Lockheed Martin's Secretly Built Airship Makes First Flight  
By Michael A. Dornheim  
02/05/2006 09:06:00 PM



SKUNKS WORKING

Lockheed Martin Advanced Development Projects is making perhaps the first realistic tests of a hybrid airship--a concept that dates back many decades but that is just now being tried at a significant scale.

The Skunk Works had secretly built the craft and hoped for a quiet first flight at its Palmdale, Calif., facility, but a few passers-by noticed the strange object in the sky.

The Defense Dept. is showing interest in two categories of airships--those that can carry large cargo at low altitude, exemplified by the Defense Advanced Research Projects Agency (Darpa) Walrus program, and those that can operate in high-altitude low-wind conditions and remain on station for long periods of time. The configuration of the Skunks Works ship indicates it is the former--a hybrid heavy-load carrier.

The interest is across the services and the notional applications are diverse, ranging from logistics--delivery of an integrated fighting unit within theater, for example--to sensor, communications and even laser-weapon relay platforms.

But airships aren't there yet. Major unresolved issues could derail the airship dream, such as their traditional delicate ground handling, and possibly prohibitive economics and vulnerability. These issues have been debated endlessly on paper, and now Lockheed Martin, a prime airship proponent, is investing to seek real answers.

A hybrid airship derives most of its lift by being filled with a lighter-than-air gas such as helium. Overall, it is heavier than air and gains the final 20% or so of lift by flying like an aircraft, but with slow takeoff and landing speeds that allow operations from short unprepared strips.

The Skunk Works made the first flight of its "P-791" testbed on Jan. 31 at its facility on the Palmdale Air Force Plant 42 airport. The manned flight was about a 5-min. circuit around the airport in the morning and appeared to be successful. The company did not announce or want to discuss the flight.

The P-791 is not part of a government contract, but rather an independent research and development project by the Skunk Works to better understand airship capabilities and technologies, such as materials, a company official says. However, it may also be a quarter-scale prototype of a heavy-lifter.

TO GAIN MORE SPAN TO ACT LIKE a wing, the P-791 is three pressurized lobes joined together. An observer of the first flight says it was about the size of three Fuji blimps blended together. The Fuji blimp, a Skyship 600 model, is 206 ft. long. That suggests the P-791 would have a gross lift of roughly 3-5 tons.

The observer saw the craft performing very tight 360-deg. turns while taxiing. It made a brief takeoff roll, climbed to a low altitude, made a few banks--including a long sweeping turn--then came back and landed. The landing approach had a nose-down body attitude that levelled for the flare. The flight was very smooth, the observer says. The craft was flown by P-791 Chief Test Pilot Eric P. Hansen.

The speed of the testbed was estimated at about 20 kt. A full-scale version would be able to go much faster, over 100 kt. Lockheed Martin has long proposed a large transport airship, at one time called the Aerocraft, which was halted around 2000 (AW&ST Feb. 22, 1999, p. 26). That design was about 800 ft. long and was to carry 1-1.2 million lb. at 125 kt. The Skunk Works was one of two contractors to receive one-year, $3-million Darpa contracts in August 2005 to study Walrus. The second Walrus phase would be a three-year demonstration effort.

Hybrid airships have a long history. The Aereon Corp. in New Jersey started experiments in the late 1950s, but they were small scale (see www.aereoncorp.com). The company tested the "deltoid aerobody" shape, also called a deltoid pumpkinseed, with a 1,200-lb. manned demonstrator in 1970-71. That was followed by several studies funded by the military at less than $1 million. In the U.K., the Advanced Technologies Group built a 40-ft.-long unmanned SkyKitten hybrid airship and flew it in 2000 (AW&ST Sept. 23, 2002, p. 30). Nothing in the field has progressed to the size or apparent sophistication of the Skunk Works testbed.

