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Posted

Uh, we got the newest drones and the latest in ABC weaponry, rocket guide systems that can spot the fleas on a dog in Afghanistan, but what on earth is a brake proportioning valve?

Posted

Does anyone know what they were testing for? Was it the skid ? Or the sudden evacuation of the rear end ?

That thing sounded like it was screaming to get to that speed, didn't the government have a problem with cheap Chinese parts a wile back failing on military stuff ?

Posted (edited)

Pretty good illustration why designing something in CAD (which this surely was) doesn't work all that well if the designer forgets to use the right load-multiplier for the application (whatever holds the rear suspension in place in this case), or if the fabrication team are a little lax welding, checking the welding, etc., or if the assembly team pull the wrong hardware off the shelf......

Somebody made a pretty basic error here to have such a total failure, and there's really no excuse for it. None. Zero. Period.

But I think everyone involved should get a trophy for trying.....

....and as long as we have vehicles like this that self-destruct, think of how much the bad guys will save on IEDs.

Edited by Ace-Garageguy
Posted

Pretty good illustration why designing something in CAD (which this surely was) doesn't work all that well if the designer forgets to use the right load-multiplier for the application (whatever holds the rear suspension in place in this case), or if the fabrication team are a little lax welding, checking the welding, etc., or if the assembly team pull the wrong hardware off the shelf......

Somebody made a pretty basic error here to have such a total failure, and there's really no excuse for it. None. Zero. Period.

But I think everyone involved should get a trophy for trying.....

....and as long as we have vehicles like this that self-destruct, think of how much the bad guys will save on IEDs.

First and foremost, the rear wheels should under no circumstances whatsoever lock up before the front ones do. They made a capital error in brake dimensioning. This is roughly the automotive equivalent of putting the wings on upside down on an airplane.

Posted

First and foremost, the rear wheels should under no circumstances whatsoever lock up before the front ones do. They made a capital error in brake dimensioning. This is roughly the automotive equivalent of putting the wings on upside down on an airplane.

I beg to differ. First and foremost, the vehicle's structure and mounting points for the suspension shouldn't fail no matter WHAT kind of brake-proportioning deficiency may occur in service. This is equivalent to stressing an aircraft structure for only 2 gees when it's known it will see 7 gees in operation. First things first.

The PRIMARY system of ANY vehicle...car, tank, boat, truck or aircraft...is the STRUCTURE that holds it all together. The brake system is a secondary system. The primary system should be able to cope with any failure of a secondary system.

Even if the brake-proportioning had been correct, achieved by valving that reduces hydraulic pressure to the rear brakes as weight transfers towards the front under deceleration (which is common, or a processor-controlled analog), there is the potential for the proportioning valve to fail in service, especially in a hostile, combat environment. The vehicle's structural integrity should NOT be compromised by any mechanical failure.

Posted

That was always on my mind as I stepped out of the aircraft into the blue.

:huh:

G

Did you at least have a chute? Because all I had was a rope that dangled out of a chopper!

On topic now, that is very sad maybe they should put a manual proportioning valve in there!

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