical classification criteria	geometry and downwash-wake	downwash-wake (Smith) and deflected massflow model (La Roche)
wing theory	N.A.	Munk’s stagger theorem applies	criteria planar and nonplanar, but all with linear vortex interference with spanload, Munk applies	wing configurations included exhibiting nonlinear vortex interference with spanload and not rendered by Munk theorem (no force free wake)
Linear, systems: Munk applies	e<1.1 h/b=0	contoured/straight wings planform	planar wing with nonplanar wake	contour
	e<1.4 with h/b=0.2	simple wingtips/ endplates	nonplanar monoplane	endplate
	e<1.5 with h/b=0.2	box/multiplanes	Nonplanar multiplanes/box/ strut/closed, C-Wing	N.A.
Nonlinear systems with streamwise staggered winglets	e<1.2 h/b>0.2	slotted edge/fanned partial	nonplanar monoplane with multiple winglets	open fanlike
Nonlinear systems with streamwise staggered winglets	e<3.0 with h/b<0.05 for Winggrid	N.A.	N.A.	Winggrid Spiroid Split-wing

e: practical limit span_efficiency
h/b: parameter h/b compares vertical dimension h of configuration to span b
N.A.; not applicable
95 ; year of publication
References:

Zimmer 83:
The aerodynamic optimization of wings at subsonic speeds and the influence of wingtip design, H. Zimmer, NASA TM-88534 1987 (translation of diss. Stuttgart 83)
Kroo 95:
Highly Nonplanar Lifting Systems, Ilan Kroo/John McMasters/Stephen C. Smith, Transportation beyond 2000: technologies needed for engineering design,NASA Langley Research Center, September 26-28, 1995
Smith 96:
A Computational and Experimental Study of nonlinear Aspects of Induced Drag, Stephen C. Smith, NASA Technical Paper 3598, Ames Research Center
La Roche 96:
WING GRID, a novel device for reduction of induced drag on wings, U. La Roche/S. Palffy, Proceedings ICAS 96 Sorrento, September 8-13, 1996
La Roche 00:
Induced Drag Reduction with the WINGGRID Device, Ulrich and Lucas La Roche, Proceedings CEAS Potsdam 00, European DragNet
Munk:
The Minimum Induced Drag of Aerofoils, NACA Report 121, Munk Max M.,

Size of effect of the WING GRID is an order of magnitude greater than with classic winglets:

wingtip type	De
wing grid	1 to 5
classical wingtips (winglets, endplates etc.)	0.1 to 0.5

Also check the Whitcomb-type winglets and the spiroid-type winglet of Aviation Partners Inc.

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