Why are F117's still flying? Well the Air Force has all the answers for you....

a reply to: boomer135

Lol. Maybe, but then it might be hard to spend all that money in Cuba.

What's the reason behind testing an aircraft already out of service and obsolete?

Well, maybe the same reason the Chinese had for testing these mock-ups back in 2010:





Reportedly, the first pic was spotted on Google Earth in 2010, in Luoyang, home to the Luoyang Electro-Optical Technology Development Center, which develops air-to-air missiles for the PLAAF.

But honestly what this reason could be beats me. If i were one of the top brass, i wouldn't put anything into the air if i already didn't know how to get it down from there. It must probably be something releated to tracking it with some new system, as the occasional presence during these flights of the Gulfstream N105TB might seems to suggest.

But still, if the F-22 and the F-35 are really "stealthier" than the F-117, i don't see a plausible reason for testing a new system against an obsolete platform.

Unless the F-117 has still some tricks up its sleeve that we're not aware about.

a reply to: CiTrus90

Put new skin on it that will eventually go fleet wide and test it against foreign radars the US keeps out around Nellis.

It's a lot cheaper to reskin one or two aircraft and find out its not as effective before it goes into service.

a reply to: Zaphod58

But why not doing the same thing on, say, an F-16 (like with the Have Glass)?

What's the inherent reason for keeping "that" retired aircrafts flight-worthy, if not for something that only the f-117 can offer?

a reply to: CiTrus90

Because stealth is more than just skin. An F-16 with RAM is still a non-stealthy F-16. An F-117 on the other hand is going to give truer readings .

a reply to: Zaphod58

Wait, i think i lost you here.

To simplify it, to simplify it really a lot, let's say there are "only" 2 ways to get stealthiness on an aircraft:
-first one, coating/RAM
-second one, its shape

If you're going to test out a new material (so we're talking about coatings/RAM and not about the shape), to see how much effective it is in reducing the RCS of an aircraft, what's the point of trying it on the F-117?

I mean, if the F-117 had an original RCS of, let's say (and i'm just throwing out numbers here) 3, while an F-16 had a RCS of 45, and when you try out the new coating you get a RCS of 1 on the F-117, wouldn't you get a RCS of 15 on the F-16?

It's really a simplification, but the idea would be that IF they're testing a new material, would it really matter that much on what they're testing it on? If the point of it all is to just test out the reduction in the RCS there would be no need to do it on a particular aircraft, or am i wrong?

[By the way, the fact that the USAF is still flying the F-117 is making me think that the A-10 should just be re-branded as the F-10 in order to not be retired.]

a reply to: CiTrus90

There's a lot more to it than that. The internal structure is just as important. Look at the RCS when the bays are open. It's almost the size of a B-52. That's because the radar is hitting the aluminum and other materials required for the bays.

As for the RCS numbers, no they won't be even close to exponentially matched. The F-117 shape is part of the stealth, as well as screens on intakes, curved inlets, stealthed canopy, etc. The F-16 doesn't have any of that.

originally posted by: CiTrus90
a reply to: Zaphod58

Wait, i think i lost you here.

To simplify it, to simplify it really a lot, let's say there are "only" 2 ways to get stealthiness on an aircraft:
-first one, coating/RAM
-second one, its shape

In order of importance, you have:
Shape
Shape
Shape
Shape
Shape
coating/RAM

Let us imagine I have a flat plate with RCS of 1m^2. I coat it with RAM and the return signal I know record is 95% of the previous, uncoated return signal, I have a RAM demonstrating 5% effectiveness (at that frequency, at the thickness, at that angle, etc, etc, et al). It at first seems counter-intuitive, but applying that to an aircraft does not mean that the RCS of the aircraft will decrease by 5%. There are complex shapes involved, and not all exposed surfaces of an aircraft can be coated with RAM. There are traveling waves creating odd reflections when it meets another surface to be dealt with that we didn't have to deal with in the flat plate at 90% incidence. We have multiple bounces/reflections of a single wave which may make the return signal weaker (or sometimes at the right angles, and right wavelengths stronger).

