Posted: 5/1/2006 1:23:45 AM EDT
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I tried to find the Box O' Truth but our server is VERY slow so I was hoping someone here could help me out. The armor on my Humvee Turret is two sheets of 1/4" steel bolted together. Would putting washers in between them, giving a 1/4-1/2" space between the two, help ballistic protection? thanks in advance ENGLT |
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I doubt an air pocket is going to do you any good. A projectile that can penetrate 1/2" of steel (two 1/4" plates) is going to penetrate 1/4" of steel, 1/4" of "air pocket" and 1/4" of steel. Think about the "pope glass" that some guys are putting on. It is showing some good protective results. While I do not think it is classified, erroring on the side of caution that is all I want to say on on open net fourm. |
Think the word your loking for is "OPSEC" |
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LT, Contact/IM Garand_Shooter. He is a CWO maintenance guru and combat engineer. He just got back from Afghanistan and helped me out with all kinds of maintenance advice last year when I was in Iraq. Especially on uparmoring humvees and specialty equipment, ordering parts, etc. He is a great resource. Essayons! - GulDuCal |
I did not realize I was looking for a word and thought I conveyed my message. But thanks 
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I would suggest trying to find some aramyd (Kevlar) material and sandwich it in between the steel plates; making a sort of "Poor Man's SAPI Plate" I figure using the old flak jackets (there should be some laying around). Just a suggestion from an MP that served "Over There". PS, we used level IIIA concelalable vests donated by the local (Jax SD) as protection since we did not have uparmored Humvees at the time (2003) |
lol, sorry man. It was an (admittedly poor) attempt at dead pan humor after only getting about 3.5 hours of sleep last night. My bad. 
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David Hayter, thought about the sand, it might work. Contractor, We have the glass for the Pope Dome but that sits above the armor plating. I was thinking about reinforcing the steel for added protection/protection from spall. I am pretty sure the 1/4 inch of air would not stop a round but I think it is supposed to assist with Spall. I also thought it might help stop a mushroomed round from pushing straight through. pbaeod, where is marez, I am currently in taji eventually headed somewhere else (opsec) as part of a BTT GulDuCal, thanks for the help, I will drop him a line. Black Tiger, Excellent Idea, we still have our SAPI plates after they issued us the ESAPI. I am trying to get ahold of some of the Kevlar mats that go on the bottom of Helicopters but it is pretty scarce. I will keep checking this board for ideas so please keep them coming. [email protected] if you want to e-mail me ENGLT Drew |
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Tag. I would think that having an air space would assist with spall, but I don't know if it will help much with actually stopping projectiles. The sand would be a good bet though. You may even find that just having two layers bolted together will do alot to stop spall even without the air space. When I was in Bosnia we had heavy kevlar mats on the floors and seats of our HMMWV's as a mine precaution. I don't know if there is anything like that being used, but you might be able to find some of that. Also, is there any chance of you being able to pull the spall lining out af an M-113A3 that's been junked and useing that? -K |
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[Contractor, We have the glass for the Pope Dome but that sits above the armor plating. I was thinking about reinforcing the steel for added protection/protection from spall. I am pretty sure the 1/4 inch of air would not stop a round but I think it is supposed to assist with Spall. I also thought it might help stop a mushroomed round from pushing straight through.] You are tracking brother, now lower the glass. Same for the doors  |
| It's in Mosul if you end up here drop a line I can give your guys classes on IED's if they want and get you time on the demo range out of our stockpile. The Idea to protect from spall is to keep the inner layer from breaking off and fragging your guys so if you have kevlar put it on the very inside of the turret next to the guner. |
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Text copied from this page published in 1943 A recent British study provides a statement of the general principles governing the attack of, and defense by, spaced armor. The essential points bearing on the use of spaced armor by the enemy, that follow, are taken from the British report. * * * Two separated homogeneous plates attacked by A.P. shot, or 2 separate plates in loose contact, are less effective in defense than a single plate of the same total thickness. This is because there is no shearing resistance over the internal free surfaces. A front cemented (face-hardened) plate separated from a rear homogeneous plate attacked by A.P.C. (armor-piercing capped) shot will, for the same reason, offer less resistance than a single cemented plate of the same total thickness. A front homogeneous plate separated from a rear cemented plate offers increased resistance to A.P.C. shot as the front homogeneous plate destroys the cap of A.P.C. shot and so diminishes the effectiveness of the projectile against the cemented surface of the rear plate. The important point in this construction is that by the use of spaced plates the cemented face can be made to be an interior surface of the system, and so afford protection against an A.P.C. shot de-capped by the front plate. For the same reason a rear cemented plate offers increased protection against a tungsten carbide cored shot, unless the core is very well protected by a cap and some form of cushion. A rear cemented plate will also offer greatly increased protection against an A.P. shot because the nose of the A.P. shot will be partly damaged by the front homogeneous plate, and so will have a still further diminished power against the cemented surface of the internal plate. From