Northrop AGM-137 Tri-Service Standoff Attack Missile (TSSAM)
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I have only one picture of the TSSAM in model form, and also the patch that reportedly was used by people working on the program, depicting the Warner Bros.'s tasmanian devil character (TSSAM/TASManian being a bit far-fetched, but...). Please don't get mixed up on the acronym, folks! (it means Tri-Service Standoff Attack Missile).
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For a reasonable approximation of what was doctored out, turn a Tacit Blue upside down and compare them. Actually, that model shows the air-launched TSSAM, the ground-launched BGM-137B had its differences.
I should know, I worked on the program from early 1989 to its cancellation. Before it was cancelled, there was an design effort under way for a derivative of the air-launched version for Britain's stand-off requirement.
I should know, I worked on the program from early 1989 to its cancellation. Before it was cancelled, there was an design effort under way for a derivative of the air-launched version for Britain's stand-off requirement.
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Thanks BillRo!
I'm not very much in the know of all the patenting process and its various stages, so forgive my asking what may sound like a dumb question, but isn't a Registered Patent automatically something freely accessible to the public once it's been granted? If so, why did no-one have access to such patents as these before?
I'm not very much in the know of all the patenting process and its various stages, so forgive my asking what may sound like a dumb question, but isn't a Registered Patent automatically something freely accessible to the public once it's been granted? If so, why did no-one have access to such patents as these before?
Steve Pace
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Shades of Tacit Blue (Whale)... -SP
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XCIIGT
I really should change my personal text
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I worked on this project. I have the patch, spec sheet and a drawing of the Tasmanian Devil riding the missile which I drew. It was a unreal day sitting the the board room watching the Live news release. When I locate the items I will post photos of them.
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Critical_NOX
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I actually mounted the inside view camera for the test. The image must a have been scraped from the video. I put it up last minute for fun, no test card requirement, awesome to watch the last second adjustment to clear both sides of the "Window". This was a very fun project but many engineering issues led to its demise. Not many picture of this beast because I spent 3 weeks shredding everything once it cancelled.
Worked TSSAM as well, B-2/TSSAM integration at EAFB. I agree, lots of engineering issues but when it worked, very impressive!
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S
Engineering and technology was solid as well as LOW capabilities. Mostly issues were due to trying to make this a multi-service, multi munition platform. How many systems launch from both a MLRS and aircraft platform. Most of the issues revolved around this multi launch platform and Multi munition requirements. When it worked, it was stellar, flying through a window from 100 miles away was impressive. The cost overruns doomed the system, not the engineering
You are correct on the design and engineering, very solid, I mis-spoke. Early on, there were manufacturing and assembly issues (I saw those first hand which contributed to some of the flight test failures). I remember when the missile started working consistently with many more successful flight tests, then cancelled, it was a shame, was an outstanding platform.
Critical_NOX
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Did you guys ever get to check out the display room in the 3-60 building? It had 2 full scale mockups of the air launched and ground launched versions, as well as a bunch of cool models of different aircraft that would carry it. I remember going to Seattle (actually Kent, WA) to Boeing's facility since they made the faux MLRS launcher for the Army version. Since the rear aspect LO requirements for that version was changed, essentially being a loitering missile dropping submunitions, the back end was redesigned, and it was having issues fitting properly in the launcher. Definitely was a fun program to work on, loading everything into that old Convair 580 and sending it off to the test site. From what I understand, there is a surviving example of the TSSAM (not sure which version) sitting out at Dugway.
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Critical_NOX
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Funny, I remember unloading the Convair 580 at the site. To get the coffin out you had to pull it halfway out with a forklift then let it teeter while you got a better purchase in the middle...little nerve racking. I didn't think TSSAM ever flew at dugway, is it on a display stand?
I don't think it ever flew at Dugway either, someone told me there was one sitting in a storage area out in the open there for a while, maybe it was a mockup, or an RCS test article.
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How does TASSM wing folds for internal stowage ? Does it fold forward or somehow backward ? Or maybe the wing have 3 sections which allows it to fold the same manner as a satellite solar panel.
Bruno Anthony
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How does it compare to JASSM?
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from "Carriage and Separation Wind Tunnel Testing: A Vital Part of Air-Launched Weapons Development Programs"
by Duane Cline
...
TSSAM Carriage and Separation WT Test Program: The AGM-137 Tri-Service Stand-Off Attack Missile (TSSAM) was a stealth cruise missile developed by Northrop Corporation at their facilities in Hawthorne, CA beginning in 1984. The large size of the air-launched variants of the TSSAM required that the wings and tail surfaces be stowed during carriage and launch, unfolding after the missile was clear of the carrier aircraft. Unfortunately, the TSSAM fuselage shape made the vehicle aerodynamically unstable with the wings and tails stowed. Northrop conducted initial store carriage and separations tests on the B-52 and F/A-18 during the initial full-scale development (IFSD) program prior to award of the full-scale development (FSD) contract in 1986.
The complexity of integrating the TSSAM on multiple different aircraft became apparent early in FSD. The original carriage and separation wind tunnel test plan called for a limited number of tests on each of the six intended carrier aircraft (about 15 tests total) over the course of 2 years. During extensive meetings with the Air Force, Navy and the various aircraft contractors Northrop learned that each group had their own definition of safe store separation and that TSSAM must meet them all with a common configuration. While developing the detailed wind tunnel test plans, the number of test configurations for each aircraft grew to account for more mission loadouts and more detailed flowfield mapping requirements– resulting in longer test durations. Tests that were originally proposed to last about 100 hours in the wind tunnel grew to 300 hours or more and a single separation flowfield wind tunnel test could last up to 6 weeks.
