Why is the Hornet limited to mach 1.8?

Stop reading Wikipedia

NATOPS prohibits speed above Mach 1.8 (A1-F18AC-NFM-000 page 1-4-5, section 4.1.3.1) - for the two seater though (22 c 1), which would be the D. Same goes for the C, but with a CLT (22 b 1). Close attention has to be paid in that section, it isn't exactly easy to read with all those conditions, sub-conditions and sub-sub-conditions.

If wikipedia has had good sources, it's OK. If you read it, look critically at what's given and try to find other sources that support whatever is written there. Same rule as everywhere. Books aren't any better by rule though. Lies or wrong facts have been copied for hundreds of years. Just look for the length of the river Rhine for example. Literally all books have been wrong for ages becase all those authors copied the same error. Pun literally intended.

Next time I fly with an ex-f18 pilot, I’ll remember to ask if he knows the answer to this.

With clean airplane, the inlet design would in particular be the reason for MMO somewhat lower than in some comparable airplanes. I recall engine limitations coming into play as well if messing with the maximum altitudes. I am aware of at least one engine that sustained some significant damage, supposedly when some of the airplane's published performance figures were exceeded by "some amount" as a part of in-flight evaluation, which sometimes tries to find the absolute limits.

Generally speaking, one thing sometimes causing a bit of confusion is not understanding that the maximum speed is not always a figure that cannot be exceeded if one simply pushed on. The "redline" is very often put in for various reasons other than it being as fast as thing could go.

Don't know about that high (high enough to break mach 1.5), but looking at the excess power charts, aerodynamic properties do seam to play a part. At least down low, there is great dip in performance around the transonic region then that disappears once you go supersonic, which would imply that there is a strong build up of shock wave induced drag which can only be surpassed by diving and not through sheer thrust. Maybe there is another such "bump" at mach 2.0?

Don't know about that high (high enough to break mach 1.5), but looking at the excess power charts, aerodynamic properties do seam to play a part. At least down low, there is great dip in performance around the transonic region then that disappears once you go supersonic, which would imply that there is a strong build up of shock wave induced drag which can only be surpassed by diving and not through sheer thrust. Maybe there is another such "bump" at mach 2.0?

There is no other bump of transonic drag at Mach 2. The rapidly increasing wave drag, or drag divergence, as the "sound barrier" is sometimes called, is a phenomenon occurring right at high transonic region, near Mach 1 and does not repeat periodically at higher even Mach numbers.

A clean or sensibly loaded Hornet easily goes supersonic in level flight.

I purchase this early access and after reading this blog I kinda wish Joint Operations was still around and school was open. Any one knows of any schools like joint ops are still around? TC

With clean airplane, the inlet design would in particular be the reason for MMO somewhat lower than in some comparable airplanes. I recall engine limitations coming into play as well if messing with the maximum altitudes. I am aware of at least one engine that sustained some significant damage, supposedly when some of the airplane's published performance figures were exceeded by "some amount" as a part of in-flight evaluation, which sometimes tries to find the absolute limits.

The same thing happens operationally occasionally. No idea how true this is, but legend has it that Russian MiG-25RB's on reconnaissance missions over Egypt were intercepted by Israeli F-4's, resulting in the MiG pilots red-lining the engines & going to over Mach 3. Allegedly both aircraft needed total engine changes after the flight.