Automotive Technology Blog

Automotive Technology

The Automotive Technology Blog is the place for conversation and discussion about electrical/electronic components, materials, design & assembly, and powertrain systems. Here, you'll find everything from application ideas, to news and industry trends, to hot topics and cutting edge innovations.

Previous in Blog: Porsche’s Most Controversial Engineer   Next in Blog: NASCAR Tire Technology: Did Goodyear Overreact?
Close
Close
Close
6 comments

Building a Better Heavy Expanded Mobility Tactical Truck (HEMTT)

Posted March 08, 2008 12:01 AM by Steve Melito

This week, Defense Update reported that the U.S. Army plans to order more Heavy Expanded Mobility Tactical Trucks (HEMTT) from Oshkosh Corporation, the self-described maker of "the world's toughest specialty trucks". Although the company's HEMTT A2 is now in production, Oshkosh plans to provide the Army with its next-generation vehicle by July 2008. Powered by a 500-hp Caterpillar C-15 engine, the HEMTT A4 will provide 55-hp more than the original HEMTT, which debuted in 1985. The Army's newest business with Oshkosh adds $321 million (USD) to a contract which will cover a total production run of 1,745 HEMTT A4's.

Today, the Heavy Expanded Mobility Tactical Truck (HEMTT) forms the backbone of the U.S. Army's logistics fleet. According to Oshkosh Corporation, the HEMTT A4 will combine "a high degree of parts commonalities" with "significant advancement in power, maintenance and solider safety". In addition to its 500-hp Caterpillar C-15 engine, the HEMTT H4 features an Allison 4500 SP/5-speed automatic transmission that is rated for 600-hp and which provides 1750 torque (gross input). The steering is power-assisted and front-tandem, and the brakes use a drum-type, air-actuated S-Cam design. With a fuel capacity of 155 gallons, the HEMTT A4 can achieve a maximum speed of 62 mph and reach a cruising range of 300 miles.

The full-line of Oshkosh HEMTT A4 vehicles will include M977 and M985 cargo trucks, M978 fuel servicing trucks (tankers), M983 tractors, M983 light equipment transporters (LETs), M984 recovery trucks with cranes and winches (wreckers), and M985 guided missile transporters (GMTs). Within each vehicle, a driver and passenger will sit in an air conditioned cab with air-ride seats and 4-point seat belts. Soldier safety features include integrated attachments for armor, under-cab protection, and heavy-duty cab mounts. Built to withstand the rigors of the field, the 77,500-lb. HEMTT A4 will ride on eight rugged, R20 XZL tires from Michelin. These tubeless tires are compatible with central inflation systems (CIS) as well as bead locks and/or run-flat devices.

Resources:

http://www.defense-update.com/products/h/hemtt.htm

http://www.oshkoshcorporation.com/about/

http://www.oshkoshtruck.com/defense/products~a4~home.cfm

http://www.oshkoshtruck.com/pdf/Oshkosh_HEMTT_A4_brochure.pdf

http://www.militarytires.com/

Photo Credit: Defense Update

Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Active Contributor

Join Date: Feb 2008
Location: Texas
Posts: 11
#1

Re: Building a Better Heavy Expanded Mobility Tactical Truck (HEMTT)

03/10/2008 3:57 PM

Kool- As a former solider I have driven the various types of HEMTT a number of times, although mostly the wrecker. I remember when the Army first got these vehicles, and we were amazed at the capabilities of these vehicles. The biggest "brag" that was going around is that no one ever got one stuck. (The vehicle is rated to go thru 52" of water). Well as a recovery specialist i had seen many vehicles burried, but not one hemtt. Well while in Desert Storm I finally proved that one could be stuck! Although it did take alot of effort. I had to go thru the area a number of times locking up the brakes. Finally the ruts got so deep the vehicle high centerd and was unable to craw out. On a final note the vehicle is equipted with two winches, which dosen't do a whole lot of good in the middle of a desert with no trees to tie on to!!!!

Reply
Guru
United States - Member - New Member Technical Fields - Technical Writing - New Member Popular Science - Weaponology - Organizer Hobbies - Target Shooting - New Member Engineering Fields - Nuclear Engineering - New Member

Join Date: Mar 2005
Posts: 3464
Good Answers: 32
#2
In reply to #1

Re: Building a Better Heavy Expanded Mobility Tactical Truck (HEMTT)

03/10/2008 4:02 PM

Thanks for your comment, Rockstar. There's nothing like a good first-hand account of how a vehicle performs in the field. And welcome to CR4! Hope to see you around in more discussions. - Moose

Reply
Active Contributor

Join Date: Feb 2008
Location: Texas
Posts: 11
#3
In reply to #2

Re: Building a Better Heavy Expanded Mobility Tactical Truck (HEMTT)

03/10/2008 4:38 PM

Thanks Moose, and as far as how this vehicle preforms in the field- unbeleivable-

eight weel drive with interaxle differental locks....amazing vehicle i have literaly climed mountains in Germany, and sand dunes in the desert with this vehicle. The cab is suposed to be "air tight" so you can drive thru a cemicial area without having to put on your mask. Although we didn't really trust it. The seals around the doors could be damaged and allow agents into the cab. One minor setback of this vehicle,(on the tight roads in Germany anyway) it has a 120' turning radius. As far as power goes, it will pull just about anythig at top speeds and you can't even hardly feel it.

Reply
Anonymous Poster
#4
In reply to #1

Re: Building a Better Heavy Expanded Mobility Tactical Truck (HEMTT)

11/24/2008 5:48 PM

Great story...what about the armor? Do you guys have any idea who designed the armor LTAS kit? Ceradyne or Plasan one would assume...

Reply
Participant

Join Date: Oct 2009
Posts: 1
#5

Re: Building a Better Heavy Expanded Mobility Tactical Truck (HEMTT)

10/27/2009 5:33 PM

Anyone know who builds the A/C unit in the HEMTT A4 cab?

Thanks!!

Reply
Anonymous Poster
#6

Re: Building a Better Heavy Expanded Mobility Tactical Truck (HEMTT)

05/21/2010 8:25 AM

Trucks have their own unique importance in our daily life but usually we don't like to have a Trucks. But we all know that without Trucks we can't get many things of our daily use at time. Similarly digger derricks have their own importance for any kind of construction projects.

Reply
Reply to Blog Entry 6 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

Anonymous Poster (2); NSCAA Coach (1); Rockstar (2); Steve Melito (1)

Previous in Blog: Porsche’s Most Controversial Engineer   Next in Blog: NASCAR Tire Technology: Did Goodyear Overreact?

Advertisement