If the RCS of the F-117 was "3", to use your random number, the F-16 would come in around "1500" and not 45. The effect of the RAM on the two aircraft is not going to be proportionate because the shapes are not the same, and when flying an aircraft's RCS is very dynamic, not static. We might be able to reduce the F-117's RCS at one aspect and frequency to "one" or even lower, but only get the F-16 to "1100" with the same application of RAM.
You also can't simply coat an F-16 with an even layer of heavy RAM. The F-117, on the otherhand, was designed from the start for a liberal application of RAM across the majority of it's surface.
Assuming you created a one-off F-16 for RCS testing, you now have a F-16 that you will have to return to standard, or find another use for. The handful of F-117's, however, remain available for threat simulations or testing against new transmitters or systems out at Groom, as a yard stick for their performance.
I think the last is probably the most likely use of the aircraft at the moment, and not the testing of new RAM. Far more likely that they are using it as a first gen VLO threat simulator -- although if Lockheed is flight testing new RAM, being close to DYCOMS makes sense, and a lot of flight testing of new materials would have little or nothing to do with the actual RCS reduction, but rather it's durability and the eventual degradation of the RAM (as well as it's effect on the RCS, of course). So it could well be doing both.

originally posted by: _Del_

If the RCS of the F-117 was "3", to use your random number, the F-16 would come in around "1500" and not 45. The effect of the RAM on the two aircraft is not going to be proportionate because the shapes are not the same, and when flying an aircraft's RCS is very dynamic, not static.
[...]
You also can't simply coat an F-16 with an even layer of heavy RAM. The F-117, on the otherhand, was designed from the start for a liberal application of RAM across the majority of it's surface.
[...]
Assuming you created a one-off F-16 for RCS testing, you now have a F-16 that you will have to return to standard, or find another use for.

Which is exactly the reason for not testing a new RAM on the F-117. If shape matters more than s̶i̶z̶e̶, ahem, RAM, i don't see the pros of testing it on a unique platform like the F-117, which will never come back in action. If the effects of the RAM are not as proportionate as we pointed out in the previous posts, i'd be more willing on spending money on a program for making the F-16 (or any other active aircraft for that matter) stealthier than for making the F-117 so.

originally posted by: _Del_

The handful of F-117's, however, remain available for threat simulations or testing against new transmitters or systems out at Groom, as a yard stick for their performance.
[...]
I think the last is probably the most likely use of the aircraft at the moment, and not the testing of new RAM.

And i completely agree with you. For me it's more plausible to think that they're testing new systems to neutralize the VLO aspects of a stealth aircraft, but once again, if i were to test such a new system, i would do so against "contemporary" stealth platforms like the F-22 and the F-35, and not against something of 30 and more years ago, because the same principles work differently on differents aircrafts.

This is what leaves me dumbfounded.

By the way, thanks a lot Zaphod and Del for your answers. It's thanks to people like you that i decided to join ATS!

originally posted by: CiTrus90
If the effects of the RAM are not as proportionate as we pointed out in the previous posts, i'd be more willing on spending money on a program for making the F-16 (or any other active aircraft for that matter) stealthier than for making the F-117 so.

I think the performance cost in adding a substantial amount of RAM to an F-16 would not be worth the small benefit. Certainly not in an operational sense. I don't think that the reduction of the F-16's signature (or the F-117 for that matter) is the end goal if they are actually testing RAM. RAM has been applied to RCS hotspots on the F-16, but I don't think you'll see a major effort to reduce the RCS further than HAVE GLASS at the moment, because again, shape is much more important in determining the RCS, and that would mean a major redesign of the aircraft. The F-117 is already designed to have RAM applied to most of it's surfaces, and the contractor is already intimately familiar with the aircraft they are using.

... if i were to test such a new system, i would do so against "contemporary" stealth platforms like the F-22 and the F-35, and not against something of 30 and more years ago, because the same principles work differently on differents aircrafts.

