The Stryker Vehicles: Striking a Temporary Balance25 January 2008
The US Army is continually ramping up its Stryker brigade with the idea that smaller wars require smaller vehicles. Richard B Gasparre asks if this really is the best technology for the job.
Demonstrating that very little is truly new, the Stryker evolved from the light armoured vehicle (LAV), originally produced by General Motors Canada for the Canadian Army in the 1970s. The US Army actually considered using the LAV when the US decided to create the formal Rapid Deployment Force in 1979, but ultimately decided to stick with the tracked vehicles it had learned to trust in previous wars.
The Marine Corps, which is a lighter and more mobile service by policy and doctrine, bought the LAV and started deploying it in 1985 with their light armoured infantry battalions. The army, however, did not field a new vehicle design after the introduction of the M2 Bradley in 1981, as its mechanised units were optimised for fighting off a Soviet invasion of Western Europe.
After the end of the Cold War, the US Army gradually entered a period of increasing reflection and deepening debate regarding the nature of future land warfare.
The unexpected difficulty of operations in Somalia and the Balkans spurred this process, as did the acceleration of information technology applications.
Ultimately, these factors led the army, along with its sister services and the civilian defence community, to embrace the 'revolution in military affairs' paradigm (RMA) in the late 1990s.
In the context of this debate, General Eric Shinseki, the army chief of staff from 1999 to 2003, decided early in his tenure that the army's force structure was too bifurcated for the challenges of the post-Cold-War era. Armoured and mechanised infantry units were too heavy, both literally and figuratively, for rapid deployment and strategic flexibility. Conversely, light units such as airborne divisions lacked the firepower and sustainability for the increasing challenges posed by emerging-world militaries.
To operate in a strategic environment of multiple, unpredictable hotspots of varying threat intensity, strategists decided that the army's organisational structure had to change from a fewer number of large divisions to a larger number of smaller brigades.
Thus was born the concept of the 'interim brigade combat team', the nucleus of the 21st century army. Significantly, the brigade-centric mandate predated specific equipment programmes; in other words, the IBCT was an organisation in search of a vehicle, not the other way around.
On the technological front, consistent with the transformation paradigm, Shinseki believed that the ultimate answer to the 'high / low mix' problem was to harness the RMA to the army's advantage. The envisioned force (now known as Future Combat Systems) was unabashedly revolutionary, but at the turn of the century, the vision exceeded the available technology.
Consequently, Shinseki championed an interim solution featuring enhancements to vehicles then in current production. The LAV was the natural candidate for the baseline platform – after all, the Marine Corps was in some ways what the army wanted to become.
THE WEIGHT ISSUE
The original IBCT concept called for the army to be able to deploy a brigade anywhere in the world within 96 hours. In support of this goal, the brigade's vehicles were supposed to be transportable by C-130, the USAF's primary crude-runway cargo carrier, to a range of 1,000 miles. A subsequent goal required the vehicles to be small enough so that three could fit on board a C-17, the successor to the C-130, at one time.
The Stryker family was clearly going to be lighter than the M1 Abrams tank and M2 Bradley infantry (or cavalry) fighting vehicles.
The Abrams, which weighed around 62t in its first incarnation, had grown to almost 70t in the M1A2 SEP version. The Bradley weighs 25t unloaded and 33.5t loaded, partly because it mounts a 25mm cannon and TOW, and partly because it is both tracked and more heavily armoured.
However, the Stryker family weighed more than the existing M113 armoured personnel carrier family, the pre-existing tracked alternative built by United Defense Industries (formerly FMC, and subsequently acquired by BAE).
The M113, which first entered service in 1961, represented a watershed for infantry mobility in its time, and is in fact still operational today. With a dry weight of about 11.5t, the M113 is significantly lighter than the Stryker. Nevertheless, the army's Source Selection Authority picked the Stryker design over the M113 and other alternatives in a 1999-2000 competition that engendered much acrimony.
So did the Stryker ultimately meet the IBCT mobility goals? The answer is yes and no, depending on how strict you want to be – but the answer itself may not matter that much.
SUCCESS OR SHORTCOMINGS?
After the Stryker became operational, the General Accounting Office (GAO) reviewed the unit's mobility performance under audited conditions in 2003. Not surprisingly, deployments of Stryker brigades required half as many C-17 flights as did similar movements of heavy brigades. By and large, though, the Stryker brigades did not quite live up to expectations:
- Stryker brigades still required five days to deploy by air under the best of circumstances, and needed 14 days in some cases. The maximum time has probably been reduced since then, but the minimum time seems to be a hard constraint.
- Even under optimal conditions, the 'H' version of the C-130 could fly a Stryker vehicle only 850 miles. Moreover, Stryker transportability was contingent on several factors, including the need to partially strip the vehicle to fit it in the cargo bay. However, the C-17 can transport three to four vehicles, depending on configuration and load.
However, these shortcomings are not the sole or even primary fault of the Stryker vehicle as such. To begin with, Strykers do not comprise all the vehicles in an IBCT brigade. Some of the other vehicles, such as fuel trucks, exceed the C-130's payload, which means that the brigade would require heavier-lift transports in any event.
Moreover, some critics of defence spending priorities infer from the shortfalls that the USAF needs more strategic transport; replacing all C-130s with C-17s would enable Stryker brigades to surpass the deployment requirements.
However, aircraft are much more expensive than vehicles: the current flyaway cost of one C-17 is roughly $275m, which would buy over 70 Stryker vehicles at 2006 costs of roughly $3.75m each. Unfortunately for logistics planners, budgeting for each service almost never explicitly incorporates such tradeoffs.
