A couple of days ago I noted that the gray-colored F-117 stealth fighter has been flying missions. This started a little discussion in the comments section with a reader. I just responded to questions about the reasoning behind black paint in the first place, and since I spent a little time typing, I thought I’d share for others who probably won’t check the comments section of that post. Or care, for that matter.
The three main ways of “seeing” an aircraft are visual, radar, and infra-red.
The F-117 deals with radar mostly via its bizarre shape which reflects radar signal off at bizarre angles so that they are not picked up as a “return”, effectively making the aircraft “invisible” to radars searching the skies.
It deals with infra-red mostly via ducted engine outlets that significantly cool the output of the plane’s jets.
It deals with visual mostly via operating at night. This approach apparently isn’t going to be the exclusive approach since daylight operations are being asked for.
The black paint certainly is part of the night-fighter approach. Whether the paint also impacts the radar (probable) and infra-red (not so probable) approaches is unknown to me. Even if it does, the chemical mix that reduces the radar and/or infra-red signatures can probably be used in colors other than black, so the choice of black seems (to me) to only really apply to the visual aspect of “being seen”.
(I guess radio transmissions are also a major way of “being seen”, but that is mainly addressed by not transmitting and isn’t really part of this discussion.)
Of the three main ways of being seen, radar is probably the most critical to defend against and visual is probably the least critical to defend against, at least for this aircraft and the missions that it performs.
Radar is the most important because not only can it be used to track and target the plane by air-defense missiles on both land and airborne systems, but it can detect the mere presence of the plane, which will raise the alert and blow the surprise. Visual is the least important because visually-guided weapons have only a small chance of actually bringing down a plane, though I believe that is how the F-117 that was shot down in the Balkans was hit.
So, the color black really only effects the visual method of “seeing” the plane. And even though that’s probably the least-important method, it was best approached with black paint since the plane only operated at night. Now that plans might be changing, black isn’t the best all-around choice.
To take it to the opposite extreme, we wouldn’t paint stealth aircraft bright orange even though optical sighting is the least important of the three main detection methods. Deer use sound and smell more than they use their eyes, but hunters still camouflage their spots because every little thing matters. I think that’s why F-117s are currently black, and I think that’s why they’re considering changing colors now that they’re considering changing operating environments.
If you have anything to add or debate, and especially if you have any good info on the black paint’s role in the radar signature of the F-117, go to the post and comment.