Perfect JDRADM Missile

I was espousing on the F-22 and F-35 boards about what I thought each could hold in number of AMRAAMs and JDRADMs. I was also thinking about a "JDRADM-LITE" that would be the same size as the AIM-9X (10 ft vs AMRAAM 12 ft)

It got me thinking about what the JDRADM might look like, so I turned to Google to check out past missile programs.

When I came across General Dynamic's AIM-152 proposal, it just SCREAMED JDRADM and JDRADM-LITE.

I know that Wiki is not the best source, so I added a second.

Here is a Hi-Res version of this GD Poster.



Here are the list of options that I believe make it the perfect physical layout for the JDRADM / JDRADM-LITE program.

1. 12 feet long so it can fit anywhere AMRAAM can.
2. 7 inch booster body and 5 inch main body allows room for folding fins in the total 7 inch profile.
3. Already designed with in-flight eject-able nosecone so gimballed radar can also contain IIR sensor during endgame engagement.
4. Booster is a separate part so it's drag is removed after fuel is spent.
5. The booster is 4.5 ft long. Thereby a 2.5 booster can be used to make a JDRADM-LITE that is the same length as an AIM-9X. Same missile, different boosters... massive cost efficiency.
6. Restartable main rocket pulse engine (with thrust vectoring) to ensure that the missile is powered during the endgame engagement. MASSIVELY reduced chance of evading missile.
7. The booster section also has thrust vectoring for HOBS shots.

I cannot think of why this layout, as opposed to a ramjet layout, would not be perfect for the JDRADM project.

Thoughts.

------edited to correct title name

3- You will never know if the IR head will engage or not before you eject the nosecone. If it goes, it goes.

5- I don't think of a massive cost cut. The guidance section (or sectionS in your case) must be the expensive stuff. Also when the missile detonates, its booster section will also be disintegrated into pieces and act as shrapnel, I presume (???).

6- Solid-fuel engines are ignited once and burn till the fuel goes out, as far as I know.

in general- That much of ejecting mechanisms and thrust vectoring will add massive costs IMO.

Just my thoughts.


By the way what is an HOBS shot?

r2d2 wrote:3- You will never know if the IR head will engage or not before you eject the nosecone. If it goes, it goes.

The missile never loses radar lock thereby almost guaranteeing a secondary IIR lock.

r2d2 wrote:5- I don't think of a massive cost cut. The guidance section (or sectionS in your case) must be the expensive stuff.

Sorry, I meant R&D cost. The overall cost will have a significant cost reduction due to “economy of scale” factors in the program cost.

r2d2 wrote:Also when the missile detonates, its booster section will also be disintegrated into pieces and act as shrapnel, I presume (???).

The booster section is dropped off many miles before the endgame engagement. Besides, the warhead of most AAMs explode in a ‘dounut’ shape. This is called an annular explosion. All the explosion force is projected to the sides of the missile, not the front or rear areas.

r2d2 wrote:6- Solid-fuel engines are ignited once and burn till the fuel goes out, as far as I know.

Take another look at the Hi-Res Poster. Look at the barrier that is ~25% from the end of the main missile motor. You will see a disk barrier. The first 25% is used to separate from the booster and then the reaction stops due to lack of fuel. When the target is within a few seconds of contact, the other 75% will ignite to ensure that the missile is under full maneuverability in the endgame engagement.

r2d2 wrote:in general- That much of ejecting mechanisms and thrust vectoring will add massive costs IMO.

Thrust vectoring is relatively inexpensive. The vanes that are in the rocket exaust are directly connected to the external fins and are controlled by a single servo. Here is a good video from Youtube that shows the connection between the tail fins and thrust vains.

r2d2 wrote:By the way what is an HOBS shot?

”High Off Bore Sight” means that the missile is launched at a target that is off to the side or rear quarter of the launching aircraft.

Here is some more info on GD's AIM-152 proposal:
1. It was tube launched. This would allow it to last longer because it was protected from the elements
2. It can be packed tightly in the F-22's or F-35's bay due to there not needing to be any clearance between the tubes.

Here is a site that has some background info on the AIM-152.

http://www.secretprojects.co.uk/forum/i ... pic=2548.0

OK last night I did not see the picture with the exploded view of the missile.

I tought that you were talking about a radar cone for long range and then an IR seeker for close range , my apologies.


On the booster ejection and continuing with a second stage rocket engine, I still find it unmeaningfull for an A2A missile. Two engines, two sets of TV, so many mechanisms, ignite booster - eject the booster & ignite second stage for %25 of its fuel - then fly w/o engine where TV is ineffective - then ignite the rest of the fuel etc.

r2d2 wrote:On the booster ejection and continuing with a second stage rocket engine, I still find it unmeaningfull for an A2A missile. Two engines, two sets of TV, so many mechanisms, ignite booster - eject the booster & ignite second stage for %25 of its fuel - then fly w/o engine where TV is ineffective - then ignite the rest of the fuel etc.

Think about what currently happens. At the end of an AMRAAM’s flight profile it is out of fuel and coasting towards it’s target. As the target tries to evade, the AMRAAM will have to change course to match the evasions. It has to use it’s fins, unpowered, to change it’s direction. It will be loosing energy fast as it still contains it’s entire missile body and is heavy (12ft at 7 inches in diameter). It this scenario, the target has an ever-improving chance (the farther away it is) of evading the AMRAAM.

