A link that seems not to be live at present: http://www.newscientist.com/ns/971011/features.html Is a report that explains the implications of Reynolds number and the fact that bee/insect wing movements in flight create vortexes that create lift in excess of that predicted by "large size" aerodynamics. The failure to predict the lift when using "normal" aerodynamic analysis is not due to incorrectness but misapplication. That speed regime (sub-, trans- and super sonic) affects aerodynamics is well known to pretty much everybody these days, but the fact that size affects aerodynamics is much less well known. The aircraft modelling fraternity knows that model-size aerodynamics are not the same as full-size aerodynamics - and it turns out that insect-size aerodynamics are different again. Due to size - ie. due to wildly different range of Reynolds number. cheers Tony -- Anthony N Morgan, Førsteamanuensis Institutt for Elektroteknikk Høgskolen i Sør-Trøndelag N-7005 Trondheim, Norway [log in to unmask] Tlf. 73 55 96 04 Fax. 73 55 95 81