NASA to delete Orion software functions

The flight software for NASA’s Orion crew exploration vehicle (CEV) has been identified as a risk to the agency’s Constellation programme schedule.

NASA’s software community has estimated that Orion will have over one million lines of code. With a need for “thousands of developer years” to complete Orion’s software verification NASA concluded that it needs to phase its implementation.

NASA and its prime contractor Lockheed Martin have been identifying software functionality and what can be written in later. This phasing plan is not expected to be completed by the CEV’s preliminary design review expected in the third quarter. Examples of this phasing include the deletion of functions not needed for the CEV’s maiden unmanned launch, Orion 1, or for the 2015 first crewed flight Orion 2. Automation will also be eliminated where operations can be conducted manually either by onboard crew or from mission control.

A NASA software document passed to Flight International says, “The spacecraft does not have to be fully autonomous for [Orion 2] only automation for time to criticality functions which do not allow for human response [is needed].”


737 output ‘may plunge to 21 a month in 2010’

By Dan Thisdell

Boeing 737 production rates could shrink to as low as 21 aircraft a month in 2010, say its US suppliers.

GKN Aerospace chief executive Marcus Bryson, who returned from a tour of US customers last week, says Boeing suppliers are “starting to talk in terms” of dramatic output cuts.

Bryson says he expects cuts in single-aisle output at Airbus and Boeing. He is sticking to his January forecast of A320 output dropping to 30 a month this year, and adds the impact on GKN – which acquired the Airbus wing components manufacturing operation at Filton, Bristol in January – would be limited owing to the company’s relatively small involvement in the current generation of Airbus and Boeing single-aisle aircraft and be offset by ramp-up of Boeing 787 and Lockheed Martin F-35 production.

Boeing
© Boeing

Output of A320s now stands at 34 a month, down from 36, and Boeing is turning out 31 737s. Boeing in April announced a cut in its 777 production rate to five a month from seven after June next year, but said it was holding 737 output steady.

Bryson’s observations on single-aisle output mirror an assessment by PricewaterhouseCoopers global aerospace and defence leader Neil Hampson, who says there is much bad news to come from both airframers on their output levels.

The question, he says, is how long they can hold off before delivering a “sober re-evaluation” of the quality of their orderbooks. A comparison of airlines’ summer passenger load figures with current expectations could be a trigger point for production realignments, he adds.

Bryson, however, puts single-aisle output levels in context by noting that only a few years ago the mid-20s a month would have been considered good, and that anything in the 30s should be seen as a bubble.


Airbus reins in 2009 A380 shipments in response to downturn

By Max Kingsley-Jones

Airbus will deliver just two more A380s this year than in 2008 after revealing plans to scale back production in the wake of the impact of the downturn on demand. It has also warned that the current tough trading conditions could require further changes.

The airframer says A380 deliveries in 2009 have been cut from 18 to 14 due to “the current economic and aviation crisis and specific customer requests for deferrals”.

This revision is the second to be announced for A380 production this year, with the airframer having reduced its earlier 2009 forecast of 21 aircraft to 18 in January. Overall it represents at least the sixth change since the original plan before the 2005 first flight, when 2009 production was expected to have ramped up to 45 aircraft (see graphic).

More changes could follow, warns Airbus, which has committed only to delivering “more than 20” in 2010. “Onward production rates and deliveries are dependent on airline demand and availability of customer financing,” it says.

Of the 18 A380s originally due for delivery this year, all but one (for Air France) were destined for existing customers Emirates, Qantas and Singapore Airlines. Of these, only Qantas has so far announced plans to defer A380s, which revealed in April that it was pushing back four A380s by 10-12 months. The change is believed to have affected 2009-10 deliveries.

Airbus, which delivered one A380 in 2007 and 12 last year, has shipped just one so far in 2009. This was the fifth A380 for Emirates, which was handed over on 24 April.

“Mitigating actions” will be taken against the “negative effects” of the revised production plan on cashflow, says Airbus. Although the deferral of four A380s represents a deficit of $1.3 billion in revenue at current list prices, Airbus says there will be “no significant impact”.