Now, compare that to GD’s AIM-152 proposal. At the end of it’s flight profile, it is using it’s POWERED, thrust-vectoring engine, to home in on the enemy. This final kill vehicle weighs maybe 30%-50% of the original total missile weight (now only 7.5 ft at 5 inches in diameter). It’s endgame ability to hit the target (not taking ECM, decoys, etc into account) will be virtually guaranteed.

If this is not the perfect AAM scenario, I do not know what is.

Now, as to the complexity of the idea…. It’s already done today. The standard (pardon the pun) anti-aircraft missile in the U.S. Navy is the Standard Family of missiles. Most of them are vertically launched with thrust-vectored, non fined, booster engines and dual-thrust rocket motors in the main missile.

Thinking of an 101. case should not create complications on the first and second etc cases' solutions.

edit. Pls see that I'm not discussing the GD design with my veeeery limited knowledge on weapon systems. This is my engineering approach in general.

Funny I was thinking the same thing; AIM-152’s general concept would make a wonderful JDRADM. One question that comes to my mind though is can a two stage missile like this take the huge loads of ejection? If it can then a missile along these lines would be outstanding. Have you seen the envelope on that thing? Crazy performance.

BDF

BDF - GREAT find on the archived article.

I do not think ejection will be an issue of the rail is designed to make contact with the booster and the main missile at the same time.

This would not be a problem with GD's tilting-pillbox launcher design.

5. The booster is 4.5 ft long. Thereby a 2.5 booster can be used to make a JDRADM-LITE that is the same length as an AIM-9X. Same missile, different boosters... massive cost efficiency.

I had a similar idea a few months ago. The problem I think is that you waste about 1' just because you add a booster from the drawings I've seen. In other words, your 2.5' booster would have only 1.5' of propellant. Not sure it's worth it..

I had another idea but I don't know if it's possible... make a booster that envelops the main missile itself. The advantages are:
- more propellant. I think it could carry about 50% more propellant.
- less loss of space vs the tandem configuration.
- only one exhaust system. ( the booster is somehow connected to the main missile exhaust )
- the thrust vectoring can be used while using the booster.
- different sizes of boosters with as much commonality as possible.

The booster would be composed of 2 components that would be ejected on each side when they're empty.

The wings/fins deploy once the booster has been ejected.

I've never seen a missile like that so I'm not sure it's possible.

Apart from this I also think it would be a great idea to have double ejector for the side bays that would be compatible with SDBs. Instead of 2 AIM-9Ms now in the 2 side bays the F-22 could have 2 JDRARMs-LITE on one side and 2 SDBs on the other.

Plus that would free the AMRAAM space inside the main bays for 2 more SDBs per main bay. Total 14 SDBs + 2 JDRARM-LITE.

Interesting idea but for the fact that it slaps the crap out of the KISS principle

Where did you get the idea that the booster wastes 1 foot of space?

Are you speaking of the combustion chamber in the base of the booster (see the photo in post #1)?

Duplicate deleted

I was looking at the NCADE:
http://www.ausairpower.net/NCADE-Cutaway-1S.jpg

As you can see the exhaust and the junction between the 2 stages takes a significant amount of space. Imagine if the booster was 2.5' long, there would not be much propellant..

The problem also with the standard booster option is that the missile cannot be rail launched. It could not be used on the F-16, and on the wing rails of the F-15. Maybe the stations along the F-15's fuselage could be modified to carry it but it's not sure it would stay backward compatible with the AMRAAM. It's a drawback if the JDRARM can't be carried on the F-15Es and the F-15Cs ( "golden eagle" ) because they could use it with their AESA radars. The F-16s could use the JDRARM-LITE.

( for my idea in fact maybe there's not need to limit the length of the main missile to 8'. With 10' drag would not be increased. It would have a longer motor, possibly a dual pulse motor, max speed would be lower but it would slow down half as fast as a 7'' missile ( half the sectional area ), and range would be better thanks to the second pulse. You're right that my idea is more complicated.. )

There's another thing also.. I was looking at the side bays and if you look attentively, you will see that there is about 2' between the front of the bay and the intake.

http://www.f-16.net/gallery_item88256.html
http://www.flightglobal.com/airspace/ph ... utaway.jpg

There's not much space but maybe just enough space to lengthen the bay with no modification to the intake and be able to fit 2 JDRARMs or 4 SDBs per side bay.

The thing also is that that the JDRARM and the SDB have a pointy nose and they have no wing, they can be mounted really close to the door. Also they have no wing at the front so maybe they would fit at the front just beside the intake.

On this picture:
http://www.f-16.net/gallery_item88256.html

it's possible to see the sidewinder. The sidewinder has a diameter of 5'' vs 7'' for the SDB and JDRARM. If they're close to the door maybe they would fit ( at the front ).

Off topic a bit, but could you attach a HARM seeker to a SDB? Could really help open a freeway for legacy planes following F-22's. Have a pre-programmed secondary target and have one F-22 "drop" 4-6 at 70k feet within 80-100 miles of suspected radar sites. Have SDB's fly to vicinity. But perhaps the real AF has better tactics then me.