One factor not mentioned so far is why a twin becomes hard to fly in a single engine configuration.

For every conventional twin, in a single engine configuration, there is one airspeed at which the combination of rudder and aileron cannot provide enough force to counteract the yaw forces caused by the remaining running engine. Below this airspeed the remaining engine will simply pull the plane in an out of control condition towards the dead engine. That airspeed is the minimal controllable airspeed or V mc in the full-scale world. Note that this airspeed is often higher than the normal stalling speed of the airplane.

Speed is life.
Contrary to previously made statements in this thread, if the airplane is in normal cruise, and you loose an engine the best possible course is to go to start a decent and slowly go to full throttle on the remaining engine to gain as much speed as possible. Then trim with rudder and aileron to maintain straight and level. With speed you have control and you are moving away from Vmc and toward safety. The wonderful little Hobbico Twin Star 25 behaves exactly in this manner when powered with .25’s. It can even do single engine touch and goes if you keep up the speed. The advice listed in this thread of going to a reduced power setting on the remaining engine only increases the probability of accidentally flying below Vmc. The other advice of treating it as a dead stick, going immediately to idle on both engines and pick a place to land guarantees avoiding Vmc but doesn’t do you any good if the dead stick is going to smash the plane in a bad off-field landing. So to extend flying time go to full throttle. BUT…for a given model that may still lead you to a Vmc condition. The single engine still isn’t strong enough to pull the airplane fast enough to maintain airspeed. This is where you have to learn what YOUR model will do in an engine out condition.

Don’t Panic!
If you’ve gone to full throttle on the remaining engine, and your plane has become a monster turning into the dead engine. Go to idle and glide. You eliminate the forces that are causing the out of control condition.

That just aint so
I have the UTMOST respect for TWINMAN and his series posted on the link but when a model looses an engine, it looses 50% of the power and about 55% of its thrust. The 90% issue he points to in his article is true of a 1:1 sale plane while the propeller of the dead engine is wind milling. The drag caused by the spinning prop does a lot to slow down a full-scale plane, that’s why you feather it as quickly as possible to eliminate the huge drag of that prop. Our model engines (IC at least) stop almost instantly so the small frontal area of the stopped prop is the drag. The bigger problem we have is not getting off the elevator. We think that height is life when it’s speed. Get the nose level or down if possible and accelerate and use all the energy you can get, and then fly home!

MTC, YMMV, Just another factor to consider.

Tom