The results of the first round of separation wind tunnel tests drove changes to the aerodynamics of the TSSAM in the stowed configuration to ensure safe and reliable separation from all the carrier aircraft. These configuration changes were significant enough to require several more rounds of wind tunnel tests of longer duration to achieve the desired launch characteristics for each carrier aircraft. We also learned that certain aircraft required testing of a wider array of aircraft configurations to fully model operational characteristics, further increasing test durations. During this period there could be 2-3 TSSAM wind tunnel tests being conducted concurrently in facilities spread across the country, posing many management and staffing challenges. By the time the TSSAM program was cancelled in 1994, more than 50 carriage and separation wind tunnel tests had been conducted.
The lessons learned on the TSSAM program informed significant improvements in the store certification process that have occurred over the past 30 years. The advances in computer computational fluid dynamics (CFD) technologies now allow detailed modeling of the flowfield around complex external store configurations. In-depth analysis of the correlation between analytical models, wind tunnel and flight test data have allowed modern store certification efforts to be conducted far more efficiently than was possible during the TSSAM program. The role of separation wind tunnel testing changed from the primary data gathering method into a valuable tool for validating CFD modeling results, significantly reducing the scope of the store certification test effort and the associated costs. Wind tunnel tests that once consisted of thousands of runs and lasted 4 to 6 weeks now consist of several hundred runs and can be completed in about 2 weeks. Similar savings in flight tests costs have also been possible as fewer test points are required to validate analytical results. The ability to model critical flight conditions has greatly improved the safety and cost of modern store certification flight test programs.
by Duane Cline
...
TSSAM Carriage and Separation WT Test Program: The AGM-137 Tri-Service Stand-Off Attack Missile (TSSAM) was a stealth cruise missile developed by Northrop Corporation at their facilities in Hawthorne, CA beginning in 1984. The large size of the air-launched variants of the TSSAM required that the wings and tail surfaces be stowed during carriage and launch, unfolding after the missile was clear of the carrier aircraft. Unfortunately, the TSSAM fuselage shape made the vehicle aerodynamically unstable with the wings and tails stowed. Northrop conducted initial store carriage and separations tests on the B-52 and F/A-18 during the initial full-scale development (IFSD) program prior to award of the full-scale development (FSD) contract in 1986.
The complexity of integrating the TSSAM on multiple different aircraft became apparent early in FSD. The original carriage and separation wind tunnel test plan called for a limited number of tests on each of the six intended carrier aircraft (about 15 tests total) over the course of 2 years. During extensive meetings with the Air Force, Navy and the various aircraft contractors Northrop learned that each group had their own definition of safe store separation and that TSSAM must meet them all with a common configuration. While developing the detailed wind tunnel test plans, the number of test configurations for each aircraft grew to account for more mission loadouts and more detailed flowfield mapping requirements– resulting in longer test durations. Tests that were originally proposed to last about 100 hours in the wind tunnel grew to 300 hours or more and a single separation flowfield wind tunnel test could last up to 6 weeks.
The results of the first round of separation wind tunnel tests drove changes to the aerodynamics of the TSSAM in the stowed configuration to ensure safe and reliable separation from all the carrier aircraft. These configuration changes were significant enough to require several more rounds of wind tunnel tests of longer duration to achieve the desired launch characteristics for each carrier aircraft. We also learned that certain aircraft required testing of a wider array of aircraft configurations to fully model operational characteristics, further increasing test durations. During this period there could be 2-3 TSSAM wind tunnel tests being conducted concurrently in facilities spread across the country, posing many management and staffing challenges. By the time the TSSAM program was cancelled in 1994, more than 50 carriage and separation wind tunnel tests had been conducted.
The lessons learned on the TSSAM program informed significant improvements in the store certification process that have occurred over the past 30 years. The advances in computer computational fluid dynamics (CFD) technologies now allow detailed modeling of the flowfield around complex external store configurations. In-depth analysis of the correlation between analytical models, wind tunnel and flight test data have allowed modern store certification efforts to be conducted far more efficiently than was possible during the TSSAM program. The role of separation wind tunnel testing changed from the primary data gathering method into a valuable tool for validating CFD modeling results, significantly reducing the scope of the store certification test effort and the associated costs. Wind tunnel tests that once consisted of thousands of runs and lasted 4 to 6 weeks now consist of several hundred runs and can be completed in about 2 weeks. Similar savings in flight tests costs have also been possible as fewer test points are required to validate analytical results. The ability to model critical flight conditions has greatly improved the safety and cost of modern store certification flight test programs.
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From 'Lessons Learned' by Leland M. Nicolai
"The Northrop engineers forgot they were building a bomb and designed a very sophisticated and elegant airframe and subsystems, leading to technical problems during development and flight testing. Each launch aircraft required a unique set of strakes affixed to the missile aft body for safe separation during the unpowered launch and all eight had to be packaged in the AGM-137 all-up round container."
That's explains those additional inverted L-shaped surfaces on F/A-18 launch video.
"The Northrop engineers forgot they were building a bomb and designed a very sophisticated and elegant airframe and subsystems, leading to technical problems during development and flight testing. Each launch aircraft required a unique set of strakes affixed to the missile aft body for safe separation during the unpowered launch and all eight had to be packaged in the AGM-137 all-up round container."
That's explains those additional inverted L-shaped surfaces on F/A-18 launch video.
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So the Northrop engineers got carried away with the technical challenges of designing, testing and developing the AGM-137?
I remembered coming across an AIAA paper that mentioned that JASSM has a pitch-up tendency during early store separation tests.
The solution was adding 2 strakes at the tail end, which will help in preventing the pitch-up from taking place, and threw them away once JASSM has safely separated from the aircraft.
The solution was adding 2 strakes at the tail end, which will help in preventing the pitch-up from taking place, and threw them away once JASSM has safely separated from the aircraft.
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