US CBO Gives OK to HULA Airships for Airlift
Imagine an aircraft that could lift 1-2 million pounds of cargo, then fly it up to 12,000 miles nonstop without needing a runway to land on. DARPA has. DID has too via our in-depth coverage of their WALRUS HULA (Hybrid Ultra Large Aircraft) airship program. Now a new congressional report is imagining it as well.
The WALRUS may be an airship, but isn’t exactly a traditional blimp. The Army Times reports that the Congressional Budget Office, a nonpartisan analytical arm of the US Congress, “likes the heavy-lift airship concept because it could do more than the airlift aircraft and surge sealift capabilities currently used when U.S. forces deploy.” DID went and found that report, which offers some interesting conclusions.
“Options for Strategic Military Transportation Systems” notes that developing and buying 15 WALRUS-class airships and operating them for 30 years would cost about $11 billion over 30 years, roughly as much as the 21 additional C-17s the USAF is seeking. The report then goes on to note that even at their lowest level of desired performance (500 tons capacity), this set of aircraft would be able to deliver 3 times as much cargo per day as 21 C-17s.
Figure 4-1 in particular illustrates the WALRUS’ niche (red line) between strategic airlift (blue line = C-17s) and strategic sealift. These options are then compared with options for increasing roll on/ roll off sealift capacity, increasing high speed sealift capacity (like the wave-piercing catamaran HSVs/TSVs that DID has covered), and prepositioning options. Indeed, the TSV option is the only one that approaches the WALRUS’ overall combination of lift and time performance, but the WALRUS offers one very large advantage that the TSV does not – direct delivery:
“In general, RSOI times [jk: Reception, Staging, Onward movement, and Integration] can be expected to range from a few days to more than a week depending on the distance from the debarkation point to the operations area and the quality of the local road or rail infrastructure in between… Among CBO’s options for improving strategic mobility, only the hybrid airships in Option 1B would have different implications for RSOI times than the transportation systems in the current force”
The report also notes two major caveats with respect to the WALRUS.
One is uncertainty, which affects the precision of its cost comparisons as well as the availability of alternatives. A C-17 purchase has a much lower risk factor, because its build and operating costs are known. The CBO acknowledges this, and notes that its cost projections for the 15 Walruses have a larger uncertainty variance.
Note, too, that even this acknowledgement assumes that the technical challenges inherent in the WALRUS’ design can in fact be overcome. The defense planners in the Pentagon have to factor that risk, and likely delivery/evaluation and certification time frames for a WALRUS option, against the known timing of the C-17 line’s shutdown when all currently contracted aircraft are delivered. Restarting a stalled or abandoned production line is slow and very expensive, as the New York Times report about the M1117 ASV armored vehicle saga (now stalled again due to Katrina) reminds us.
Complicating matters even further, DID has noted elsewhere that the current C-17 fleet is wearing out before its time due to the heavy demands currently being placed upon it. As one component of that use, many US armored vehicles are not routinely (or not at all) transportable by C-130, and go by C-17 instead; DefenseTech.org has noted that future vehicles aren’t likely to fare much better. The problem goes well beyond that, however, as StrategyPage explains:
“The C-17 entered service ten years ago, and those first few aircraft quickly compiled 3,000 flight hours supporting peacekeeping operations in Bosnia. Each C-17 has a useful life of 30,000 flight hours, but the current force is flying such long, and hard (landing on rough fields) flights that many of the early model C-17s will be worn out within five or so years. This attrition is accelerated by the fact that the early model C-17s are structurally different, and weaker, than the later model C-17s. The wing box in the center of the fuselage was insufficiently strong for the loads placed on it. This was corrected later in the production run, but those early planes are going to wear out faster than later model planes of the same flight hours.” (Hat Tip: Trent Telenko)
This information is not in the CBO’s report, and the net effect is that the C-17s’ 30-year maintenance costs are likely to be higher than the CBO forecast based on figures to date. It also means that the urgency of supplementing/ replacing current fleet aircraft, and keeping the C-17 production line open to give the USAF future options, rises.
Another important issue noted by the CBO is overflight:
“Overflight rights might be more difficult to obtain for airships because their passage would be much more apparent than that of a conventional aircraft. Consequently, nations willing to quietly allow high altitude overflights might be more reluctant to permit low, slow overflights by airships.”
Overflight can and will use international waters for substantial portions of its trips, of course, and in many cases it could use those avenues exclusively at a potential cost of lengthening travel time in some cases. To offer a current example, however, think of supplying US forces in Afghanistan. Jet aircraft traversing Pakistani airspace aren’t really noticed. Sustained, regular WALRUS overflights would be, which would carry political consequences there. Alternatively, they could traverse Russian and Central Asian airspace, which may prove safer but would be equally noticeable to those populations.
Dealing with such issues could therefore be expected to become an integral part of WALRUS-related CONOPS (Concepts of Operations).
DID will remain very interested in HULA concepts like the Walrus; like the CBO, we believe it’s an option with a lot of potential. It’s important to point out, however, that procurement decisions aren’t made in a vacuum and that other programs and considerations intrude.
This is, of course, precisely why the CBO report is worth reading. In addition to its insights about the WALRUS program et. al., it is highly recommended to anyone who wishes to begin to put themselves in the decision-makers’ shoes, and consider some of the macro-scale trade-offs and planning factors that weigh on long-term military procurement decisions.
Additional Readings & Sources
- DID – WALRUS-related anchor post with full background, description, and links
- See also all WALRUS related DID coverage, and all DID coverage related to blimps, HULAs, and LTAs in general.
- Congressional Budget Office (September 2005) – Options for Strategic Military Transportation Systems [PDF Format]