The other day the Atlantic ran a photo piece about the remarkable DIY weaponry of the Syrian rebels, and, as always, it was impressive. There's a lot of hard work and ingenuity going into these improvised weapons. Of course, one of the most interesting was the Sham 2 armored car/light tank vehicle that we've covered here before.
The tank, which was built on an as yet unidentified car chassis (I suspect a Peugeot for some reason) is notable for its use of cameras and video screens, and especially the PlayStation-type controller used to aim its 7.62 mm roof turret-mounted machine gun.
A home-built tank that uses a videogame controller to point a gun is, of course, prime internet-post bait, and there's been many stories written about the vehicle. Many suggest that the armor of the vehicle is likely to be inadequate for most purposes. As Wired reported,
But it’s hard to say how effective the machine really is at resisting bullets. If the armor is sloppily built, it risks being knocked out by “spall.” That’s what happens when a piece of armor is hit by a projectile of sufficient power, and the armor is strong enough to stop the round from penetrating, but is still hit with enough force to cause a concussive blast wave to detach shards of material from the armor’s interior side. The blast wave then propels that material through the interior of the vehicle at incredibly high speeds. That can be very lethal to passengers and crew, and means that bad armor can often be worse than no armor at all.
You can't really blame the designers/builders. They're working with whatever they have, and are doing a pretty amazing job. Still, Wired may have a point. But I think there could be a relatively easy and cheap solution.
If we think about it, car chassis converted to armored weapon platforms aren't that different than the converted ironclads the Confederacy was building in the American Civil War, like the famous CSS Virginia (also known as the Merrimac, from the Union ship it was converted from). Both are taking platforms never designed to handle the weight of armor (either a wooden ship cut to the water line or a clapped-out beater with the body removed) and armoring them anyway.
What ships like the Virginia did to maximize the protection of their armor was to angle the armor plates, which gives more protection than vertical armor for the same amount of weight. Most tanks since WWII and on have used this principle as well.
The Sham II does have a well-sloped front, so my suggestion would be to re-mount the existing side armor panels at a useful slope, to make a sort of casement shape not unlike the Virginia. Not that I expect any Syrian Rebels are reading this, but just in case they're planning on tweaking the Sham II on the cheap, and to help enhance the safety of their crews, that's my advice. Advice from a guy who's never been in a war, typing comfortably thousands of miles away.