Even more fundamentally, the need for, and practicability of, such rapid deployment is open to question. If nothing else, the political and strategic commitments to enable such deployments require weeks if not months to build. Moreover, most situations that would warrant the large-scale insertion of ground troops would not allow the removal of those troops on short notice. In a perfect world, war planners want 'easy come, easy go', but in real life, combat deployments tend to be 'hard in, hard out'.
TRACKS VS WHEELS
Because it was effectively the incumbent armoured vehicle, the tracked M113 platform was the Stryker's primary competitor. The tracks-vs-wheels (TVW) debate is almost as old as the mechanised military vehicle itself, and can get as strident as doctrinal debates over religion.
In fact, UDI formally protested the SSA's decision, asserting that the competition was biased in favour of the wheeled entrants in general and the LAV in particular. As dispute arbitrator, the GAO was sympathetic to some of UDI's complaints, but ultimately rejected its protest.
To simplify greatly, the TVW debate is just another manifestation of the generalist-versus-specialist tradeoff. Tracks play the generalist role because they provide vehicles with better terrain versatility, tactical manoeuvrability, and overload capacity than wheels do.
Conversely, wheels are on-road specialists because they put less wear and tear on roads and vice versa.
The former is important in nation-building situations where infrastructure development is an important tool in winning hearts and minds; the latter means that wheeled vehicles have better fuel efficiency and mid-range theatre mobility than tracked vehicles (which often require wheeled transporters to get to battlefields).
The sound-bite version of this issue, however, glosses over a number of complicating factors. To begin with, some purported advantages simply don't exist. For example, tracked APCs can travel as fast as Strykers; conversely, wheeled vehicles can be amphibious if equipped with water jets.
Furthermore, the utility of many design differences depends on the situation. For instance, low-slung tracked frames are more stable but also more vulnerable to mines. Similarly, tracks are more difficult to damage than tires, but a damaged track (unlike a shot-up wheel) immobilises a vehicle.
However, design enhancement trends seem to be helping wheels more. Stryker crews can change tire pressure from inside the vehicle, thus increasing terrain versatility without exposure. (In the future, all-wheel drive and steering, especially if columns or axles are independent, could give wheels the pivoting capability of tracks, and more.) On the other hand, banded tracks combining steel and rubber tend to give up the advantages of all-steel tread even as they gain some of the abilities of tires.
The most important design issue, though, derives from the emphasis RMA places on lowering battlefield visibility: wheels are quieter. This might seem insignificant given the noise conventional diesels make, but it will become more meaningful as the Army adopts hybrid diesel-electric or battery-dominant engines.
Ultimately, however, the key issue is not design, but the battlefield version of supply and demand. Tracks may be better off road, but to the extent that war becomes urbanised, or nations build more roads, wheeled vehicles become more useful. This was especially true for the Army in 2000 because it had no wheeled combat vehicles (the Humvee is not technically a combat vehicle, even when armoured). Diversification is most important at zero, not at the margin.
Much has been made of the Stryker family's modularity, in which a common design supports multiple configurations. Chassis commonality, however, is not a new idea. The army backed into the idea with the M113, which was originally designed as an APC.
When the concept proved highly valuable, the army developed a number of variants. Indeed, the USAF has modified the C-130 in the same way (e.g. the AC-130 gunship), and recent combat aircraft designs, such as the F/A-18 and the F-35 JSF project, follow this principle.
The Stryker family comprises two main variants: the M1128 MGS (mobile gun system) with a 105mm tank cannon; and the M1126 ICV (infantry carrier vehicle), the baseline APC.
The ICV has eight additional configurations:
- M1127 RV – reconnaissance vehicle
- M1135 NBCRV – nuclear / biological / chemical reconnaissance vehicle
- M1129 MC – mortar carrier
- M1130 CV – commander's vehicle
- M1131 FSV – fire support vehicle
- M1132 ESV – engineer support vehicle
- M1133 MEV – medical evacuation vehicle
- M1134 ATGM – anti-tank guided missile
Not surprisingly, the manned ground vehicle family, which is integral to the FCS concept, features the same paradigm of several vehicles built around a common power suite, if not a standardised full platform.
Many of the planned MGV configurations are directly comparable to the Stryker line. In fact, the MGV's most radical departure from the Stryker line-up is the non-line-of-sight cannon, a 155mm howitzer that will provide long-range indirect fire; in contrast, the Stryker's mobile gun system is essentially a flat-trajectory line-of-sight weapon.
Probably the most ironic development in the Stryker saga is that the front-line operators of the equipment have been far more complimentary than the civilian critics. Usually, operational complaints about systems bubble up from the bottom, but soldiers and officers in Iraq have praised the Stryker's mobility and even survivability in the face of mines and RPGs.
Naturally, a number of caveats are in order here: The Stryker brigades were first deployed to the Middle East in late 2003, and therefore missed the actual conventional war. This makes comparisons with the heavy mech divisions, and even the M113, incomplete.
The Stryker brigades were formerly non-mechanised infantry units built around trucks and Humvees. Naturally, the Stryker looks good compared to non-combat vehicles, but this is not the relevant choice. Many of the innovations that have enhanced Stryker performance, such as RPG-defeating cage armour, would have benefited alternative designs equally. By the same token, if a Stryker requires a 3.5t armour add-on to be survivable, then its effective weight is 22t, not 19t.
Finally, soldiers ultimately judge vehicles in the real world, not in a lab where ceteris paribus conditions can be enforced. Changes in strategy, tactical learning, enemy initiatives, and many other non-Stryker developments can impact Stryker performance for better or worse. Unlike on the test track, what counts is not always what you have, but what you do with what you have. After all, the French actually had more tanks than Germany in 1940.