The assembly has a first guide vane having a first end, a second end opposed to the first end, and a second guide vane having a first end, a second end opposed to its first end. A first end structure spans between the first guide vane first end and the second guide vane first end. A second end structure spans between the first guide vane second end and the second guide vane second end. The first guide vane, the second guide vane, the first end structure, and the second end structure are integrally formed together to form a double vane with a continuous outer surface, and a continuous inner surface.