AIM-260

BDF

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True. Thinking about advanced propellants like gels. That lets you play with throttling or even stopping and restarting motors as desired rather than according to a pre-specified schedule. There have been rumors about gels in AIM-120D already.

Gel fueled rocket motors were speculated before the -120D was introduced. I believe unclassified docs have since shown that the 'D uses the same motor as the 'C7.
 

BDF

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More usable volume is probably dependent on your propulsion system. A solid motor is always going to be cylindrical so anything outside that is going to be wasted space, more drag, more weight.

One could potentially utilize the volume around the motor created by the aero-shape for packaging guidance, actuators, batteries etc. though. That way you extend the length of the motor for added range or speed.
 

sferrin

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True. Thinking about advanced propellants like gels. That lets you play with throttling or even stopping and restarting motors as desired rather than according to a pre-specified schedule. There have been rumors about gels in AIM-120D already.

I used to have a timeline, decades ago, that showed AIM-120 planned improvements. Gels were in there but I wonder if it was a fad that has faded. To my knowledge no missile in service, anywhere, uses gel fuel. Wonder if when it's all said and done gel doesn't have enough bang for the buck.
 

Grey Havoc

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To my knowledge no missile in service, anywhere, uses gel fuel. Wonder if when it's all said and done gel doesn't have enough bang for the buck.

I think that it has been cost and production considerations which have held back the technology.
 

sferrin

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To my knowledge no missile in service, anywhere, uses gel fuel. Wonder if when it's all said and done gel doesn't have enough bang for the buck.

I think that it has been cost and production considerations which have held back the technology.

Consider all the moving parts, the space and weight they take, and the cost/reliability hit they impose. And they don't really deliver a huge bump in ISP. Better than solid, sure, but not to the levels of liquid propellant. And you lose volume that could be used for propellant for the hardware to pressurize and feed the gel into the combustion chamber. . . IIRC the latest edition of Sutton's book doesn't even cover gel fuels. I had an earlier edition and bought the newest one (well, newest a year or two ago) to see what progress had been made in gel fuels and it didn't even cover them. They had been removed.
 

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Didn't the Meteor get a gel fuelled throttable engine from Bayer-Chemie?

The Meteor VFDR is solid-fuel. I suspect they looked at a gel option (I see a paper out there that seems to evaluate gel in a very Meteor-like missile) but I don't see anything to suggest they actually changed over.
 

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Curious, what are the odds that the AIM-260 operates on cryogenic fuel? One thing I've heard about is that the new AIM-260 requires specialized bunkers and storage facilities.


That implies that the AIM-260 might require specialized storage conditions; if the thing is top-secret and highly-classified, I'm sure there's ways to set things up without having to spend 6.5 million on a bunker for them.

Alternatively, the new rocket features fuel that's otherwise unstable or highly combustable and thus requires new storage mechanisms.

This would also explain why the AIM-260 doesn't seem to be a ramjet; for instance, as with the E-2D, the Americans chose an older technology (PESA) over a newer technology (AESA). In the E-2D's case, there were potential advantages to the older technology, that is to say, since the radar energy emitted came from a magnetron in PESA, they could use a more powerful PESA to offset the efficiency losses of PESA, meaning that PESA would have been the superior choice. Using cryogenic or exotic fuels, likewise, might make it not compatible with a ramjet design, but compatible with a dual-pulse rocket motor.

===

Also, could AIM-260 simply refer to the mile range of the AIM-260 in terms of aerodynamic range? That'd put it at 420 km of range, which, if you consider the K-77M (known 200 km range) and the PL-15 (unknown, but should be longer than the K-77M given the PL-15's greater length), is superior but not by much.
 
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Inst

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I remember reading somewhere rumors about breakthroughs in American rocket propulsion technology that underlaid the next generation of American missiles. CUDA and its like, supposedly, manage their range gains by relying on sensors to achieve KK, and using the space that would have otherwise gone to explosives to fuel instead. But how much additional range could you get from that type of technology?
 

GARGEAN

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Also, could AIM-260 simply refer to the mile range of the AIM-260 in terms of aerodynamic range? That'd put it at 420 km of range, which, if you consider the K-77M (known 200 km range) and the PL-15 (unknown, but should be longer than the K-77M given the PL-15's greater length), is superior but not by much.
R-77M range known from where?
 

