PDA

View Full Version : lol... Force Protection Vehicle 60 MPH Brake Test


Ring
10-01-12, 20:02
http://www.liveleak.com/view?i=228_1348353185
An Undocumented Worker
10-01-12, 20:13
Houston, we seem to be experiencing technical difficulties.
a0cake
10-01-12, 20:16
It's called a JERRV / Cougar type MRAP in case anyone was wondering. Sometimes they randomly catch on fire due to electrical problems. When the halon system goes off (either randomly or due to a fire), it really screws your day up. Also, if you're riding in the very back toward the rear door, any and all bumps, no matter how small, will introduce the top of your head to the roof, so wearing a harness is absolutely necessary. It's all worth it though -- they've been known to survive 500 pound IED's.
Alex V
10-01-12, 20:46
Axle hop much?

When racing Corvettes and the new GTO's we know to get off the throttle as soon as you experience axle hop to prevent a broken rear. Clearly those guys did not get the memo.

Anti-lock breaks or propped break pedal modulation would have helped.
Suwannee Tim
10-02-12, 08:03
Back to Ye Ole Drawing Board.
Zhurdan
10-02-12, 08:24
Loooow Riiii-derr.
Business_Casual
10-02-12, 08:45
Anti-lock breaks or propped break pedal modulation would have helped.

Was just wondering myself how ABS works on those big rigs - is it the same or are trucks different? :confused:
ICANHITHIMMAN
10-02-12, 08:51
Wow and to think all I had was a hummer the axle never fell of. aOcake thanks for the heads up what a POS!
pilotguyo540
10-02-12, 12:00
Was just wondering myself how ABS works on those big rigs - is it the same or are trucks different? :confused:
It works basically the same but it only pulses 2-3 times a second, vs about 40 (if i remember right) in cars. The compressed air system for the brakes is less responsive than the hydraulic systems.
SomeOtherGuy
10-02-12, 12:07
Don't worry, that'll buff out.
VooDoo6Actual
10-02-12, 12:21
Wheelhop as exhibited in video is always a inherrant problem w/ coil suspension vehicles.

You can see the driveshaft/universal joint struggle w/ the kinetics etc. in the video until it finally succumbs & can see the driveshaft disarticulate from transfer housing etc.

Torsion/ladder/sway-bars/stiffer lower control arms will most likely be the final cure for those suspected inherrant problems. Cougars/Buffalos etc. generally have the same suspension problems & issues.
An Undocumented Worker
10-02-12, 18:16
From what I understand they were doing a test of the parking brake in an emergency stop. From the description the parking brake is on the driveshaft, and can't be modulated. The other rumor is that the rear axle assembly is supposed to seperate from the chasis during an explosion, so that may explain some of it.


It still looks bad though.
pilotguyo540
10-02-12, 18:55
From what I understand they were doing a test of the parking brake in an emergency stop. From the description the parking brake is on the driveshaft, and can't be modulated. The other rumor is that the rear axle assembly is supposed to seperate from the chasis during an explosion, so that may explain some of it.


It still looks bad though.

Looks like you were right. If you watch the video again, the front wheels just spin and appear in no way to be helping with breaking. The driveshaft is pushed beyond its limits and turns into a jump rope. It finally gives out and becomes a pole vault. This is exactly why tests are performed.
GTifosi
10-02-12, 19:20
From the description the parking brake is on the driveshaft, and can't be modulated
Sure it can: don't take it to full lock and don't let any latch engage to keep it there.
Pulse it or slow steady pull, but don't just reef it and hang on for dear life.

Works on a fully loaded M929 dump truck and a fully loaded HEMTT, so should work on that too I imagine.
CarlosDJackal
10-02-12, 20:44
I don't see what the big deal is. The brakes worked, didnt it? :D
High Tower
10-02-12, 21:43
We used those quite a bit in '09. I liked them. We didn't have much in the way of problems with them that wasn't user induced anyway. The AC always worked. The RG-33 is nicer, but its a bit too big for some roads/gates.