Airbus says it is considering using an open rotor engine on its replacement for the A320. The company has been working with CFM to develop the engine, which has primary and secondary counterrotating turbine vanes on the outside of the engines rather than being encased in a nacelle. Exposing the turbines makes the bypass ratio a lot bigger and that improves efficiency.
Not to worry, this idea will go nowhere in the US. Open rotor engine airliners were already tried in the US in the 1990ās, and the airlines said no thanks. Same reason the Q400 and the Saab 2000 went nowhere, American airline passengers will not ride on anything with a prop. And voters will not tolerate an airplane that sounds different than a jet whether or not it is any louder or it makes noise limits. Ask any airport that has banned the Piaggio Avanti turboprop(Santa Monica, Ocean Reef).
Are you sure? I thought that airline passengers go for low cost more than anything. Like in the car industry when everyone thought it had to be a 12mpg V8 or at least a big V6 in their truck, yet the 20mpg+ inline 4 turbos with better acceleration and less noise are quietly taking over.
Iām sure Boeing is going to respond with the 737MAX 11, which will immediately be grounded because they installed the wings upside down or something.
Well they have adjourned sine die development of hydrogen, first flight of airline prototype was due 2030, so looking for something to put on their website full of computer simulations.
My guess is that if Safran does dust off the open rotor, it will appear with a chicken wire cage around the prop fans to slow them down when they break off.
Itās Deja Vu all over again ā¦ I recall these very loud experiments back in the late 1980s. And the same wild predictions of fuel savings. Fact is, more conventional turbofans have made huge advancements too since then. Iām guessing that CFM secure EU Green money to fund this work, at a healthy profit margin. Donāt expect to see one soon on a commercial aircraft.
Iāve been hearing this one since working on an acoustic model in college in 1982. I have to say that Iāll believe it when I see it. Acoustics, icing, blade retention, and blade off issues have thus far proven to be overwhelming.
Fortunately engineering isnāt governed by such thinking. So just because someone else couldnāt do it, a very long time ago, doesnāt mean it wasnāt a good idea that should be looked at again. Imagine if some fool had told Frank Whittle (and the others that were also working on successful designs) that the jet engine had already been tried, where would we be now. The main reason it could fail in the US is a mixture of isolationism andā¦ oh yeah, thatās the main thing.
Never said it couldnāt be done. I worked on the deicing system for what would have been the MD95, before the project was dropped due to no interest by the airlines. That plane became the 717 after the McDonnell Douglas/Boeing takeover/merger. Politics and passenger preference is what I was referring to. There have been no new prop driven pt 121 airliners designed since the 1990ās, again due to lack of interest by the pt 121 airlines. American passengers do not like and will avoid riding on any currently flown pt121 prop airliners. The only exception would be in Alaska, where there is not much in choices. Even the pt380 airlines that the pilot unions and Congress want to move to pt121 mostly use older regional jets, not props. Then there is the politics involved with noise restrictions. From what I understand noise restrictions in Europe and Canada are more restrictive than in the US. That is why I doubt this proposal by Airbus will get very far.
Presumably this is for a rear mounted configuration, correct (a la MD-95)? Canāt imagine how this would pass certification muster from a safety perspective.
The US tried it, the aircraft was at Farnborough one year. These engines arenāt vastly different from the A400Mās turboprops. The tech is sort of closing in on the propfan from both ends. Fans are getting fewer and bigger blades, turboprops are getting more fan like blades. Eventually they will meet in the middle.
The huge question is whether or not voters will wake up to the con job that humans are causing runaway warming of earthās climate, which is not and cannot happen.
Accurate temperature measurements like weather balloons, satellite sensors, and tide gages show only slow warming since the end of the cool era that drove Viking farmers out of southwest Greenland. (The Medieval Warm Period was warmer than today climate was stable.)
The āsaturation effectā of overlap of spectra of carbon dioxide and dihydrogen monoxide limits rise to a small amount most of which has already been realized. (Changes in water vapour show there is not a positive feedback mechanism.)
Whereas the well known effect of orbit changes - āMilankovich Cyclesā - varies climate.
So the only benefit is lower operating cost but at what price in aircraft capital cost and safety?
