Thanks for that interesting backgrounder about the F-4 impact test. Wonder if anyone else can confirm/deny that....
Assuming that it DID have its engines, I went looking for some data that would allow a basic type of comparison with impacting airliners....
....according to information from Jane's....
...the Phantom jet has two General Electric J79-GE-17 turbojets with an afterburning thrust of 17,900 lbs; each of them weighs 1,740 kg (3,835 lbs) and has a diameter of 992 mm (39"), with a total weight of 3,480 kg (7,656 lbs) for the two side-by-side mounted engines, and an average impact area density of 3.21 psi.
...large commercial airliners like the Boeing 767 and 747 come in many variations (models), with a large selection of engines - though General Electric and Pratt & Whitney supply nearly all of them, with about a 50-50 split. Recent models of these airliners use engines with a thrust ranging from 52,000 to 61,000 lbs, a weight of some 4,200 kg (9,200 lbs), and a diameter of 2,463 mm (97"), for an average impact area density of only 1.24 psi, which is apparently four times less severe than the Phantom's engines.
Actually however, much of that large engine frontal area is due to the high-bypass fan (which the military jet doesn't have), while much of the weight is concentrated in the "core" part of the engine, which contains the compressor and turbine stages. This core part of the engine has an average impact area density roughly the same as the Phantom's engines, possibly slightly higher. The shafts BTW are thin-wall hollow pipes, several inches in diameter.
Speed is the more important factor -- the test Phantom was doing 475 mph, while the WTC impacts were at a little over 300 mph -- hitting a small target gets more difficult at higher speeds.
Jaro
-----Original Message-----
From: goldinem@SONGS.SCE.COM [mailto:goldinem@SONGS.SCE.COM]
Sent: Friday October 12, 2001 1:49 PM
To: radsafe@list.vanderbilt.edu
Subject: Terrorist and nuclear plants
A couple of points about nuclear plants:
First, I was advised by a former Vietnam-era pilot, after showing the
Sandia video with the F4 Phantom on the rocket sled, that the plane had no
engine, it was only an airframe. He suggested, as many others have
recently, that the engine internals (the turbine shaft) are the most
serious risk to a structure. So, while the F4 video is spectacular, it
probably doesn't really represent reality. Personally, having seen
construction of containment buildings, I find it absolutely inconceiveable
that an aircraft or jet engine shaft could penetrate the structure, but I'm
not a civil engineer.