The Long Endurance Multi-IntelligenceVehicle (LEMV) has been an elusive ISR goal for the Department of Defense through numerous false starts and half-completed contracts, but on August 7th at 6:49 pm EST a new LEMV hybrid blimp first took to the air at Lakehurst Navel air station in NJ.
The vehicle, longer than a football field, is based upon a design by Hybrid Air Vehicles, LTD, and developed by Northrop Grumman. Many new considerations have come into the design of this airship, but there are some old myths to be dispelled as well.
Spy Video of the Spy Blimp?
This is not actually an oxymoron — in military use, the blimp will be flown so high that it is unlikely to be easily noticed and can be outfitted for a minimal radar signature.
Isn’t There a Danger of it Exploding in a War-zone?
While the vehicle does presently carry fuel and use conventional engines, the lifting gas is inert Helium and not the flammable Hydrogen that was used in the Hindenburg that infamously met its demise in 1937 at the same Lakehurst Air Station in NJ.
The video in the Hindenburg link above mentions the difficulty that craft had in landing, which this design addresses. Some question the effect of bullets on an airship, but experience with the Goodyear blimp shows that they get many bullet-holes in the gas bags, but because the pressure is only slightly higher than atmospheric pressure (just enough to give it shape) and the volume is so great, the effect of the leaks is minimal.
How Does This Airship Get Its Lifting Power?
It is a common misconception that the airship is just “lighter than air” and, thus, floats (aerostatic lift). The classic cigar-shaped blimps and zeppelins only derive about 90% of their buoyancy from the lifting gas (hydrogen, helium, or hot air).
The balance is provided by forward movement (aerodynamic lift). This is the same benefit of attack angle that airplanes use as they fly through the air. The combination makes it possible to land the craft, but instability in winds is an issue. The new airship uses the lifting gas for only about 60% of its lift. You can notice in the video that the airship is angled up first and then moved forward as it rises in the air.
Other Stability Factors: “Vectored Thrust”
“Vectored thrust,” the ability to direct the thrust in more than one way, included in the design, allows the craft to be pushed vertically or, when properly outfitted, sucked to the ground like the reverse of a hovercraft. It is vectored thrust which allows the airship to first angle up before taking off in the above video. The total combination of lifting options make this vehicle a “hybrid” and causes it to be more stable in the air and for landings.
The skirts along the bottom of the craft can aid in holding the craft to the ground. The potential to suck the vehicle to the ground could reduce or, in some cases, eliminate the need for a ground crew. Here is the LEMV take off:
The Ground Crew
No complex vehicle operates independently. Maintenance, fueling, and, for most airships, landings and takeoffs require an infrastructure. One thing to notice in the video is the lack of a fixed mooring mast that was so common in the “heyday” of dirigibles.
It is generally a good idea to tie an aircraft down when it is not being used for flight, and this may be even more important for airships. So important was the mooring tower that when the height of the Empire State building was increased, incorporating a mast for dirigibles was cited as the reason (although impractical and never used for that purpose). Mobile mooring platforms were developed and this is what might be seen moving away from the craft in the above take off video. Eventually, little or no ground crew will be required to land the craft. Here is some of an all-important, but less glamorous, landing:
The Economical Airship
DOD efforts to strategically economize its use of petroleum have come under fire recently in Congress by oil-soaked politicians. The airship represents another element of that toolbox. Although there have been calls to use airships for cargo, and the craft could carry 7 tons up to 2400 miles at a top speed of 30 mph, it would take more than 3 days.
Fixed-wing aircraft use less fuel in flight. It is the takeoffs and landings that are most inefficient. Therefore, for long-distance cargo, fixed-wing seems to be the way to go. But for shorter cargo flights of up to 800 miles, airships can be very economical. They also will not require a prepared landing area.
But where the economics really show up for the LEMV is as a surveillance platform.
Intelligence, Surveillance, and Reconnaissance (ISR)
Although, for crossing civilian airspace, the vehicle must have a flight crew — for up to three weeks, the vehicle can act as a UAV and remain airborne with the operation controlled from the ground. It has been described as an “unblinking eye.” But at the right height, this “eye” commands not only a wide view with a huge radar antenna, but can incorporate imaging equipment usually relegated to spy satellites or many separate drone flights. The cost is conservatively estimated at 1/10th the price of alternative options. It also fills a special niche. It is not so easy to pull a satellite in for repairs or for an upgrade to the latest technology, and drones don’t stay up for more than about 12 hours.
An Intelligence Failure
Unfortunately, there is a risk to continued funding of cost saving measures like the LEMV. The potential for fuel savings is huge, but the project has been delayed by a lack of funding. Such cost-saving measures have ironically been attacked by the same Congressional members that advocate a balanced budget and have classically favored military spending. It seems that it is OK to save money as long as it is not oil money. No matter who wins the upcoming election, Congress continues to hold the purse strings, and oil lobbying efforts seem to control at least some members of Congress.
For further reading see also:
- civilian adaptations
- Northrop Grumman LEMV,
- Hybrid Air Vehicles, LTD,
- Previous Cleantechnica.com article
Photo Credit: Northrop Gruman