Rolls Royce developing new engine for Airbus

I have been informed by someone-who-shall-remain-nameless at Rolls Royce of a project that I know will light a fire in some of your hearts. Please note that while this comes from a usually reliable personal friend of mine, theres currently no independant confirmation of this.

Airbus have employed Rolls Royce to further develop an engine design that was presented to them in 1999, nothing special so far eh? Read on.

THe engine is designed to propel (in a 2 engine format) a 240 seat aircraft to Mach 1.8 with afterburner and sustain without afterburner, supercruise to Mach 1.1 and also cruise at a second speed of Mach 0.9. The engines efficiency is supposed to be the same at Mach 1.8 as that of a 400 seat 747 fully laden over the same route, and a range that makes it capable of doing transpacific routes, which the Concorde wasnt capable of.

The engine is designed as both a turbojet at highspeed and as a turbofan at low speed, which is an innovative new solution to fuel consumption issues. As more speed is required, the engine silently reconfigures itself internally to produce the best airflow, fuel efficiency and thrust for the desired speed.

The aircraft, which apparently has a tentative codename of the A39X, will fly at Mach 0.9 to Mach 1.1 while over land (where speedwise the sonic boom is much less than at higher mach numbers and is acceptable to the JAA and FAA) and Mach 1.8 overseas and is planned for 2015, so if Airbus decide to go ahead with it, expect an announcement from them within the next couple of years.

If that comes to pass then it looks like Boeing may be blowing the cobwebs off the Sonic Cruiser if they want to play too. Providing they manage to keep the workings of this engine to themselves (or an industrial partner - most likely) for long enough to secure a worthwhile lead over the competition that too would be good news for Rolls Royce.

Neat! I really hope it pans out and some independant confirmation come out soon. I wonder what it will look like, probably VERY aerodynamic.

Originally posted by RichardPrice
THe engine is designed to propel (in a 2 engine format) a 240 seat aircraft to Mach 1.8 with afterburner and sustain without afterburner, supercruise to Mach 1.1 and also cruise at a second speed of Mach 0.9. The engines efficiency is supposed to be the same at Mach 1.8 as that of a 400 seat 747 fully laden over the same route, and a range that makes it capable of doing transpacific routes, which the Concorde wasnt capable of.

The engine is designed as both a turbojet at highspeed and as a turbofan at low speed, which is an innovative new solution to fuel consumption issues. As more speed is required, the engine silently reconfigures itself internally to produce the best airflow, fuel efficiency and thrust for the desired speed.

I'll believe it when I see it.

From a mechanical point of view, can you describe how you turn a turbofan into a turbojet engine? What happens to your fan?

Originally posted by Aether

From a mechanical point of view, can you describe how you turn a turbofan into a turbojet engine? What happens to your fan?

I dont quite know the ins and outs, but the main difference between the two types of engine is that in a turbofan engine, as much as 90% of the intake air is blown out the side of the engine and not passed into the actual reaction chamber for burning, whereas in a turbojet engine, all the intake air is burnt with fuel and expanded.

Technically I guess that the fan doesnt go anywhere, its what happens to the air afterward that defines the type of engine.

Originally posted by RichardPrice

Originally posted by Aether

From a mechanical point of view, can you describe how you turn a turbofan into a turbojet engine? What happens to your fan?

I dont quite know the ins and outs, but the main difference between the two types of engine is that in a turbofan engine, as much as 90% of the intake air is blown out the side of the engine and not passed into the actual reaction chamber for burning, whereas in a turbojet engine, all the intake air is burnt with fuel and expanded.

Technically I guess that the fan doesnt go anywhere, its what happens to the air afterward that defines the type of engine.

I remember reading somewhere about RR developing a system that changed how much are went into the engine Vs how much was diverted away depending on the load and height the plane was at. It was a few years ago and have heard nothing since, will try to find it again

This is sounding a little like the HOTOL project (RR were said to be developing a multi function/mode engine - IIRC the idea was that it could operate as a jet then ramjet then rocket and back again depending on the environment it was to be operating in at any given time) back in the 1980's?

I wonder if it is some of the R&D work done back then yeilding some commercial promise so many years further down the line?

It could just be a revisit of future engine design with no tenative plans to develop a plane.

Waynos,

I doubt that Boeing would dust off the Sonic Cruiser unless the airframe was capable of uch speeds. More liekly they will move towards a new design using the composite mateiral found in the 787. Now that would make things very very interesting.

If indeed these engines pan out they are the equiv. of the holy grail. Speed of sound transport at subsonic efficency.

However, If it is possible, I wonder if the military would step in and same mememememememe and not allow comercial apps for a bit???

Originally posted by FredT
It could just be a revisit of future engine design with no tenative plans to develop a plane.

From what Ive been told, its definately with a mind to a particular application, but it could simply be a future design development.

If indeed these engines pan out they are the equiv. of the holy grail. Speed of sound transport at subsonic efficency.

Well, not quite subsonic efficiency, 400 passengers verses 240 passengers for the same route and fuel costs, but then again its nowhere near what Concorde drank so its a (huge) step in the right direction.

However, If it is possible, I wonder if the military would step in and same mememememememe and not allow comercial apps for a bit???

You are forgetting, who exactly can Rolls Royce sell this to in the military market? The EU doesnt have any large bombers that this would fit on, the engine will probably be too large for fighters, and Rolls Royce certainly wouldnt accept the US Military telling it not to market it in a huge and very profitable market

Fred, why do not think the Sonic Cruiser could be a basis for a competing aircraft? Admittedly we have seen no such design from Airbus, only what has been said on this thread, but I would imagine that the Sonic Cruiser would require relatively little tweaking to be mach 1.8 capable? Perhaps a slightly narrower cross section, longer fuselage and a sharper nose would be enough with these R-R engines. The basic aerodynamic layout of the Sonic Cruiser certainly appears well suited to higher speeds and I wouldn't be surprised if a future Airbus design did resemble it. I thought the limiting factor on the Sonic Cruiser was engine efficiency and cost if it went any faster? I admit I'm no expert on the subject and I'm merely guessing on what I've seen.

From a mechanical point of view, can you describe how you turn a turbofan into a turbojet engine? What happens to your fan?

nothing more simpler, the bypass way use an controlable doors that can change the air flow to the normal turbofan flow (out of the chamber-like an propeller) or like an turbojet (to the chamber), you dont need new fans or turbines (but i think that is needed an special axial or centrifugal compressor stage -one of the last stage-)

i doubt that RR is seriusly thinking in an engine development for big comercial planes, but its possible that the new engine (or proyect) is for the small bussisnes-private jet market.

[edit on 24-3-2005 by grunt2]