AeroFranz

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There is so much talk about 'insensitive' munitions, that i can't imagine deploying a weapons system that needs to be molly-coddled. If you can't keep a missile sitting on a deck for an hour in the Indian Ocean on a hot day, then its military utility is questionable, IMHO.
 

marauder2048

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This would also explain why the AIM-260 doesn't seem to be a ramjet; for instance, as with the E-2D, the Americans chose an older technology (PESA) over a newer technology (AESA). In the E-2D's case, there were potential advantages to the older technology, that is to say, since the radar energy emitted came from a magnetron in PESA, they could use a more powerful PESA to offset the efficiency losses of PESA, meaning that PESA would have been the superior choice. Using cryogenic or exotic fuels, likewise, might make it not compatible with a ramjet design, but compatible with a dual-pulse rocket motor.

There were no T/R modules of suitable power density/volumetric efficiency and weight and cost in the UHF band. There still really aren't.

There's no way the Navy would ever accept cryogenic, hypergolic or any really any liquid fuels; they are all banned for shipboard use.

The only possible exception might be monopropellants like HAN (see NCADE).
 

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This would also explain why the AIM-260 doesn't seem to be a ramjet; for instance, as with the E-2D, the Americans chose an older technology (PESA) over a newer technology (AESA). In the E-2D's case, there were potential advantages to the older technology, that is to say, since the radar energy emitted came from a magnetron in PESA, they could use a more powerful PESA to offset the efficiency losses of PESA, meaning that PESA would have been the superior choice. Using cryogenic or exotic fuels, likewise, might make it not compatible with a ramjet design, but compatible with a dual-pulse rocket motor.
There's no way the Navy would ever accept cryogenic, hypergolic or any really any liquid fuels; they are all banned for shipboard use.

The only possible exception might be monopropellants like HAN (see NCADE).
Or use what ever the missiles like the Harpoon, Tomahawk, LRASM and Naval Strike missiles to power their turbojet engines. I imagine it need to be design in such a way that the risk of leaks and the like is minimized.
 

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This would also explain why the AIM-260 doesn't seem to be a ramjet; for instance, as with the E-2D, the Americans chose an older technology (PESA) over a newer technology (AESA). In the E-2D's case, there were potential advantages to the older technology, that is to say, since the radar energy emitted came from a magnetron in PESA, they could use a more powerful PESA to offset the efficiency losses of PESA, meaning that PESA would have been the superior choice. Using cryogenic or exotic fuels, likewise, might make it not compatible with a ramjet design, but compatible with a dual-pulse rocket motor.
There's no way the Navy would ever accept cryogenic, hypergolic or any really any liquid fuels; they are all banned for shipboard use.

The only possible exception might be monopropellants like HAN (see NCADE).
Or use what ever the missiles like the Harpoon, Tomahawk, LRASM and Naval Strike missiles to power their turbojet engines. I imagine it need to be design in such a way that the risk of leaks and the like is minimized.
I would imagine zero maintenance or fueling.
 

marauder2048

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Or use what ever the missiles like the Harpoon, Tomahawk, LRASM and Naval Strike missiles to power their turbojet engines. I imagine it need to be design in such a way that the risk of leaks and the like is minimized.


Good point. You can't rule out hybrids; hydrogen peroxide /JP-10 or HAN/JP-10. I think both of those could meet storability and insensitivity requirements.
 

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Or use what ever the missiles like the Harpoon, Tomahawk, LRASM and Naval Strike missiles to power their turbojet engines. I imagine it need to be design in such a way that the risk of leaks and the like is minimized.


Good point. You can't rule out hybrids; hydrogen peroxide /JP-10 or HAN/JP-10. I think both of those could meet storability and insensitivity requirements.
Hydrogen Peroxide in the concentrations needed for a hybrid rocket is not something you want onboard of a ship, period. Just ask the Kursk what happens when things go pearshaped.
 

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Or use what ever the missiles like the Harpoon, Tomahawk, LRASM and Naval Strike missiles to power their turbojet engines. I imagine it need to be design in such a way that the risk of leaks and the like is minimized.


