Dick Johnson methodology for measuring glider performance

I don't disagree with this post but I would say that, overall, DJ's testing was good at pointing out the gliders that performed particularly well compared with its competitors - and this was often confirmed by the choices of top competition pilots. Example: ASW20 versus Mini Nimbus and LS3a.

It worked the other way, too. When DJ tested the ASW 20 and LS-3 (not the later LS-3a), they both had remarkable, essentially equal performance. This was confirmed by those who flew the two gliders in that first year or two (ours was delivered in 1978). For a brief period, they were equally favored by competition pilots in the U.S.

Then the rush to the ASW 20 began. At first this was a bit baffling. Except for the higher wing weight of the LS-3, what was there about the '20 that seemed to capture so many pilots' favor? Then it became evident that the two types were no longer equal. They still climbed together but the '20 had an advantage in glide.

I profiled the top surface of my LS-3 wings and discovered a "flat spot" where post curing had apparently shrunk the wing over the spar cap. Building up this flat spot fully restored the glide performance, equally dramatically compared with other types as well as other LS-3s. A few owners (e.g., Jim Cox, IIRC) went even further, building up the leading edge where the profile was apparently a bit too blunt compared with the published coordinates as well as fixing the flat spot, with similarly impressive results.

But by that point, not only had time passed the LS-3 by but DJ's tests of the LS-3a seemed to indicate that the later version had inferior glide performance right out of the box, allegedly because of a thicker profile caused by the molds not being completely stable (see heated exchange of letters in "Soaring" mag about that time). My own impression was that the early LS-3a gliders were quite good, but that impression didn't last.

In any case, the reputation of the LS-3 remains today as inferior to the original ASW 20a despite DJ's original published test.

Chip Bearden
ASW 24 "JB"