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Tacit Rainbow: Northrop AGM/BGM-136 Anti-Radar Drone

TinWing

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Meteorit

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Does anyone have an idea how far work on the ground-launched BGM-136B got? And, for that matter, on the ground-launched MGM-137B TSSAM variant?
Also, why the ground-launched Tacit Rainbow was designated BGM and the TSSAM MGM although they both were to be launched from MLRS launchers?
 

Andreas Parsch

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Meteorit said:
Does anyone have an idea how far work on the ground-launched BGM-136B got? And, for that matter, on the ground-launched MGM-137B TSSAM variant?
I don't know for sure, but I'll risk a guess (well, two guesses, actually ;) ).

The TACIT RAINBOW was essentially a USAF program, and I wouldn't be surprised if the Army's BGM-136B variant was more like a formal statement saying "See, this is a joint program, so we deserve more money ..". In reality, I've never read anything about the ground-launched variant except that it "existed" (formally, at least).

As for the ground-launched TSSAM, I'd guess that this reached the flight test stage. The Army was in the program for 7 years (1986-93), and it would be rather strange if they had just watched the development of the air-launched missile all the time. Unfortunately, it appears to be rather difficlut to get any firm information on TSSAM at all, including e.g. a decent photo.

Also, why the ground-launched Tacit Rainbow was designated BGM and the TSSAM MGM although they both were to be launched from MLRS launchers?
Theoretically, it could mean that the ground-launched TACIT RAINBOW had only few modifications, so that it was still air-launchable as well. This would justify the B letter (denoting "Multiple Launch Options"). OTOH, it could also (and at least as likely) be just another screwed-up designation :) .
 

Meteorit

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Thanks for the reply, Andreas. And welcome to the forum!
 

TinWing

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Andreas Parsch said:
Meteorit said:
Does anyone have an idea how far work on the ground-launched BGM-136B got? And, for that matter, on the ground-launched MGM-137B TSSAM variant?
I don't know for sure, but I'll risk a guess (well, two guesses, actually ;) ).

The TACIT RAINBOW was essentially a USAF program, and I wouldn't be surprised if the Army's BGM-136B variant was more like a formal statement saying "See, this is a joint program, so we deserve more money ..". In reality, I've never read anything about the ground-launched variant except that it "existed" (formally, at least).

As for the ground-launched TSSAM, I'd guess that this reached the flight test stage. The Army was in the program for 7 years (1986-93), and it would be rather strange if they had just watched the development of the air-launched missile all the time. Unfortunately, it appears to be rather difficlut to get any firm information on TSSAM at all, including e.g. a decent photo.

Also, why the ground-launched Tacit Rainbow was designated BGM and the TSSAM MGM although they both were to be launched from MLRS launchers?
Theoretically, it could mean that the ground-launched TACIT RAINBOW had only few modifications, so that it was still air-launchable as well. This would justify the B letter (denoting "Multiple Launch Options"). OTOH, it could also (and at least as likely) be just another screwed-up designation :) .
I would think that after the Army lost its GLCM inventory to an arms reduction agreement, the ground launched Tacit Rainbow might have seemed like an orphan.

If the GLCM represented a core capability in the European theatre, the BGM-136B might always have been seen as a subsidiary system - hard to justify in the face of declining budgets.
 

elmayerle

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MGM-137B got as far as early flgiht test demonstrations (five if memory serves me correctly after more than a decade) which showed a few development problems. The flight test that would've demonstrated the resolution of the majority of these problems was fueled and ready to go at the test site when this variant of TSSAM was cancelled. The Army version did have some distinct differences from the air-launched versions in order to maximize volume usage and payload while staying within the length envelope of the MLRS "box". It was propelled from the launcher to operating speed by two 10 ft. long, six in. dia. solid rocket moters that boosted it from a stand-still to Mach 0.4 in 10 seconds. How do I know all this? Simple, I was an engineer on TSSAM from early 1989 through the end of the program and most of that time I specialized in certain aspects of the Army variant.
 

James1978

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TinWing said:
I would think that after the Army lost its GLCM inventory to an arms reduction agreement, the ground launched Tacit Rainbow might have seemed like an orphan.
The GLCMs were never an Army asset, they belonged to the USAF
 

elmayerle

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Ground-launched TSSAM was in the first round of development flight tests. The final test of this round was due to go the day after the US Army cancelled it's participation in the program. This test would've tested a number of fixes from problems we'd found in the previous tests. Believe me, the test footage of the launch was always quite impressive; the footage of the last actual test flight was rather less so due to problems that were found and subsequently corrected. The test previous to that one was nearly picture perfect. I know, I was on that program with special responsibilities for the Army variant. If the Army hadn't pulled out, there was also an extended-range variant under preliminary design that traded a modest drop in payload for significantly more range.

Now, yes, I know the differences between the air-launched and ground-launched versions, but I'm not at all sure if I'm yet allowed to get too detailed here.

Oh, there was also a very preliminary study on combining aspects of the ground-launched and air-launched vehicles to produce a ship-launched one.
 

sferrin

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elmayerle said:
Ground-launched TSSAM was in the first round of development flight tests. The final test of this round was due to go the day after the US Army cancelled it's participation in the program. This test would've tested a number of fixes from problems we'd found in the previous tests. Believe me, the test footage of the launch was always quite impressive; the footage of the last actual test flight was rather less so due to problems that were found and subsequently corrected. The test previous to that one was nearly picture perfect. I know, I was on that program with special responsibilities for the Army variant. If the Army hadn't pulled out, there was also an extended-range variant under preliminary design that traded a modest drop in payload for significantly more range.

