Re: Minor aerodynamic problem
Actually, that makes it worse . . .
A failure in one engine is quite likely to propagate to the other one. The Germans discovered this in the HE-177 bomber which used a pair of DB V-12s in each of two nacelles to drive a single prop on each wing. The setup was highly incendiary, and the airplane quickly became extremely unpopular with the surviving crews. The Russians re-discovered the same problem some years later in the TU-144, with the same results. Even the legendary Vulcan fell victim to this. Someone got a (posthumous) medal for not letting the stricken bomber crash into a town. The USAF lost a B-58 Hustler in the UK to adverse yaw when one of the outboard engines flamed out: Instant flat spin and airframe destruction. Also, look up "unstart yaw" in regards to the SR-71. Stuffing multiple high performance engines into a single nacelle is poor design, and hanging them out at the far ends of the wings is even worse. A review of the long, unhappy annals of aviation disasters over the years shows this arrangement to be a design error, just like the O rings on the Challenger.
Engine failures DO occur, and sometimes they are uncontained. The trick is to design your aircraft so that loss of an engine doesn't affect the structural integrity of the airframe or seriously compromise control authority. This is especially important on really high performance aircraft because these are operating at the very limits of the technology and perhaps sometimes a bit beyond.
I don't have a problem with the engines - my problem is with the airframe packaging. It looks great, but it is not a fault-tolerant design. Aircraft in general, and especially aircraft like this, need to have some safety margins in case of component failure.
There is also the good possibility that the final aircraft will not look at all like the concept. Remember that these guys are raising money and political backing from people who don't know much about airplanes beyond they do/don't want a window seat, and talking about adverse yaw and failure propagation will scare off the money. The renderings LOOK great - flat black, stubby fins, it screams SPEED . . . but as shown, it has some serious problems if there is any problem at all with any of the state-of-the-art bleeding edge technology engines, and history shows us there will be, sooner or later. Good design avoids these known problems, and that's my complaint here. The airplane looks great, but if anything goes wrong, it will be completely unforgiving.
Make the engines work properly and reliably, then design the airframe around it. I really do hope it is a success, and I'd love to fly it.