Is it time for Booster Engines?
In the world of automobiles, engine stop/start appeared now and again but didn't catch on. Now fuel is so expensive it's regularly on even upmarket vehicles. For aircraft should we be starting to think about more complex configurations?
Booster engines have appeared now and again but I don't recall anything in the western civil arena since the Trident 3. Is there now a case for having engines used for only part of the flight?
Take-off (particularly with engine failure) is a big deteriminent on what engines you have although it is a tiny portion of the whole flight. The Trident booster was to reduce runway requirements, not for example to sustain/enhance cruising speeds or levels.
I know they didn't install a booster out of choice, but maybe with fuel costs as they are now, it would make sense to have smaller, less powerful main engines supplemented by boosters. Remember the more engines you have for take-off the less power excess you need, and the less rudder moment you have to fly with.