Hi there the Mast recess position on the Flow fuselage is 9cm further back from the nose vs the Aero, when putting them both tip to tip (the Aero is obviously shorter at 80cm, but measured from front I mean). So that's the distance approx that the Aero foil is further back - if using similar wings - obviously as we have some high aspect and low aspect wings, they sit a bit differently/sizing is different- but that's the basic difference in nr´s yes. Hope that helps.