Helicopter recovery model that releases t' blades after boost by usin' t' motor ejection charge t' drop t' fin can off t' back attached t' a Keelhaul®©™ harness, eliminatin' t' need for a burn string.  Blade shape no is accomplished by slicin' t' balsa blades diagonally lengthwise (partially, nay a complete cut-through) then bendin' t' balsa with t' aid o' pre-cut jigs and gluein' t' cuts t' set t' final shape.