and we started talking about the ShinMaywa US-2, which is a very cool search-and-rescue airplane and just so very friend shaped
and someone noted with surprise that this 26 ton (when empty) airframe has a stall speed of only 50 knots which is like. a tiny bit faster than the slowest something like a Sopwith Camel can fly?? anyway the reason (well, one of) it can do this is incredibly cool. see, there's a secret 5th engine on board internally, a 1300hp turboshaft that drives an air compressor. this compressor blows air through ducts on the flaps and tail control surfaces, redirecting air downwards to increase its lift and in line with the rudder and elevators to enhance its controllability
this is just really fucking cool and watching videos of this thing doing low speed landings is just unreal, like watch this:
it just... floats down! this enormous monster of a machine can just drift down like a feather. this is my new hyperfixation aircraft of the day
EDIT: @Iryx has a better explanation of how the compressed air stuff works
the secret fifth engine part of this is actually even more complicated than that! Normally if you tried doing this without a secret fifth engine, you'd get what's called "boundary layer separation", where the airflow peels off of the airfoil before it should, making a mess of turbulent air over your wing and killing any gains you were getting from deflecting the air at that steep of an angle (and probably more than that! boundary layer separation is Bad). here's a pic of it 
what that secret fifth engine is doing is adding just enough airflow in just the right places so that the airflow remains attached to the wing the whole time. I don't think this would have been possible in the era before computational fluid dynamics, and it's really neat to see it used in a modern reprise of what seems like an outdated mode of flight
