The Woracle

The US Marine Corps is still working to gather support for its “troops from space” concept of using a spaceplane to rush a squad from the US to anywhere in the world within 2h, to head off a crisis or take out a bad guy. And the Marines think the nascent space tourism market could be a source of the technology they need.

"This is the same thing the commercial sector is trying to do, except we are not bringing them back to the same place," Lt Col Paul Damphousse told the Space Frontier Foundation's NewSpace 2007 conference in Washington on Thursday.

He was talking about the USMC's SUSTAIN initiative - for Small Unit Space Transportation And Insertion - which he likened to the iconic dropship in the movie Aliens, and which raised more than eyebrows when the concept was first proposed in 2002.

Vision vehicle - the dropship from Aliens

Boeing has flown the X-48B Blended Wing Body technology demonstrator at NASA Dryden in California. The company did not immediately announce the 21 July flight because its quarterly earnings release - including an extra $500 million in R&D expenses for the 787 - got in the way.

The company might also be a little concerned that, as has happened more than once before, someone will look at the BWB and see Boeing's next airliner. Now who would do a thing like that?

It's only a model...

Nice to see Northrop carrying on Grumman's naval aviation legacy by winning the US Navy's unmanned combat air system demonstrator programme. But it is only a first step.

Now the X-47B UCAS-D has to convince the Navy that an unmanned aircraft can take the place of a manned aircraft on its precision-managed carrier decks - then Northrop Grumman can face off against Boeing again in a competition to develop an operational N-UCAS by 2020.

Assuming the programme survives that long.

A Cat with no tail

DARPA may have cancelled its programme to develop a 500t-payload cargo transport, but airship maker Wordwide Aeros says it is going to build its partially bouyant Aeroscraft anyway - albeit on a smaller scale.

And what is an Aeroscraft? It's an air vehicle that dynamically controls a combination of helium bouyancy, aerodynamic lift and thrust vectoring to take off and land vertically, manouevre on the ground and cruise at speeds up to 120kt and altitudes up to 12,000ft.

And what am I smoking?

Son of Walrus, the Aeroscraft ML866

Sources tell me that Hellcat and Intruder 2 are among names being considered by the US Navy for Northrop Grumman's X-47B unmanned combat air system demonstrator. Get your votes in!

I vote for Hellcat, but just in case I am offering to sell the film rights to my latest book, Flight of the Intruder 2.

I was researching the Joint Precision Approach and Landing System (it's exciting being an aerospace journalist) when I came across this Newport News artist's concept of the US Navy's next aircraft carrier, the CVN-21.

Newport News is owned by Northrop Grumman, and Northrop has all or part of every aircraft on the deck: the F/A-18s and F-35s parked with wings folded, the E-2 taking off and even the X-47 unmanned combat aircraft waiting to launch behind the F-35.

I find it interesting (it can also be sad being an aerospace journalist) as it illustrates how important winning the Navy's UCAS demonstrator programme could prove to be for Northrop. Provided, of course, it successfully demonstrates that unmanned and manned aircraft can coexist on the significantly busier decks of real carriers.

I said . . . . . . . . . . . . . Stop! (US Navy photos)

DARPA has posted a video of the planned Oblique Flying Wing X-plane demonstrator on its website. The animation shows the tailless flying wing sweeping smoothly from 0 degrees to 65 degrees as it accelerates from Mach 0.6 to Mach 1.2.

It looks surprisingly real - down to the wobbly "camera" tracking - and deceptively simple. If it flies as planned in 2011, the OFW X-plane will be the first supersonic, tailless, variable-sweep flying wing - and making it fly will be far from easy.

X-factor - Northrop's OFW demonstrator (DARPA photo)

MiG has unveiled a full-scale mockup of a low-observable unmanned combat air vehicle, called Skat, at the MAKS 2007 show in Moscow. I can't show you pictures yet, but I can direct you to this Russian TV report and to here and here.

Itar-Tass says the tailless flying-wing Skat, which resembles Boeing's X-45C, is intended for strikes against air defence systems, aircraft and ships, and would be armed with X-31A anti-ship and X-31P anti-radar missiles and TV-guided weapons.

