Lilienthal had made "whirling arm" tests on only a few wing shapes, and the Wrights mistakenly assumed the data would apply to their wings, which had a different shape. The Wrights took a huge step forward and made basic wind tunnel tests on 200 scale-model wings of many shapes and airfoil curves, followed by detailed tests on 38 of them. An important discovery was the benefit of longer narrower wings: in aeronautical terms, wings with a larger aspect ratio (wingspan divided by chord—the wing's front-to-back dimension). Such shapes offered much better lift-to-drag ratio than the stubbier wings the brothers had tried so far. With this knowledge, and a more accurate Smeaton number, the Wrights designed their 1902 glider.