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(YouTube)

I came across the following Norwegian F-35 video launching a live missile from its right bay door. Of course, opening the door and launching the missile drastically increases RCS, but it seemed to operate quite slowly, about 3-4 seconds for the whole operation.

My questions are:

  1. Is combat-operation of the bay door really so slow or does it speed up for a lesser chance of detection by today's powerful A2A radars?

  2. Is 3-4 seconds of an exposed RCS increasing surface tactically significant? Obviously, if it wasn't there would be no need to overly stress the components if unnecessary.

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3-4 seconds may lead to a detection, but then again 1-2 seconds could too with a sophisticated radar system. The important thing is that 3-4 seconds is short enough that a detection would be extremely hard to exploit; by the time a missile could be launched the contact would have disappeared.

If by some chance a station managed to get a missile off in that short time-frame it would probably miss. There are 2 types of radar guided missiles:

  1. Semi-Active radar homing: semi-active missiles only have a radar receiver, they home in on a target using radar painted by a ground station or airborne radar. If the targeting radar station loses lock then the missile will go wide
  2. Active radar homing: active missiles have their own radar emitters which get switched on when they get close to their target, so they are no longer relying on the ground station which is much farther away. They still rely on the ground station to get close enough to use it though, so while active missiles have a better chance it's still very unlikely

So shaving a second off that time would give very little benefit. Having a door open longer would be bad though. In the book "Skunk Works" by Ben Rich and Leo Janos (former director of the Lockheed Skunk Works) Major Miles Pound wrote about his experiences in the first Iraq war flying an F117 when a bomb bay door got stuck open after dropping:

We came in at three in the morning using only eight airplanes and needing only two tankers to get us there and back, and took out three of the four nuclear reactors and heavily damaged the fourth. Once that first bomb hit all hell broke loose. I dropped my bombs, but I couldn’t get my bomb-bay door closed. That was as bad as it could get because a right angle is like a spotlight to ground radar and a bomb-bay door is a perfect right angle. And out of the corner of my eye I saw a missile firing up at me. I had one hand on the eject lever and the other trying to manually close that stalled bomb bay. As the missile closed on me, the door finally did, too, and I watched that missile curve harmlessly by me as it lost me in its homing. About an hour later I began breathing again.

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    $\begingroup$ "they home in on a target using radar painted by a ground station" That's not accurate. The target may also be painted by another aircraft or by the launching aircraft itself (which I believe is the most popular scenario). $\endgroup$ – DeepSpace Mar 10 at 11:32
  • $\begingroup$ @DeepSpace, it certainly can, but I am not sure it is most popular scenario—there is not that many fighters on patrol these days and they don't know where the stealth attackers will pop up, so surface-to-air is more likely than air-to-air. $\endgroup$ – Jan Hudec Mar 10 at 22:23
  • $\begingroup$ Good point @DeepSpace, I've edited accordingly. $\endgroup$ – GdD Mar 10 at 23:33
  • $\begingroup$ @DeepSpace for most angles when dealing with air-air encounters the doors would not be visible to the opposing aircraft. From the ground they're pretty much always visible. $\endgroup$ – jwenting Mar 11 at 9:05
  • $\begingroup$ The bomb bay doors were open long enough on F117A that the Serbs were able to shoot one down, so I wouldn't say that shaving a second off the open time is insignificant. $\endgroup$ – TomMcW Mar 12 at 2:52

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