Propellers make a comeback on a new type of aircraft engine

Propfans will be cleaner and more fuel-efficient | Science & technology

7/30/2021 1:42:00 AM

In a more environmentally conscious world where cutting aviation emissions is of increasing importance, propellers may be staging a comeback

Propfans will be cleaner and more fuel-efficient | Science & technology

GE, an American engineering group, and Safran, a French company then called Snecma. The pair are now developing a new version, which they reckon could reduce fuel consumption and CO2emissions by more than 20% compared with the best jet engines currently in use. And the new propfan will be capable of running on unconventional sources of energy, such as synthetic aviation fuel, hydrogen or a hybrid-electric system. Flight tests are scheduled for 2025.

ATEEZ Hit No. 1 on Emerging Artists Chart, While BLACKPINK's Lisa, Chloe Debut in Top Five 'Could be other indictments coming': Surprises at court hearing for Trump moneyman Jo Lasorda, wife of Los Angeles Dodgers manager, dies at 91

The newpropfan differs from older designs in various ways. Like the engines on theAN-70, it will sit under the wings, with an open fan at the front. Unlike theAN-70’s engines, though, it will use a single rotating open-fan. It does have a second ring of blades immediately behind the front fan, but these do not spin. Instead, they act as vanes that guide the flow of air backwards. The new arrangement is less complicated than the older one, and should be easier to maintain.

The new propfan is also lighter, which itself saves fuel and hence emissions. This is not just because the fan housing has been eliminated. The thrust reverser—which on a conventional jet engine uses a series of deflectors to slow an aircraft once it has touched down on the runway—has also gone. Instead of deflectors, the pitches of both the rotating blades and the static vanes can be adjusted on the new propfan to reverse its thrust.

One problem with propfans, though, is noise. This was particularly high inside the cabin of the modifiedMD-80. The combination of a single ring of blades, and advances in acoustic design should let the engine meet current and anticipated noise regulations, says

CFM.There has been concern about what would happen if a propfan blade broke off. A conventional jet engine is designed to contain a breakaway blade within the fan housing. With no such housing, there is nothing to stop such a breakaway striking the aircraft’s fuselage or wing, with potentially catastrophic results. That could mean parts of the aircraft near the open blades will need to be reinforced.

The best thing, though, is to stop the blades breaking in the first place. For that, new materials will help. One legacy of theMD-80 propfan was the pioneering use of extremely strong blades made from carbon-fibre composites. This technology has progressed, and the fan blades in jet engines and the propellers of modern turboprops are now routinely made from composites. These blades are proving their durability by safely notching up millions of flight hours, says a spokeswoman for

CFM.Mounting the propfans under the wings of an aircraft is more in keeping with the way modern airliners are built. It also makes maintenance and safety checks easier. However, the consortium says it can producer a “pusher” version if an aircraft-maker wants to design a plane with its engines at the rear, like the old

Kathryn Hahn to Play Joan Rivers in Showtime Limited Series Afghanistan girls soccer team given asylum in Portugal Georgia Secretary of State: My job is to make sure we have honest and fair elections

MD-80.New aircraft designs are in the works, but the two main builders of airliners, Boeing and Airbus, have yet to commit themselves to any big, new projects.CFMhopes the propfan will be a contender for a new generation of short- and medium-haul aircraft, although it could be used on large wide-body aircraft, too. If flight tests go well, in a decade or so travellers might find the aircraft they are boarding is once again powered by propellers.

Read more: The Economist »

How Taiwan's last 'fire fishing' boat is keeping tradition alive

As night falls, a group of fishermen set sail off the coast of northern Taiwan, where they prepare to catch sardines with a traditional method: fire.

The World Surf League, Oakland A’s And English Soccer: This Week’s Most Interesting Sports Business StoriesIn this week’s SportsMoney Playbook: pro surfing's wave of opportunity, Nascar's union effort and the Athletics' stadium woes. Plus: why hooliganism remains embedded in the English soccer fan identity.

The sell-out Charlotte Tilbury Mystery Box is making a comeback for 2021Mark your calendars...

Target Sells Meal Bags That Come Ready to Eat, So Excuse Us While We Buy All 4 DinnersTarget sells meal bags that serve three or more people, come in four types of dinners, and can be made in minutes.

Weird Fashion Lady Gaga Is Making A ComebackGaga’s theatrical looks are a blessing on the timeline 1st, you should be the one to know everything is weird in fashion, duh! well if you don't know resign. no need to explain, i love how weird it is.

Court denies 'Making a Murderer' Steven Avery new trial, currently serving lifeCourt denies netflix's 'Making a Murderer' Steven Avery new trial, currently serving life

DaBaby Makes Things Worse in New Offensive VideoRapper addresses homophobic comments in sexist self-directed clip as GLAAD adds to the chorus of rebukes against him 🤢🤢🤢 He ended bts He's over