I agree that the lifter's ion [induced] wind adds to the aerodynamic drag during ascent (I think that's what you're saying, note you could say the same of a helicopter's propeller induced wind)
Anyway in the case of the lifter this wind is relatively slow (of the order of 1 m/s, about 100 times slower than the entraining ions which are not very good "paddles" and not very numerous), and the profile is usually quite aerodynamic, so the corresponding drag is quite small. This means that in practice the thrust needed for takeoff isn't much more than the device's weight. Example (Blazelabs 100g payload lifter): total weight of lifter + payload = 187gf, let's see what current is needed for a thrust of 187gf. The gap being 92mm, by applying the EHD thrust formula: thrust in gf = 0.5*i*d with i in mA and d in mm we find that we need a current of 4.1mA (187/(0.5*92)). In practice Xavier found that the lifter almost took off at 4.2mA, and definitely flew and tensed its tethers at 4.4mA: http://www.blazelabs.com/e-exp14.asp (do watch the video) Michel ----- Original Message ----- From: "Harry Veeder" <[EMAIL PROTECTED]> To: <vortex-l@eskimo.com> Sent: Monday, February 19, 2007 9:54 PM Subject: [Vo]: Lifter aerodynamics > An "ion-wind" may produce enough force to let the lifter hover, but can > it produce enough force to let the lifter (and its expanded > electro-aeordynamic profile) _ascend_ through the air? > > Harry
