Lockheed Martin
Lockheed Martin’s ACV 1.1 prototype. Photo courtesy Lockheed Martin.
Personnel capacity: 3 crew, plus 11 embarked Marines (capability to increase to 13)
Speed: greater than 60 mph on land, 5 knots in water
Power: 711-horsepower Caterpillar C13 engine
Reserve buoyancy: 25 percent
Lockheed Martin’s ACV entrant is touted as a simple design that focuses on off-road missions while ensuring a robust swim capability for years to come.
Frank Bohlmann, director of ground vehicle weapon systems, told USNI News that the company has worked on the ACV and MPC programs for a combined eight years now and rolled all the user feedback received during that time into the current design.
“So everything from the large tires up through the double-wishbone suspension, which is a very similar suspension from what we’ve used before, very good offload, lots of clearance between the tires and the vehicle – the Marine Corps spends the bulk of their time off-road so we’ve designed the vehicle for that.”
ACV program manager Patrick Shepherd said that the Marines intend to operate the vehicles on roads 20 percent of the time and off-road 80 percent, so Lockheed Martin focused on off-road mobility and survivability. The frame can adjust its height to ride low to the ground for greater speed on paved roads or higher up for a smoother ride off-road, he said. And the tires can flatten when operating in an urban environment to avoid ripping up the local infrastructure.
Similar to the BAE Systems offering, Havoc has a raised interior floor that does not attach to the bottom of the vehicle for additional blast protection while operating on land.
For water operations, Lockheed Martin has added reserve buoyancy packs to the outside of the vehicle, giving 25 percent reserve buoyancy – which is more than the Marines required. Combined with a 711-horsepower Caterpillar C13 engine – the largest of the four competitors – and user-friendly independent thrusters in the water, the company is offering “plenty of power, plenty of reserve buoyancy, and we’ve got a suspension that can handle up to 25-percent weight growth, so we think we’ve got a very very capable vehicle” with plenty of room to accommodate future modifications, Bohlmann said.
In addition to room for future growth, Shepherd said another key feature is simplicity.
“To keep it relevant, we’ve actually kept it very simple. A lot of companies will make a very integrated digital display, touch screens – we’ve kind of gone to the other end where all the smarts is behind the scenes,” he said.
“The driver’s station is very simple, the maintenance is very simple, looking to make it so it’s just like you would work on a normal car. It drives like a normal car in land and water. We’re trying to keep it as simple as we can to keep from having high-maintenance requirements.”
SAIC
TERREX 2 completes swim test in Charleston, South Carolina. Photo courtesy SAIC.
Personnel capacity: 3 crew, plus 11 embarked Marines
Speed: 7 knots at sea
Power: 600-horsepower Caterpillar C9.3 engine
Reserve buoyancy: 23 percent
In contrast to the user-friendly simplicity Lockheed Martin aims for, SAIC designed its TERREX 2 vehicle to enhance operators’ situational awareness. The troop commander’s seat is back with the embarked Marines, and the commander’s station is equipped with a screen displaying day/night images from a front, rear, left and right camera outside the vehicle. The 11 embarked Marines can all see the troop commander’s screen, giving them an idea of what to expect when they exit the vehicle.
Additionally, the driver’s station features an array of screens – some of them redundant, in case one is damaged – with obstacle avoidance features, situational awareness sensor feeds and more.
SAIC and its partner ST Kinetics chose to emphasize ground operations, where the ACV will spend the bulk of its time, whereas other competitors highlighted their entrants’ launch and recovery and other sea-based capabilities, senior director Bernie Ellis told USNI News.
“It’s going to spend anywhere from two to five percent of its time in the water, so you have to design it to meet the minimum requirements in terms of safely operating in the sea,” Ellis said.
“There’s objective and threshold, so in terms of competition, you want to be as close to objective … as you can. But the majority of what you want to do is optimize and shoot towards land mobility, if you spend 98 percent of your time on the land. Having great water mobility for two percent of the time is not good. So land mobility is a primary driver. Force protection, that’s a big driver. Reliability is a big driver.”
Ellis said the vehicle has a V-over-V hull, which creates a crush zone to reduce the impact of a blast on the floor. Marines would put their feet on footrests attached to the seat across the aisle from them to keep their feet from absorbing any energy from an under-belly blast. This design – compared to the BAE Systems and Lockheed Martin design where the floor the troops walk on isn’t actually connected to the bottom of the vehicle and wouldn’t absorb any blast energy – means the troops cannot keep their feet on the ground during transit but also creates a more spacious interior while the Marines are entering and exiting and arranging their supplies.
General Dynamics
General Dynamics’ offering for ACV 1.1. USNI News photo.
The General Dynamics prototype features a roomy interior, much like the SAIC vehicle, with a lower floor to create more room and footrests to keep the Marines from blast energy.
Unlike SAIC, however, “we put a lot of emphasis on the water mobility aspect, so we have a lot of reserve buoyancy, a lot of growth for the Marines in the future,” ACV 1.1 program director Scott Stilson told USNI News. Compared to SAIC and BAE Systems’ hydraulic propulsion systems for the vehicle’s swim mode, General Dynamics went with a mechanical system – “so no hydraulics, no hydraulic leaks, and we’re very efficient at transferring energy back to the propellers.”
With a 600 horsepower engine, double-V hull design used on other ground vehicles and speeds at least equal to the legacy AAV, the General Dynamics ACV is “focused on performance, protection and payload,” Stilson said.
“I think the real distinguishing feature is really the balanced design. Being able to do everything really well, and the energy that it takes to come up with that design, to me that’s actually what separates us,” he said, attributing that success to both General Dynamics’ robust systems engineering teams as well as an eagerness to incorporate user feedback throughout all the MPC and ACV testing periods.
The company conducted extensive trade studies to find the right balance between weight, protection and performance; water and land capabilities; and other tradeoffs.
“This isn’t what GD wanted necessarily, we listened to the Marine and tried to incorporate that also into the trade studies so they have a vehicle that meets their needs,” he said.
The fifth competitor, Advanced Defense Vehicle Systems, did not bring its vehicle to Modern Day Marine.
