Picatinny engineers get howitzers unstuck and back on TrAK

By Ms Audra Calloway (AMC)March 2, 2012

M777A2 on TrAK
1 / 3 Show Caption + Hide Caption – (Photo Credit: U.S. Army) VIEW ORIGINAL
Instruction on the TrAK
2 / 3 Show Caption + Hide Caption – M777A2 Chief Engineer Gaby Jarani explains how the wheels of the M777A2 get stuck in sand and rocks. The weight rests on the wheels, which dig into the sand and cannot move. In the background an engineer pumps the howitzer onto the TrAK system so tha... (Photo Credit: U.S. Army) VIEW ORIGINAL
Dislodging the M777 155mm howitzer
3 / 3 Show Caption + Hide Caption – Soldiers of the 172nd Infantry Brigade in Afghanistan work at dislodging their M-777 155mm howitzer from a three-foot deep hole it dug after firing several projectiles. The huge weapon weighs 9,800 pounds and can launch projectiles more than 30 kilom... (Photo Credit: U.S. Army) VIEW ORIGINAL

When Soldiers in Afghanistan move their M777A2 howitzers to adjust their aim, they can literally become "stuck in a rut" when the wheels get trapped in the sand and rocks.

To help alleviate this issue, engineers at Picatinny Arsenal have designed the Traverse Assist Kit (TrAK) to make the howitzer faster and easier to move.

The TrAK is an add-on system that provides M777A2 gun crews with the ability to rotate and pivot the gun 360 degrees in adverse terrain, explained Gabriel Jarani, M777A2 Chief Engineer for the Program Executive Officer for Ammunition's Joint Project Manager Towed Artillery Systems.

During M777A2 firing missions, the TrAK is expected to reduce time and fatigue for service members.

"About a year ago we got reports from the FOBs (Forward Operating Bases) in Afghanistan that Soldiers were having trouble traversing the howitzers," Jarani said.

"In normal ops, an artillery man tries to put his howitzer on reasonably stable ground--level and not too loose. But when you're in the FOBs, you don't really have much choice where you put your gun," he explained.

Often FOBs have artificial terrain, which means it is uneven and leveled by filling it with rocks that are soft and loose. So when the cannon is fired, the force jolts the cannon pushing the gun into the loose ground.


When cannoneers currently need to rotate the howitzer to reposition it for fire, a service member on each side of the howitzer will manually pump hydraulic lifts on both sides of the howitzer to raise the howitzer until the entire system rests on its two wheels.

Then, to rotate the howitzer, additional troops will grab the muzzle of the gun and push the howitzer to the correct position.

"The gun sits on the wheels and you literally turn the gun on its wheels," Jarani explained.

This is where the problems can begin.

"This is something they normally want to do in about three minutes. What they're finding in Afghanistan is that with all this rough soil it can take ten minutes, it can take 20 minutes."

The process is taking longer because the weight of the howitzer, which usually rests on the back end of the system, is being placed on the wheels. This additional weight is pushing the wheels further into the uneven ground.

"So all the weight is on the wheels, which sink into the ground. Now you have to push the howitzer out of a rut to move it."

Not only do troops have to push the 9,800-pound howitzer out of a rut, but when the howitzer shakes free, the force often pushes it too far.

"It doesn't move, it doesn't move and then when it finally moves, it gives all at once and the Soldiers don't really have control of it. It doesn't help to not have it move, and then it moves too much so they have to move it back."

To solve the problem, engineers designed the TrAK, essentially a deployable "Lazy Susan" between the two wheels that can be raised and lowered.

When Soldiers need to rotate the howitzer, troops position a base plate on a piston and then hydraulically lower the base plate to the ground so that all the weight sits on the TrAK instead of the wheels.

This lifts the wheels off the ground so they do not get stuck in the rocks.

"Now you pump the gun up, but instead of pushing the howitzer on the wheels, you spin it around on a pivot like a Lazy Susan," Jarani said.

"This is actually easier in my estimation as far as reducing strain on the crew. Keep in mind they might have to do this dozens of times in one day, and certainly fatigue is an issue," said Jarani.

The TrAK system was developed in-house at Picatinny by design engineers Jonathan King and David Lee from the Armament Research, Development and Engineering Center, with support from acquisition experts at the PEO Ammunition.

TrAK is scheduled for fielding in Afghanistan by October.

Related Links:

"PEO Ammo picks up 155mm Lightweight Howitzer program"

"Excalibur 155mm artillery round vignette" (video)

"Excalibur: Turning 'artillery cannon into a sniper rifle'"

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