The box-wing is actually a really old design - contemporaries of the Wright brothers were experimenting with it. The main advantage is reduced drag. Airflow doesn't like points, and wingtips contribute a lot to the overall drag. Closed wing means no tip, and therefore less drag.
Of coarse box-wing has its problems, too. They claim to have solved some of those issues. I'll remain skeptical until the flight test proves their claims.
The 1/4 scale model means almost nothing. A colleague put an electric motor on an 8-ft chunk of foam and flew that around. The power to weight ratio of small r/c aircraft is ridiculous, and it does not scale to full sized aircraft.
Well the question is if they scaled everything in the 1/4 scale model, including power. They say it is flying since 2007 so we have to assume they did their homework before trying to make the current full scale prototype.
It doesn't work like that because all of the factors don't scale at the same rate. I'm not an engineer, so unfortunately I can't elaborate with much detail for you, but the general concept is that factors like aerodynamic efficiency and power efficiency can't be scaled up and down independently in a rudimentary way.
The simplest one probably is that lift and drag scale with wing area, while aircraft weight scales with its volume. That means that, if you do things at quarter scale, you have 1/64 or about 1.5% of the weight, but 1/16 or about 6% of lift. Consequently, almost everything flies at that scale. The model plane will also be extremely robust, as its landing gear can take 1/16 of the original one, but has to carry only 1/64th.
All of these are, of course, only valid to a rough approximation; look up "scaling laws" if you want to learn more)
That's not true at all. Their claims about wind tunnels are also ludicrous. Take a peak at the Reynold's number wikipedia page sometime. That's EXACTLY how aerospace engineers do preliminary calculations: by scaling aerodynamic factors (which is completely viable with a nearly incompressible fluid like low speed air).
The idea that it gets MORE efficient by having more cargo violates the energy equation. Literally. That concept was disproved (utterly) when the sound barrier was broken.
I haven't looked at their claims, but strictly speaking it isn't impossible that adding cargo increases efficiency. How? Well, if the cargo is added in a location that moves the aircraft's center of gravity closer to the aircraft's neutral point (the center of lift for the entire aircraft), then less trim force from the elevator will be necessary for level flight, resulting in reduced trim drag.
I'm not saying that their claims are correct, just that added weight can potentially result in improved performance, depending on how much weight it is and where the weight is placed.
Of coarse box-wing has its problems, too. They claim to have solved some of those issues. I'll remain skeptical until the flight test proves their claims.
The 1/4 scale model means almost nothing. A colleague put an electric motor on an 8-ft chunk of foam and flew that around. The power to weight ratio of small r/c aircraft is ridiculous, and it does not scale to full sized aircraft.