A flight demonstrator is to be built, says Itar-Tass. Skat looks to be equivalent to Boeing's proof-of-concept X-45A for the DARPA/USAF UCAV programme, which ended in 2005 with a successful demonstration of automous pre-emptive destruction of enemy air defences.

So now India plans to build an unmanned combat air vehicle demonstrator. I'm not holding my breath, but I am wondering why the US Air Force withdrew from the Joint Unmanned Combat Air Systems programme, leaving the US Navy to carry on alone.

Perhaps my collegue Steve Trimble over on The Dew Line is correct and the USAF's UCAV work has not stopped, but gone into the black world. It is hard to believe that its pioneering work with DARPA on the Boeing X-45A has simply been squandered.

Russia's MiG says it will fly a UCAV demonstrator within two years. BAE Systems plans to fly the UK's Taranis in 2010 and Europe's Dassault-led Neuron is to fly in mid-2011. All are stealthy flying wings designed to attack heavily defended targets.

But Neuron, Taranis and MiG's Skat are all playing catch-up to what was achieved - and seemingly discarded - with the X-45A. The US Navy plans a carrier demonstration of Northrop Grumman's X-47B in 2011, but publicly the USAF has dropped UCAVs in favour of a new manned bomber. That looks likely to be only part of the story.

MiG's Skat (For more mockup pictures, see Sergey Kuznetzov's blog http://pilot.strizhi.info/)

Wonder where unmanned aircraft are going? Bigger, smaller, higher, longer? Take a look at Qinetiq's solar-powered Zephyr, which has just completed a 54h flight, beating the official world unmanned endurance record of 30h 24min, set by Northrop Grumman's jet-powered Global Hawk in 2001.

A fragile-looking thing, the hand-launched Zephyr is at the vanguard of efforts to extend the persistence of UAVs beyond hours to days, weeks, even years. Solar power, hydrogen fuel, even in-flight replenishment are being researched. The most extreme of these efforts is DARPA's Vulture project to demonstrate technology for a UAV that stay aloft for five years.

I'm not joking, check out this video...

Now that's what I call a stretch goal.

But why all this effort, and how can it be feasible? The why is easier than the how.

The X Prize Foundation and Google have announced a $20 million prize for the first privately funded robotic rover on the Moon. This follows the $10 million Ansari X Prize for the first private suborbital flight, won by Burt Rutan's SpaceShipOne.

It's a bigger challenge, and a richer purse, but I am not sure the Google Lunar X Prize will grab the public's attention in the same way. It's a robot not a human, after all. And as NASA's plucky Mars rovers illustrate, robots are not as good at grabbling headlines.

But the timetable will give NASA something to think about, as it plods along its way back to the Moon. The grand prize of $20 million for the first rover on the Moon reduces to $15 million on 1 January 2013 and the competition is to be terminated on 31 December 2014.

Pratt & Whitney Rocketdyne has just tested a subscale combustor for a dual-mode ramjet/scramjet under the FACET programme to demonstrate a combined-cycle powerplant for DARPA's planned Falcon HTV-3X hypersonic test vehicle. The combustor was ground-tested from Mach 2.5 to Mach 6.0.

Lockheed Martin's Skunk Works is designing the HTV-3X. As the attached video shows, the unmanned vehicle would take off under turbojet power then accelerate to a speed where the ramjet when take over, then transition to scramjet mode to cruise hypersonically before returning to a runway landing.

Like most DARPA programmes it's a technological stretch - and Lockheed hasn't even built and flown the unpowered HTV-2 yet - although I've got my fingers crossed for this one. But, as Boeing's George Muellner jokes: "Hypersonics is the future...and always will be."

Part 1

Part 2

NASA has just posted an update on the Boeing X-48B Blended Wing Body demonstrator, along with some cool pictures of "Skyray 48".

First flown in July at NASA Dryden, the subscale unmanned X-48B has completed six flights and is now on the ground for maintenance and modification - including replacement of the fixed extended slats with slatless leading edges - and a software update.

......................................................................................................................................................................................Two X-48Bs have been built to explore the low-speed flight control characteristics of the BWB, but now NASA says they could also be used to evaluate the configuration's low noise and its handling characteristics at transonic speed.