Radical response

By Stephen Trimble

Stage lengths of between 185km (100nm) and 1,850km create a competitive problem for conventional air transport. For a typical 1-2h flight, would-be airline customers must pass through a non-flying gauntlet, from commuting to and from remote airports to facing clogged lines for security, check-in and baggage claim. It is often easier and cheaper to drive.

This basic conundrum has produced a series of radical solutions by aviation entrepreneurs, ranging from exotic business models, such as air taxis, to exotic aircraft designs, such as vertical take-off and landing (VTOL) airliners. For various reasons, including lack of infrastructure and technical complexity, none is yet to topple the imperfect primacy of the fixed-wing turboprop or jet.

Now Abe Karem, a widely respected aerodynamicist and innovator, has entered the mix. As founder of Karem Aircraft, he has quietly launched a new programme called the TR53 AeroTrain, a 120-seat, optimum speed tiltrotor (OSTR) dedicated to solving the 185-1,850km air transport problem.

“As the urban and suburban environments develop, VTOL transport is becoming more attractive and more urgent,” Karem says.

Karem Aircraft
© Karem Aircraft

LARGE GAPS

“The dream [of a VTOL airliner] didn’t materialise because of large gaps between efficient fixed-wing transports such as the Boeing 737 and all previously proposed VTOL transports in fuel efficiency, safety record, cruise speed, cruise altitude and pressurisation,” he says. “OSTR is designed to substantially close all of these gaps. Our commercial design is the TR53, the closest aircraft to a ‘VTOL 737’ we know how to design.”

Since launching the programme last year, Karem Aircraft has started to acquire and build pieces of the TR53’s advanced propulsion system, starting with the rotor and transmission.

“The AeroTrain development plan is focused on designing, analysing and testing the elements of the aircraft that are most different from the existing aircraft inventory,” Karem says.

The TR53 would share a similar fuselage with the 737-600, with a 32m (106ft) length and 3.96m cross-section accommodating six-abreast seating.

The most visible difference involves the design of the propulsion and aerofoil. Instead of a pod-mounted turbofan on a straight low-wing, the TR53 would feature two, 16m-diameter tiltrotors on either side of the fuselage on a 34.5m-span high-wing with dihedral wingtips.

But that is not the TR53’s only departure from conventional narrowbody technology. The primary structure for the fuselage and wing would be composite, a potential first in the narrowbody class. The aircraft also would have fly-by-wire controls.

INITIAL POWER

The TR53 would initially be powered by the 6,200shp (4,620kW) Rolls-Royce AE1107C engine, which powers the Bell Boeing V-22 Osprey. But Karem has plans to integrate an undisclosed, “advanced” propulsion system optimised for the TR53’s unique, optimum-speed technology. The advanced system would “provide significantly enhanced performance”, Karem believes.

Bell Helicopters
© Bell Helicopters

The TR53 is the commercial spin-off of Karem’s OSTR technology. Meanwhile, the US Army is also funding a Karem Aircraft/Lockheed Martin team to design the TR75, an OSTR with a 23m-diameter rotor to haul cargo. An advanced engine produced to support the army’s Joint Heavy Lift (JHL) programme, if funded, may carry over to the civilian programme.

As the designer of the fixed-wing General Atomics Predator and rotary-wing Boeing A160 Hummingbird unmanned aerial vehicles, Karem has built a reputation over the past two decades as one of the US military’s most technically agile and operationally successful innovators.

Karem is also fully aware that the puzzle of making VTOL transport as easy, safe and efficient as fixed-wing flight has never been solved.

“Fairey, a small British company, made the first serious effort with the 42-passenger, 180kt [333km/h] Rotodyne. The Boeing 222 and Lockheed designs also fed this dream,” says Karem.

Fairey cancelled the Rotodyne programme in 1962. The VTOL aircraft was doomed by its relatively slow cruise speed and the comparatively inefficient combination of a tip-jet driven rotor and twin propellers for vertical and horizontal propulsion. Military and airline orders were promised, but sales never materialised and the UK government withdrew funding support.

