The advantages are (theoretically) lower structure mass per passenger. But airplane cabins are pressurized, and lightweight pressure vessels 'want' to be cylinders or spheres, not big flat boxes.
There's a aerospace engineering student who gave a thesis talk on the disadvantages of blended wing-body, and offers some possible solutions.[2]
(Source: I have an aerospace engineering degree from Embry-Riddle)
There are a number of engineers at NASA and Boeing working on the X-48 who would disagree with you on this one.
The main advantage of the blended wing body is to reduce the skin friction drag [0] of the aircraft relative to the typical fuselage and wings. You have less surface area in contact with the air relative to the amount of internal volume. There may be some increase in the profile drag (i.e. the cross section of the aircraft) but is made up for by the reduction in the skin friction drag.
> The fuel burn of a B2 is far higher pound for pound than a 737.
This isn't really a fair comparison. They are two aircraft optimized for entirely different things.
I’m willing to accept that a gold bullion transporter can look closer to a flying wing, but with any reasonable cargo density you are back to the standard design.
Trying to intuitively explain CFD results is apparently just as hard as dispelling the Bernoulli nonsense about airfoils.
I’m right and high aspect ratio wings are a harder materials science and design challenge than blended wings. There is a reason 10000x as much engineering effort is going into folding carbon fiber wings for passengers/cargo. The folding is to increase fuel economy through aspect ratio and fit in terminal box.
Everything I have said is trivial to prove with CFD and experimentally. I get that popular science articles need to entertain the masses.
Let me ask you this, why is the tail of passenger aircraft upward sloping?
> Skin friction drag is a drop in the bucket compared to parasitic and lift induced
I'm trying to rectify it with papers that say "In civil aviation, skin-friction drag accounts for around 50% of the total drag in cruise conditions" [0]
> I’m right and high aspect ratio wings are a harder materials science and design challenge than blended wings
I understand that higher aspect ratio reduces drag too and that the planes should all look like scaled up gliders with their long skinny wings. But as you said, it is harder. So is it a clear cut answer that exploring blended wing designs is a waste of time?
> Let me ask you this, why is the tail of passenger aircraft upward sloping?
To prevent tail strike during take-off and landing when you are at a high angle of attack.
[0] https://www.sciencedirect.com/science/article/pii/S037604212...
https://www.technologyreview.com/2013/01/24/180345/hybrid-wi...
The pressure vessel problem is much more concerning to me—I can’t think of a way to solve it that wouldn’t massively increase weight and/or reduce usable space.
To be fair, the B2/737 comparison isn’t particularly fair—they were optimized for wildly different things, and only one design was significantly constrained by acquisition and operational costs.
Long thin fuselages dramatically increase drag due to skin friction. Blended wings have better lift to drag ratios, meaning for a given amount of fuel consumption (to overcome drag) you get higher payload/better range.
The B2 has twice the range of a 737 and cruises 20% faster.
Long high aspect ratio wings and streamlined body are how you get fuel efficiency.
The fuel burn of a B2 is far higher pound for pound than a 737.
This idea gets even more ridiculous when you consider the cargo area is a pressure vessel. There is a reason the body is isomorphic with a welding tank.
Edit: I suppose I wouldn’t care about this, but the Biden Administration plowed climate money into a blended wing military concept, which 1 day with any CFD software shows is stupid.