During the great “Bash Bush because not every Humvee was Armored” era, I wrote a long piece on the engineering challenges involved in up-armoring Humvees. (**see extended entry) A new story in the USA Today confirms it was not as simple as everyone thought.
By Gregg Zoroya, USA TODAY
The Army is baffled by a recent spate of vehicle accidents in Iraq — many of them rollovers involving armored Humvees — that have claimed more than a dozen lives this year.
One key concern: Soldiers lack the skills to handle the heavier Humvees and are losing control as they speed through ambush areas before insurgents detonate roadside bombs.
“An individual feels that if he goes faster he can avoid that threat,” says Lt. Col. Michael Tarutani, an Army official tracking the accidents. “But now he’s exceeded, first, maybe his capabilities, and then maybe the speed for those conditions.”
In the past four full months, the numbers of serious vehicle accidents and fatalities in Iraq have more than doubled from the previous four months, records provided by the Army show. In the first 10 weeks of this year, 14 soldiers were killed in accidents involving Humvees or trucks. All but one died in rollovers. If that rate continues, the number of soldiers killed in such accidents this year would be almost double the 39 soldiers killed in 2004. Detailed records involving Marines were not available.
The Army is trying to determine whether the dramatic increase in the number of Humvees in use in Iraq — or an increase in the amount of miles they are being driven — might explain the higher number of accidents. It also is questioning whether the handling and center of gravity in Humvees may have been altered by armor plating bolted on in Iraq or shields added around gun turrets.
Adding to the mystery is that many of the rollover accidents involve the newest generation of factory-produced armored Humvees, vehicles thoroughly tested by the Army and with an even lower center of gravity than those without armor plating.
That really should come as no mystery to anyone with even a rudimentary understanding of engineering or physics. It’s called momentum. If you skid 3000 pound vehicles to a sideways stop, you will flip a certain number of them. Try that with an additional 2000 pounds of armor and you will flip a whole lot more of them. Center of gravity be damned.
I’m not going to bore you with a bunch of math -and this is simple “back of the envelope” calculations anyway- but consider this…
Momentum = Mass * Velocity. (p=m*v)
Lets pretend you can take a 3000 pound Hummvee and turn it sideways up to 30MPH before it flips. (3000lbs*30mph=90,000) So it be said that when sideways momentum exceeds 90,000 the vehicle flips. Now let’s do the math backwards to see when a 5000 pound Humvee flips. 90,000/5000lbs = 18MPH Almost half the speed.
You can’t lower the center of gravity low enough to fight math like that. (even admittedly rough math)
So let me say this as clearly as I can. Up-armoring Humvees has killed people. But that is not the question. The question is; Has it saved more than it killed? I don’t know that answer. I presume it has. (In effect, that question is at the basis of all engineering problems.)
What this shows is that military and engineering problems should be decided by military people and engineers and not rabid Democrats willing to compromise our soldiers’ safety to gain political power.
In case you read that wrong, I’m not in any way suggesting that armoring Humvees has caused MORE soldiers to die. I doubt that to be the case. (though I would like to see the numbers) Again my point is that physics does not care about which political party wants power.
Leave the engineering to engineers and not people on the campaign trail.
**The post I mentioned above never got published. I was about 2/3rds of the way thru writing my post when Jay posted something less technical but similar enough that I just orphaned mine. For the sake of reference, here is my previously unfinished post from December 11, 2004:
Humvee Armor Problem more complicated than it looks
To the average civilian, it seems ludicrous that all Humvee’s should not be armored. And to be sure, the folks on the left are trying to make the fact that they aren’t into a political issue. But like so many things in life, it just ain’t as simple as it looks.
To start at the beginning -after all I might have a liberal or 2 reading- I’ll begin with the name. Humvee is the way we pronounce HMMWV which stands for High Mobility Multipurpose Wheeled Vehicle.
Let’s start with the high mobility part. The Humvee replaced the perennial Army Jeep. [link] The Jeep served us well for XXX years but it suffered from a few drawbacks. For starters, the damn thing flipped over and killed people. That is why the Humvee is so wide. As the name implies, a major part of the design specification was that the vehicle be “highly mobile.” The Humvee was never designed to be an armored combat vehicle. That’s why we have Strikers and Bradleys.
Now- I’ll let you in on a military secret nobody on the left has figured out. Armor is heavy. Real heavy.
Adding an armor kit to a Humvee can add as much as 2200 pounds to the weight of the vehicle. To put that into perspective, that is almost as much as the weight of a Toyota Corolla. If you’ve ever towed a trailer, you know how the added weight affects your vehicle. Imagine if we took your car and tossed a Toyota Corolla on top. It would cause a host of problems.
The tires could not handle the weight. The engine would strain, the transmission, rear end, brakes, cooling, etc, etc, etc all need to be upgraded. It is simply not possible to Fed-Ex these guys a “Humvee Armor Kit in a Box” and tell them to have at it. If only engineering were that simple.
If you add 2000 pounds to the weight of a 3000 pound vehicle you then create a slow moving target that is very likely to break down when you need to move the fastest. The Army is, for obvious reasons, reluctant to make the guys over there to stop doing their own in field armor, but in the end, they many not be any safer. The vehicle will not move as fast, nor stop as fast.
A friend of mine is presently in Germany on his way home. He was in Iraq for 3 weeks when his “self armored” Humvee was in an accident because the driver could not stop the thing fast enough. One guy died and my friend will require multiple surgeries on his back and will never be the same. Did the weight of the retrofitted armor make the difference? I have no idea. But the incident serves to illustrate that you just can’t slap a bunch of metal on a Humvee and magically declare it armored. There is more to it than that. These guys may think they are making themselves safer but, paradoxically, they may be putting themselves, statistically, in greater danger.
The newest model of the Up Armored Humvee is the M1114. It has a bigger engine, better brakes, different transmission it even has a heaver chassis. (That’s main structural frame.) In a completely different machine than a non-armored HUMVEE. [and there I left it…]
(mini update: Jay points out my units of mass should be kilos and not pounds. The units are irrelevant, the math/physics still stays the same. )