Now, yes, I know the differences between the air-launched and ground-launched versions, but I'm not at all sure if I'm yet allowed to get too detailed here.

Oh, there was also a very preliminary study on combining aspects of the ground-launched and air-launched vehicles to produce a ship-launched one.

Gotta quesiton for you. A while back in the Correspondence section of AvWeek a writer commented on a JASSM photo that was run of it flying through the door of a bunker or something. They said essentially it wasn't such a great feat as they'd done the same thing with TSSAM years earlier and that THAT photo had also been run in AvWeek. I vaguely remember the picture. Any chance you might have it for upload? ;)
 

elmayerle

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I don't have it for upload after this time (not even certain I can find the bloody thing), though the unclassified video of it is part of a declassified sales tape that I've got in with all my other VHS tapes. The flight test was one of the first of the Navy air-launched versions and was picture perfect, hitting the center of the simulated window so close that it took out the camera behind the window.
 

elmayerle

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I had occassion to check with a co-worker who used to work on Tacit Rainbow, the ground-launched version never got beyond the proposal stage. *chuckle* He tells me that there was a joke about doing a scaled-down version for use by autos against police radar. :D
 

Meteorit

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elmayerle said:
I had occassion to check with a co-worker who used to work on Tacit Rainbow, the ground-launched version never got beyond the proposal stage. *chuckle* He tells me that there was a joke about doing a scaled-down version for use by autos against police radar. :D
OK, so the "mystery" has been solved. Thanks for your valuable input, Evan.
 

BillRo

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Elmayerle confused this topic a little by introducing information on the TASSM stealthy cruise missile program run out of Northrop Aircraft Division in Hawthorne. The Tacit Rainbow, later the AGM-136A, was an anti-radar loitering drone and was done by Northrop Ventura Division at Newbury Park. It was a joint Navy/Air Force effort and flight test was accomplished at China Lake with Navy assets. The Air Force provided their aircraft when needed (F-16, B-52) and some captive flights launched out of Edwards. The Air Force were responsible for the container.

I got to the program as production design was starting, so had nothing to do with the configuration. As to the question about Army involvement, I saw a video of a test article being ejected out of a launcher (MRLS?) but it was not too successful as the item sort of trickeled out of the end. By '85 there was no sign of Army involvement.

Attached are some of the information I collected when the project was revealed to the public. Since a significant number of missiles were flown before it was cancelled. perhaps this topic should be moved to Military.
 

Attachments

AeroFranz

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YES! Thanks BillRo, you made my day. I had been waiting for a long time to get better info on Tacit Rainbow. One thing in particular puzzles me: the wing swivels 90 degrees upon deployment, but does it also get 'sucked up' to nest itself between the front and aft belly fairings?
The picture labeled 'TR assy' and the picture with three AGMs on an F-16 show something that looks like a fixed triangular horizontal surface that is not present in all the other pictures. Was that a result of flight testing? not enough static margin?
I am also curious about the way the fuselage end with a 'double-bubble' cross section. The top circle is for the engine, but what was the bottom one for?
Sorry about all the questions, but Tacit Rainbow is a pretty neat vehicle with lots of curious solutions!
 

BillRo

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The wing had a post on it and it fitted into a socket on the body with a cam track; as the wing rotated by spring power it popped up into the gap making a nice faired surface. The bomb lugs on the top also were spring loaded to fair into the upper surface. The spade at the back was for air launch to stabilize the bird until the tails deployed; it was then jettisoned. There are two versions, one for fighter carriage as on the F-16 TER and the smaller one for the B-52 rotary bomb racks, a geometry issue.
 

BillRo

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As to the aft fuselage shape I am not too sure; I thing we needed room for the rudder actuator and for aero drag reasons you cannot have surface closing angles greater than 7 degrees. If you continued the lower fuselage surface out, the missile would be a foot longer and heavier so they just chopped it off.
 

AeroFranz

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Thanks for the explanation - I am always curious to find out the reason behind unconventional technical solutions, and this air vehicle presents quite a few. :)
 

BillRo

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I looked at some pix of it in a structural test rig and it has a socket at the center of the lower bulged aft fuselage. I would not be surprised if the ground launch booster rocket was supposed to fit there - if that ever happened.
 

BillRo

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Interesting Flateric; the configuration on the cup and sticker (high wing, apparently cruciform tail) is not the same as the Northrop design as flown. Is it an early version or did McDonnel Douglas (as shown on the cup) have an unsuccessful competitor to Northrop?
 

flateric

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A competitor! That's adding rarity!
 

overscan

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BillRo said:
Interesting Flateric; the configuration on the cup and sticker (high wing, apparently cruciform tail) is not the same as the Northrop design as flown. Is it an early version or did McDonnel Douglas (as shown on the cup) have an unsuccessful competitor to Northrop?
https://apps.dtic.mil/dtic/tr/fulltext/u2/a379856.pdf

In January 1990, the Air Force competitively awarded Raytheon
Company a $29.8 million fixed-price-incentive-fee contract with
an award fee as a second source producer of the Tacit Rainbow.
Pretty sure Raytheon, McDonnell-Douglas and E-Systems were all subcontractors/partners to Northrop on Tacit Rainbow, rather than a second proposal team. The drawing may be notional - was Tacit Rainbox shape classified?
 

BillRo

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Shape was classified. We had to come up with a representative item to develop the container with the same dimensions, inertia and weight that looked nothing like TR; I called it the "Mule". I wonder what McDonnel-Douglas did. It had a Williams engine.
 
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