Karem’s tiltrotor configuration is a seemingly unlikely approach to succeed where Fairey failed. The V-22 has proved valuable to the US Marine Corps and US Air Force as a uniquely capable transport. But the concept has not been embraced by airlines like previous military-proven technologies, such as jet transports.

According to Karem’s approach, that failure is because the V-22 suffers from the same efficiency problem as helicopters. Their rotor speeds are relatively fixed to support vertical flight, leaving them grossly overpowered during cruise.

FUEL CONSUMPTION

As a result, rotorcraft are consuming substantially more fuel during cruise than a jet-powered fixed-wing aircraft. For example, says Karem, available seat-kilometre costs for a Sikorsky S-92 helicopter are more than 10 times greater than for a 737 on a similar journey.

Karem thinks he has solved this efficiency problem by inventing a method to change the rotor speed to support optimal levels for vertical lift and forward flight. OSTR technology also combines a light rotor system with stiff blades to achieve high efficiency over a range of speeds.

“The OSTR is about combining an efficient transport capability with a robust vertical take-off capability. One of the major challenges that must be overcome is the drastically different requirements on the rotor in hover and in high-speed forward flight,” says Karem.

“To bridge this gap,” he adds, “OSTR uses a variable speed rotor system that can vary RPM [revolutions per minute]. A cruise RPM might be 20-50% of a maximum hover RPM.”

Karem has already worked to tackle this problem for helicopters with the A160, a long-endurance UAV helicopter. The A160 features a Karem-designed variable speed rotor system. The A160 has demonstrated unrefuelled flight of nearly 20h, and is perhaps capable of 30h flight.

Boeing
© Boeing

“In the same way that moving from a turbojet to a turbofan increases efficiency, the large-diameter rotor of the TR53 effectively provides a very high bypass ratio,” Karem says.

The trade-off for the improved efficiency of a 16.2m-diameter fan, which compares with 1.55m-diameter CFM56 turbofan, is a “small price” for speed. While the 737 typically cruises at Mach 0.8, the normal cruise for the TR53 would be limited to Mach 0.6.

In hover mode, the aircraft consumes fuel at significantly higher rates. But Karem noted that helicopter mode flight should represent a “relatively small percentage” of overall flight time given a well-executed operation. “It should be noted that turbofan engines are particularly inefficient in on-airport operations including taxi, take-off and landing and low-altitude flight,” adds Karem.

The extra fuel required to perform hover operations can be offset in cruise, where the engine’s higher bypass ratio should yield fuel savings compared with even the most modern narrowbody aircraft. That advantage mean fewer carbon dioxide emissions with even the TR53’s initial engines being the Rolls-Royce AE1107C, says Karem.

Reducing nitrous oxide emissions, however, would require a more advanced engine core than offered by the AE1107C, he said. The R-R engine has been designed to power military transports, high-altitude UAVs and business jets, but not commercial airliners.

Karem says that he has not formally started soliciting letters of intent from airlines. And Karem Aircraft has decided not to market or exhibit the aircraft at the Paris air show next month. “However,” says Karem, “we feel strongly that AeroTrain will be a game-changer when it comes to passenger transport.”

The “game-changing” description is not mere cliche. Technology is not the only barrier for the TR53 concept to be fully realised. It requires the air transport industry and regulatory structure to adapt to an aircraft that does not require airports or even runways.

“To fully capitalise on the new capabilities offered by AeroTrain, airlines will have to think outside the traditional ‘airport runway-to-airport runway’ box,” says Karem. “Eventually, we hope that forward-thinking airlines and transport planners will allow passengers to board an airplane closer to the front door than their current airport, experience fewer delays, and land closer to their destination than they can today.”

This may be the catch. Even if Karem can master the technical challenge of proving an efficient tiltrotor, its acceptance could be limited without a radical change in his customer’s behaviour.

Karem’s military customer has the advantage here. Army officials are motivated to abandon their dependence on airports and runways, which must be obtained and then defended, to move people and equipment long distances.