Why wouldn't they be doing both? We're far more likely to see a threat of the F-117's caliber than of the F-22's in the near term. And again, if they are testing RAM, much of it could have nothing to do with improving RCS reduction itself, but rather on material performance and degradation ("wear and tear") and how that over time reduces the effectiveness of the RAM.

originally posted by: _Del_

And again, if they are testing RAM, much of it could have nothing to do with improving RCS reduction itself, but rather on material performance and degradation ("wear and tear") and how that over time reduces the effectiveness of the RAM.

But if it was meant to test material performance and degradation, couldn't they just use any other aircraft? I really doubt that F-117s have the same flight envelope of a F-22/35. Aerodinamically they're completely different and, most of all, their mission is not the same. So i can't really see how working on a new coating for the F-117 could lead to tangible benefits on a different aircraft.

originally posted by: _Del_

Why wouldn't they be doing both? We're far more likely to see a threat of the F-117's caliber than of the F-22's in the near term.

Because i can't believe that since the F-117 became operational till our days, the USAF didn't come up with a way to pick it on a radar or any other system. I would never, ever, put something in combat operations without being sure that i could counter it first. What if it fell in enemy hands for example, like it happened during Allied Force in '99, and the enemy got a hold of it and produced its own version?

Such an unexpected present doesn't seem likely to me.

Obviously, this reasoning doesn't apply in the case of a "silver bullet" platform, but IMHO that's the reason some aircrafts never come out of the black world.

So, if the F-22/35 are really a step ahead of the F-117, and represent the state of the art of stealth, i'd put my money on systems to counter them. Otherwise, why not picking up the Ho 229 and test its multylayer structure for stealthiness? It doesn't make sense, because it's clearly outdated, no?

a reply to: CiTrus90

It has little to do with the flight envelope. Its about how the material stands up to many things. How easy it is to remove and work on, how it stands up to flight in general, how much signature is reduced, etc. A lot of factors that you don't test on just any platform.

The RAM that was recovered in 99 is almost completely different from what's in use today. It changes every do often and gets harder to detect through new materials, new ways to apply it, etc.

You want to test using the most realistic way you can. That means applying it to a stealthy platform for testing. But with a limited number flying you don't want to lose any operational aircraft just for testing. This compromise works perfectly.

Because i can't believe that since the F-117 became operational till our days, the USAF didn't come up with a way to pick it on a radar or any other system. I would never, ever, put something in combat operations without being sure that i could counter it first. What if it fell in enemy hands for example, like it happened during Allied Force in '99, and the enemy got a hold of it and produced its own version?

Here's where it gets tricky. Of course the US has a way to detect stealth. We built the damn things and know how to see them, whether it be radar, IR, whatever. Its alot easier to detect something when you know how it works, i.e. the rcs, shape, etc. Even the British on some of their planes can detect the F-22 at like 65 miles and the F-35 at 35 miles or something like that. but the bad news is its usually too late by then.

My guess is the F-117s are flying over new radar systems being built by china, russia, etc to test exactly how good they are and if they are able to get a radar lock on the aircraft. Cause if you cant lock onto them then it doesn't matter if you can see them or not. I think the testing of new RAM materials is a secondary.

originally posted by: Zaphod58
a reply to: CiTrus90

It has little to do with the flight envelope. Its about how the material stands up to many things. How easy it is to remove and work on, how it stands up to flight in general, how much signature is reduced, etc. A lot of factors that you don't test on just any platform.

[...]

You want to test using the most realistic way you can. That means applying it to a stealthy platform for testing. But with a limited number flying you don't want to lose any operational aircraft just for testing. This compromise works perfectly.

But if the point of all of this was to just test out a new RAM it would be much easier and cost effective to build something like McDonnell did with the X-36, a subscale prototype/testbed. You could just slap everything you wanted on it, test it as much as you want, replace everything you want as much as you want, and all of this without the fear of loosing an operational airframe.
And without the need to keep an outdated aircraft flightworthy.

Moreover, if they were testing a new RAM, this thing has got to be some sort of paint that can be applied to other aircrafts. Otherwise it's more skin deep, but that would mean changing every single panel on the F-117 with the new material, which doesn't make sense at all.

