> when a missile miss and slams into the ground.

A lot of them are designed to explode before hitting the target for maximum damage.

A fully-fueled private jet is an inefficient missile, but it exceeds the raw chemical energy of most in-theater single-target tactical missiles (although the energy conversion is far less precise and efficient).

But yes, that's a lot of kinetic mass dead-stopping on a hard surface and 1 to 2 kiloliters of jet fuel.

Technically called a wet explosion. Fuel deflagration, not explosive detonation.

The private jet carries up to 3.5 tons of fuel and weighs over 10 tons at take off. A Kalibr cruise missile is maximum 500kg of explosives and the heaviest variant is 2.3 tons over all.

Its not surprising at all that the jet makes a huge hole in the ground. Jet fuel is more energetic than RDX, while converting that energy slower. So both the chemical and kinetic energy is much higher with the jet then with a russian cruise missile. If anything the crater is surprisingly small.

The fuel would not have contributed to the crater. Fuel does not explode, not at the speed needed to form a crater. It requires oxygen. No matter how much fuel was present, there was not enough oxygen in the immediate vicinity of the crash to burn that much fuel.

The fact that there was a fire long after the impact shows the fuel was not burnt in the crash. Fuel hung around long enough to still be burning at least several seconds afterwards, long after the crater was formed. That is why it wasn't a missile. Missiles use high explosives (propellants and warheads) which burn up all at once to generally leave a non-burning crater.

Some back-of-napkin math yields a crater depth of a little under a meter ... which is in the ballpark of images.

aircraft (1.5m radius cylinder x 18m long) at 6700kg = 51.54 kg/m3 aircraft density... over ~1,500kg/m3 average soil density x aircraft 18m length = 0.63m

=.63m / 2-foot penetration below ground level... which is what the pictures show.

Soil is dense. Aircraft are marshmallows compared to soil.

> The fuel would not have contributed to the crater.

In the explosive sense, I agree. Depending on how much fuel they had, it could’ve been a decent percentage of the aircraft’s weight, though.

surely velocity and elasticity need to go into that calculation as well

Nope. Speed doesnt contribute to crater depth. Faster makes a wider crater, not a deeper one.

https://en.wikipedia.org/wiki/Impact_depth

When the object is near supersonic spèeds (throught the various materials) even the strenght of the materials becomes very secondary. A meteor made of sand makes the same crater as one made of stone.

Just to address the elephant in the room, that was also the "vulnerability" deliberately exploited in the 9/11 attacks.

What do you mean deliberately exploited? Given the information made available in the past 25 years, they didn't seem to plan for such engineering failure, it was more likely pure luck. I mean, crashing a plane, counting that the fuel would flow through the elevator shafts, still burning, and that it would soften the iron columns enough to make them buckle... it needs a competent team to plan that with certainty.

IIRC some the guys who hijacked the planes took flying lessons and were notoriously uninterested in takeoff and landing compared to steering, according to their instructors. They weren't very sophisticate.

I'll give you the benefit of the doubt, though. In a conspirational mindset, if it was a false flag operation (and it did help USA find support to rearrange the Middle East oil control, get rid of their old bomb stock, and a few other perks), a State certainly has the proper people to plan such scheme, and the actual hijackers would only need to know which face and height of the towers to hit, and at what angle and speed.

I meant the "vulnerability" that planes, especially early in the flight, also contain significant fuel that causes cascading damage beyond the impact.

I get that my comment probably didn't reach the "insightfulness" threshold for HN, but geez, go easy on me.

Ah, my bad. The word "vulnerability" threw me off.

I'd guess that wasn't deliberate also, since logistically, it was better to hijack the plane while it was in range of their target, and it had enough fuel to make it look like kidnapping instead of terrorism to delay the response. One can't ignore that a refueled plane weighs about 20-25% more, though.

I don't know how to break this to you, but the reason the 9/11 hijackers weren't interested in learning how to take off and land was because they were going to hijack the planes mid-air and then crash them, not land them. It wasn't because they weren't "sophisticated" and lacked interest.

What, that planes are heavy and move fast?

This is because there is more mass to the plane than most missiles. And that mass going those kinds of missile-like speeds is going to create quite a shockwave and crater. Contrary to what many people are saying, the fuel contributes very little to the crater size.

Citation: I'm a former airplane and missile guy.

Shouldn't the missile warhead contribute to the crater size though?