The Woracle

An unusual aeroplane is among the latest batch of pictures on 1000aircraftphotos.com. It is the Aerofan Single Twin, c1984. It is a clean machine, but details seem sparse. Anyone know anything about it? The name suggests two engines driving one propeller, as in the Learfan.

I have a soft spot for pushers, although few have been commercially successful. I loved the Beech Starship, and always look up when I hear the distinctive sound of a Piaggio Avanti overhead.

Aerofan Single Twin (Bernhard Klein Collection via 1000aircraftphotos.com)

The dozens of small manufacturers building LSAs - light sport aircraft – have just been given what they most wanted…and feared. Cessna has decided to enter the market. It’s like getting the Good Housekeeping seal of approval from the 800lb gorilla in the room.

Cessna’s decision to build a two-seat sport aircraft follows an exhaustive analysis of the market and is a massive endorsement for the LSA concept. And, judging by the proof-of-concept aircraft flown late last year, it marks the birth of a modern Cessna 150 – one of the most-produced light aircraft of all time.

Another classic in the making?

Northrop Grumman is to become the full owner of Burt Rutan's Scaled Composites, which has been acting as a rapid-prototyping "Skunk Works" for the US defence giant. Northrop has owned 40% of Mojave, California-based Scaled since 2003, and the links between the companies have become more evident recently.

This is not the first change of ownership in Scaled's checkered, if illustrious, history.

Scaled's Proteus tests a new radar for Northrop's Global Hawk

Someone at Eclipse Aviation must have gone "oh, oh" a few weeks back when Cirrus Design unveiled its new single-engine jet. Because the Eclipse Concept Jet, built and flown in secret and revealed at this week's Oshkosh show, looks similar the Cirrus's "the-jet", which so far exists only in mockup form.

Both have their single turbofan engine mounted above the fuselage, exhausting between a V tail. Great minds think alike? Or are there just a lot of Global Hawk groupies out there?

Eclipse flies, Cirrus poses

Cessna did it last year, Eclipse has just done it and now Embraer is going to do it.

The concept jet.

Car companies have been doing it for years. Unveil a concept car at a motor show to create some excitement, grab some headlines and capture some customer feedback. Maybe something like it will make it into the showrooms. Maybe not.

To keep up the momentum behind its move into business aviation, at September's NBAA bizav show in Atlanta, Embraer will unveil a full-scale mockup of a mid-size jet to fit between its Phenom 300 and Legacy 600. A concept jet, not a real one...yet.

Steve Trimble has posted new pictures of the Iranian-developed Saegheh fighter over on his blog, The DEW Line. Look past the Blue Angels colour scheme and you will see subtle but significant differences between the two aircraft featured that suggest Iran's "Lightning" is more than simply a reverse-engineered Tiger with two tails.

The first aircraft, presumably the earliest, looks pretty much like an F-5E and even the twin fins have a "tacked-on" appearance.

But the second aircraft, while similar in planform, has a number of differences including enlarged and reshaped inlets.

The first aircraft's inlets are F-5 sized and shaped. The second one (right) has rectangular inlets that appear larger, and the wing leading-edge root extensions are slightly different.

A closer look shows the second aircraft's intake trunk is bulged compared with the F-5E's classic "coke-bottle" shape, although the auxiliary inlet is still there.

The base of the fin also has a more faired-in appearance, so the second aircraft could be the production version. The reason for the inlet redesign is not clear as the nozzles of both aircraft look similar, suggesting the engines have not changed.

But maybe there is a bigger engine in the pipeline, making for a higher performing aircraft. Which might explain why they would spoil the classic lines of the F-5 by doubling up on tails.

Meanwhile, this picture from Tehran's military parade on 22 September shows two of the round-intake aircraft and one square-intake (top left)

Remember DARPA's Quiet Supersonic Platform programme? It's best known for proving that an aircraft can be shaped to modify its sonic boom. But the industry teams involved also completed substantial conceptual design work on low-boom supersonic strike aircraft - and business jets.

Now Hawker Beechcraft, which as Raytheon Aircraft was part of Northrop Grumman's QSP team, has received a patent as a result of the work. The patent is for a method of developing an aircraft configuration by first defining a target sonic boom signature.

And designing an aircraft to eliminate the characteristic "double bang" sonic boom produced by a traditional N-wave shockwave signature produces some interesting results:

A subscale prototype of the controversial duPont Aerospace DP-2 vectored-thrust V/STOL aircraft, which has received $63 million of US government funding thanks to Congressman Duncan Hunter, has completed a couple of short tethered hovers in California.

The timing is probably not accidental, as Congress voted to cut duPont's funding after a hearing into the project earlier this year. The money runs out on 31 December, but Hunter says he will still try to put funds for the DP-2 into the 2008 defence budget.

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.

Lockheed Martin has rolled out the first supersonic STOVL F-35B Joint Strike Fighter. Think about those words - "supersonic" and "STOVL". I worked in future projects at Hawker Siddeley in the late 1970s, so I have an idea of how hard it is to get those two characteristics together in one aircraft. Most of the designs I worked on used Harrier-style vectored thrust, which put a big fat engine right in the middle of the airframe - not exactly what you want for supersonic fineness. Remember Boeing's X-32?

But the F-35B looks quite sleek. The secret is its shaft-driven lift fan, installed behind the cockpit under a massive rear-hinged door that engineers have dubbed "the 56 Chevy hood". The lift system allows the engine to produce about 40,000lb of vertical thrust without needing reheat. About half that comes from the lift fan and the rest from the roll posts and rear swivelling nozzle. The system worked extremely well on Lockheed's X-35B concept demonstrator.

The potential disadvantage could be its complexity. To transition from wingborne to jetborne flight, doors have to open, clutch engage, gearbox and two-stage contra-rotating fan spool up, vanes move and nozzle swivel. The process is automated to make it simple for the pilot, but there are still a lot of moving parts. As F-35B ground and flight testing gets under way in 2008, the reliability of the system will be a critical factor.

A closer look at the first F-35B shows the changes from the CTOL F-35A. The lift fan is visible behind the truncated canopy under the sloping door, which helps direct air in the fan in forward flight. The lip of the lift-fan duct, called the "horsecollar", is a revised design that smoothes the airflow into the duct and which has increased the fan's performance in engine ground tests. Behind the lift fan are the open doors of the auxilary inlet that provides extra airflow to the engine at low speed. Below the fan is the open door that covers the variable-area vane box nozzle, used to vector lift-fan thrust for hover flight control.

A couple of other changes are notable - the retractable refuelling probe fitted to the STOVL F-35B and F-35C carrier version, but not the US Air Force-standard F-35A. Also the two-piece nosegear doors, which replace the single-piece "barn door" that catches a little too much crosswind on the first F-35, aircraft AA-1.

Gulfstream has launched its G650 widebody business jet. A new Gulfstream is big news and the G650 looks, well, like a Gulfstream. It looks like a pumped-up G550, but it's all-new, including the type certificate, which will say GVI - sixth in an illustrious line stretching back 50 years to the GI (my favourite).

It's bigger, faster and flies further than the G550 - bigger, faster and further enough for Gulfstream to put the G650 into a different market segment (ULRVLJ - ultra-long range very large jet?) and keep building the G550. But where does all that extra speed (Mach 0.925) and range (7,000nm) come from?

Where's the swoopy wing and radical area ruling? The G650 looks so...Gulfstream.