The P-791 uses four air cushions as landing gear, located on the outer lobes. Taxiing the vehicle could be like flying a hovercraft, except one with greater exposure to winds. An advantage of the air cushions is they could be reversed to suck the aircraft onto the ground to resist winds for cargo operations. Air pressure may also be the best way to spread landing loads into the inflatable structure. It's not clear if there are any devices, such as wheels, to keep the airship from sliding sideways when taxiing in crosswinds. The craft has a special towing system.

GROUND HANDLING IS A MAJOR ISSUE facing hybrid airships. Conventional lighter-than-air craft require large ground crews and, because they are especially sensitive to winds on the ground, the airstrip is an area ripe for accidents. Hybrids are only slightly heavier than air, and a hybrid must show large improvements in ground handling over a standard blimp to be successful. The P-791's current limits are to remain in the hangar if winds are above 5 kt., and there is a 10-kt. limit for taxiing and flight. That could restrict its flight test in windy Palmdale. It's not clear how the pilot was performing the balletic spins on his taxi-out--whether purely with vectored thrust, or by spinning around one sucked-down air cushion, or other means.

The P-791 appears to have four propellers--two at the tail and two on the sides. The tail units appear to be able to pivot for yaw vectoring, and it's unclear if the ones on the sides can move. One knowledgeable individual says there are four vectored propulsors used for ground handling, but it's not clear if these are the main propellers, or separate units perhaps connected with the air cushion system. The rings around the motors may be shrouds for the propellers and/or gimbal rings for vectoring. Vectored thrust can be useful for lighter-than-air blimps, which lose conventional control authority as they approach zero airspeed while landing, but a hybrid airship lands with some airspeed that may keep the tail control surfaces effective. But for control during low-speed air cushion taxiing, vectoring would seem essential.

The P-791 appears similar to the proposed full-scale version of the British SkyKitten, called the SkyCat. They have similar overall shapes--though the Skunk Works design is wider--and similar propulsion layouts, and both use air cushion landing gear. Perhaps the two programs have people in common.

One of the partner names on the side is TCOM, which makes aerostats and envelopes for airships.

"Hybrid airships have been the subject of studies and questions for half a century," one expert says. "Now it stops being hype and they will meet reality."

Aviation Week & Space Technology  

lockheed has been clocking some serious hours over the past ten years, and they come out with a giant helium balloon? I call bullshit.

I hear they use some advanced new technology (possibly in origin) that makes them lighter than air!

Quoted: lockheed has been clocking some serious hours over the past ten years, and they come out with a giant helium balloon? I call bullshit.

+1 it is a cover for their flying saucer program. looks like sombody already beat me to it.

Quoted: lockheed has been clocking some serious hours over the past ten years, and they come out with a giant helium balloon? I call bullshit.

DARPA was funding a idea of a monster-airship, able to carry something like a million pounds. This version is a mini proto-type. Imagine how much faster this would be to move men and material versus by ship.

those that can operate in high-altitude low-wind conditions and remain on station for long periods of time

I worked on this a little when I was at NORAD.  Lots of interest in these things--they can carry lots of payload for several months.  Imagine one of these with Predator-type sensors, watching the border areas in AZ or NM.  We were looking at them for look-down radar around the borders, to spot air-defense threats.  Or, you could put a comms relay suite on board, and fly it over your side of a battlefield, to provide stationary overhead comms links to your forces.  Imagine never having to worry about line-of-sight again!

Quoted: those that can operate in high-altitude low-wind conditions and remain on station for long periods of time I worked on this a little when I was at NORAD.  Lots of interest in these things--they can carry lots of payload for several months.  Imagine one of these with Predator-type sensors, watching the border areas in AZ or NM.  We were looking at them for look-down radar around the borders, to spot air-defense threats.  Or, you could put a comms relay suite on board, and fly it over your side of a battlefield, to provide stationary overhead comms links to your forces.  Imagine never having to worry about line-of-sight again!

Good point, cheaper that satellites, makes these stratellites. I'm not sure if this was an offshoot of the Walrus program or not.

