Why planes with more engines don't fly faster?

[SluggoF16]

Originally Posted by motormaker

My Dad, a old B-24 pilot swore he would never fly or fly in a 2 engine plane across any ocean.��

I have a couple of trips across the ponds (the little east one and the bigger west one) with just one engine, another with just two engines. However, it DOES make one think, and spend a lot of time looking at the cold Atlantic below. About every 45 minutes the F-16 radar would perform a self-test if it wasn't being actively used, in which the radar antenna would park itself in the upper left position and then bang around slightly 2-3 seconds. The rumble was perceptible and would usually result in a "heightened state of awareness", one never got used to it. Or on occasion the air conditioning/pressurization would "woof" or "huff" and then get very quite; the common pilot reaction was "WHAT!!??" I never had that happen over the open ocean but at night 30 miles SE of downtown Baghdad it's equally disconcerting.

[Dane_in_LA]

Originally Posted by Stefan_from_Germany

Some truth to this but not entirely correct. Transport category aircraft (airliners) need to be able to maintain a specified minimum climb gradient after a take with an engine failure. That climb gradient is much shallower than a typical all engine take off. Aircraft are not required nor able to recover the lost engine's power with the remaining engines. They only must meet the minimum gradient specified by relations, which is as litte as 2.4% for twin engine aircraft.

https://www.skybrary.aero/index.php/...y_Jet_Aircraft

Having said that, it is true that twins typically have more power reserves than four engine aircraft as they need to be able to achieve minimum climb gradient on just one of two engines (50%) as opposed to three of four engines (75%).

I had a feeling that full thrust compensation wasn't a thing, but happy to see that the principle holds.