My colleague Steve Trimble went to the Society of Experimental Test Pilots' annual symposium this year, and met some of my personal heroes like Eric "Winkle" Brown. I wanted to go, but a least he brought me back a video. So I have picked a couple of my favourite clips.

The first is of NASA Dryden's F-15 modified to test Gulfstream's Quiet Spike telescoping nose boom, which is intended to reduce the sonic boom of a supersonic business jet (and apparently it worked as designed).

The second is of NASA Dyrden's F-18 completing a "hands-off" contact with the drogue during the first ever autonomous aerial refuelling demonstration, conducted jointly with DARPA (it was a dry run, no fuel was exchanged).

Sources tell me DARPA is about to award Bell Boeing a small contract to study a stop-fold tiltrotor. Or restart studies, I should say, as both companies have previously looked at tiltrotors that stop and fold their rotors to go faster.

In 1972, Bell tested a 25ft-diameter stop-fold rotor in a NASA Ames windtunnel. This demonstrated the feasibility of stopping the rotor and folding the blades back along the nacelle to reduce drag, and then redeploying the blades and spinning up the rotor.

The concept was shelved because the technology was not available to overcome the added complexity and weight of the stop-fold mechanism, and the lack of an engine able to convert from driving the rotor to producing thrust.

Now it looks like tiltrotor experts Bell Boeing will get a chance to dust off the concept, apply technology now available, and perhaps run another windtunnel test. With the demise of Boeing's stopped-rotor Canard Rotor Wing, it's another way to get to a high-speed rotorcraft.

Tilt to take off, fold to go faster (Boeing artwork)

On the subject of carting 30t of armoured fighting vehicle around the battlefield, the US Air Force's approach to airlifting the Army's weight-challenged FCS vehicles has become clearer with release of details of the planned Speed Agile concept demonstration.

The cool name reflects the Air Force's desire for "speed agility": high lift at low speeds for short take-off and landing from improvised airstrips combined with efficient cruise at speeds beyond Mach 0.8 - something traditional STOL aircraft are not good at.

The baseline specs for Speed Agile are revealing: at least 500nm radius carrying a nominal 29.5t payload at speeds above Mach 0.8, with a mid-mission hot-and-high landing and take-off in under 2,000ft - 1,500ft is desired.

And the cargo box looks familiar - it has the same 4m loading width as the Airbus A400M, which is fast becoming the standard for intra-theatre transport as payloads outgrow the C-130.

No-one gets to build a demonstrator for Speed Agile - the 34-month programme will involve concept design and windtunnel validation of low-speed and transonic performance. But it is one of a raft of Air Force Research Laboratory projects paving the way for AJACS - the Advanced Joint Air Combat System - planned as a replacement for the C-130.

STOL, speed, stealth - and sex appeal

Steve Trimble over on The DEW Line reveals Boeing has a DARPA contract to study a disk rotor high-speed rotorcraft. Like most things in aerospace these days, this is not a new idea.

Swiss architect and designer George Vranek, on his diskrotor website, traces the concept of a circular rotor with retractable blades back to Germany in 1962 and also mentions a 1992 NASA Ames study.

US engineering firm owner Frank Black has tried for years to find backers for his Modus Verticraft concept, and now Nowegian firm SiMiCon is working on a retractable-blade disk rotor UAV.

Perseverance pays off, and Piasecki Aircraft appears to be having some success with its X-49A "Speedhawk" - a Sikorsky H-60 modified with Piasecki's vectored-thrust ducted propeller (VTDP). The attached video shows the helicopter has exceeded 170kt in flight testing.

The X-49A is flying at Boeing's test centre in Delaware, and Dave Harvey on rotorhub.com, says the US giant is interested in combining the VTDP with the optimum-speed rotor technology from its A160T Hummingbird unmanned helicopter. That would make an interesting combination.

The Salt Lake Tribune has just run a profile of local gyroplane developer Groen Brothers Aviation. It contains a brief reference to "design issues" uncovered in September during the preliminary design review for the Heliplane high-speed rotorcraft demonstrator GBA is designing for DARPA.