My guess is the F-117s are flying over new radar systems being built by china, russia, etc to test exactly how good they are and if they are able to get a radar lock on the aircraft. Cause if you cant lock onto them then it doesn't matter if you can see them or not. I think the testing of new RAM materials is a secondary.

But once again, why testing an outdated platform against contemporary system? It's highly unlikely the F-117 will get back into service, so if i had to test possible adversary radars i would do so against contemporary fighters (i.e. F-22/35), which, as far as i understand, have a different (and more efficient) way to achieve stealth than the F-117.

Either, i probably see too much into this testing or someone at the Air Force is having a good laugh right now...

originally posted by: CiTrus90
But if the point of all of this was to just test out a new RAM it would be much easier and cost effective to build something like McDonnell did with the X-36, a subscale prototype/testbed. You could just slap everything you wanted on it, test it as much as you want, replace everything you want as much as you want, and all of this without the fear of loosing an operational airframe.
And without the need to keep an outdated aircraft flightworthy.

You think designing and building and then flight testing a new platform is cheaper than keeping a couple of F-117's airworthy? I'm sure there are spares enough to keep a handful of F-117's in the air just from cannibalizing the rest of the fleet in storage. Don't need a new contract. Don't need a new contract for support. Don't need to develop new maintenance procedures for a new aircraft. No new supply line. Don't need to wait a couple years to get a testbed flying and deemed operational.
We don't even know that they are using it to test RAM, as opposed to as a threat simulator. Or both. Or even just keeping maintainers current enough, and see that the storage is effective enough that they might be recalled if necessary (the "official" story).

Moreover, if they were testing a new RAM, this thing has got to be some sort of paint that can be applied to other aircrafts.

It could be paints. It could be blankets. It could be putties. There are all sorts of materials that turn radio waves into heat these days.

But once again, why testing an outdated platform against contemporary system? It's highly unlikely the F-117 will get back into service, so if i had to test possible adversary radars i would do so against contemporary fighters (i.e. F-22/35), which, as far as i understand, have a different (and more efficient) way to achieve stealth than the F-117.

There are aspects and frequencies at which the F-117 is going to be much less visible than the F-22/F-35 for one. It is also broadly representative at first generation attempts at a VLO aircraft. There may be foreign aircraft in that class using similar techniques for reduction, optimized at the same frequencies, that the public does not know about, but the USAF does.

a reply to: CiTrus90

Hmm, let's see here.... design, build, and test a new platform. That's a couple hundred million minimum for a small scale demonstrator, BEFORE fuel and support costs.

Take a known, tested, stealth platform out of storage for an occasional flight...cost of applying new materials, and occasionalmaintenance by an already trained and qualified crew.

Yep, a brand new platform makes so much more sense! [/sarcasm]

a reply to: Sammamishman

Ah, joyriding awesome jets sounds like a great idea.

originally posted by: CiTrus90

But still, if the F-22 and the F-35 are really "stealthier" than the F-117, i don't see a plausible reason for testing a new system against an obsolete platform.

Unless the F-117 has still some tricks up its sleeve that we're not aware about.

There's plenty of good reasons. The structure & returns of F-117 is extremely well characterized, making it perfect for testing incremental changes in technologies on the aircraft side. And simultaneously on the detection side.

Because of the 2-way nature of radar, the power of returns falls as 1/R^4, with R being the distance, times the cross section. So a given cross section (size of radar return depending on the materials & structure of the craft, not the distance) means you can expect to detect at a certain distance with a certain level of technology in the receiver. So if the F-117 airframe has a shape based cross section of X you could extrapolate detection at distance D1 to shorter distance D2 for shape-based cross section of Y corresponding to a more modern design.

Now you change materials and ECM on the F-117, and see how well you can detect. It's one step up in realism from indoor lab testing (first and cheapest) but far, far, less expensive than a newly built demonstration craft.

link

F117s seem to be pretty active again multiple sightings recent pretty cool video in the link as well.

They are still handy