Ok I’ll start with the High bypass turbofan video.  This will be a series of short posts on this video, point by point.

1:09 - narrator claims WW2 bombers had water injection, for engine cooling.

WRONG, twice.  No bombers had any water injection system, and water injection was NOT FOR ENGINE COOLING!  Water injection was used on FIGHTER AIRCRAFT to reduce knock at high engine power settings.  It does cool the MANIFOLD INLET CHARGE, not the engine.  The water supply (30-50 gallons) was used very quickly, providing only 5 or 10 minutes of war emergency power.  In a dogfight, 5 minutes with an extra 400 hp can be the difference between life and death.

Water injection was never used on bombers, because all that water is extra weight.  Extra weight is less bombs you can carry, or a lower altitude you can reach.  An extra 5 MINUTES of 15% more power will make no difference whatsoever, against fighter planes trying to shoot you down that are already 200 mph faster, when they are fighting their way to the target and back for many hours, under attack for hours at a time.