Yeah I'm not sure this project passes the smell test. I don't know much about airplanes but a few things seems off when I think of this design in terms of basic physics.
The "boxwings" seem to be a worst of both world approach. It ads a lot of surface going across the air and thus a lot of drag, without providing the width which would usually make available the torque necessary for stability and control.
Torque is (force * distance) and, for roll control, this distance is usually provided by wide wings. An airplane having shorter wings would probably go through the air more efficiently (provided you didn't add a second set of wings on top of the first one) but would not provide much control to enable safe flight in all possible conditions. Short wings don't provide much leverage on the roll axis.
It also seems like in this design the top part of the "boxwings" plays the role of the tail of the plane. However, it looks like we get the same (force * distance) problem but on the pitch axis. In order for the tail to give a good amount of torque for pitch control, it has to be located away from the wings and the center of the aircraft.
Again, I'm just guessing based on physics here but since there is no tail other than the one located near the bottom wings, it might be difficult to stop the plane from pitching up or down out of control.
If we were to design planes for efficiency only, they would look like arrows or missile. They would have minimal wings or fins to slow them down. The reason, we have to have things sticking out far from their middle, is to add the ability to safely control them in a wide variety of conditions.
This aircraft has both lots of wing, thus a lot of drag and yet the extra wingage doesn't get the wings positioned away from the center where they would add the most stability and control. Unless the "Laminar Flow", "Wake Propulsion", "Open Thermodynamics", "Subsonic Area Ruling" or the other technobably things mentioned on the website somehow compensate for this, it seems like a lose-lose design.
IAAAE (I am an aerospace engineer). Actually, long (or wide, to use your term) wings tend to be more efficient. The term you're looking for is "high aspect ratio," which efficient airplanes (see the Global Flyer, for example) have in abundance. It is the ratio of wing span squared to wing area (viewed from above, not the front). The explanation for why this is true is complicated, but this gives a good overview:
Yeah, this isn't insane. Basically it's a T-tail horizontal stabilizer where the vertical stabilizer has been split in four sections and placed outboard to clear the rear-mounted propeller. There's nothing wrong about this. The stabilizer might be a little farther forward than some designs (it's not clear where the c.g. would be looking at that drawing, one assumes in the middle of the four passenger seats), but not radically so.
That's not saying it's an amazing new design which will break records or anything (it can't be -- subsonic aerodynamics is literally an 80-year-old-mature technology). But it's attractive and looks like a clean design at first glance.
If I understand correctly, this seems like yet another reason why this Synergy design would be sub optimal. The two sets of short low aspect ratio wings are theoretically less efficient than one set of long high aspect ratio wing. Correct?
I don't know what their numbers are, but for an aircraft of its class, the lower wings don't look like they have an abnormally low aspect ratio. The upper wings look to be of a higher aspect ratio than conventional elevators. Since elevators are a source of drag (they usually have to provide some downforce to trim the aircraft in level flight, and you can't make lift without making drag), that could be a win. But then they're close to the CG, so they'll need to provide more trim force (short lever arm as you mentioned), and the advantage might be lost.
Of course there are other factors at work. For example, Jet A carries more energy per pound than 100LL and diesels are more efficient, so you carry less fuel for a given range. But the engine needs to be stronger to run a higher compression ratio, so that's some added weight. Every little design feature of an aircraft interacts with every other design feature. Aircraft design can be a tremendously unintuitive affair. That's why it's so fun.
So, the proof's in the pudding. The ultimate arbiter of an efficient aerodynamic design is its lift-to-drag ratio, or how much drag is generated for a given amount of lift produced. (See http://en.wikipedia.org/wiki/Lift-to-drag_ratio) They should be getting good data off their scale model, and if the model's L/D ratio is high and they've done their homework to reflect the full size aerodynamics, then they might have something.
Actually, if you read their Kickstarter, they claim to be getting better fuel efficiency with higher cargo weight. They claim this is because it somehow lowers their drag. They also claim that L/D is unimportant for their aircraft, which is why a scaled test is useless to them, even in a wind tunnel. This doesn't pass the smell test for this AE.
Long wings doesn't give more controll. The increased radius gives a higher inertia when rolling. It would make it more stable, but also slower. Acrobatic aircraft usually have short wings for this reason.
The "boxwings" seem to be a worst of both world approach. It ads a lot of surface going across the air and thus a lot of drag, without providing the width which would usually make available the torque necessary for stability and control.
Torque is (force * distance) and, for roll control, this distance is usually provided by wide wings. An airplane having shorter wings would probably go through the air more efficiently (provided you didn't add a second set of wings on top of the first one) but would not provide much control to enable safe flight in all possible conditions. Short wings don't provide much leverage on the roll axis.
It also seems like in this design the top part of the "boxwings" plays the role of the tail of the plane. However, it looks like we get the same (force * distance) problem but on the pitch axis. In order for the tail to give a good amount of torque for pitch control, it has to be located away from the wings and the center of the aircraft.
Again, I'm just guessing based on physics here but since there is no tail other than the one located near the bottom wings, it might be difficult to stop the plane from pitching up or down out of control.
If we were to design planes for efficiency only, they would look like arrows or missile. They would have minimal wings or fins to slow them down. The reason, we have to have things sticking out far from their middle, is to add the ability to safely control them in a wide variety of conditions.
This aircraft has both lots of wing, thus a lot of drag and yet the extra wingage doesn't get the wings positioned away from the center where they would add the most stability and control. Unless the "Laminar Flow", "Wake Propulsion", "Open Thermodynamics", "Subsonic Area Ruling" or the other technobably things mentioned on the website somehow compensate for this, it seems like a lose-lose design.