So I contacted DARPA, which said: "We underestimated the difficulty in achieving 400mph cruise performance with an existing engine and airframe. Nobody has ever flown a rotorcraft at 400mph." Understatement - the fastest a rotor has flown sideways is 249.1mph, attached to a Westland Lynx in 1986.

GBA calls the Heliplane a "gyrodyne": it takes off and lands like a helicopter using a tipjet-driven rotor, but cruises like an autogyro, with the rotor unpowered and thrust provided by a pair of turbofans. Gyrodynes are not new, but pushing one to 400mph is - that's twice the speed McDonnell's XV-1 Convertiplane tipjet compound autogyro achieved in 1956.

Designing a reaction-drive rotor system that can produce sufficient lift, generate minimum drag, carry the loads and be stable at high speed has proved to be a challenge. DARPA says GBA is working to resolve "a few remaining design issues", then it will decide whether to proceed to full-scale windtunnel testing of the rotor system.

It must be all this talk of reviving old ideas, but Robot World News is running a story about a new look at an old idea - too old for even me to remember - the cyclogyro.

The what? The cyclogyro is a sort of flying paddle steamer - lift and thrust is provided by several long, thin aerofoils that rotate around a horizontal shaft. It looks like this 1930s design (from The Douglas Self Site):

Now a paper published in IEEE/ASME Transactions on Mechatronics details an experimental cyclogyro-based micro-UAV. This incorporates a new variable angle-of-attack mechanism enabling it to hover, climb and fly backwards.

If you feel the urge to know more, there is an explanation of the cyclogyro at this National University of Singapore website. It includes this video of a tethered flight:

Thanks to Sentinel Chicken over on secretprojects.co.uk for posting this video of Lockheed Martin Skunk Works' P-791 hybrid airship. The late Mike Dornheim of Aviation Week broke the story about the Skunk Works flight testing the P-791 in February 2006. As Sentinel Chicken points out, whoever posted the video on break.com did not know what it was.

How Rosie Odonnell Travels - Watch more free videos

The P-971 was a privately funded subscale technology demonstrator for a heavylift cargo airship of the type studied under DARPA's Walrus programme until it was cancelled. Worldwide Aeros also studied a hybrid airship under Walrus and recently received a DARPA contract to demonstrate its "control of static heaviness" system in flight.

Just when you thought you'd heard the last of duPont Aerospace's DP-2 V/STOL transport project, after US Congress finally cut off its funding, a new controversy has erupted over NASA's decision to let the company keep the Pratt & Whitney Canada PW535A engines powering the prototype. DuPont argues the engines were purchased with a NASA grant and are its to keep. Without them the project is history.

The DP-1C prototype managed two 45-second tethered, unmanned hovers at the end of September, the culmination of $63 million in funding earmarked for duPont over 19 years by congressman Duncan Hunter. Congress finally pulled the plug in June after a special hearing at which the DP-2 was portrayed as a monumental waste of money.

You can read duPont's version of events in its testimony at the hearing. And if you want to see the "flying nostril" make its brief hovers, you can watch the videos here and here.

The internet has been abuzz with stories about a new US space weapons programme, all based on an erroneous report in the Washington Post about one of my favourite DARPA projects - the Falcon hypersonic cruise vehicle technology demonstrator.

Falcon has been around for yonks, but the Post managed to mangle the wording of the House-Senate conference report on the 2008 defence budget. This zeroed out the US Navy's Conventional Trident Modification programme to convert nuclear missiles into precision bombers, but provided $100 million for a new Prompt Global Strike programme. The money came from CTM and the US Air Force's Common Aero Vehicle project to develop a conventional-warhead ballistic missile re-entry vehicle - but is not going to Falcon, as the Post reported.

NASA has sent me a two-CD set (how seasonal!) on its revitalised Fundamental Aeronautics programme. One is the presentations from the programme's recent annual meeting (saved for later posts). The other is a 12-minute movie produced by the programme and entitled "Today's Research...Tomorrow's Flight".

I have shamelessy ripped some clips from the DVD to show you some of the concepts NASA is using to focus its research. The first of these is the cruise efficient short take-off and landing (CESTOL) airliner. NASA's idea is that, by reducing take-off distance, aircraft can use runways that are too short for today's A320s and 737s, increasing the capacity of existing airports. Steeper departures and approaches will also reduce noise. The challenge is acheiving STOL without sacrificing cruise speed and while meeting tomorrow's tougher noise and emissions limits.

