The F117 is the first true stealth aircraft, how strong is its stealth capability? Public data from the United States say that under the radar wave detection of the X-band, the RCS values of the front and side of the side are smaller than those of mortar shells, that is, between 0.001 and 0.01 square meters. This data is very good even today, but why in 1999, F117 was shot down by the missiles of the ground air defense forces, resulting in early retirement?
How exactly was the F117 shot down?
There have been many opinions about the reasons for the F117 being shot down, some people say that when the plane took off from the Italian airport, the information was sent out by the mobile phone, and there have been people reporting their whereabouts along the route, so the F117 is equivalent to "naked running" throughout the process. Others say that the ground air defense forces seized the moment the F117 opened the bomb hatch door to drop the bomb, locked on to the target, and launched the missile. But in fact, these statements are not correct.
None of these statements are true
The real reason the F117 was shot down was that there was a flaw in its stealth design. As we all know, the F117 is almost composed of straight lines, this design can make the radar wave hit up, crawl along the straight line, and then reflect out at the end of the line, so as long as the end of the line is not in the direction of the radar wave emission, then the enemy can only receive a small reflected signal, thus achieving stealth.
The F117 is all straight lines, which are meant to allow radar waves to crawl
But this is only one of the secrets of F117 stealth, its second magic weapon, is the resonance of radar waves, that is, when there are two corresponding relationships and materials on the aircraft's body, such as parallel straight lines, the radar waves hit by them will disappear because of the resonance relationship, just like the "elimination" game, which is also the "edge parallel" theory of modern stealth fighters.
These lines have parallel lines
F22 follows the same theory
If you look closely, almost all the edges of the stealth fighter are straight, and you can find another parallel line, and the F117 is also designed in this way, but the problem is that its tail is hanging, and there is a flaw. The straight line of the F117's vertical tail is parallel to the cockpit B-pillar, which is true, but the problem is that its vertical tail is tilted outward, and the cockpit B-pillar is inward-leaning, which means that the relationship between the two is actually not completely parallel, so once the radar wave hits the two, it is impossible to play "elimination".
The cockpit B-pillar and the hanging tail appear to be parallel
Hanging out of the tail out of the big thing
In fact, Loma's skunk factory was aware of this problem when it was designed, and on the F117's technical demonstration machine "Haifran", the tail was tilted inward, strictly parallel to the cockpit B-pillar, achieving perfect stealth. But in this design, the flight performance of the aircraft is really unbearable, and it may not even be able to fly after enlargement, so it can only be changed to extrapolation. Stealth aircraft are designed to be such that there is always a trade-off between stealth performance and flight performance.
The tail of "Hayforn" is inverted
In order to cover up this natural flaw of the F117 as much as possible, the skunk factory also thought of many ways, such as using a wave-permeable material to make a hanging tail, while applying a thick stealth coating, which is indeed very effective, in the previous operations, the ground air defense unit even if it uses the meter wave radar, can not find the target.
The F117 tail is made of transmitted material
Coincidentally, on March 27, 1999, the ground air defense unit was replaced with a new meter-wave radar. It is worth mentioning that in fact, the stealth coating of F117 can also absorb miwave radar waves, rather than being ineffective against miwave radar as previously rumored. This is because its stealth coating adds conductive materials between the composite laminates, such as toner, metal fine powder, etc., which can improve the radar wave absorption capacity of specific frequencies by adjusting the dielectric properties and magnetic properties of the laminates, so F117 will learn the radar situation deployed along the way through accurate intelligence each time before performing the mission, so as to make targeted adjustments.
Hang off the coated F117
It seems that accurate intelligence is also one of the prerequisites for stealth, but this time the ground air defense units are not replaced by a standard radar, but a VHF-band meter-wave radar modified by themselves. If it were a standard radar imported from Russia, the United States would have obtained accurate intelligence long ago, and there would not have been such a fatal omission.
Radar and anti-aircraft missiles for ground forces
More coincidentally, this earth-based modified meter-wave radar, the radar wavelength is about 2.63 meters, which is consistent with the straight line length of F117's vertical tail, which can invalidate the radar wave linear crawling theory, which is like "the blind cat caught the dead rat", so that the flaws in the F117's out-of-the-pitched tail are magnified. But in fact, even so, the F117 is not easy to catch, the ground air defense force tried three times, and finally locked on to the unfortunate F117 and shot it down.
What a coincidence
The wreckage of F117
After the F117 was shot down, not only was the flaw in the tail exposed, but even the wreckage fell into the international market, and its coating materials, detailed design, and all the secrets about stealth could not be kept, so it had to be retired in a hurry. In recent years, it has been put back into service, responsible for simulating other countries' stealth fighters, which is a residual heat.
The F117 is back in service