Two features will be especially excellent for aerodynamic efficiency:
1) Having the two trailing wings in the wake of the first.
2) Three times the wingtips.
From a structural standpoint, all the extra reinforcement in the fueslage to hold up the fuel tanks in the overhead space will most certainly lighten the airframe and also having the fuel tanks up there will present an optimal safety situation that the FAA will most certainly appreciate.
Finally, single-engine designs are a cutting-edge solution for optimum efficiency and safety. You don't even have to bother with a Vr!
Good luck certifying one engine. There are in flight shut downs.
The fuel tanks will be an issue. Firewalls exist so that when a tank is punctured the passengers are safe.
I am not seeing the 70% claimed drop in fuel burn. I look at each feature and estimate the fuel savings and in no way do I get anything more than 25%. This would be like comparing my undergrad design to real world. I missed 25% of the empty weight as I didn't fully account for wiring, fire suppression, and how heavy joints in aircraft design are.
Everyone wants joint free CFRP. There is massive research on continuously woven structure going on today. But that is to cut 5% of weight.
Fuel is in wings as that reduces moment at the wing root and thus saves weight.
I do not see features to take hitting a pot hole on a taxiway. Also a tail engine means structure to carry the thrust to the drag (wings and fusalage). While simple wings are fun to design, a triple wing has more structure per wing area.
A triple wing also has a stall in certain angles of attack. The whole reason horizontal stabilizers are built for downforce is that during rotation a rear wing will stall. This is a non-trivial concern.
I normally love new concepts. This is a school project missing fundamental design features. BWB evacuation is far easier than fuel over passengers to certify.
1st: a 2nd engine.
2nd. features to prevent wing stall during moderate angles of atrack.
3rd: fuel fire safety
4th, landing gear robustness for pot holes
5th the structure isn't built for the wobble of a hard landing.
6th everyone likes V-tails untill planning test certification (stall margins, engine out takeoff). Then they don't
I want a BWB with lifting body and without the drag of the vertical stabilizer. Twin stabilizers are sexy and draggy.