Re: Synergy Aircraft - was it a "rope-a-dope" after all? We see this fenomen on modern gliders sink rate/speed polars, some where at medium high speeds the curve bend sharply down even more, (sink rate increase more with speed) due to that the laminar flow length is changed (wing bottom) when nose is pointed down, less AoA, the curve can not be described with a simple equation. The Synergy with help of suction will hopefully bend the other way. Some members here say we can not fool the rule saying speed increase with the cube of power increase, but that is not correct on any aircraft, it is just a lasy dog for quick estimates, it depends on where on the drag polar curve we are, so it changes with altitude due to the changes in IAS/TAS (we come to a different place on the curve) that rule of thumb is a combination of the power/thrust change with speed and the airplane polar curve. the thrust= power * efficiency * (550) / V = equation is fixed, (but the efficiency change with speed) sometimes the power change with speed too, just to make things more interesting, so we (me) can make calulations till I dye (I don't want to die) it will not be 100 % correct anyway.