NASA's targets for an "N+1"-generation subsonic airliner, to enter service in 2012-2015, include a 33% reduction in field length relative to the 737. For the N+2 generation (2018-2020 EIS) it is 50%, and for N+3 (2030-2035) it is a whopping 70% reduction. Technologies include over-wing nacelles and circulation-control wings to increase lift and reduce noise. Not sure Airbus or Boeing are ready to go quite this far with their next-gen narrowbodies...

My former colleague Guy Norris has a story in Aviation Week about Northrop Grumman's future airlifter work with the US Air Force Research Laboratory. I can't link to his story, but here's the gist:

Northrop is proposing a tailless flying wing with powered-lift system for AFRL's Speed Agile technology demonstration to refine the concept of a STOL transport to replace the C-130 towards the end of next decade. AFRL is looking for a design able to combine a take-off distance under 2,000ft with a cruise speed over Mach 0.8 - while carrying a 30t payload.

Like it or not, the blended wing-body airliner will not go away. Those that like the BWB point to its aerodynamic and structural efficiency, its ample volume for passengers, cargo and fuel. Those that don't point to its lack of windows. non-circular pressure vessel and edge-of-the-envelope flying qualities. But if the world starts to take the environment seriously, and demands that aviation dramatically cuts its fuel consumption, emissions and noise, where else can airlines go? Solar-powered passenger-carrying airships?

Here is NASA's vision of one possible future:

There is an interesting chart from a recent NASA presentation that illustrates the BWB's fundamental attraction - for the same volume it has a third less surface area than a conventional tube-and-wing airliner. And less surface area means less friction drag. The same presentation also charts the evolution of BWB designs, from the 800-passenger, 7,000nm-range monster conceived by McDonnell Douglas in the early 1990s to Boeing's X-48B subscale demonstrator.

The X-48B is the culmination of research begun in the late 1990s and using a 450-seat BWB as the reference design for a series of small-scale windtunnel models to investigate the configuration's challenging flight dynamics. There was to be a 14%-scale, 35ft-span low-speed flight demonstrator, the X-48B, but it was cancelled by NASA when aeronautics fell out of favour. Instead, Boeing and Cranfield built the 8.5% X-48B, which first flew in July 2007 (watch the video here).

Where next? Well NASA has funded Boeing to investigate the noise benefits of a BWB. It is also funding Boeing, MTI and UCI to mature the blended wing-body design concept produced by the UK/US Silent Aircraft Initiative ... Cal Poly, meanwhile, will refine its concept for a 100-seat hybrid wing-body STOL airliner under NASA grant.

The Silent Aircraft Initiative was a three-year effort by the Cambridge-MIT Institute to develop a credible concept for a 2025-timeframe airliner that would be inaudible outside the airport boundaries (see Flight's story and a video here). Cal Poly's concept is a 2020s-timeframe, low-noise, powered-lift airliner designed ease airport congestion by using shorter runways. And, guess what, neither is a tube with wings.

The Pentagon boffins have been keeping mum, but the DoD's fiscal year 2009 budget request lifts the lid on Blackswift - DARPA's prototype hypersonic aircraft. Formerly the Falcon HTV-3X, and being designed by Lockheed's Skunk Works, the unmanned Blackswift is intended to take off conventionally on turbojet power, transition to scramjets, cruise at Mach 6 for an extended period, then return to a runway landing. If it succeeds, Blackswift will be a worthy successor to the Skunk Works' Blackbird.

Sharon Weinberger at Wired's Danger Room was first to blow Blackswift's cover, and in January alerted us to an InsideDefense story that DARPA was to seek $750 million for the demonstration programme. DARPA's FY2009 request is for $70 million on top of the $35 million to be spent in FY2008. Here's what DARPA's budget documentation has to say:

"The Blackswift Test Bed program will develop an extended duration hypersonic test bed which will allow for the study of tactics for a hypersonic airplane that includes a runway take-off, Mach 6 cruise and runway landing. This test bed is an evolution of the reusable Hypersonic Cruise Vehicle developed under the Falcon program.

