Does F-117 has RWR or not ?

[garrya]

Can someone with insight tell me whether the F-117 has RWR or not ? ( i vaguely remember one member here involved with the F-117 but can't recall which one)
Anyway some diagram of control panel and cockpit photo suggest that F-117 indeed has a RWR called the "radar location system"


There is even 1 photo of the alleged system

There also exist the photo of the hatch itself


On the otherhand both the F-117 program manager and the Skunk Works engineer insisted that there is no RWR ever installed on F-117

It has been noted that by 2006, the system was not listed in official hazard and crash responders documents which are posted online here. The diagram showing the RLS doors are still there, but it does not identify it as being something that is accessible like the rest of the aircraft's retractable antenna, so it seems as if the doors were permanently sealed or filled-in at some point in time. This could have occurred during a depot overhaul or upgrade.
While we have a picture, written and first hand accounts of the Radar Locator System, it seems that its existence is still highly doubted by some—including the man that largely oversaw the development of the jet—senior Skunk Works engineer and F-117 program manager Alan Brown

I chatted at length with Mr. Brown about the F-117 and this obscure, and let's face it, mysterious feature. He was as puzzled as I was. After sending him the picture of it, he was kind enough to respond with his conclusions
"This picture doesn’t look like anything that was ever put on a F-117A airplane, and as such I am inclined to discount the story entirely. The only possibility to my mind is that the USAF made the modification themselves without Lockheed’s knowledge, but that itself is impossible for me to believe, knowing how well we followed up with the airplane in the field. Lockheed Skunk Works always had a cradle-to-grave philosophy in terms of follow-up with its products in service."
Mr. Brown was even nice enough to contact his successor as F-117 program manager, Sherm Mullin, to see what his thoughts were about the RLS enigma. His reply was just about the same as Mr. Brown's, stating that "it was never put on the F-117, period." Although he did mention that it could have been a concept from a study that occurred from 1984 to 1985 that apparently went off the rails conceptually and was disbanded with prejudice as a result.
During roughly that same time period it is known, although not well documented publicly, that the F-117 was tested with some fairly elaborate modifications. This supposedly included a handful of sensor systems in addition to the jet's stock Infrared Acquisition And Designation System (IRADS). We know that a passive electronically scanned array (PESA) radar was flown on one F-117 in a specially-built radome fitted on the Nighthawk's iconic wedge-like nose. Maybe RLS was one of the other mods that was deemed successful, and was accommodated for in some F-117s built, but never fully installed.

http://www.thedrive.com/the-war-zone/95 ... r-locators

The hatch could also be similar to the cheek array bay on F-22 ( the bay exist but no sensor actuallly there )

[boilermaker]

Would seem crazy if the A/C did not have some kind of radar detector since flying stealth requires one to aVoid signals or passively exploit the signals

[garrya]

Would seem crazy if the A/C did not have some kind of radar detector since flying stealth requires one to aVoid signals or passively exploit the signals

it seem like the mystical system is only intended to take snapshot of the environment rather than working full time, making it not very useful against pop up threat

[wrightwing]

The major limit for F-117s, was a lack of RWR, etc.... They had to basically fly very specific routes, calculated to avoid threats. The lack of real time situational awareness, contributed to the shootdown.

[basher54321]

Can someone with insight tell me whether the F-117 has RWR or not ? ( i vaguely remember one member here involved with the F-117 but can't recall which one)

MD - some info here
viewtopic.php?f=22&t=52250&start=60

[gustav109]

I was avionics on the 117 from 88-91. The RLS system was fully deactivated by the time I was on the program, and most of the antenna arrays were permanently retracted. I was told it never worked properly and rarely used. There was never a replacement system during my tenure.

[smsgtmac]

The terms RLS and RWR are not very interchangable BTW.

[garrya]

The terms RLS and RWR are not very interchangable BTW.

If the RLS ( radar locator system ) was not a RWR, what would it be ? I first thought it could be a radar altimeter but that unlikely.

I was avionics on the 117 from 88-91. The RLS system was fully deactivated by the time I was on the program, and most of the antenna arrays were permanently retracted. I was told it never worked properly and rarely used. There was never a replacement system during my tenure.

So RLS existed in early stage of the program and fully deactivated long before the Serbia incident? Do you know what year it was deactivated?
Why Alan Brown and Sherm Mullin didn't know about this ?

[skyward]

Maybe the R is for radiation. The F-117 was design for cold war and should be able to carry a nuclear bomb. Having a radiation locator system can help it go around hot zones.

[garrya]

Maybe the R is for radiation..

