Will these engines replace jets in future?

Member for

6 years 8 months

Posts: 2

I hope this is the right forum... I was just wondering, what is the probability that open rotor engines will replace jet turbofans in the future? I have been doing a lot of reading on the subject, and from my understanding they are more fuel efficient but also slower and noisier than conventional turbofan engines.. they're also quite hideous looking in design. I personally don't like them, and would hate to see them replacing the turbofan jet engine that we all know and love. Would anyone care to comment on this?

For those of you who don't know about these engine types, here's a link: http://www.sustainableaviation.co.uk...en-rotor-engine-briefing-paper.pdf

This is what they look like: http://www.safran-group.com/spip.php?page=popin-photo&id_document=7010&type=1&lang=fr

Original post

Member for

11 years 7 months

Posts: 268

There was a lot of research done on open rotors, contra-rotating and variable pitch turbofans, in the 1980's and 1990's. They all showed good improvements in fuel efficiencies. Rear fan open rotors like those in your link have been around since the mid 1940's, see Metropolitan Vickers F.3 and F.5.

http://i729.photobucket.com/albums/ww291/joncarrfarrelly/METROVICK_F5_01.png

So this is an idea which keeps getting reinvented. The reason that open rotors are not likely to be used is that they are noisy both outside and inside the aircraft, and they give rise to vibration. Also, they have no containment in the event of blade failure.

More likely to be used are the contra-rotating and variable pitch ducted front turbofans, in my opinion. The best chances of this happening are if the airframe manufacturers also break with tradition and introduce a matching efficient design, to capitalise on the broader characteristics of the new engine, such as the blended wing approach. The engines will most likely be embedded fully or partially, not open mounted.

Engine and airframe developers would need to get together on thus, as one group doing it by itself would not achieve the maximum benefit.

(Your first link does not work)

Steven

Member for

11 years 6 months

Posts: 652

An MD-80 and a 727 both flew with an installation one side.

As mentioned above it was more efficient in many way but annoyingly noisy.

Not just in a decibel sense, the type and pitch of the noise was very irritating.

The Optica used a ducted fan and had an irritating buzz and an Islander flew with a pair of ducted fans. Again, like the open 'Propfan' the ducted fan was irritatingly noisy.