"Key technologies that will be demonstrated include efficient aerodynamic shaping for high lift to drag, lightweight and durable (reusable) high-temperature materials and thermal management techniques including active cooling, autonomous flight control, and turbine-based combined cycle propulsion.

"It is envisaged that flying this hypersonic aircraft test bed in a relevant, flight environment will permit the futire development of enhanced-capability reusable high-speed vehicles for intelligence, surveillance, reconnaissance, strike and other national need missions. This program will transition to the Air Force following completion of flight-testing."

DARPA's Falcon programme continues, with two unpowered, rocket-boosted HTV-2 hypersonic test vehicles scheduled to be flown in FY09 to pave the way for Blackswift. The Skunk Works, meanwhile, is to complete the Blackswift preliminary design and ground test the integrated high-speed turbojet and scramjet propulsion system by the end of FY09. No news yet on when Blackswift might fly, but it should look like this...

I've taken the bullet on your behalf and ploughed through DARPA's fiscal year 2009 budget request to look for goodies. Here's what I've found.

New programmes for FY09:

Multi-Modal Missile - manportable surface-to-surface and surface-to-air weapon with direct and indirect fire modes against vehicles, bunkers, helicopters and UAVs.

Small UAV Strike Munition - inexpensive, lightweight precision-guided submunition to be delivered by a loitering weapon launched from an unmanned aircraft.

Stealthy, Persistent, Perch and Stare (SP2S) - a VTOL micro air vehicle based on the Aerovironment Wasp that will land on a perch, collect data and fly home.

FY09 funding for existing programmes:

Heliplane - $16m to demonstrate the tipjet-driven rotor for Groen Brothers' high-speed gyroplane (assuming they succeed in FY08 in cutting tipjet noise by more than 10dB)

Oblique Flying Wing - $29.6m to begin construction of the unmanned X-plane demonstrator for Northrop Grumman's supersonic, tailless variable-sweep asymmetric flying wing.

CASTLE - $7.5m to complete preliminary design of a persistent, unmanned gunship to be armed with electromagnetic guns, directed-energy weapons or vertical-launch missiles.

Rapid Eye - $15.9m to complete preliminary design of a rapid-reaction HALE UAV to be rocket-deployed from the US to anywhere in the world in 1-2h for ISR and comms missions.

Vulture - $11m to begin building a subscale demonstrator for a "pseudo-satellite" ISR UAV able to stay on station for more than five years. The demonstator goal is a year-long flight.

When a test flight lasts only minutes and ends in a fiery plunge into the ocean, you want to make sure the radios work - to ensure telemetry data is safely sent to the ground. So Boeing is testing the antennas for the US Air Force Research Laboratory's X-51A Scramjet-Waverider hypersonic demonstrator in the anechoic chamber at Edwards AFB.

Powered by a Pratt & Whitney Rocketdyne scramjet that uses the fuel to cool itself, the first X-51A is scheduled to fly in August 2009 - dropped from a B-52 50,000ft over the Pacific, boosted to Mach 4.7, where the scramjet will light and run for 5min, accelerating the vehicle to Mach 6.7 before the tanks run dry and it plunges into the ocean. Those radios had better work.

It ended up in a hangar covered in bird crap, that's what. A remnant of an unhappy time in NASA's recent history, the Orbital Sciences-built X-34 was photographed by Ashley Wallace in storage at Edwards AFB in California. The X-34 was built as a flying testbed to demonstrate technology for future low-cost reusable launch vehicles.

(Picture by Ashley Wallace, from airliners.net)

The unmanned X-34 was intended to be air launched from Orbital's Lockheed L-1011 mothership and accelerated to Mach 8 by a NASA-built oxygen/kerosene rocket engine. The vehicle was designed to land on a runway and fly up to 25 times to test composite structures, resuable propellant tanks and thermal protection systems, and autonomous flight operations.

Orbital got as far as captive-carry tests on the L-1011 before the X-34 was cancelled in 2001, along with Lockheed Martin's mightily ambitious X-33 single-stage-to-orbit RLV technology demonstrator (video). Spiralling costs and changes in NASA's RLV thinking were blamed. Two completed X-34s and parts for the third were transferred to the US Air Force.