Quoted: lockheed has been clocking some serious hours over the past ten years, and they come out with a giant helium balloon? I call bullshit.

A giant helium balloon that if it becomes full size and gets funded will carry a shitload of equipment and troops just about anywhere.

It would change much of the heavy airlift world.

Quoted: those that can operate in high-altitude low-wind conditions and remain on station for long periods of time I worked on this a little when I was at NORAD.  Lots of interest in these things--they can carry lots of payload for several months.  Imagine one of these with Predator-type sensors, watching the border areas in AZ or NM.  We were looking at them for look-down radar around the borders, to spot air-defense threats.  Or, you could put a comms relay suite on board, and fly it over your side of a battlefield, to provide stationary overhead comms links to your forces.  Imagine never having to worry about line-of-sight again!

You mean like these?  

www.fas.org/nuke/guide/usa/airdef/tars.htm

I know, you meant untethered, but it really doesn't matter for staionary wide area surveillance, does it?  I think the lock-mart blimp is pretty cool, a million pound heavy hauler that cruises at 120 knots would fully kick ass.  It would be great for hauling tanks and bradleys around, one at a time in my C-17s makes for one heck of a slow airlift.  

and even laser-weapon relay platforms.

imagine a platform flying circles around a hot zone for a month or more turning BG's into burn victims!  All the while acting as a communications relay and able to drop logistics support.  It is like the Submarine of the sky.

actually imagine a full size one of those things as the first stage for a true 'no kidding' two stage to orbit reusable launch vehicle. Carries a 1.5 million pound orbiter to 100,000 feet drops it, and it accends the rest of the way to orbit. That's a pretty slick answer to the problem of building and RLV.

Quoted: Quoted: those that can operate in high-altitude low-wind conditions and remain on station for long periods of time I worked on this a little when I was at NORAD.  Lots of interest in these things--they can carry lots of payload for several months.  Imagine one of these with Predator-type sensors, watching the border areas in AZ or NM.  We were looking at them for look-down radar around the borders, to spot air-defense threats.  Or, you could put a comms relay suite on board, and fly it over your side of a battlefield, to provide stationary overhead comms links to your forces.  Imagine never having to worry about line-of-sight again! You mean like these?  www.fas.org/nuke/guide/usa/airdef/seek-0000003c1.jpg www.fas.org/nuke/guide/usa/airdef/tars.htm I know, you meant untethered, but it really doesn't matter for staionary wide area surveillance, does it?  I think the lock-mart blimp is pretty cool, a million pound heavy hauler that cruises at 120 knots would fully kick ass.  It would be great for hauling tanks and bradleys around, one at a time in my C-17s makes for one heck of a slow airlift.

Talk about a high value vulnerable target though, although I suppose it would be big enough that you could mount Phalanx on it or an array of those new missile interceptors they were developing to mount on APC for iraq, that should be a reletivley easy software change to lock onto AAMs vs RPGs.

Quoted: Talk about a high value vulnerable target though, although I suppose it would be big enough that you could mount Phalanx on it or an array of those new missile interceptors they were developing to mount on APC for iraq, that should be a reletivley easy software change to lock onto AAMs vs RPGs.

First off, think 73,000 feet.  At that altitude it can be well back of the forward line of battle and not be in any danger, yet still provide the look-down capability you need.  Most high-value sensor platforms (AWACS, JSTARS, etc.) do that now--their orbits are far enough back, behind a fighter screen, that they are pretty safe, and yet still have a tremendous field of view.  IIRC, the studies we were looking at while at NORAD said we would need less than 10 to cover the entire coast of the US from Maine to Texas (can't remember exact number, but it was in the single digits).  

Second, there's not very many countries in the world that have the capability to reach both that far and that high.  

The cool thing about them is their endurance.  We were looking at some revolutionary fuel cell technology that could make a mission last 2-4 MONTHS.