FLYING WING

Flying wing , or blended-wing aircraft is an old invention. If we forget earlier toys, then two German brothers made first flying model during WWII. Then, Russians tried it in the fifties of XX century. ("Letayuschcheye Krylyo").

The design has plenty of advantages , mostly in excellent aerodynamics.

But - it has one major disadvantage , at least for public mass transport: it has weak longtitudinal stability at low speeds. This in turn translates into a small , but important risk in one , albeit short, phase of flight - that between V1 and V2 , during takeoff,

In simple words ; if anything happens with propulsion just after takeoff , at very low height, then the aircraft will loose stability and fall . Similarly, by missed approach at low speed.Conventional aircrafts may still glide to landing straight without propulsion, provided that the safety zone is there.

Of course, with multiple engines ,e.g 24 of them , the risk of a loss of propulsion is very, very small.

But, on the other hand , today's aircraft also provide very small chance of any malfunction during these critical several seconds of takeoff. Nevertheless, hundreds hours of training and meticulous procedures are devoted only to those seconds,

Anyone who, as a kid, built paper planes knows, what flight stability is,

This is also why birds have tails. Although tails are not aerodynamically efficient - they generate a lot of drag.

By birds, too...