It was always an unusual-looking bird, but Scaled Composites' Ares had a certain style. Not any more. Mojave-based photographer Alan Radecki has captured the long-stored Ares taxiing under its own power and boy does it look ugly now, covered in lumps and bumps of unknown purpose.

Ares then... (Bernard Klein Collection photo from 1000aircraftphotos.com)

...and now (Alan Radecki photo)

It's conference season again, and last week it was the Air Force Association's winter symposium in Orlando - where I grabbed 5min with Frank Mauro, vp advanced systems development at Lockheed Martin's Skunk Works. Here's some of what he said.

Polecat (video) - LM has decided against building a replacement for the P-175 Polecat flying-wing UAV that crashed in December 2006. Polecat was mainly about low-cost composites, Mauro says, and that work is continuing under the US Air Force Research Laboratory's Advanced Composite Cargo Aircraft programme - Skunk Works with fly the highly modified Dorier 328Jet late this year.

VARIOUS (video) - Mauro says a lesson learned from the private-venture Polecat was a need to get governent partners on board to share the cost and risk, so the Skunks are working to get backers for the VARIOUS VTOL UCAV demonstrator. This is mainly an engine integration challenge, he says. The VARIOUS has three small Teledyne gas turbines, one for cruise and two driving fans embedded in the wing.

Hybrid airship (video) - The Skunk Works is preparing to fly its P-791 hybrid airship demonstrator again, and Mauro says Lockheed is looking for a partner to commercialise the aircraft, having decided against entering the commercial market itself. An unmanned version is being proposed to Raytheon for the JLENS cruise-missile defence system, as an alternative to tethered aerostats.

RATTLRS (video) - The Mach 3-plus missile demonstrator could still fly this year, but more funding will be required, Mauro says, after Rolls-Royce suffered foil bearing failures in the YJ102R high-Mach turbine engine. An Office of Naval Research programme, RATTLRS is designed to cruise above Mach 3 for 5min.

Morphing UAV (video) - Lockheed's DARPA funding ran out before the Skunk Works could fly its folding-wing morphing wing UAV. Mauro says the problem was the lack of a 150lb-thrust engine. All the engines delivered said 150lb on the box, he says, but only produced about 75lb - not enough to get the UAV off the ground.

It's not every day a new form of propulsion makes its first flight: the turbojet in August 1939 (Heinkel He178), the ramjet in April 1949 (Leduc 010), the scramjet in July 2002 (University of Queensland HyShot). Now it's the turn of the pulsed detonation engine (PDE) - a simple, lightweight powerplant that promises efficient operation over a wide range of speeds from 0 to Mach 4.

In a PDE, combustion is supersonic (detonation) rather than subsonic (deflagration), resulting in the more efficient conversion of fuel into thrust. PDEs have few moving parts. A fuel/air mixture is injected into a tube and ignited, creating a supersonic detonation wave that travels down the tube and is expelled, producing a pulse of thrust. Grouping several tubes together and firing each many times a second produces constant thrust.

It's taken a few years longer than planned, but the US Air Force Research Laboratory and partners ISSI and Scaled Composites finally accomplished the first PDE-powered flight in late January. The modified Long-EZ was powered by a four-tube PDE, each tube firing 20 times a second, producing 200lb peak thrust. The flight was short, just a few tens of seconds, taking place within the length of the Mojave runway, but it was a first.

(Pictures by Alan Radecki)

Blackswift may have emerged out of Lockheed Martin Skunk Works' Falcon hypersonic technology demonstration, but DARPA is looking for competitive bids to design and build the unmanned demonstrator, issuing this solicitation in early March:

"The Tactical Technology Office (TTO) of the Defense Advanced Research Projects Agency (DARPA) is soliciting proposals to develop an extended duration hypersonic testbed known as Blackswift. The Government seeks development of a reusable hypersonic testbed that utilizes an integrated air-breathing propulsion system.

The Blackswift flight test program is pursing development and demonstration of near-term (2012) capability. The Government is soliciting original conceptual flight testbed design approaches from the aerospace community that meet or exceed these objectives."