On the display at the Aero aviation show in Germany was this carbon-fiber two-thirds scale rendition of the famed Czech fighter trainer, the L-39 Albatross. Since the fall of the Soviet Union, the ‘tross has become a rich-guy toy and there are quite a few knocking around the US in private hands. So what was this? Had the Czechs pulled another one out the hat, perhaps adapting an APU engine for this mini-fighter? The truth was even weirder. The little jet wasn’t a jet at all, but a ducted fan driven by a BMW S1000RR motorcycle engine having its neck wrung in flight to what’s got to be near the engine’s breaking point.