Do you get Open Rotor?

[twistedenginestarter]

I do sympathise with Keesje. Airlines wet themselves over saving 5-10% fuel so why don't they buy Keeje's Turboliner and save 20% for only slightly longer flight durations?

Nevertheless I'm still intrigued to see where Rolls' vision of the future fits in. What essentially is the difference between a turboprop and an open rotor?

It would appear open rotors can go a bit faster but turboprops can already do M0.72 at 37,000 feet. That's not much slower than a 737.

Turboprops have gears but then again it looks to me as though Rolls' motor has a gear to get one of the rotors to counter-rotate.

Rolls has failed to win anything recently with their RB285. Is open rotor just to divert attention from their weakness in the narrow body market?

[WillDAQ]

don't they buy Keeje's Turboliner and save 20% for only slightly longer flight durations

They don't buy it because it doesn't exist and it doesn't exist because it is a high risk technology.

[westhawk]

I remember seeing something like this on a proof of concept demonstrator at Paris or Farnborough back around '87 or '88. At that time GE called the concept UDF for unducted fan. One UDF engine was mounted on an MD-80 series airplane while the other side carried the standard JT8D-200 series fanjet. It was billed as being able to provide massive fuel savings to cost conscious airlines. But what was remembered by crowds witnessing the flight demo was the cacophony of ear-splitting noise emanating from the beast. Between that, concerns expressed over the structural integrity and damage tolerance of the blades and the development of higher bypass and more efficient fanjets, the project never really went anywhere. The idea still has it's supporters to this day though, so it resurfaces from time to time.

Edit: I found an interesting historical perspective on the project here. Enjoy!

[Flash2001]

I remember following the UDF at the time it was first tried. They lined the fuselage with Helmholtz resonators and still couldn't control the noise.

After an excellent landing etc...

[Intruder]

The "open rotor" engines, despite their relatively green characteristics, will still be unpopular with many anti-aviation campaigners as they are significantly noisier than ordinary turbofans.

NASA working on 'open rotor' green (but loud) jets ? The Register

With all the noise complaints already, it is unlikely we'll see any of these on airliners.