Radical response

By Stephen Trimble

Stage lengths of between 185km (100nm) and 1,850km create a competitive problem for conventional air transport. For a typical 1-2h flight, would-be airline customers must pass through a non-flying gauntlet, from commuting to and from remote airports to facing clogged lines for security, check-in and baggage claim. It is often easier and cheaper to drive.

This basic conundrum has produced a series of radical solutions by aviation entrepreneurs, ranging from exotic business models, such as air taxis, to exotic aircraft designs, such as vertical take-off and landing (VTOL) airliners. For various reasons, including lack of infrastructure and technical complexity, none is yet to topple the imperfect primacy of the fixed-wing turboprop or jet.

Now Abe Karem, a widely respected aerodynamicist and innovator, has entered the mix. As founder of Karem Aircraft, he has quietly launched a new programme called the TR53 AeroTrain, a 120-seat, optimum speed tiltrotor (OSTR) dedicated to solving the 185-1,850km air transport problem.

“As the urban and suburban environments develop, VTOL transport is becoming more attractive and more urgent,” Karem says.

Karem Aircraft
© Karem Aircraft

LARGE GAPS

“The dream [of a VTOL airliner] didn’t materialise because of large gaps between efficient fixed-wing transports such as the Boeing 737 and all previously proposed VTOL transports in fuel efficiency, safety record, cruise speed, cruise altitude and pressurisation,” he says. “OSTR is designed to substantially close all of these gaps. Our commercial design is the TR53, the closest aircraft to a ‘VTOL 737’ we know how to design.”

Since launching the programme last year, Karem Aircraft has started to acquire and build pieces of the TR53’s advanced propulsion system, starting with the rotor and transmission.

“The AeroTrain development plan is focused on designing, analysing and testing the elements of the aircraft that are most different from the existing aircraft inventory,” Karem says.

The TR53 would share a similar fuselage with the 737-600, with a 32m (106ft) length and 3.96m cross-section accommodating six-abreast seating.

The most visible difference involves the design of the propulsion and aerofoil. Instead of a pod-mounted turbofan on a straight low-wing, the TR53 would feature two, 16m-diameter tiltrotors on either side of the fuselage on a 34.5m-span high-wing with dihedral wingtips.

But that is not the TR53’s only departure from conventional narrowbody technology. The primary structure for the fuselage and wing would be composite, a potential first in the narrowbody class. The aircraft also would have fly-by-wire controls.

INITIAL POWER

The TR53 would initially be powered by the 6,200shp (4,620kW) Rolls-Royce AE1107C engine, which powers the Bell Boeing V-22 Osprey. But Karem has plans to integrate an undisclosed, “advanced” propulsion system optimised for the TR53’s unique, optimum-speed technology. The advanced system would “provide significantly enhanced performance”, Karem believes.

Bell Helicopters
© Bell Helicopters

The TR53 is the commercial spin-off of Karem’s OSTR technology. Meanwhile, the US Army is also funding a Karem Aircraft/Lockheed Martin team to design the TR75, an OSTR with a 23m-diameter rotor to haul cargo. An advanced engine produced to support the army’s Joint Heavy Lift (JHL) programme, if funded, may carry over to the civilian programme.

As the designer of the fixed-wing General Atomics Predator and rotary-wing Boeing A160 Hummingbird unmanned aerial vehicles, Karem has built a reputation over the past two decades as one of the US military’s most technically agile and operationally successful innovators.

Karem is also fully aware that the puzzle of making VTOL transport as easy, safe and efficient as fixed-wing flight has never been solved.

“Fairey, a small British company, made the first serious effort with the 42-passenger, 180kt [333km/h] Rotodyne. The Boeing 222 and Lockheed designs also fed this dream,” says Karem.

Fairey cancelled the Rotodyne programme in 1962. The VTOL aircraft was doomed by its relatively slow cruise speed and the comparatively inefficient combination of a tip-jet driven rotor and twin propellers for vertical and horizontal propulsion. Military and airline orders were promised, but sales never materialised and the UK government withdrew funding support.

