ComNavOps just finished reading a fairly detailed article on another blog that debated the merits of the F-35 and the Advanced Super Hornet being proposed by Boeing. One of the points that was made was that the F-35 was stealthier by some factor and, therefore, superior. That got me to thinking … Why is a given level of stealth better than another level? Proponents of various platforms (and I’m talking about aircraft, now) argue vehemently about the levels of stealth that their favorite aircraft possesses, or does not.
Let’s take a momentary side trip to dip our toe into the water of stealth. Stealth is commonly expressed as Radar Cross Section (RCS) and in units of square meters, the smaller the better. That’s intuitively obvious and understandable. The smaller the RCS, the harder it is to detect the stealth object. The problem is that the numbers are meaningless. An aircraft has an RCS of 1.0 sq.m., for example. OK, so what? What does that mean in terms of detection? How far away can that aircraft be detected and under what conditions? I think it’s safe to say that none of us have the training to translate the RCS into actual detection criteria. Add to that the fact that RCS depends on what facet (angle) of the aircraft the detecting radar is looking at, what frequency the radar is using, backscatter, backscatter detection capability by the detecting radar, ambient interference, and a host of other factors and it’s clear that meaningful stealth discussions are well beyond most of us. What we fall back on are arbitrary numbers. Aircraft A has an RCS of 1.0 sq.m. and aircraft B has an RCS of 1.5 sq.m. so we conclude that aircraft A is 33% better than aircraft B. That’s numerically correct but operationally meaningless to us.
Sure, there are arbitrary levels of “visibility” assigned to various RCS: Low Observable, Very Low Observable, etc. but how do they relate to real world operations?
What we should be looking at is stealth as it relates to mission accomplishment. Is the level of stealth possessed by a given aircraft sufficient to allow it to accomplish its mission? If a given level of stealth is sufficient then having a greater degree of stealth is pointless and simply adds cost.
Here’s a simple example. Instead of aircraft, let’s consider a person who is trying to walk up to within rifle range to shoot me. If I see him before he does so, he fails. If his rifle has a range of 100 m and I can see him at 120 m, he fails. If, on the other hand, I can’t see him until 90 m, because he’s wearing camouflage (stealth), and his rifle range is 100 m, he can accomplish his mission and shoot me. That’s simple but here’s the key point … If he has additional camouflage that prevents me from seeing him until 50 m, he doesn’t gain anything. He still accomplishes the mission and the extra camouflage didn’t help. If the mission happens to be to close within 50 m then the extra camouflage is needed. You see? The required degree of stealth is related to the mission.
The point is that once the necessary degree of stealth has been achieved, extra stealth is pointless.
Let’s take it back to aircraft. If an RCS of 1.0 sq.m. is sufficient to accomplish the types of missions that the aircraft is intended for, an RCS of 0.5 or 0.01 or 0.0000001 doesn’t gain anything and simply adds to cost.
Let’s take it back to JSF and Hornet which is what everyone gets all wound up about. What level of stealth does the JSF need to accomplish its mission set? I don’t know and neither do any of you. Does the base Hornet have sufficient stealth to accomplish the mission set? Again, I don’t know and neither do you. Does the Super Hornet have enough? Does the Advanced Super Hornet have enough? Supporters and detractors of each aircraft sling RCS numbers back and forth without having any idea of what it means in terms of mission accomplishment.
|Advanced Super Hornet - Stealthy Enough?|
Again, someone is going to comment that extra stealth will allow the given aircraft to get even closer to the target or maybe fly in formation with enemy aircraft and laugh because they can’t see us even though we’re wingtip to wingtip. Well, if that’s the mission then the extra stealth is necessary. If that’s not the mission then the extra stealth is waste. Remember, stealth is like the extra knot of speed in a surface ship: each knot above around 20 kts comes at an exponentially increasing cost (I’m looking at you, LCS). Likewise, each “ounce” of additional stealth comes at an enormous cost. Therefore, stealth needs to be assessed relative to mission accomplishment.
There is no public data relating stealth to mission accomplishment that I’m aware of. The JSF is supposed to be stealthier than the Super Hornet but does the difference matter in terms of mission accomplishment? My gut feeling is that the Super Hornet is sufficiently stealthy to accomplish all but the most demanding missions. Is that difference sufficient to justify the mind-boggling cost of the JSF program? I don’t know. I think the Navy could accomplish its strike fighter missions with the Super Hornet (and maybe adopt the Advanced Super Hornet). Remember, stealth can be achieved through electronic countermeasures, optimized tactics, deception, and other means. It doesn’t all have to come from the aircraft’s airframe. Indeed, the Navy’s rather tepid endorsements of the JSF suggest that they feel the same. Given the cost of the JSF, I’d like to see the Navy drop the F-35C and continue with Super Hornets and Advanced Super Hornets long enough to go back to the drawing board and design a new, dedicated, optimized Navy strike fighter that isn’t a compromised disaster and doesn’t depend on non-existent, PowerPoint wishful thinking technology – a plane that has a laser focus on the required mission set and nothing more. Whether that requires stealth, networking, 360 degree sensor fusing, Mach+ speed, etc. should be determined strictly by the mission requirements not by the fact that someone thinks it would make for a nifty PowerPoint slide.