When does MECO typically occur around (height wise) in real life

[Spaced Out]

I know the Falcon 9 usually cuts of just around 62-64 kilometers but what about rockets like the Delta IV and Delta IV Heavy? I know there is no set height because of different payload weights but I just want an average.

[Gaarst]

Between 120km and 180km depending on the configuration and the mission for Delta IV. (Source, pp27-31)

Most two and two-and-a-half stage rockets MECO over 100km since the most efficient configuration is a large powerful first stage and a very small upper stage. The Falcon 9 is an exception since its first stage is relatively small to allow for easier recovery.

Three stages rocket obviously stage much lower but if you consider MECO to be the second stage shutdown for these, then you get similar altitudes (eg: Proton-M stages at 42km and 120km (source, p9), Saturn V at 60km and 170km (source, p27)).

Edited August 17, 2017 by Gaarst

[YNM]

As what @Gaarst said.

If I might add, usually rocket stages are divided by what work they're expected to do. Earliest rockets used solid fuels - no way to stop the ignition. Even those that had liquid fuel too often was only ignitable once or on the ground. So most rockets will have stages intended to lift them to heights, and then some more stages to make the orbit. The numbers could be arbitary but modern optimized design tends to use the lowest number of stage possible, which is one for each.

Edited August 17, 2017 by YNM

[wumpus]

2 hours ago, Gaarst said:

 the most efficient configuration is a large powerful first stage and a very small upper stage.

While the most efficient configuration is complicated (there is no trivial way to optimize it), a good starting configuration is often equal amounts of delta-v from each stage (another good starting point is each stage half the mass of the previous one).  And while the upper stage should typically use a very small engine, it doesn't always follow that the fuel&oxidizer tanks have to be tiny.  It certainly helps to have a small dry weight (including payload), but you need the wet weight for delta-v.  Don't forget it is far easier to get delta-v without the dry weight of an additional stage.

Don't forget that the Falcon9 first stage provides a lot more delta-v when it isn't coming back to land (and the first stage is considerably more powerful with the 1.1 and later models that started trying to perform a powered landing).

[YNM]

21 hours ago, wumpus said:

Don't forget that the Falcon9 first stage provides a lot more delta-v when it isn't coming back to land (and the first stage is considerably more powerful with the 1.1 and later models that started trying to perform a powered landing).

In such cases they usually put in more payload instead. I presume it works out about the same. Or they could loft in a different trajectory such that it comes about the same in the end.

[monstah]

Ah, from the thread's title I thought the OP meant this:

In any case, have some related information.