Karem’s tiltrotor configuration is a seemingly unlikely approach to succeed where Fairey failed. The V-22 has proved valuable to the US Marine Corps and US Air Force as a uniquely capable transport. But the concept has not been embraced by airlines like previous military-proven technologies, such as jet transports.

According to Karem’s approach, that failure is because the V-22 suffers from the same efficiency problem as helicopters. Their rotor speeds are relatively fixed to support vertical flight, leaving them grossly overpowered during cruise.

FUEL CONSUMPTION

As a result, rotorcraft are consuming substantially more fuel during cruise than a jet-powered fixed-wing aircraft. For example, says Karem, available seat-kilometre costs for a Sikorsky S-92 helicopter are more than 10 times greater than for a 737 on a similar journey.

Karem thinks he has solved this efficiency problem by inventing a method to change the rotor speed to support optimal levels for vertical lift and forward flight. OSTR technology also combines a light rotor system with stiff blades to achieve high efficiency over a range of speeds.

“The OSTR is about combining an efficient transport capability with a robust vertical take-off capability. One of the major challenges that must be overcome is the drastically different requirements on the rotor in hover and in high-speed forward flight,” says Karem.

“To bridge this gap,” he adds, “OSTR uses a variable speed rotor system that can vary RPM [revolutions per minute]. A cruise RPM might be 20-50% of a maximum hover RPM.”

Karem has already worked to tackle this problem for helicopters with the A160, a long-endurance UAV helicopter. The A160 features a Karem-designed variable speed rotor system. The A160 has demonstrated unrefuelled flight of nearly 20h, and is perhaps capable of 30h flight.

Boeing
© Boeing

“In the same way that moving from a turbojet to a turbofan increases efficiency, the large-diameter rotor of the TR53 effectively provides a very high bypass ratio,” Karem says.

The trade-off for the improved efficiency of a 16.2m-diameter fan, which compares with 1.55m-diameter CFM56 turbofan, is a “small price” for speed. While the 737 typically cruises at Mach 0.8, the normal cruise for the TR53 would be limited to Mach 0.6.

In hover mode, the aircraft consumes fuel at significantly higher rates. But Karem noted that helicopter mode flight should represent a “relatively small percentage” of overall flight time given a well-executed operation. “It should be noted that turbofan engines are particularly inefficient in on-airport operations including taxi, take-off and landing and low-altitude flight,” adds Karem.

The extra fuel required to perform hover operations can be offset in cruise, where the engine’s higher bypass ratio should yield fuel savings compared with even the most modern narrowbody aircraft. That advantage mean fewer carbon dioxide emissions with even the TR53’s initial engines being the Rolls-Royce AE1107C, says Karem.

Reducing nitrous oxide emissions, however, would require a more advanced engine core than offered by the AE1107C, he said. The R-R engine has been designed to power military transports, high-altitude UAVs and business jets, but not commercial airliners.

Karem says that he has not formally started soliciting letters of intent from airlines. And Karem Aircraft has decided not to market or exhibit the aircraft at the Paris air show next month. “However,” says Karem, “we feel strongly that AeroTrain will be a game-changer when it comes to passenger transport.”

The “game-changing” description is not mere cliche. Technology is not the only barrier for the TR53 concept to be fully realised. It requires the air transport industry and regulatory structure to adapt to an aircraft that does not require airports or even runways.

“To fully capitalise on the new capabilities offered by AeroTrain, airlines will have to think outside the traditional ‘airport runway-to-airport runway’ box,” says Karem. “Eventually, we hope that forward-thinking airlines and transport planners will allow passengers to board an airplane closer to the front door than their current airport, experience fewer delays, and land closer to their destination than they can today.”

This may be the catch. Even if Karem can master the technical challenge of proving an efficient tiltrotor, its acceptance could be limited without a radical change in his customer’s behaviour.

Karem’s military customer has the advantage here. Army officials are motivated to abandon their dependence on airports and runways, which must be obtained and then defended, to move people and equipment long distances.