Good point. You can't rule out hybrids; hydrogen peroxide /JP-10 or HAN/JP-10. I think both of those could meet storability and insensitivity requirements.
Hydrogen Peroxide in the concentrations needed for a hybrid rocket is not something you want onboard of a ship, period. Just ask the Kursk what happens when things go pearshaped.
I was mkre point out that the navy does use liquid fuel missiles.

Besides, hydrogen peroxide is not the only game in town anymore.
 

marauder2048

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Hydrogen Peroxide in the concentrations needed for a hybrid rocket is not something you want onboard of a ship, period. Just ask the Kursk what happens when things go pearshaped.

I mentioned hydrogen peroxide because there was a joint Navy and Air Force effort on hydrogen peroxide + hydrocarbon
fuels in the early 2000's.

The shipboard ban dates from 1988 and even the AF has restrictions on moving liquid fueled missiles around.

But there was talk about potentially relaxing things on the shipboard side as a result of SM-3 IIB likely requiring
a liquid stage to meet the perf reqs.
 

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They also tolerate OTTO II monopropellant for torpedoes, because as nasty as it is, there's no good alternative.
 

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Advancing battery tech might finally kill OTTO II before long. One hopes, anyway.
 

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bring_it_on

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Anyone have details on this effort and whether it led to additional development work??

As the next evolution in missile agility, the Air Force is looking at integrating small but capable divert and attitude control systems (DACS) into new and existing missile systems. This will increase the agility of the missile and allow for interception of faster or maneuverable targets. During Phase I, CFDRC supported this goal by defining two miniaturized thruster designs that utilize gelled hypergolic propellants to maximize divert performance and missile maneuverability while insuring IM compliance. Each design offers different strategies for system integration.

The primary design employs an annular face shut off approach coupled with an expansion-deflection nozzle to provide an extremely compact unit. A second design that incorporates a vortex-type combustor with a conventional nozzle is slightly longer. Both possess high performance. During Phase II CFDRC will: 1) Fully assess performance associated with a range of gelled propellant combinations (ionic liquids, innovative oxidizers, etc.) relative to the baseline MON25/MMH and 2) Fabricate, hot fire test and validate both thruster concepts. CFDRC is already in negotiations with industry partners about potential follow on programs that integrate system components (i.e. propellant tanks, valves, gas generators, etc.) to perform a full scale system demonstration that paves the way for ultimate flight qualification.

BENEFIT: A paradigm shift in operational performance is possible using a DACS within an air-to-air missile airframe. Immediate applications include any Next Gen missile tailored for JSF weapons bay storage and future AIM-9X/AIM-120 Block upgrade programs. Since propellant gelation improves the IM rating of any hypergolic propellant combination numerous additional military and commercial applications exist including: 1) missile intercept kill vehicles (THAAD, EKV, GMD); 2) extraterrestrial ascent/descent engines; 3) in-space orbital maneuvering and station keeping thrusters; 4) storable upper stage liquid booster motors; 5) missile main propulsion and 6) underwater propulsion/power. Consequently the proposed Phase II miniaturization of gelled propellant thrusters possesses wide range of military and commercial opportunities.

 

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sferrin

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Advancing battery tech might finally kill OTTO II before long. One hopes, anyway.

SCEPS is making a comeback...

If you think putting out an OTTO II fire is fun...try burning lithium.
Thought what they're describing was so awesome in the Mk50 that they ditched it and made the Mk54 with a more traditional propulsion system.
 

bring_it_on

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I hadn't come across this earlier. Not sure it is related but interesting none the less.

During Phase 2, SPILAB will build a prototype for hypersonic wind tunnel testing to confirm that a multiple aperture seeker can view through a hot bow wave. BENEFIT: The actively cooled, multi-aperture seeker will enable hypersonic missiles and munitions to navigate and target using forward looking infrared sensing. The seeker will be useful for both Air-to-Surface and Air-to-Air missiles. The forward looking imaging capability will also be useful for future aircraft traveling at hypersonic speeds.

 

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Wow...I wouldn’t have thought IR homing inn the hypersonic regime practical.
 

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Advancing battery tech might finally kill OTTO II before long. One hopes, anyway.

SCEPS is making a comeback...

If you think putting out an OTTO II fire is fun...try burning lithium.
Thought what they're describing was so awesome in the Mk50 that they ditched it and made the Mk54 with a more traditional propulsion system.

