XM-13 Shillelaga Missile Prototype

[wichitaslumlord]

XM-13 Shillelagh Missile Prototype

I just picked up this interesting piece. The previous owner identified it as a developmental prototype for the MGM-51 Shillelagh program. It is 152mm in diameter and 49 1/2 inches long.
The fins are fixed in place with 4 screws each and there is no possible provision for them to move on this particular missile. The fins are quite precision and are milled from billet stock. This is obviously not workable with something fired from a tube. There is no motor of any kind, just a billet aluminum plug to which the fins are mounted. It has a connector and a steel stud in the center.

The all black section in the middle of the missile (pictures 3,4,and 5) rotates quite freely on precision bearings and has one large slot and one narrow slot 180 degrees apart from each other. The owner said these were for tiny keys which engaged with the guns rifled barrel, spinning this section only - to provide stabilization. Strange, but in the very beginning of the program, they may have looked at almost any possibility....
I took pictures of this section with one piece of aluminum skin removed. The only thing connecting the front half of the missile to the rear half is the small shaft in the center of picture 3. It is hard to imagine this could endure the stress of launch and flight without distortion.

This is a very well made, precision piece and it bears a paint scheme which is consistent with testing. The body is divided into 4 sections longitudinally in an alternating white and black scheme and each section is numbered with roman numerals.

Any help in identification would be greatly appreciated. THANKS! Pat

 

[HAZORD]

Does it have any timeframe dates anywhere?

 

[US-Subs]

Pat,
I could be way off here, but it doesn't look to me as though it belongs to that program. Prototypes can take many different routes, but flight test dummies (which is the normal explanation for the markings) normally need to reflect some basic weight/balance/components expected to be on the final product. As you mentioned, yours is not consistent with that type of projectile. I would further ask, as a missile, how is this to be propelled? Where are you putting the nozzle(s), etc.

The fins and general configuration are reminiscent of one of the ADSID variants, but also a couple of submunition designs from the early 90s. I did a quick look for similar items, but have not located them yet. There were so many designs during that period that popped up and then disappeared almost immediately, it was extremely difficult to track them and keep up with the changes - CLAW, LOCASS, Assault Breaker.... You might get a project name and by the time you found a photo either it the project was already dropped or had moved to a completely new generation or design type. If I get a chance this weekend I'll try and search more deeply, but it seems like the TGSM program (intended for MLRS/ATACMS) had one variant that was a long sub with fold out fins that were similar.

Here is a picture of the ADSID with similar fins, acceptable for airdropped and unguided, but not something I'd thing of for a tube fired missile. I've been wrong before though -

 

[weberoed]

yes this is an early sensor, I have a folder of it with more pictures. Appears it is an early USAF sensor being designed for deployment to the Delta region VN.

 

[wichitaslumlord]

Hello all.

Hazord, I have not found any markings other than the fin placement stamps on the base. I also have not completely disassembled it yet, but there may be some marks internally.

Thanks for the suggestion Jeff. The fins do look quite similar. I am still curious about the rotating section in the middle. A lot of work and loss of strength went into making this section.

I look forward to any information and pictures that weberoed or US Subs may have. THANKS in advance! Pat

 

[HAZORD]

I would add, that fins that large are for low velocity items. High velocity items require much smaller fins. The fins on the Shillelagh are smaller than the fins on an older 2.75 inch rocket.

 

[wichitaslumlord]

I would add, that fins that large are for low velocity items. High velocity items require much smaller fins. The fins on the Shillelagh are smaller than the fins on an older 2.75 inch rocket.

That makes perfect sense. These monsters would be pretty draggy at high speed. THANKS! Pat

 

[HAZORD]

Yes, those fins would be pretty "draggy", because that is what they are designed for, to keep the item going point first. They are not steering fins, because they can't rotate. Large fins are needed for low velocity, to provide enough force for course correction because of the small amount of air flowing over them. In addition, the servos that rotate the fins need to be the proper strength to move them. A Shillelagh travels 1,060 feet per second. It would take huge servos to move fins that large at that velocity.