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Launching Airplanes from Catapults, Part 3: Airbus' Eco-Climb Concept

By Rain Noe - November 21, 2012

in Cars

While many eyes in the commercial airline industry were undoubtedly watching the U.S. Navy's EMALS (Electromagnetic Aircraft Launch System) testing, it is Airbus that has first stepped forward suggesting commercial applications. Earlier this year the manufacturer announced "Smarter Skies," a series of concepts and promotional videos revealing where they want to be by 2050.

One component in their plan is for an EMALS-like system, though they never directly refer to military subcontractor General Atomics' invention; instead the company calls it "Eco-Climb," writing that "Aircraft could be manoeuvred onto a track system and accelerated using either electro-magnetic motors built into the track or an inductive circuit within the aircraft itself." Starting at 0:52 in the promo video below, you can see they're envisioning a much wider platform than what EMALS uses, this one scaled up to accommodate a commercial jetliner:

In the previous entry we looked at the advantages of EMALS over steam-driven catapults; but what's the benefit of having an electromagnetically-propelled takeoff, rather than a conventional one, for a commercial airliner?

Listen to the changing sound of engines during flight and it's obvious: an aircraft draws on its power reserves more during takeoff than at any other time... However, this takeoff power only is required for a very brief portion of the total flight. Once cruising in the sky overhead, an aircraft doesn't need as much to maintain altitude. So why not source the energy required at takeoff from an innovation installed on the ground?

An assisted takeoff - using some form of propelled acceleration - would mean aircraft could be lighter, with smaller engines consuming less fuel...A continuous "eco-climb" would further cut noise and CO2 emissions....

With less time and distance required for takeoff, the runways could be shortened by up to 1/3rd, minimising land use, and enabling airport capacity to increase or new micro-airports to emerge. These could be located near city centres - or the mega-cities that will become a reality - with space becoming even more of a premium.

It's been more than a century since the Wright Brothers needed a catapult to get their contraption to fly. They would undoubtedly be astonished to see us circling back to the same concept, and Airbus envisions a twist Wilbur and Orville might not have signed off on: "The ultimate, albeit very extreme, concept," the company writes, "is to have a system that not only launches but also captures the aircraft, removing the need for landing gear." Gee, what could go wrong?

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William Dawson

11 years ago

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U.S. Navy EMALS is a valid concept in this application but for the fact it has yet to prove a reliable and consistent performer. PRT Advanced Mag-Lev Systems won a NASA three-phased contract for electromagnetic horizontal launch catapults. PRT designed, produced and tested an alternative Rhomboid Airgap Linear Induction Motor (LIM) that is much simpler, more efficient and less costly. A Phase 1 prototype catapult was demonstrated in 2000 but when the Bush administration changed the NASA objectives, horizontal launch was abandoned and so was funding for the next contract phases. With no clear application, industrial investment proved impossible to obtain. The US Navy is committed to EMALS by the size of the existing and ongoing outlay but the TSG-EMCAT design (successor to PRT) should be a contender for this application.

The drawback of using a powered trolley is the limit of friction between the ground and the wheels of the trolley. If the mass is increased to enable the linear force to be sufficient then the resulting additional mass will be a grave burden and represent a significant hazard were the aircraft to overtake the trolley. The extreme work load of the rotary motor is not to its advantage whereas a LIM distributes its workload over the whole length of the track. There is no above ground hazard as the trolley is barely visible. There is no frictional limitation or added mass, the applied force is totally controllable and the work of accelerating the mass of the aircraft is performed by the motor so full thrust may in fact never be required for take off.

While such a facility would only be installed at hub airports it would not alter the performance specification for an aircraft. But as aircraft flights are concentrated at hub centres the reduction in emissions and fuel would be significant. Not so long ago automatic landing technology was a rarity, now it is commonplace at hubs and there is no cost incentive involved only safety. As emissions are a hazard to our safety there is reason enough seriously to consider this, when the saving in fuel and improved runway time are factored in the incentive to do so is compelling.
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Jonathan

11 years ago

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Airbus release these pipe dreams every now and then. It's pure greenwashing. They have no intention of implementing these things, and none will be realised in our lifetime (in civilian aircraft).

The airline industry is well known for changing the subject and preferring to talk about things that "might", "could" happen in 40 years, rather than address their horrendous record on CO2 emissions, which are the only things catapulting at the moment.
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Androo

11 years ago

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Instead of anything as complex as EMALS, why not just an extremely high-torque electric motor-driven drag-racer of a trolley that attaches to the underside of the aircraft (as pictured). No need for any complicated inductive circuitry, just a scaling up of existing technology that is already happily mass-commercialized.
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