I think the main problem was expense, not safety. Plus the target set of Russian titanium nuke boats took a back seat to more pedestrian D/Es that didn’t require higher performance than the traditional mk46 Otto II plant.

The new micro torpedo is likely going to be shipped in the external counter measures tubes anyway.
 

sferrin

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I hadn't come across this earlier. Not sure it is related but interesting none the less.

During Phase 2, SPILAB will build a prototype for hypersonic wind tunnel testing to confirm that a multiple aperture seeker can view through a hot bow wave. BENEFIT: The actively cooled, multi-aperture seeker will enable hypersonic missiles and munitions to navigate and target using forward looking infrared sensing. The seeker will be useful for both Air-to-Surface and Air-to-Air missiles. The forward looking imaging capability will also be useful for future aircraft traveling at hypersonic speeds.


They've tested stuff similar to this before. (I think on HEDI Kite but it was during that timeframe.) They have a cool gas layer flowing over the seeker window (which is flat) to keep the window from overheating.

"High Endoatmospheric Defense Interceptor (HEDI) was a two-stage missile that operated high within the atmosphere and just beyond it. Its goal was to develop a nonnuclear interceptor capable of destroying an ICBM reentry vehicle within the Earth's atmosphere, operating at altitudes between 50,000 and 200,000 feet. The High Endoatmospheric Defense Interceptor (HEDI) used an infrared seeker in nosecone which must endure temperatures of 1,500 to 2000°F as well as high pressure. The sapphire window was cooled by flowing gaseous nitrogen. The interceptor could reach a speed of Mach 7 in 8.5 seconds."

DehkQvdU0AAP09u.jpg
 

sferrin

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Quick and dirty. 152" long x 8" dia.

View attachment 632435

I might suggest shortening the nose a bit. Maybe by 8''. So the new length would be about 144 In.

Lesser radome error slope for seeker.
Quick and dirty. 152" long x 8" dia.

View attachment 632435

I might suggest shortening the nose a bit. Maybe by 8''. So the new length would be about 144 In.

Lesser radome error slope for seeker.
In that case I'd shorten the radome but keep the KKV length the same by stretching the fuselage and adding more fuel.
 

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@bring_it_on : the link specifically mentions active cooling on each seeker's apertures (they have multiple apertures just like a fly does). I guess that actively cooling multiple smaller apertures was easier than for a single larger one.
 

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In/For an air-to-air application, I wonder if the bio-inspired multiple aperture design is being explored to aid in seeker survivability and CM resistance ?
 

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It's a very plausible case too. Passive protection against cold laser for example would certainly be enhanced.
 

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One of things that came of the Liquid fuel powered Martel study in the UK was the benefits of pulsing the motor. Taking advantage of the ability to stop and start the engine they realised they could extend the range of the weapon.
 

bring_it_on

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One of things that came of the Liquid fuel powered Martel study in the UK was the benefits of pulsing the motor. Taking advantage of the ability to stop and start the engine they realised they could extend the range of the weapon.

And now we are able to do this with solid rocket motors as well, and the tech is one of the areas that DARPA is investing in for future missile technology (@ 17 or so minute mark, DARPA - Next Gen. Air to Air Missile technology) so it isn't beyond the realm of possibility that it shows up in the future on JATM variant or another missile.

View: https://www.youtube.com/watch?v=yI8QxYUWjng
 
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Doesn't MIM-104 MSE already use a dual pulse motor?

I believe DARPA is actually I taking it a step further and trying to make a throttleable solid rocket in OpFires. Not sure how they can achieve that. Dual pulse doesn't seem that challenging comparatively.
 

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These are three different things. A dual pulse motor is basically compartmentalizing the SRM so that the two pulses can be fired independently and timing varied based on mission need. That way you can extend the coast phase. OpFires is using a hybrid approach ("liquid augmented SRM") to throttle the motor for precision control. That requires a new hybrid motor design and can't be back-fitted on existing systems without funding individual SRM upgrades for each program. This (the video above) is talking about fitting nozzles on existing SRMs that can allow an existing SRM to be extinguished and restarted as needed. Even multiple stop/start cycles may be possible with existing SRMs (not having to design a completely new motor).. So all three are distinct approaches.
 
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