Army testing new Joint Light Tactical Vehicles (JLTVs)

ARLINGTON, Va.:  The U.S. Army and Marine Corps are using the newly built government prototypes of the Joint Light Tactical Vehicle to refine program requirements through rigorous ballistic, performance and reliability testing.
It's all part of an effort to field a next-generation tactical vehicle that can hit speeds of 70mph, withstand roadside bombs and other threats, drive through off-road terrain and fly through the air beneath a CH-47 Chinook or CH-53 helicopter, service officials said.
"The whole purpose of this TD (technology development) phase is toget the requirements right," said Brett Johnson, JLTV chief engineer.

The three contractor teams for the current 27-month technologydevelopment phase -- BAE-Navistar, Lockheed-BAE and General TacticalVehicles -- each delivered seven prototype vehicles engineered to reach an unprecedented blend of performance, payload and protection.
Following a Milestone C production decision in 2013, the Army plans to buy 55,000 JLTVs and the Marines plan to buy 5,500. Full production is slated for 2015.
"The JLTV Program is implementing the competitive prototyping policy forthe Army. What we have in this technology development phase is threecontractor teams to help us inform our requirements," said Lt. Col.Wolfgang Peterman, JLTV product manager. "As we get results from the testing, we will feed that back into our requirements."
The Army-led program will put the vehicles through blast, mobility and performance testing at AberdeenProving Ground, Md., and reliability testing at Yuma Proving Ground,Ariz., as part of an effort to refine the requirements for the nextphase of the competition, the Engineering and ManufacturingDevelopment, or EMD phase.
Ballistic hulls and armor coupons have already been tested; now thevehicles will undergo additional survivability testing against avariety of known and anticipated threats, program officials said.
A formal request for proposal for the EMD phase is slated for June2011, to be followed by contract awards in December of 2011, Petermansaid.
"When we go to EMD phase, it will be a full and open competitionagain. Our plan is to award two contracts for the EMD phase," he said.
The testing during the TD phase is aimed at lowering risk andproduction costs by finding and solving challenges which may ariseearlier in the developmental process.
"We're developing prototypes and requirements for the next phase sothat when we enter the next phase we will have a low-risk program,"said Dean Johnson, Marine Corps deputy program manager, JLTV.
The vehicles are built with 85-percent common parts. For example,all of the JLTV variants are built with a 2500 series Allison 6-speedautomatic transmission.
There are three different variants or categories of JLTV:
  • Category A is a four-person general purpose vehicle with a curbweight of 13,000 pounds and the ability to carry 3,500 pounds ofpayload and 3,500 pounds of add-on armor.
  • Category B is six-person infantry carrier with a curb weight of15,000 pounds. It is able to add 4,500 pounds of payload and 4,000pounds of armor.
  • Category C vehicle is a two passenger utility vehicle with a short cab/open bed for hauling equipmentor putting on shelters. Category C has a curb weight of 15,000 poundscan carry 5,100 pounds of payload with crew, fuel, gear and a fullcompliment of armor.
In addition, the Army and Marine Corps are preparing to acceptdelivery of a new Enhanced Protection Variant of the JLTV, which is amodified Category A vehicle designed with additional protections. Eachof the vendors will deliver an Enhanced Protection Variant in the nextseveral months, program officials said.
Engineering Challenge
The JLTV is engineeredto push the envelope of technological possibility and build a lighttactical, mobile vehicle which has the ability to thwart IEDs and otherkinds of attacks.
"The basic challenge that we faced was trying to create a totalintegrated prototype, not so much a particular challenge with asubsystem but rather putting all the systems together and still meetingour full payload, full protection and full performance envelope," saidBrett Johnson.
The vehicles are built with variable ride height suspension designedto give the chassis the ability to raise and lower off the grounddepending on road conditions. The suspension can raise and lower thevehicles from five inches off the ground to fit on some of the MarineCorps ships all the way up to up to 22 inches off the ground formaximum protection from under blast attacks and IEDs, Brett Johnsonsaid.
"Two of the vendors chose an air-bag style suspension to raise andlower the vehicle which you see on commercial tucks. The third onechose a hydropnuematic strut with a compressible fluid to raise and lower the vehicle," he said.
Each one of the prototype vehicles has four-wheel independentsuspension which uses a double-wishbone racecar-like suspension -- twowishbone-shaped structures that work to keep the vehicle's wheels in aperpendicular position to the ground, Brett Johnson said.
Also, all the vendors employed a central tire inflation system whichis an on-the-fly system that can regulate tire pressure; the system canadjust tire pressure from higher pressures for higher speed conditionson flatter roads to much lower pressures in soft soil such as sand ormud, said Brett Johnson.
Instead of having a belt-driven alternator, the vehicles are builtwith an integrated generating system that is sandwiched between theengine and transmission.
"A flat alternator is more efficient. These are very efficient machines for generating power, much more than a belt-driven machine," said Brett Johnson.
The JLTV has a requirement to generate 30 kilowatts of exportable power -- to include 10 kilowatts of on-board 28-volt DC power.
"There's a point at which alternators reach their maximum. We haveas big as 500 amp alternators out there; the problem is they take a lotof RPMs in the engine to keep the speed high enough on a belt-drivensystem to get the power out of them. Once you get past about 1500 RPMs-- you are racing the engine. These systems can generate steady streamof three to four times as much power at 1300 RPMs," said Brett Johnson.
There is a requirement for a general range of 400 miles in thisphase, but that will likely lower to 325 after looking at how much fuelthe vehicles can carry, he said.
International Efforts
The U.S. and Australia have entered into a Land Force CapabilityModernization Project Arrangement for the TD phase of the JLTV,effective as of January of last year.
The Australian vehicles will feature right-hand operation, but thevehicles will maintain 90-percent commonality with the left-handedprototypes. In addition, the Australian vehicles will not exceed a 20kg weight difference. Australia has contributed $30 million to the JLTVeffort.
"We want transportability and reliability as well. We decided to invest in theU.S. program because their program meets a lot of our requirements. Weare fighting the same fight and facing the same threats that the U.S.Army faces," said Australian Army Lt. Col. Robin Peterson, JLTV programmanager.
The U.S.-Australian collaboration is aimed at reducing risk,lowering costs and enhancing testing and simulation for both countries.

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