R is for Radar according to the panel

[MD]

The RLS is no longer a system that is installed in the F-117, and all functions of it were deactivated in the early-mid 80s. Am not certain it was installed on all aircraft. In the pictures above of the antenna (that is an old diagram from early Dash 1 revisions), the left RLS antenna location was removed and faired over, while the right RLS location was replaced by the UHF LOCOMM antenna, which was the antenna used for limited UHF comms when the upper and lower UHF blade antenna were retracted. In fact, when the LOCOMM antenna was devised (previously, there was no comm ability when the blade antenna were retracted), the lower UHF blade antenna was disconnected, even though it was still in-place, and extended/retracted. It was just not hooked up to anything.

As mentioned, RLS and RWR are completely different systems. The RLS instrument panel position shown on the right side panel, was replaced by a 3-switch panel called the Antenna panel: with 1 switch for extend/retract all comm antennas, 1 switch for extend/retract Localizer antennas, and 1 UHF Top/Auto/Bottom (which antenna to use) switch. On the ICS panel, there was also an audio switch labeled "RLS" that was deactivated and had no function.

As I understand the RLS system, it was once tied to or related to the RCS recorder system that was onboard. Basically that was a system comprising of sensors tied to the aircraft's avionics that took data from ground tracking radars to enable the RCS of the individual aircraft to be checked. The control panel for this was on the left inner console, but the instrumentation for it and the beacon for allowing tracking by ground based radars was only installed when the tests needed to be accomplished, and these were installed on the aft wall of the left weapons bay, again when testing was needed.

With regards to RWR, none was installed in the F-117. For one, with how 117 mission planning was done with regards to planning around known fixed threats (didn't care about mobile threats) and how flying the planned black line was paramount, you didn't want guys reacting to what they see on an RWR, and thus messing up the planned routing. But even more importantly, nothing should pop up on an RWR in any kind of tracking mode, otherwise the planning was shite or the stealth technology was. But the biggest reason there was no RWR was that there was no way to incorporate it. RWR antenna of the time were "nubs" that would have to be installed on both sides of the nose and both sides of the tail. This couldn't be done on the 117 airframe without seriously messing with the RCS of the airframe, so none was ever installed, as it was determined it should not be needed.

[garrya]

Thanks for your insight MD

[hornetfinn]

Thank you MD, very interesting! I've been thinking about F-117 as a reusable cruise missile with a human strapped inside to do the targeting/bombing mainly. I know that's a gross simplification, but I can see that RWR could've have had serious negative effect on combat performance even if RWR antennas could've had without compromising RCS. But it must've been really weird to fly against powerful IADS in that thing at first. It was so backwards compared to all other attack aircraft and their tactics until then (or even after)...

[MD]

Thank you MD, very interesting! I've been thinking about F-117 as a reusable cruise missile with a human strapped inside to do the targeting/bombing mainly. I know that's a gross simplification, but I can see that RWR could've have had serious negative effect on combat performance even if RWR antennas could've had without compromising RCS. But it must've been really weird to fly against powerful IADS in that thing at first. It was so backwards compared to all other attack aircraft and their tactics until then (or even after)...

The jet was an ergonomic nightmare as it was originally designed, and the guys who took it to downtown Baghdad on the first night of the war in Jan '91 got to experience some of this. Don't know if I've related this or not before here, but I'll do so only because it's applicable to what I bring up here.

When I was in training for the F-117, one of our civilian instructors....Mr Klaus Klause related a story of how ergonomics slowly but surely came to be for this jet. First night of Desert Storm in '91, he was one of the first wave of F-117s going into Baghdad to hit the command centers located deeper than the radar sites on the border the Army AH-64s had hit at almost the same time. It wasn't really known at that time if stealth technology actually worked, as it had never been tested in real-world combat. The F-117, being slapped together from miscellaneous odds and ends from the A-10 (cockpit), F-15A (gear/components), F-16A (FBW) and F/A-18A (engines), it wasn't very ergonomically friendly in the cockpit in a number of ways. As Klause is getting over Baghdad, the AAA that was filling the air in a general barrage fashion starts immediately shifting in his direction, as if it's tracking him. So he begins to slightly change course (which is not recommended for a number of reasons), and the AAA keeps tracking him, with airbursts going off all around him. Finally he really starts maneuvering (to hell with not recommended), thinking "this stealth crap is bullshat, Lockheed the lowest bidder" and other choice thoughts, finds his target, drops his bombs and gets the literal hell out of there.

Crossing outbound to friendly territory to the south, he's getting his systems back on-line, Fencing out, and notices that his position (nav) lights are still on and thats how the gunners were seeing him: visually. Back then in the 117, there were 5 different switches controlling 5 different external lighting systems, located in 5 completely separate places in the cockpit. On fence-in, he'd forgotten the position lights switch. A few years later, the USAF installed a single "all external lights- extinguish" switch on the left wall panel for ergonomic sake, aptly named the "Klaus switch".

[popcorn]

LOL...Thanks for sharing MD.