the point of view of attack, the effectiveness of capped (A.P.C.) and uncapped (A.P.) projectiles varies in different calibers owing to a differing balance of advantages and disadvantages. Though a cap tends to preserve the point of the ogive (the curved and pointed head of the projectile) during perforation of the front plate, the cap itself is destroyed by the same action, and thus kinetic energy is wasted. In one caliber the reduction of energy due to loss of the cap before reaching the interior plate may result in failure to perforate, whereas in a larger caliber the loss may have a less pronounced effect on the ultimate performance, resulting in perforation of 2 plates of the same quality and equally well matched. It is true that an A.P. or A.P.C. shot tends to turn towards the normal on perforating a plate, but in the case of spaced armor any advantage which might be gained thereby is likely to be neutralized by the acquisition of a transverse angular velocity which may result in increased yaw. For this effect to be appreciable, plates should be separated by a distance of at least one caliber. Another page found here has this to say: Another common design feature among tanks is to use spaced armor, in other words rather than being solid there is a space between layers. This was first introduced in WWI and became especially common in WWII as the technique was especially good at defeating shaped charge warheads, which do not depend on kinetic energy for effectiveness. Some common types of spaced armor include slat armor, screens, or solid sheets attached outside the main armor of the tank, or alternatively an extra layer inside the main armor face. One more from here Spaced armor is an early response to the proliferation of shaped charge warheads. At the time, tank armor was strong enough to defeat nearly all kinetic weapons, and/or more importantly the prime man-portable and light anti-tank weapons used a shaped charge of high explosive. For these to be effective, they need to detonate at a predetermined distance from the surface of the armor plate (usually quite close). Farther than this distance and the resultant explosive gas/plasma jet has lost integrity or may be at an incorrect angle; closer than this and (usually) the jet has not had the distance to properly form. Spaced armor is the practice of adding thin sheets of armor set off from the main body of the armor, held on by spacing brackets. The advantage of this is that incoming shaped charge warheads (HEAT) will detonate based on the position of the outer armor shell, which is (by design) an incorrect position for penetrating the lower armor plate. Although not as effective as reactive armor, spaced armor is cheaper, easier to mount, and less dangerous to nearby infantry. |
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This one I know is not OPSEC as it is visable to all. Take some Hummer windshields w/metal frame and weld them at the top of the turret armor. This provides sniper/blast protection while still giving the gunner a full field of view. Drawbacks are tha added wieght and the fact that the gunner has to rotate the turret to engage any and every threat instead of simply shooting his M-4 over the side. Depends on your threat. |
| This is an adaptation of the “hillbilly armor” widely used earlier on. Hell it is still in use. Windshields can be ordered or salvaged from inoperable vehicles. I have also seen some Hummers with sections of the gun shield cut out and glass inserted. Again better field of view for the gunner while keeping his head behind the cover. |
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Interesting....with any luck, our platoon will be getting ASVs and my team is designated to train up and operate it, so I might not have a whole lot of worry about it...but its still kinda 50/50. Thanks for the info man! Ill tell my team leader about it and see what we can do. |
While I Would like to see how well the armor around me will protect me I don't think I want it posted on the web that the armor will stop round X but not round Y. Don't get me wrong, if I get the chance I will find out just what it will and willnot stop but I'm not going to post it on the web. If a 7.62x54 (?dragunov round I think?) will go through it I do not want ali babba to know that. Drew ps, Pics forthcoming |
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Spaced armor in the form of sheets were placed over the flanks of some tanks, but understand that the penetrating capability of an RPG-7 (google-fu if you like) is 6 inches and up. If you have a half inch of armor or 1/4 x 2 with a spacer I dont know that it matters - assuming someone hits the turret with an RPG. I would be more concerned about IED frags, especially or 7.62 mm. Check the MOUT FM(90-10-1) for penetrating data of 7.62-I won't post it here for OPSEC purposes. I would suggest sandbags on the outside, or space and put sand in, but if the weight of the turret gets too heavy the pressure may make it bind. Need to test that. At some point the weight makes it hard to spin. Since you're an EN LT I would suggest call.army.mil for IED knowledge. If you haven't started there and tapped into them that's the one-stop-shop I'd suggest. |
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It's easier than washers, and will create the space this whole thread is about. The actual material in the space is irrelevent - it was air originally. As for the armor, I got hold of a section of tank skirt form one of our burnt up tanks over there - it went with me to every range we ran and made a great steel target downrange. We never were able to put a hole in it, but I can't garantee our .50 cals ever actually hit it. Odds are, though, that the turret shields will stop most of you threats as they are, assuming they are made of anything like that skirt section was. Dang, I knew I should have thrown that tank skirt section in our CONEX for the trip back! |
 Here's the secret ingredient. Once you've assembled the piece, you soak the carpet with water or moonshine before heading out to patrol. Now the projectile has to go through metal, liquid soaked carpet, and then metal. Tada! 
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